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293 Cards in this Set
- Front
- Back
A newly discovered microscopic structure is hypothesized to be a living organism. Which of the following characteristics would support the contention that this “organism” may be alive? It contains DNA. It consists of a single cell. It maintains a constant internal environment. All of the above. |
All of the above.
All of these characteristics are shared by all living organisms. However, to be considered "living," an organism must possess all of the characteristics described in the chapter. |
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Advancing biological knowledge depends on rigorously testing hypotheses about the living world. True False |
True.
Rigorous hypothesis testing is the core of scientific inquiry. |
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Scientists begin constructing a simplified view of nature by doing experiments and forming theories. True False |
False.
The first steps in the scientific method are observation and hypothesis formation. Experiments are subsequently performed to test the hypothesis. The experimental results are then analyzed and used to support or reject the hypothesis. The term theory is reserved for well-tested and well-supported hypotheses. |
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Which of the following would you expect to find in common among cells from a rose, a mushroom, and a cat? DNA Tissues Viruses Organs Biospheres |
DNA
DNA is universal in all cells. While viruses may often infect cells, they are not typically present in healthy cells. The other choices are all structures larger than a cell. |
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A prediction is made before observations or hypotheses have been formed. True False |
False
Predictions are made after observations have been carried out and a hypothesis has been formed. Scientific Method Steps: Observations, Hypothesis, Predictions, Test. If the Hypothesis is supported, you go back to do more tests. If the Hypothesis is rejected, create a new or revised hypothesis. |
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Consider the studies conducted by Dr. Burkholder to determine the cause of the mysterious die-offs plaguing fish in the rivers of North Carolina described in the chapter. Her postulation that the deaths were caused by a type of organism called a “protist” is considered a(n) Experiment Observation Hypothesis Theory Test |
Hypothesis
Recall that a hypothesis is a testable explanation for a given observation. In this case a test, or experiment, was used to determine the validity of the proposed hypothesis |
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Which of the following is not a scientifically testable hypothesis? The growth of peanut plants is affected by soil nitrogen concentration. El Nino-induced weather patterns influence fish harvests in the Pacific. Biological diversity is the result of single divine creation. High dietary fiber leads to lower cholesterol in humans. Natural fires lead to the rejuvenation of certain plant communities. |
Biological diversity is the result of single divine creation.
Using divine creation as an explanation for biodiversity requires a faith-based hypothesis that an all-powerful deity exists. Science cannot work with such hypotheses because they are inherently untestable |
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Your television won’t turn on, and you speculate that a circuit breaker in the house has been tripped. In scientific terminology, such reasoning would best be described as Forming conclusions from the result of experiments. Controlling variables in a repeated manipulation of nature. Developing an observation based on a hypothesis. Developing a hypothesis based on an observation. Testing a prediction generated from a hypothesis. |
Developing a hypothesis based on an observation.
This is the process of going from observation (the television won't turn on) to tentative explanation (hypothesis about the circuit breaker). |
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In most living systems, the energy that powers life comes ultimately from Plants Animals Fungi Bacteria The sun |
The sun.
Most living systems ultimately derive their energy from the sun. However, there are examples, such as ecosystems present at the bottom of the ocean, which do not rely ultimately on the sun for energy |
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In a particular food web, the leaves of oak trees are eaten by moth caterpillars. Some of the caterpillars are then eaten by birds, which in turn are eaten by snakes. In this food web, the consumers are the Oak trees Oak trees and caterpillars Caterpillars and birds Birds and snakes Caterpillars, birds, and snakes |
Caterpillars, birds, and snakes
The oak trees (plants) are the producers; the remaining organisms in the scenario would be considered a type of consumer. |
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Most biologists currently estimate the total number of species that exist on Earth to be somewhere between _______________ million. 1 and 2 2 and 3 3 and 30 30 and 100 100 and 500 |
3 and 30
For more information, see Section 2.1, The extent of Earth’s biodiversity is unknown. |
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Which of the following is not found in the kingdom Bacteria? Membrane-bound organelles DNA Organized cell structure Ability to reproduce Ability to use energy |
Membrane-bound organelles
Bacteria are prokaryotes, which by definition means they lack internal membrane–bound organelles. All other choices are universal properties of life. |
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A number of reasons exist for the evolutionary success of the kingdoms Bacteria and Archaea. Which of the following characteristics allow these prokaryotes to be so successful? Rapid reproduction Diverse methods of obtaining nutrients The ability to survive extreme conditions The ability of some to live with oxygen and others to live without oxygen All of the above |
All of the above
Bacteria and Archaea take advantage of all these characteristics to be successful. |
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Organisms that share physical traits are almost always members of the same species. True False |
False
Recall that convergent features are similarities that exist between groups of organisms but do not necessarily indicate relatedness. DNA analysis provides a much more powerful and accurate tool for determining relatedness. |
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Prokaryotes derive their energy from a variety of sources. Which of the following terms does not accurately describe prokaryotes? Chemoheterotrophs Chemoautotrophs Photoheterotrophs Photoautotrophs All of the above |
All of the above
Prokaryotes have the ability to obtain energy from other organisms and from the sun. They can also obtain their carbon from other organisms and from inorganic substances. Therefore, all of the terms apply to the prokaryotes. |
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When groups of organisms share characteristics because they evolved the same features independently, rather than through common descent, we call these characteristics Systematic Convergent Ancestral Derived Evolutionary |
Convergent
Convergent evolution is a process that can produce similar characteristics in organisms as a solution to environmental challenges, rather than through common descent. It can thus be a problem for systematists trying to determine evolutionary relationships on the basis of shared characteristics alone. |
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Viruses can reproduce, evolve, and possess DNA. This makes viruses “alive.” True False |
False
Refer to chapter 1 for all of the characteristics of living organisms. Although viruses can evolve, reproduce, and possess DNA, they do not have all the characteristics of living organisms, and are essentially DNA in a protein coat. |
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DNA technology was the primary tool used to determine that the Archaea belonged to a different evolutionary group from the Bacteria. True False |
False
Recall from the text that DNA studies initially alerted scientists to the existence of the Archaea domain. |
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In the Linnaean hierarchy, what are the units of classification, from smallest to largest? Species, genus, order, family, phylum, class, kingdom Kingdom, species, order, genus, family, class, phylum Species, genus, family, order, class, phylum, kingdom Phylum, family, genus, species, order, kingdom, class Family, species, genus, order, kingdom, class, phylum |
Species, genus, family, order, class, phylum, kingdom
Recall the catchphrase “King Phillip Cleaned Our Filthy Gym Shorts” to help you remember the correct order. |
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The name “Homo sapiens” reflects the species name and genus name for humans, in that order. True False |
False
In a scientific name, the first name is the genus (Homo) and the second is the species (sapien). |
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The group of organisms called “protists” were the first to utilize sexual reproduction. True |
True.
The exchange of DNA with another organism to pass it to offspring was an adaptation that first appeared in the protists. |
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The common characteristic of red tides, malaria, and potato blight is that they are all Caused by bacteria. Caused by protists. Caused by fungi. Diseases of plants. None of the above. |
Caused by protists.
All three of these conditions are caused by protists. Some protists are pathogens. |
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All protists, like bacteria, are microscopic, single-celled organisms. True False |
False
Although the large majority of protists are single celled and microscopic, notable exceptions—such as slime molds and seaweeds—exist. |
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Extensive root systems and the presence of a waxy cuticle are among the reasons plants have become so successful on land. True False |
True
The root system provides water and nutrients, and the waxy cuticle helps prevent desiccation. |
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Which one of the following is not found in both the gymnosperm and angiosperm plants? Well-developed vascular systems for internal transport Extensive root systems for acquiring water and nutrients Seeds that disperse from the parent and thus increase offspring survival Sexual reproduction using special structures called "flowers" Products that are useful for human consumption |
Sexual reproduction using special structures called "flowers"
Flowers are found in the angiosperms only. Instead of flowers, gymnosperms form cones or cone-like structures for protection of their seeds. |
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Maintaining biodiversity is a primary key to a healthy ecosystem. When ecosystems are healthy, humans can harvest a wide variety of useful materials. Which of the following useful products comes from nonhuman species? One-fourth of all prescription drugs The oxygen we breathe Meat and dairy products Vegetables and wood All of the above |
All of the above
All these are products that come from nonhuman species. Therefore, the more diverse an ecosystem, the more usable products may be derived from that system. |
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A lichen is best described as A sexually reproducing plant A mutualistic relationship A primitive prokaryote A pathogenic fungus An invasive species |
A mutualistic relationship
Lichens are created by a mutualistic relationship between a fungus and a photosynthetic microorganism in which both partners benefit from the interaction. |
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A researcher has just discovered what she thinks is a new species. Initially, all she knows is that it is eukaryotic. To which of the kingdoms below could this new organism possibly belong? Animalia Protista Fungi Plantae Any of the above |
Any of the above
All the kingdoms listed contain eukaryotic organisms. |
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A population of fungi that reproduce sexually is more likely than an asexual population to evolve following resistance exposure to an antifungal chemical. True False |
True
Sexual reproduction is a major source of genetic diversity that allows a population to evolve in response to stress, whereas asexual reproduction makes identical clones. |
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Both plantlike protists and plants Are prokaryotic Have some cellular organelles in common Serve as decomposers in an ecosystem Evolved after the first animals appeared Were among the last multicellular groups to evolve |
Have some cellular organelles in common
Plants and plantlike protists are both eukaryotic, so similar cellular organelles are to be expected. The decomposers of an ecosystem typically are fungi. Recall that protists represent an early stage in eukaryotic and multicellular evolution, so the last two answers are also incorrect. |
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The elements hydrogen, nitrogen, and carbon can all form ionic bonds with other elements. contain neutrons in their atomic nuclei. have numerous electrons that orbit the inner core of their atoms. are common elements in the molecules that make up living organisms. all of the above |
are common elements in the molecules that make up living organisms.
Recall that hydrogen does not typically contain neutrons or have multiple electrons orbiting the nucleus. Also, ionic bonds are formed only between elements that can easily donate or accept electrons. All three of these elements are common to living organisms. |
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Which of the following statements about covalently bonded molecules is false? Electrons are shared between the atoms that make up the molecule. Noncovalent bonds may also be present, especially if the molecule is large. Opposing electrical charges hold the molecule together. The chemical bonds that hold the molecules together are relatively strong. Protons and electrons are present in the atoms that make up the molecule. |
Opposing electrical charges hold the molecule together.
Recall that ionic bonds are caused by the attraction of oppositely charged ions. Covalent bonds result from the sharing of electrons between atoms. |
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Which of the following statements about water is true? It contains two of the most common elements on Earth. It is critical for many of the chemical processes found in living systems. Polar substances that can form hydrogen bonds will dissolve in it. Nonpolar substances like oils are not soluble in it. all of the above |
all of the above
Water is made of hydrogen and oxygen, which are abundant elements. It is also a key component of many biological processes. Because water is polar, it will form hydrogen bonds with other polar molecules but not with nonpolar compounds. |
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Hydrogen bonds and hydrophilic interactions are weak chemical bonds that hold together atoms within a molecule. strong chemical bonds that hold together atoms within a molecule. weak chemical bonds that hold separate molecules together. strong chemical bonds that hold separate molecules together. interactions that hold protons and neutrons together within the atomic nucleus. |
weak chemical bonds that hold separate molecules together.
These bonds form between molecules, or within specific parts of molecules, to help stabilize structure. |
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A pH value of 0 represents the lowest possible concentration of free hydrogen ions in a solution. True False |
False
A pH of 0 represents the highest possible concentration of hydrogen ions and consequently the highest acidity. |
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The molecule adenosine triphosphate (ATP) is most closely related to which class of macromolecules? nucleic acids fats carbohydrates proteins membranes |
nucleic acids
The “A” in ATP stands for “adenosine,” a modified adenine nucleotide. |
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Which of the following represents a polymer of amino acids? ATP Fats Carbohydrates Proteins Membranes |
Proteins
Polymers are repeating units of monomers. Amino acids are the monomers used to make proteins. |
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In a saturated fat, you would expect to find all of the following except single-bonded carbon atoms. double-bonded carbon atoms. hydrogen atoms. nonpolar bonds. covalent bonds. |
double-bonded carbon atoms.
“Saturated” means that the maximum number of hydrogen atoms are attached to each carbon, eliminating the possibility of double bonds between carbon atoms. |
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A compound capable of forming hydrogen bonds with water is probably held together by noncovalent bonds. contains at least some polar covalent bonds. should act as a good buffer for acids and bases. does not dissolve well in water. is hydrophobic. |
contains at least some polar covalent bonds.
Hydrogen bonds form between water molecules and the partially charged portions of other polar covalent molecules. |
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Chemical reactions always begin and end with the same number and type of atoms, although those atoms are usually rearranged during the reaction. True False |
True.
Although new products are made in chemical reactions, the equation must always balance in terms of number and type of atoms involved. That is, matter can be neither created nor destroyed, only rearranged. |
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Which of the following is not an example of a compound that would fall into the category of monomers? monosaccharides DNA amino acids nucleotides none of the above |
DNA.
DNA is a polymer made from nucleotide monomers. |
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Proteins, DNA, and starch are all carbon-based compounds. polymers. held together mainly by covalent bonds. made of atoms that contain protons and electrons. all of the above |
all of the above
All of these statements are true. |
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Glucose is to cellulose as guanine is to DNA starch protein phospholipids fatty acids |
DNA
Glucose is a building block used to make cellulose. Guanine is one of several building blocks used to assemble molecules of DNA. |
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Which of the following components would not be found in a typical phospholipid bilayer? cholesterol glycerol fatty acids thymine carbohydrates |
thymine
Recall that the nucleic acid thymine is one of the building blocks of DNA. You would not typically find guanine associated with a phospholipid bilayer. |
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In a phospholipid bilayer, the hydrophobic tails of the phospholipid molecules are pointed outward so that they are in maximum contact with water. True False |
False
Just the opposite: the tails are pointed inward to avoid water. See the diagram in Figure 5.20. |
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Because of their ingestive mode of nutrition, animals function as ________ in ecosystems, but never as ________. consumers and decomposers; producers producers; consumers and decomposers producers and consumers; decomposers decomposers; producers and consumers decomposers and producers; consumers |
consumers and decomposers; producers
Producers capture energy directly from inorganic sources (for example, the sun) and convert it to organic energy, as the plants in a food web do during photosynthesis. The animals in a food web gather premade organic energy from other organisms, in the role of either consumers or decomposers. |
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Organ systems are found only in recently evolved deuterostomes, including chordates and vertebrates. True False |
False
Organ systems are found in most protostomes as well as all deuterostomes. |
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Tissues and symmetry are found in all animals except sponges. True False |
True
Sponges have specialized cells, but they are not organized into true tissues. Sponges also lack organized body plans. All other animals have both true tissues and some form of symmetry. |
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Cnidarians are a group of animals that have neither tissues nor organs. organs but no tissues. two tissues but no organs. three tissues but no organs. both tissues and organs. |
two tissues but no organs.
Cnidarians, such as jellyfish and coral, have two distinct tissue layers but lack coherent organs. |
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Earthworms have complex organ systems for digestion and circulation. True False |
True
Despite their external simplicity, earthworms have well-developed circulatory and digestive systems. |
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Which phylum of animals contains the greatest number of species among eukaryotes? annelids mollusks arthropods echinoderms chordates |
arthropods
Arthropods—a diverse phylum including crustaceans, spiders, and insects—is the largest eukaryotic phylum, mostly because of the stunning success of insects. |
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Which of the following traits describe(s) deuterostomes? bilateral symmetry at all life stages dorsal notochord embryonic mouth develops from the blastopore dorsal hollow nerve cord all of the above |
dorsal hollow nerve cord
All deuterostomes have a dorsal hollow nerve cord, whereas notochords are found only in chordates, not in echinoderms. |
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Which of the following is not a function of the echinoderm’s water vascular system? regeneration gas exchange movement feeding providing suction for tube feet |
regeneration
Although many echnioderms, such as sea stars, do have a remarkable ability to regenerate lost body parts, this is not a result of their water vascular system. Everything else on the list is. |
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Which of the following animals shows an embryonic developmental pattern that classifies it as a deuterostome? bird snail insect worm none of the above |
bird
Recall that in deuterostomes, the second opening that forms at either end of the body cavity eventually develops into the mouth. This group includes all vertebrates, such as the bird. |
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Which of the following lifestyles would be most likely for an animal with radial symmetry? flight burrowing climbing trees sessile marine active swimming |
sessile marine
Radial symmetry is most beneficial for an animal that is stationary because it allows uniform access to the environment in any direction. |
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The simplest way to distinguish a prokaryotic from a eukaryotic cell is to check for a plasma membrane. a nucleus. DNA. proteins. whether the cell is a single-celled organism. |
a nucleus.
All cells have plasma membranes, DNA, and proteins. There are single-celled representatives from both prokaryotes and eukaryotes. Of the choices given, the most reliable way to tell the difference between cell types is the presence of a nucleus, which is found only in eukaryotes. |
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Proteins that are destined for insertion into a membrane are one product of the rough ER. True False |
True
Proteins destined for use in the cytosol are made by free-floating ribosomes rather than by ribosomes bound to the rough ER. |
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The Golgi apparatus is one destination for substances that have been packaged into transport vesicles by rough ER. True False |
True
Rough ER produces transport vesicles, some of which find their way to the Golgi apparatus, where additional processing of their contents occurs before those contents are directed to their final destinations. |
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Both chloroplasts and mitochondria have multiple membranes. have highly structured innermost membranes. are found only in eukaryotic cells. are involved in cellular energy processing. all of the above |
all of the above
For more information, see Figures 6.15 and 6.16 in your textbook. |
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Which of the following macromolecules are found in the plasma membrane? lipids only lipids and proteins lipids, proteins, and nucleic acids proteins and nucleic acids proteins only |
lipids and proteins
The chapter refers to the mixture of lipids and proteins creating a “fluid mosaic.” |
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In terms of basic structure, elephant cells and oak tree cells both are prokaryotes. have chloroplasts. have a cell wall. have mitochondria. all of the above |
have mitochondria.
Because elephants and oak trees are both eukaryotes, they would both require the energy production functionality of mitochondria for survival. Recall that only plant cells have cell walls and chloroplasts. |
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Which of the following statements about prokaryotes is false? Just like eukaryotes, prokaryotes have a plasma membrane. Prokaryotic cells concentrate important materials for the cell’s survival. The substance known as “cytosol” is found within the bacterial nucleus. Prokaryotic cells are much smaller than most eukaryotic cells. Ancient prokaryotes may have given rise to some eukaryotic organelles. |
The substance known as “cytosol” is found within the bacterial nucleus.
Cytosol is found in prokaryotes but not in the nucleus, since this organelle would be absent. |
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According to the fluid mosaic model of cell membranes, proteins are rigidly fixed in the phospholipid bilayer. the most common types of molecules in the membrane are proteins. basic membrane structure results from the ways in which proteins interact with water. the membrane is a highly mobile mixture of phospholipids and proteins. the unique properties of cell types are determined by their phospholipids. |
the membrane is a highly mobile mixture of phospholipids and proteins.
The fluid aspect refers to the fact that both phospholipids and proteins are somewhat mobile within the bilayer. The mosaic refers to the patchwork distribution of proteins across the membrane. |
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The best way to identify a cell as either prokaryotic or eukaryotic is to determine whether it came from a single-celled or multicellular organism. it contains DNA enclosed within a membrane-bound compartment. it has a cell wall. it has cytosol. all of the above |
it contains DNA enclosed within a membrane-bound compartment.
The only definitive characteristic listed is the presence or absence of a nucleus (the membrane-bound compartment in which the cell stores DNA). |
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In a microscope, you observe an organelle that consists of a series of interconnected tubes and appears to be connected to the outer membrane of the nucleus in a eukaryotic cell. What is the likely identity of this organelle? mitochondrion lysosome Golgi apparatus vacuole endoplasmic reticulum (ER) |
endoplasmic reticulum (ER)
The ER consists of a series of interconnected tubes scattered throughout the cytosol. The connection to the nucleus allows material produced in the nucleus to directly enter the ER through the nuclear pores. |
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Metabolic reactions that break down complex molecules into smaller compounds, thereby releasing usable energy for the cell, are best described as biosynthetic. catabolic. catalytic. photosynthetic. enzymatic. |
catabolic.
This is the definition of catabolic reactions. |
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The production and breakdown of _______ is often coupled with the metabolic reactions of biosynthesis and catabolism. aspirin DNA ATP methane |
ATP
ATP is the currency of metabolism. It is frequently made or used in conjunction with other metabolic reactions. |
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Which of the following statements about enzymes is true? Enzymes do not alter the total energy yield for a reaction. Enzymes are proteins whose three-dimensional shape is key to their function. Enzymes speed up reactions by lowering activation energy. Enzymes are highly specific for the reactions they catalyze. all of the above |
all of the above
All of these statements about enzymes are true. |
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Carbonic anhydrase is an enzyme that speeds the capture of in photosynthesis, thus facilitating carbon transfer from plants to animals. True False |
False
The action of carbonic anhydrase has nothing to do with photosynthesis. It is an enzyme that catalyzes the conversion of and into ions in your blood. |
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Which of the following statements regarding the relationship between metabolism and life expectancy is false? In general, larger animals with a slower metabolic rate have a longer life expectancy than smaller animals with higher metabolic rates. The rate of metabolism is inversely related to overall life span. The accumulation of free radicals produced during metabolic reactions can increase life span by protecting critical cellular components. In humans, women typically have lower metabolic rates and higher life expectancy. All of the above are false. |
The accumulation of free radicals produced during metabolic reactions can increase life span by protecting critical cellular components.
Recall that free radicals are toxic by-products that are generated during metabolic reactions. They produce detrimental effects on cells by oxidizing critical cellular components such as DNA and lipids, resulting in their damage. |
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A metabolic pathway requires ATP for energy and enzymes for catalyzing the production of biological building blocks. True False |
True
A metabolic pathway must have rich energy, such as ATP, for the catalysis of any molecule with the help of enzymes to form new biological molecules. |
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Which of the following would not be considered a type of metabolism? oxidation of methane molecules catabolic pathways that break down complex carbohydrates the capture of light energy for use in making glucose the manufacture of ATP from the breakdown of glucose all of the above |
oxidation of methane molecules
Although the oxidation of methane is a type of catabolic reaction, it is not considered a type of metabolic reaction that would occur naturally inside an organism. |
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A common way in which cells capture the energy released during the breakdown of large molecules is to add electrons to smaller, specialized molecules that can accept them. This process of electron acceptance is otherwise known as biosynthesis. metabolism. reduction. catalysis. a pathway. |
reduction
Reduction is the transfer of energy through the acceptance of electrons by a molecule. It is the opposite of oxidation, in which electrons are released. |
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Before they can react, many molecules must first be destabilized. This state is typically achieved through changing the chemical composition of these molecules. oxidizing the molecules by adding electrons. changing the reaction from a biosynthetic to a catabolic pathway. the input of a small amount of activation energy. none of the above |
the input of a small amount of activation energy.
This small amount of added energy is usually sufficient to overcome the activation energy barrier and destabilize the molecule. |
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In the enzyme-catalyzed reaction where , what will be the effect of inactivating the Enzyme 2? B, C, and D will all still be produced. B and C will still be produced, but not D. B will still be produced, but not C or D. A will still be produced, but not B, C, or D. None of the labeled substances will be produced. |
B will still be produced, but not C or D.
Because Enzyme 2 catalyzes the conversion of B into C, no C will be made. This means that Enzyme 3 cannot convert C into D, so no D will be made, either. However, because Enzyme 1 is still functional, A will be converted into B. |
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The process through which a newly formed daughter cell becomes different from the original parent cell is cell differentiation. binary fission. cell cycle. meiosis. interphase. |
cell differentiation.
Recall that cell differentiation is an important part of the developmental process through which specialized cell types are produced. As described in the chapter, the human body has about 220 types of specialized, differentiated cell types. |
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Before a cell can enter mitosis, it must first pass through interphase. phase. phase. S phase. all of the above |
all of the above
The entirety of interphase (, , and S) consists of events that are necessary precursors to mitosis. |
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________ is the process whereby an equal amount of parental genetic material is distributed between daughter nuclei destined for separate daughter cells. DNA duplication DNA segregation meiosis late prophase cytokinesis |
DNA segregation
“Segregation” means separation. DNA segregation is the equal separation of chromosomal material into daughter cells. This stage occurs during mitosis. |
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The key feature of metaphase in mitosis is that the nuclear membrane begins to break down. new DNA is synthesized. chromosomes are no longer in a duplicated form. individual chromosomes line up along the equator of the cell. all of the above |
individual chromosomes line up along the equator of the cell.
See Figure 10.10; the single-file arrangement of chromosomes along the metaphase plate characterizes metaphase. |
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Cytokinesis, the physical act of cell separation, occurs by the same mechanism in both plants and animals. True False |
False
Because plant cells have a cell wall, cytokinesis cannot occur through the simple inward pinching of membranes, as it does in animal cells. In plants, a new partition called a “cell plate” wall is first laid down between what will become the daughter cells, and then a membrane forms to complete the separation process. Refer to Figure 10.11 and Figure 10.12 to see a diagram of this process. |
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If you compare the chromosomes of a cell as it enters interphase with the same chromosomes just before the cell begins mitosis, a key difference would be the total number of chromosomes that are present. whether the chromosomes are duplicated. whether homologous pairs of chromosomes are present. the number of different kinds of chromosomes present. all of the above |
whether the chromosomes are duplicated.
The primary purpose of S phase, which is a major portion of interphase, is to duplicate chromosomes in preparation for cell division. |
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A cell whose haploid number is 12 will have ________ chromosomes present at prometaphase of mitosis. 48 24 12 6 cannot determine from the information given |
24
Cells undergoing mitosis are diploid. If the haploid number of a cell is 12, then the diploid number is 24. |
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In humans, mitosis produces an exact genetic copy of the parent cell. results in diploid daughter cells. does not produce sperm or eggs. makes daughter cells whose chromosomes are unduplicated. all of the above |
all of the above
All of these statements are true of mitosis in humans and in any diploid organism. |
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Consider a cell that begins meiosis with 30 total chromosomes. How many chromosomes will be present in each resulting daughter cell by the time the division process reaches metaphase II? 0 15 20 30 60 |
15
By the time the cells reach metaphase II, they have already completed meiosis I (reduction division) and are therefore haploid. Each cell will have 15 chromosomes. |
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In which of the following stages would a human cell not be diploid? prophase of mitosis telophase of mitosis metaphase of mitosis prophase of meiosis I metaphase of meiosis II |
metaphase of meiosis II
Cells are diploid throughout all of mitosis and throughout most of the first division of meiosis. |
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Mendel used ________ as his research organism to study patterns of genetic inheritance. garden peas snapdragons horses Siamese cats mice |
garden peas
Mendel first used the garden pea to make his revolutionary study of inheritance patterns. |
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In Mendel’s model of inheritance, what he described as units of inheritance we now refer to as genes. chromosomes. homozygotes. heterozygotes. phenotypes. |
genes.
We now know that genes (or alleles) are the units of genetic information that Mendel was describing when he imagined their segregation into gametes. |
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A purple-flowered pea plant has the genotype PP. Which of the following statements about this plant is false? Its phenotype is white. It has a homozygous dominant genotype. When bred to a white-flowered plant, its offspring will all be purple. The gametes produced will all have the same flower color allele. It is of the true-breeding variety. |
Its phenotype is white.
According to the shorthand notation used in the textbook, PP is the homozygous dominant genotype that results in a purple phenotype, not white. |
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An individual with the genotype ii would have blood type A B AB O cannot determine |
O
Recall that in the case of blood type in humans, the i allele does not produce any cell surface proteins. Therefore, for an individual that is ii, no cell surface proteins would be present on red blood cells and the person would have blood type O. |
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The Punnett square method is useful as a tool for analyzing genetic crosses because alleles separate equally during gamete formation. True False |
True
The first step in making a Punnett square is assigning the possible gametes that can be made by each parent to adjacent sides of the square, assuming that all gametes can be made with equal probability. This assumption is possible because of allele segregation during meiosis. |
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Being able to use a Punnett square to track the pattern of inheritance in a two-characteristic cross (for example,, pea seed color and seed shape) demonstrates Mendel’s idea of allele segregation. blending inheritance. environmental influences on genes. independent assortment. incomplete dominance. |
independent assortment.
The law of independent assortment states that the alleles for different genes segregate (assort) independently of one another during gamete formation. This is true because those genes are likely on separate chromosomes, which do not influence each other when they separate during meiosis. |
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The observation that individuals afflicted with albinism also always have vision problems is an example of codominance. incomplete dominance. pleiotropy. epistasis. polygenesis. |
pleiotropy.
Recall that “pleiotropy” refers to situations in which a single gene has influence over multiple, different traits. As we saw in the text, a pleiotropic gene is one that can influence two or more different traits simultaneously, such as in the example with albinism and vision problems. |
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In humans, the genetic commonality of height and skin tone is that they are both regulated by the same pleiotropic gene. strictly environmentally induced with little or no genetic component. clear violations of Mendel’s basic laws of genetic inheritance. controlled by multiple genes with a strong environmental influence. cases of genes exhibiting incomplete dominance. |
controlled by multiple genes with a strong environmental influence.
These traits are controlled by multiple genes. They are also strongly influenced by environmental factors, such as nutrition and sun exposure. |
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Which of the following statements about mutations is false? Mutations are the source of new alleles for genes. Organisms are able to create mutations to meet their specific needs. Mutations are random events and can happen in any cell at any time. Most mutations tend to be harmful or have no effect on organisms. Occasionally, mutations can be beneficial to organisms. |
Organisms are able to create mutations to meet their specific needs.
There is no evidence that organisms have any control over the kind of mutations that occur in their genetic material. |
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Assuming your blood type is AB, you can donate blood to people with type _________ blood and can receive blood from people with type _________. O; AB A; B B; A AB; O O; O |
AB; O
Because your blood cells would have both A and B cell surface proteins on their surface, your blood would be acceptable only to others with type AB blood. Also, people of blood type O are considered universal donors because their blood cells do not contain any cell surface proteins; and therefore you would be able to accept this blood type. |
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The X chromosome in humans is an example of an autosome. the only human sex chromosome. present only in females. always found in single copy. none of the above |
none of the above
Both X and Y are types of sex chromosomes in humans, and X is found in both males and females. Human males are XY, and females are XX. |
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A person is genetically XX and develops as a male. How can this be explained? In humans, males are XX. A mistake of genetic analysis must have taken place, because XX cannot develop into a male. The SRY gene is also present in this individual. The X chromosomes have nothing to do with sex determination in humans. none of the above |
The SRY gene is also present in this individual.
It is possible (although rare) for the portion of a Y chromosome that determines maleness (the SRY gene) to become associated with an X chromosome and thus produce male characteristics in an individual who does not have a Y chromosome. |
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In the absence of crossing-over, Mendel’s law of independent assortment does not apply when genes are located on the same chromosome. True False |
True
Linked genes (those present on the same chromosome) do not show independent assortment, unless they are located very far apart from one another on the chromosome so that crossing-over is likely to occur. |
|
On chromosomes, a pair of linked genes will be found only on autosomes. sex chromosomes. the same chromosome. opposite ends of the same chromosome. none of the above |
the same chromosome.
Genetically linked genes are present on the same chromosome, regardless of type. |
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If two parents are heterozygous for an autosomal recessive disease, they are both considered genetic carriers for the disease. their children have no chance of inheriting the disease. their children have a 50 percent chance of inheriting the disease. all of their children will also be heterozygotes. all of their children will have the disease. |
they are both considered genetic carriers for the disease.
Heterozygotes have one dominant (in this case, normal) and one recessive (in this case, disease-causing) allele. Therefore, they do not show the disease, but they can pass along the disease-causing allele to their offspring, making them genetic carriers. If two heterozygotes mate, on average one-fourth of their children will have the homozygous recessive genotype and consequently be affected by the disease. |
|
In humans, X-linked genetic diseases are associated with one of the sex chromosomes. include hemophilia and Duchenne’s muscular dystrophy. can be seen in both males and females. tend to be expressed more in males than in females. all of the above |
all of the above
Because X chromosomes are present in males and females, both can show X-linked diseases. Most X-linked genetic diseases are recessive in nature. Males express them more frequently, however, because they need only one copy of the defective gene, instead of two for females. |
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Down syndrome in humans is an example of normal genetic recombination. a change in the overall number of chromosomes. an X-linked recessive disorder. a single-gene autosomal mutation. a change in the structure of one of the sex chromosomes. |
a change in the overall number of chromosomes.
Down syndrome results when an individual receives three copies of chromosome 21 as the result of an error during meiosis. |
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Which of the following diseases is not influenced by a person’s genetic makeup? heart disease cancer diabetes arthritis none of the above |
none of the above
Many diseases, including all of those listed here, are caused by multiple gene interactions with various environmental factors. Therefore, to some degree, all of the diseases listed are influenced by a person’s genetic makeup. |
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Crossing-over is expected to occur infrequently for genes located very close together on the same chromosome. True False |
True
The closer together two genes are, the less likely they are to be involved in a crossing-over event. |
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Consider a species that reproduces sexually and has a total of three pairs of chromosomes (two pairs of autosomes and one pair of sex chromosomes). In the absence of crossing-over, how many different offspring combinations can a mating pair produce? 4 8 9 16 64 |
64
Each parent would be able to produce gametes with 23 = 8 different combinations of chromosomes. In a mating event, there would therefore be 8 × 8 = 64 possible combinations of offspring. |
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Microbiologists quickly responded to the paper by Dr. Wolfe-Simons claiming to have discovered organisms using arsenic to construct their DNA; one of the most challenging criticisms involved the researcher’s inability to account for arsenic’s toxicity to other organisms. publishing the paper prior to the conventional peer review. the preparation of the bacterial DNA using nonconventional protocols. the lack of comparative information on closely related bacteria within the Halomonadacea family. |
the preparation of the bacterial DNA using nonconventional protocols. |
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Which statement best summarizes the information presented in the graph below? There is a strong correlation between the amount of applied fertilizer and the average number of leaves per corn plant. Higher applications of fertilizer produce proportional increases in corn yield. Fertilizer application is a cost-effective means of increasing farm profits. Leaf growth represents energy not directed to corn production and the two variables show a negative correlation. |
There is a strong correlation between the amount of applied fertilizer and the average number of leaves per corn plant. |
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Which of the following represents conducting an experiment? dialing a telephone number comparing prices of computers checking your midterm grades online predicting the outcome of a basketball game |
dialing a telephone number |
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The repeated replanting of the seeds from wild mustards that showed unusually prolific growth of the flower buds led to what modern cruciferous plants? turnips and kolirabi kale and cabbage cauliflower and kale broccoli and cauliflower |
broccoli and cauliflower |
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Which statement best summarizes the information presented in the graph below? Higher applications of fertilizer produce proportional increases in corn yield. Fertilizer application up to 200 kg/hectare is a cost-effective means of increasing farm yields and profits. Proportional increases in irrigation are needed to maximize the growth potential of applied fertilizer. Factors other than fertilizer availability can limit the yield of corn. |
Proportional increases in irrigation are needed to maximize the growth potential of applied fertilizer. |
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A medical diagnosis is a(n) observation. experiment. theory. hypothesis. |
hypothesis. |
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Land biomes are most commonly defined by their food webs. the dominant animal life in them. the dominant plant life in them. the combination of dominant plant and animal life in them. |
the dominant plant life in them. |
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The term autotroph can be interchanged with the term producer; both terms refer to organisms that obtain energy from the nonliving part of their environment. True False |
True |
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DNA is an example of the molecular level of biological organization. True False |
True |
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When you dial a telephone number you are making an observation. testing a hypothesis. conducting an experiment. both b and c |
both b and c |
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Multicellular organisms are constructed from many types of specialized cells. Why might this be more advantageous than being a single-celled organism? Specialized cells can do a given job better than a general-purpose cell can. Specialized cells can survive independently of the multicellular organism. Nonspecialized cells do not live as long as specialized cells. Nonspecialized cells are unable to stick together to make up a multicellular organism. |
Specialized cells can do a given job better than a general-purpose cell can. |
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Which of the following is an experiment? reading a blood pressure gauge examining an X-ray taking prescription medicine making a medical diagnosis |
taking prescription medicine |
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Which of the following statements is true? Producers obtain their energy from other organisms. Producers represent the final energy transfer in a food chain or web. Consumers obtain their energy from other organisms. Consumers represent the initial energy transfer in a food chain or web. |
Consumers obtain their energy from other organisms. |
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Once supported by a predictable experimental outcome, a scientific hypothesis is never reexamined. still cannot be considered to have been proven true. can be used to predict the outcome of all future similar events. is elevated to the status of theory. |
still cannot be considered to have been proven true. |
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Although vaccination can provide a lifelong protection against some diseases, flu vaccines are rarely effective against next year’s flu because the virus that causes flu is not alive. can evolve quickly. can change its cell membranes and block the action of the vaccine. can develop into immune bacteria and neutralize the action of the vaccine. |
can evolve quickly. |
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More than one adaptive trait in the pronghorn has been influenced by the presence of predators; in addition to its great speed the pronghorn also has a four-chambered stomach. strong teeth. camouflage coloration. hollow hair. |
camouflage coloration. |
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Which organism might harvest energy from iron? a human a cricket a bacterium a goat |
a bacterium |
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In which of the following objects would the energy content be most directly connected to solar energy? an apple a hamburger a slice of pizza a grilled cheese sandwich |
an apple |
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Once experimental data verifies a prediction the hypothesis is considered proven. True False |
False |
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Charles Darwin introduced the concept of adaptation, which he defined as features that help organisms survive and reproduce. allow an organism to resist the pressures of evolutionary change. allow organisms to change their environment in ways that best ensure continued survival. All of the above are aspects of the definition of adaptation. |
help organisms survive and reproduce. |
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Which of the following sequences correctly represents the biological hierarchy of a multicellular organism? cells à tissues à organs à individual tissues à organs à cells à individual individual à cells à organ systems à tissues organ systems à organs à tissues à individual |
cells à tissues à organs à individual |
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DNA is one of the features common to all known forms of life; it forms the protective outer membrane of cells. it is produced expressly for reproduction and is found only in egg and sperm. it is the blueprint that guides the growth, development, behavior, and reproduction of all organisms. its absence in viruses is the basis for classifying them as nonliving. |
it is the blueprint that guides the growth, development, behavior, and reproduction of all organisms. |
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Some bacteria can sense direction using magnetic particles in their cells. True False |
True |
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The organs that constitute an organ system often work cooperatively to maintain homeostasis. True False |
True |
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Polar bears are white, which makes them difficult to see as they stalk seals; their white fur is an example of an adaptation. True False |
True |
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The group with the greatest diversity in the strategies used to obtain carbon and energy is the Fungi. Animalia. prokaryotes. Plantae. |
prokaryotes. |
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A lineage is a group of relatives that have a common ancestor. True False |
True |
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The current classification system used by biologists is complex and unchanging. universally accepted by all biologists. based on four generalized types of living organisms: the Bacteria, the Archaea, the Eukarya, and the Protista. updated and revised whenever new information becomes available. |
updated and revised whenever new information becomes available. |
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Which of the following would you most likely find surviving in a boiling-hot spring? an archaean bacteria a eukaryote none of the above |
an archaean |
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Which of the following statements about bacteria is false? They help a variety of organisms digest their food. They can provide the nitrate necessary for plant nutrition. They can be used to clean up oil spills. The membranes from their organelles can be used to produce medicines. |
The membranes from their organelles can be used to produce medicines. |
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The structure labeled A, below, is cilia, used by both prokaryotes and eukaryotes to move through fluid. True False |
False |
|
The most inclusive category in the Linnaean classification system is order. phylum. kingdom. species. |
kingdom. |
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The broadest classification category currently used by most biologists is the domain. True False |
True |
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Convergence is an evolutionary process that produces similar but not shared derived traits in organisms having common life histories but not common ancestors; which of the pairs of features is not convergent? the caudal fins of the whale and shark the opposable thumbs of the human and panda the hands of the chimpanzee and human the wings of the bat and bird |
the hands of the chimpanzee and human |
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Evolutionary tree diagrams representing the relationships between various organisms can be drawn only when those organisms share a common cellular metabolism. distinct lineage. common cellular organization. common ancestor. |
common ancestor. |
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All bacteria have the same shape. True False |
False |
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What best explains why bacteria can reproduce so much more rapidly than an organism like a mushroom? Mushrooms reproduce using spores that require a lengthy exposure to the environment before the outer coating can break open. Bacteria live in extreme environments and can avoid having to wait for more favorable conditions to reproduce, like mushrooms and other plants. Because most disease-causing bacteria are avoided by consumers, whereas organisms like mushrooms are quickly eaten, preventing rapid population growth. Mushrooms reproduce sexually, so the proper mating types must contact one another before reproduction can proceed. |
Mushrooms reproduce sexually, so the proper mating types must contact one another before reproduction can proceed. |
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The most restrictive category in the Linnaean classification system is species. order. kingdom. phylum. |
species. |
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Descendant organisms do not share any features with their descendants. have all the same features as their descendants. share some features with their ancestors. do not have features their ancestors lacked. |
share some features with their ancestors. |
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Evolutionary trees have been successfully used to identify which multicellular species are most closely related to humans. explain how evolution works. explain why most carnivorous mammals have four or five toes. explain the potential impact of global climate change. |
identify which multicellular species are most closely related to humans. |
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Prokaryotes differ in several ways from eukaryotes; one of the most distinctive is the absence of a plasma membrane. having hereditary material composed of DNA. the presence of chromosomes. a nucleus that encloses the cell’s DNA. |
a nucleus that encloses the cell’s DNA. |
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When success is defined as the greatest number of living individuals, Earth’s most successful inhabitants are the vertebrates and birds. fungi and animals. bacteria and archaea. plants and animals. |
bacteria and archaea. |
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Like any disease or parasite, viruses need to reach new hosts to extend the infective cycle, which explains why such a large number of viral infections are associated with the urinary and cardiovascular systems. digestive and respiratory systems. nervous and integumentary systems. reproductive and integumentary systems. |
digestive and respiratory systems. |
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Microscopic examination can often resolve questions in taxonomy, for example, cells that possess a nucleus are never classified as eukaryote. fungi. archaean. protist. |
archaean. |
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Which of the following avian species are most closely related? Picoides villosus and Picoides borealis Picoides borealis and Phylloscopus borealis Numenius borealis and Picoides borealis Numenius americanus and Grus americana |
Picoides villosus and Picoides borealis |
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Bacterial cells can typically be described by one of the following three shapes: the sphere, rod, or cube. the rod, sphere, or corkscrew. the corkscrew, cube, or rod. the cube, sphere, or comma. |
the rod, sphere, or corkscrew. |
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Archaea, Bacteria, and Eukarya are the three biological domains. True False |
True |
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The rate of evolution in prokaryotes may be accelerated by lateral gene transfer; a process that appears to move genes from one branch of an evolutionary tree to another. True False |
True |
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Mutualistic organisms are more commonly termed parasites. True False |
False |
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During a red tide air pollution turns the sunrise and sunset bright red, which, in turn, makes beaches appear red. fish die from water pollution and bleed as they wash up on the shoreline. single-celled protists become so numerous that they color the water red, brown, yellow, or other colors. fish eat large quantities of red-colored food items and temporarily become red themselves |
single-celled protists become so numerous that they color the water red, brown, yellow, or other colors. |
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Despite having cell walls like plant cells, this feature is not considered a shared derived trait between the fungi and plants because fungal cell walls are incomplete. chitin rather than cellulose is the primary structural component of a fungal cell wall. digestive enzyme can be secreted through the cell wall of a hypha. glycogen rather than glucose is a primary structural component of a fungal cell wall. |
chitin rather than cellulose is the primary structural component of a fungal cell wall. |
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Protists are not considered to represent a complete evolutionary lineage because there are three lineages within the group. they evolved long ago. they evolved recently. there is only one lineage within the group. |
there are three lineages within the group. |
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What adaptive advantage do the numerous projections shown below in the microphotograph of the foraminiferans, a type of zooplankter, confer? predator protection—they are difficult to eat mobility—the projections function like oars buoyancy—the projections reduce the rate of sinking food acquisition—prey items are impaled |
predator protection—they are difficult to eat |
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Fertilization is the event occurring when a(n) egg and sperm unite to first form a zygote and eventually an embryo. pollen tube grows through the style and reaches the ovary. pollen grain is transported by wind or insect to the female portion of the plant. pollen grain is released from the male portion of the plant. |
egg and sperm unite to first form a zygote and eventually an embryo. |
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The hyphal mass, or body, of a fungus is constructed from interwoven filaments called mycelia. True False |
False |
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Life on Earth appears to have began in the water; the first organisms believed to colonize the land were bacteria. plants. fungi. animals. |
plants. |
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Researchers are attempting to develop a plant that will turn from green to white when in the presence of minute amounts of explosives; what plant molecule needs to be removed from the leaf surface for the system to function as intended? glycogen lignin chlorophyll rhodophytin |
chlorophyll |
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What best explains the differences in shoot weight shown in the graph below? Commercial fertilizers often contain harmful contaminants that can suppress growth. Sterilized growth environments remove competitive bacteria and fungi, allowing plants to experience their best possible growth. Commercial fertilizers can be tailored to meet the needs of specific plants, producing the best possible growth for that species. Mycorrhizal fungi not only increase the availability of soil nutrients but often transport them into the plant root. |
Mycorrhizal fungi not only increase the availability of soil nutrients but often transport them into the plant root. |
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No single characteristic is sufficient to describe a kingdom; for example, plants and some bacteria share in common the ability to photosynthesize. the presence of a cell wall and the absence of a plasma membrane. a heterotrophic lifestyle. the ability to reproduce sexually. |
the ability to photosynthesize. |
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As a major plant group the bryophytes are characterized by the absence of vascular tissue. the absence of seed production. a flagellated sperm. all of the above |
all of the above |
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What capability did the development of a vascular system provide? Greater efficiency at capturing energy from sunlight. Greater efficiency for nutrient transport and structural support. It permitted plant life to establish on land. It allowed the developing embryo to remain protected until better growth conditions became available. |
Greater efficiency for nutrient transport and structural support. |
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The domain Eukarya is presently subdivided into four kingdoms as shown below, although new information concerning the protists could increase that number. True False |
True |
|
The primary body of a fungus is known as the mycelium. gymnosperm. mitochondrion. septum. |
mycelium. |
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Stomata normally open and close throughout the day; however, if unable to close, plant tissues could be damaged as excess carbon dioxide reaches toxin levels within the leaf. oxygen escapes creating a hypoxia within the leaf tissues. water rapidly escapes causing dehydration. all of the above |
water rapidly escapes causing dehydration. |
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What resources do plants use to produce the sugar molecules that plant cells use for fuel? carbon dioxide, water, and light energy water and pond scum nitrogen and oxygen water, nitrogen, and iron |
carbon dioxide, water, and light energy |
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Which statement best summarizes the adaptive value of xylem? Xylem is specialized for transporting food molecules like sugar. Xylem is the reinforcing protein that in combination with cellulose allows plants to grow vertically. Xylem cells open and close to admit carbon dioxide into the leaf during photosynthesis. Xylem is specialized for transporting water and dissolved nutrients. |
Xylem is specialized for transporting water and dissolved nutrients. |
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Without angiosperms, bryophyte reproduction would almost entirely cease. True False |
False |
|
The cuticle predisposed plants for a terrestrial existence by improving water retention. True False |
True |
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Without the symbiotic association between plant roots and mycorrhizae the diversity and abundance of animals and fungi would probably be much less. True False |
True |
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Lichen can be useful as pollution indicator species; lacking a cuticle they tend to readily absorb airborne pollutants. True False |
True |
|
The flower is the basic reproductive structure of a plant; thus, all plants produce flowers. True False |
False |
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The evolution of the lung was a critical development in the adaptation of animals to a terrestrial lifestyle; the first vertebrates to breathe using a lung were the reptiles. True False |
False |
|
Most animals reproduce sexually; fertilization begins a developmental sequence that progresses from zygote to blastula to gastrula. gastrula to zygote to blastula. blastula to zygote to gastrula. zygote to gastrula to blastula. |
zygote to blastula to gastrula. |
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What occurs during ecdysis or molting? Mammals, for example, dogs and cats, shed hair. Birds lose worn or damaged feathers from their bodies. The cuticle of some phyla is shed to accommodate additional growth. All of the above illustrate ecdysis. |
The cuticle of some phyla is shed to accommodate additional growth. |
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Recent analysis of the cell membranes of sponges indicates a much closer relationship to other animals than previously thought. True False |
True |
|
Conservation biologists estimate that 20 percent of the world’s bird species that existed 2,000 years ago are now extinct. True False |
True |
|
The success of the amniotic egg was the development of a completely water- and airtight shell that prevented moisture loss. True False |
False |
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Ctenophores can be distinguished from cnidarians by the presence of a complete digestive system. True False |
False |
|
Keratin is an important and widespread structural protein in animals, forming structures as diverse as feathers, toenails, and the carapace of crabs. True False |
False |
|
Chitin occurs in several kingdoms and numerous animal phyla but its greatest adaptive expression is seen in the annelid tube worm cases. tunicate notocord. echinoderm water vascular system. arthropod exoskeleton. |
arthropod exoskeleton. |
|
Fruit flies, blow flies, and black flies share a similar life history strategy; they first appear as maggots, pupate, and eventually emerge as adult files. This type of development is called incomplete metamorphosis. complete metamorphosis. somatic differentiation. hermaphroditic development. |
complete metamorphosis. |
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The figure below shows the vertebrates and arthropods as being distantly related, yet each has features, like limbs and jaws, seen in no other groups. How can such obvious similarities be disregarded in favor of embryological development as a basis for classification? The decision to overlook certain features reveals the arbitrary nature of classification and explains why there is so little agreement among taxonomists. Taxonomists have not disregarded limbs; they were likewise inherited from a common ancestor but secondarily lost by the mollusks, annelids, and echinoderms. Embryos are securely protected during development and experience little selection pressure; shared inherited features are best explained by a common ancestor. Examination of the embryos of all animals with body cavities reveals limbs, but they are unnecessary for some lifestyles and so they degenerate. |
Embryos are securely protected during development and experience little selection pressure; shared inherited features are best explained by a common ancestor. |
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The conservation organization Ocean Blue has developed a seafood recommendation list that advises avoiding many captive-reared species; why might seafood reared in captivity be less desirable? Aquaculture often diverts food production away from staples to an exported crop. Aquaculture’s intense biological activity often degrades local water and land quality. Captive-reared species may be exposed to pollution like heavy metals that can be difficult to detect. all of the above |
all of the above |
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Although adult echinoderms display radial symmetry, they are not considered to be closely related to the cnidarians and ctenophores. True False |
True |
|
Sharks and the ray-finned fishes differ in several ways; the most significant difference is the composition of the skeleton. True False |
True |
|
Rather than mandibles like most arthropods, spiders have fangs, which explains why most spiders spin webs. liquefy their prey with an injectable toxin. have a protective cuticle. have compound rather than simple eyes. |
liquefy their prey with an injectable toxin. |
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Cnidarians have a gastrovascular cavity rather than a complete gut; in what way(s) would this arrangement be less functional? A blind-ended cavity increases the probability of parasite attachment within the cavity. Gastrovascular digestion is less efficient because the more powerful digestive chemicals seen in advanced animals, like stomach acids, would be destructive with this type of organization. Lacking a mouth and the capacity for chewing greatly reduces the potential prey items available for cnidarians in comparison to other animals. Because undigestible materials must pass out through the same opening used to enter the cavity, a single item must be completely digested and expelled before digestion of a new food item can begin. |
Because undigestible materials must pass out through the same opening used to enter the cavity, a single item must be completely digested and expelled before digestion of a new food item can begin. |
|
The success of mammals is due in large part to several highly effective reproductive strategies, which include the mammary gland for nourishing their young. the placenta for supporting the growth of the embryo. internal fertilization. all of the above |
all of the above |
|
Some aspects of both cardiovascular disease and depression may share a common origin in an inflammatory response that may be initiated by the consumption of trans fat. True False |
True |
|
In the illustration below, a positive ion is surrounded by water molecules. negative hydrogen atoms positive hydrogen atoms negative oxygen atoms positive oxygen atoms |
negative oxygen atoms |
|
Macromolecules are typically formed by repetitively adding small monomers together; which macromolecule is properly matched with the appropriate monomer? polypeptide—amino acid nucleic acid—amino acid polysaccharide—nucleotide triglyceride—cholesterol |
polypeptide—amino acid |
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After adding a small amount of Solution A to Solution B, the pH of Solution B declines from 8 to 3. Solution A must contain a salt. an acid. water only. a base. |
an acid. |
|
A solution with a pH of 7 is neither acidic nor basic. True False |
True |
|
The atoms in water molecules are held together by hydrogen bonds. True False |
False |
|
One function of nucleotides is energy transfer. Carbohydrates can be used to store energy. These related processes are important because if we could not store and transfer energy, we would have to match our energy input (eating) exactly to our energy requirements, even while sleeping. there are not enough kinds of amino acids for proteins to be used as energy storage molecules. energy transfer and storage are processes that are unique to humans, and therefore are used to determine the classification of people. energy transfer is how we take the energy we gather from photosynthesis and transfer it into water molecules for later use when we need energy. |
if we could not store and transfer energy, we would have to match our energy input (eating) exactly to our energy requirements, even while sleeping. |
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The chemical reaction that represents the combustion of glucose is C6H12O6 + O2 à CO2 + H2O; _____ are the reactants. CO2 and H2O O2 and H2O C6H12O6 and O2 C6H12O6 and CO2 |
C6H12O6 and O2 |
|
Nonpolar molecules are highly charged. True False |
False |
|
Chemists often represent the structure of atoms using p, n, and e to indicate the numbers of protons, neutrons, and electrons; which atom would have an atomic weight of 30? 10 p, 10 n, 10 e 15 p, 15 n, 15 e 15 p, 0 n, 15 e 0 p, 15 n, 15 e |
15 p, 15 n, 15 e |
|
How many atoms are present in a single molecule of C8H10N4O2? 4 8 12 24 |
24 |
|
Cholesterol is commonly found in the cell membranes of warm-blooded animals because excess dietary cholesterol is stored in cell membranes. cholesterol is involved in the muscle contractions needed to move an animal around its environment. it prevents the cell membrane from becoming too flexible at body temperature. warm-blooded animals tend to consume large amounts of cholesterol-rich foods. |
it prevents the cell membrane from becoming too flexible at body temperature. |
|
Which of the following combinations of atoms would form ionic bonds? H+ and O Na+ and K+ Na+ and Cl- PO4- and I2- |
Na+ and Cl- |
|
The carbon dioxide you breathe out is carried to the lungs in the blood. Carbon dioxide, when dissolved in water, is an acid. How does the body prevent your blood from becoming too acidic on the way to your lungs? Buffers in the blood release OH- ions to make the blood more basic. Buffers in the blood accept H+ ions to make the blood less acidic. Buffers in the blood release H+ to make the blood more basic. Buffers in the blood accept OH- to make the blood less acidic. |
Buffers in the blood accept H+ ions to make the blood less acidic. |
|
ATP is a universal fuel for living organisms. The energy that ATP molecules deliver in chemical reactions is stored in covalent bonds between the molecule’s phosphate groups. covalent bonds between the molecule’s sugar and phosphate groups. hydrogen bonds between the bases of two of these molecules. ionic bonds between the molecule’s sugar and base. |
covalent bonds between the molecule’s phosphate groups. |
|
Based only on the illustration below it could be predicted that ice floats on liquid water because the crystal structure of ice is more regular than that seen in liquid water. the distance between water molecules in ice is greater than in liquid water. the cool temperature of ice reduces the extent of molecular motion relative to liquid water. when ice forms the hydrogen bond in the water molecule becomes nonpolar; ice behaves like oil. |
the distance between water molecules in ice is greater than in liquid water. |
|
A solution with a pH of 3 is acidic. nonpolar. basic. neutral. |
acidic. |
|
Electrons are found in the nucleus of an atom. only in complex molecules. in one or more shells that surround the atom’s nucleus. in both the nucleus and inner shell of an atom. |
in one or more shells that surround the atom’s nucleus. |
|
All the isotopes of a particular element have the same number of protons. True False |
True |
|
The outer electron shell of a nitrogen atom can hold up to eight electrons, but contains only five. As a result, nitrogen can form _____ covalent bonds. zero one three eight |
three |
|
In water, phospholipids arrange themselves such that their fatty acid head groups are facing the water. their hydrophobic tails are kept away from the water. saturated fatty acids face the water while unsaturated fatty acids are separated from the water. the charged atoms on their fatty acid chains can interact directly with the water molecules. |
their hydrophobic tails are kept away from the water. |
|
One of the symptoms of kidney disease is the presence of proteins in a patient’s urine. To quickly test for kidney disease using a urine sample, a doctor might add a chemical that causes a color change when nitrogen, but not oxygen, is present. nitrogen, but not phosphorus, is present. only oxygen and hydrogen are present. only carbon and hydrogen are present. |
nitrogen, but not phosphorus, is present. |
|
The strongest possible chemical link between two atoms is a(n) covalent bond. hydrogen bond. noncovalent bond. ionic bond. |
covalent bond. |
|
Steroids and proteins are different types of lipids. True False |
False |
|
Chemical reactions do not change the identity of the participating atoms; all atoms present at the beginning of the reaction must be present at the end. Balance the chemical reaction by indicating the number of molecules necessary for each reactant and product: _____Cl2 + _____ NaBr = _____Br2 + _____NaCl. 1; 1; 1; 1 1; 2; 1; 1 1; 2; 1; 2 2; 2; 1; 2 |
1; 2; 1; 2 |
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Which of the following is not a function of the plant vacuole? storage of ions, pigments, and toxins production of ATP breakdown of macromolecules with enzymes support of overall plant structure |
production of ATP |
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The cell in the figure below is moving by producing pseudopodia. This type of movement is a result of the reorganization of a certain component of the cytoskeleton (labeled). microtubules elongating at the leading edge of movement. microfilaments disassembling at the trailing edge of movement. different types of intermediate filaments located in different parts of the cell. motor proteins attached to microtubules pushing the plasma membrane forward. |
microfilaments disassembling at the trailing edge of movement. |
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The Golgi apparatus is the place where a cell’s genetic material is stored. sorts proteins and lipids and sends them to their final destination. captures energy from sunlight and sends it to mitochondria. creates energy by converting ribosomes to proteins. |
sorts proteins and lipids and sends them to their final destination. |
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Ribosomes are very small nonmembranous organelles associated with the synthesis of protein. DNA. membrane phospholipid. the membranous organelles. |
protein. |
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specimen is positioned between the energy source and the viewer. energy (light or electrons) passes through the specimen. lenses are positioned between the specimen and the viewer. all of the above |
all of the above |
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Which of the following statements about mitochondria and chloroplasts is false? They were probably primitive eukaryotic cells. They contain their own DNA. They are able to make some proteins. They reproduce independently of the cell in which they reside. |
They were probably primitive eukaryotic cells. |
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Microtubules are responsible for moving and positioning organelles inside the cell. the formation of pseudopodia. reinforcing and supporting cell structure. strengthening skin cells. |
moving and positioning organelles inside the cell. |
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What components of the plasma membrane of an animal cell would you find at its innermost surface, directly exposed to the cytoplasm? phospholipid tails only proteins only phospholipid heads and proteins phospholipid heads and nucleic acids |
phospholipid heads and proteins |
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Multicellularity does not characterize all types of organisms living today; which eukaryotic kingdoms retain unicellular representatives? protists (slime mold), plants (algae), and fungi (yeast) animals (plasmodium), plants (algae), and fungi (yeast) protists (algae) and fungi (yeast) animals (plasmodium), protists (algae), and fungi (yeast) |
protists (algae) and fungi (yeast) |
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A membrane that is selectively permeable causes damage to the cell by allowing solutes to enter and leave the cell indiscriminately. True False |
False |
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The word fluid in the term fluid mosaic model refers to the fact that membranes are a patchwork of lipids and proteins. membranes are selectively permeable. the proteins within a membrane freely move around. the membrane assembles and disassembles as necessary for cell function. |
the proteins within a membrane freely move around. |
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The relative abundance of a specific organelle is often predictable when cell function is considered; for example, the _____ could be expected to contain more lysosomes than an average cell. photosynthetic cells of a leaf brain cells that produce large amounts of proteins to send signals to other cells acid- and enzyme-producing cells that line your stomach cells that roam around your body engulfing and consuming bacteria |
cells that roam around your body engulfing and consuming bacteria |
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Prokaryotic cells are generally larger than eukaryotic cells. True False |
False |
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Certain cells found in humans are identical to certain cells found in plants. True False |
False |
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The boundary structure that physically defines a cell is the plasma membrane. protein channel. hydrophilic layer. phospholipid side chain. |
plasma membrane. |
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Nuclear pores allow the nucleus to pass through the plasma membrane. True False |
False |
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Volvox, the multicellular green alga shown below, has flagellated cells on its surface cells but not on interior cells. How might this condition develop? Interior cells attempt to grow flagella, but the lack of open space suppresses the effort. Interior cells discard the genetic instructions for flagella once their interior position is established. The commitment of resources for photosynthesis reduces the availability of protein and other biomolecules needed to produce flagella. Signals from surface cells or the absence of signals from the environment to the plasma membranes of the interior cells suppresses the growth of flagella. |
Signals from surface cells or the absence of signals from the environment to the plasma membranes of the interior cells suppresses the growth of flagella. |
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Advancement in biology was hindered by the concept of spontaneous generation, the belief that nonliving objects could spontaneously come to life. What aspect of the cell theory specifically refutes this idea? Every living organism is composed of one or more cells. All living cells come from preexisting cells. Cells are the smallest unit of life possible on Earth. The components of a cell do not individually retain the distinctive characteristics of life. |
All living cells come from preexisting cells. |
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The nucleolus is the region of the cell where chromosomes are found. the name of the double layer of membranes that forms the boundary of the nucleus. the region of the nucleus where ribosome production begins. a piece of DNA wrapped around proteins. |
the region of the nucleus where ribosome production begins. |
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Biologists call an agent that spreads an infectious disease a vector. What is the vector for malaria? a protist of the species Plasmodium a mosquito of the species Anopheles a bacterium of the species Listeria The vector is presently unidentified. |
a mosquito of the species Anopheles |
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The boundary that surrounds the contents of the nucleus is the plasma membrane. nuclear envelope. nuclear pore. cytosol. |
nuclear envelope. |
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The magnification of a specimen by a light microscope is a result of the bending of light as it passes through glass lenses. the focusing of electron beams by magnets. the reflection of light off a specimen. using chemicals to physically enlarge cells. |
the bending of light as it passes through glass lenses. |
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Which of the following statements is false? Eukaryotes use RNA as the hereditary genetic material. Eukaryotes can be multicellular. Eukaryotes have a membrane-enclosed nucleus. Eukaryotes have membrane-enclosed organelles. |
Eukaryotes use RNA as the hereditary genetic material. |
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Until recently public health officials had mistakenly believed that the mosquitoes responsible for transmitting malaria primarily live indoors, and thus officials had concentrated eradication efforts on dwellings. True False |
True |
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Eukaryotic cells contain membrane-bound organelles. True False |
True |
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All of the chemical energy in ATP is used during a chemical reaction. True False |
False |
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The shape of an enzyme does not affect its activity. True False |
False |
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All molecules have a combination of kinetic and potential energy. If an external heat source were used to increase the kinetic energy of a group of molecules, the potential energy of the group would decline because the sum of kinetic and potential energy always equals 100 percent. be unaffected because no changes in the bonding pattern of the molecule had taken place. also increase because potential and kinetic energy are directly proportional to one another. It is not possible to predict the result using the information provided. |
be unaffected because no changes in the bonding pattern of the molecule had taken place. |
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An enzyme and its substrate find each other by chance encounter. magnetic attraction. catalysis. oxidative reactions. |
chance encounter. |
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Enzymes catalyze only anabolic chemical reactions. True False |
False |
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A decrease in potential energy between reactants and products is typical for what type of chemical reaction? anabolic reactions catabolic reactions the formation of peptide bonds those occurring without the aid of an enzyme |
catabolic reactions |
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Recent studies on weight loss have shown that without a rigorous training regimen exercising muscle will preferentially burn carbohydrates rather than fat, providing support for the observation that exercise alone is ineffective in promoting weight loss. True False |
False |
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In the reaction CH2O + O2 à CO2 + H2O, carbon is reduced and hydrogen is oxidized. carbon is oxidized and oxygen is reduced. carbon and hydrogen are reduced. carbon and oxygen are oxidized. |
carbon is oxidized and oxygen is reduced. |
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When ATP breaks into ADP and a phosphate group, energy is given off. True False |
True |
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Biosynthetic reactions require many things, including carbon dioxide and water. glucose and water. enzymes and ATP. sunlight and CTP. |
enzymes and ATP. |
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Physiologists monitored metabolite concentrations generated during exercise in three groups of individuals (those with poor fitness, average fitness, and exceptional fitness); which statement best summarizes their findings? Exercise was beneficial to all groups, but those benefits concluded immediately upon cessation of the exercise; to be significantly beneficial, the duration of exercise must be lengthened. The metabolic responsiveness of unfit individuals was extremely low; unfit individuals are unlikely to experience benefits from exercise for at least 30 days after starting an exercise program. Exercise produced an almost immediate positive metabolic effect in which the strength and duration was proportional to the fitness level; exercise was beneficial to all participants. Metabolites extracted from the blood of unfit individuals was shown to suppress the level of metabolism of cells growing in tissue culture. |
Exercise produced an almost immediate positive metabolic effect in which the strength and duration was proportional to the fitness level; exercise was beneficial to all participants. |
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In photosynthesis, the carbon used to make sugars is provided by enzymes. provided by carbon dioxide. extracted from DNA. oxidized to make sugars. |
provided by carbon dioxide. |
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It is possible to predict the amount of energy released during a chemical reaction (as shown in the illustration below) because the _____ law of thermodynamics states that _____. first; energy and matter are equivalent second; any use of energy affects the entire universe first; the total amount of energy in a defined system remains constant second; energetic systems become less organized over time |
first; the total amount of energy in a defined system remains constant |
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Which of the following compounds is the least oxidized? C6H11O6 CO2 CH4 HCOOH |
CH4 |
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Living systems must work to remain ordered. They pass off their disorder in the form of light. sound. heat. water. |
heat. |
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A calorie represents the number of grams of fat in a food product. number of times an enzyme can be reused before it must be replaced. amount of energy needed to raise the temperature of one liter of water by 1ºC. temperature at which a gram of food is completely converted into carbon dioxide. |
amount of energy needed to raise the temperature of one liter of water by 1ºC. |
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Which of the following strategies is not used by cells to help enzymes and substrates find each other? locating enzymes used in the same biochemical pathway near each other in the cytoplasm having certain reactions occur within a specific organelle embedding more enzymes in the plasma membrane producing heat to increase the frequency of molecular collisions |
producing heat to increase the frequency of molecular collisions |
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The image below diagrams the action of an enzyme. When a substrate locks into the active site of an enzyme, the enzyme changes shape to mold itself around the substrates. Generally, the size of a substrate is larger than the size of the active site into which it must fit. When the substrate enters the active site, the active site must stretch to fit. Before catalysis can occur, a substrate must change its shape so that it fits into the active site of the enzyme more precisely. Most active sites are only designed to hold one substrate. In this image, two substrates enter the active site, creating a tighter fit. |
When a substrate locks into the active site of an enzyme, the enzyme changes shape to mold itself around the substrates. |
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Sugar molecules are more oxidized than carbon dioxide molecules. True False |
False |
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An insect devouring a leaf is an example of the second law of thermodynamics in action. True False |
True |
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_____ reactions use energy to build complex molecules. Catabolic Anabolic Photosynthetic Redox |
Anabolic |
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Chemical reactions can occur without the input of any energy. True False |
False |
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The term thermal energy describes the orderly movement of electrons along a conductor (such as a wire). movement of photons as they travel through space. attractive power of two magnets toward one another. random movement or vibration of the molecules of any substance (water molecules in a beaker, for example). |
random movement or vibration of the molecules of any substance (water molecules in a beaker, for example). |
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The heat given off by living systems can increase the likelihood that a given chemical reaction takes place. Why is this true? The enzymes that catalyze reactions in living systems work increasingly better as the temperature decreases. The heat given off lowers the internal cellular temperature, which allows reactions to proceed more quickly. The heat allows photosynthesis to occur more rapidly. The heat speeds molecular movement, increasing the likelihood of collisions between an enzyme and its substrate. |
The heat speeds molecular movement, increasing the likelihood of collisions between an enzyme and its substrate. |
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Metabolic pathways are relatively uncommon in cells; most biologically significant molecules are obtained intact from a well-balanced diet. True False |
False |
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Only animal cells carry out oxidative phosphorylation. True False |
False |
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ATP synthase is a protein involved in the redox reactions of the electron transport chain. True False |
False |
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The energy source that makes oxidative phosphorylation possible comes from phosphate group transfers from ATP. electrons transferred from NADPH. electrons transferred from NADH. electrons removed from CO2 during its oxidation. |
electrons transferred from NADH. |
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The NADH produced by the Krebs cycle donates electrons to the electron transport chain. True False |
True |
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The process that produces ATP from sugars begins with glycolysis; when fatty acids are used the process begins with oxidative phosphorylation. the Calvin cycle. the electron transport chain. the Krebs cycle. |
the Krebs cycle. |
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The energy carriers NADPH and NADH differ structurally. Functionally they are quite similar; each transports electrons and hydrogen ions released in catabolic pathways. are quite similar; each transports electrons and hydrogen ions to anabolic pathways. are somewhat different; NADPH receives electrons and hydrogen from catabolic processes, whereas NADH delivers those items to anabolic processes. are somewhat different; NADH receives electrons and hydrogen from catabolic processes, whereas NADPH delivers those items to anabolic processes. |
are somewhat different; NADH receives electrons and hydrogen from catabolic processes, whereas NADPH delivers those items to anabolic processes. |
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The figure below is a diagram of the inner mitochondrial membrane. The H+ were pumped across the membrane by the electron transport chain. The H+ were released when ATP phosphorylated a membrane protein. ATP was used to pump the H+ across the membrane. Oxygen must release two H+ in the intermembrane space before it can move into the matrix. |
The H+ were pumped across the membrane by the electron transport chain. |
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The mitochondria of plants contain thylakoids. True False |
False |
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All of the following elements can be found in the photosynthetic intermediary molecules leading to sugar; which element does not remain in the final product? carbon phosphorous hydrogen oxygen |
phosphorous |
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The burning pain in your muscles during strenuous exercise is a result of the buildup of lactic acid during fermentation. signals sent to the nervous system by O2-starved cells. the accumulation of pyruvate in the absence of oxidative phosphorylation. the lack of ATP needed to regulate the pain receptors in your muscle cells. |
the buildup of lactic acid during fermentation. |
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The outcome of the Calvin cycle is the capture of energy from sunlight. synthesis of sugars like glucose, fructose, and sucrose. production of pyruvate. breakdown of complex molecules and the subsequent release of energy. |
synthesis of sugars like glucose, fructose, and sucrose. |
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In mitochondria, the energy released by electrons as they move through the electron transport chain is used to transport electrons from the thylakoid matrix to the cytosol. acetyl CoA into the Krebs cycle. protons into the mitochondrial intermembrane space. pyruvate into the first reaction of glycolysis. |
protons into the mitochondrial intermembrane space. |
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The illustration below indicates that photosynthesis and cellular respiration are both complementary and balanced; the existence of fossil fuels like coal and petroleum suggest in the past, the amount of photosynthesis occurring exceeded the amount of cellular respiration. sugars were only one of several products of photosynthesis. reduced carbon-rich molecules could be produced independently from the photosynthetic process. the energy release from respiration must have exceeded energy use in photosynthesis. |
the energy release from respiration must have exceeded energy use in photosynthesis. |
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Several energy carriers can be found in eukaryotic cells; the most versatile, as indicated in the illustration below, is ATP. NADPH. NADH. FADH2. |
ATP. |
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The inner membrane of a mitochondrion is highly folded. Which of the following explains why this is the case? The folds protect the proteins in the inner membrane from the toxic by-products of cellular respiration. The folds increase the space available for electron transport chains, increasing the efficiency of ATP production. The extra folds make the mitochondrion more efficient at capturing carbon dioxide. The antenna complexes in the inner membrane form clusters that force the membrane into folds. |
The folds increase the space available for electron transport chains, increasing the efficiency of ATP production. |
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Most of the oxidation reactions that produce NADH in a cell take place in the Krebs cycle. glycolysis. photosynthesis. the electron transport chain. |
the Krebs cycle. |
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Which of the following applies to chloroplasts? They have an intermembrane space and a matrix. They have three membrane-enclosed compartments. Unlike mitochondria, they lack a stroma. They carry out both photosynthesis and respiration. |
They have three membrane-enclosed compartments. |
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Several plant pigments have significant antioxidant qualities and can protect a cell from the damage inflicted on its biomolecules by free radicals. True False |
True |
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The ETC in the chloroplast or mitochondrion gradually lower the energy content of an electron as it passes from carrier to carrier, similar to the reduction in energy content of a cannonball that reaches the high point of its flight and then returns to the ground. bowling ball bouncing down a flight of stairs and landing temporarily on each step. pair of sunglasses that intercepts ultraviolet radiation before it reaches your eyes. recently baked pie cooling on the counter before it can be cut and eaten. |
bowling ball bouncing down a flight of stairs and landing temporarily on each step. |
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Examine the illustration below; which statement best summarizes the contribution of Photosystem I (PSI) during photosynthesis? PSI provides the initial energy boost to the electrons on their way to Photosystem II (PSII). PSI generates the excited electrons that initially accumulate within the thylakoid space and eventually drive ATP synthesis. PSI generates the high-energy electrons that are transported by NADPH to the Calvin cycle and will eventually reduce the carbon in CO2. By cycling between reduced and oxidized states, PSI regulates the transmembrane passage of protons between the stroma and the thylakoid space. |
PSI generates the high-energy electrons that are transported by NADPH to the Calvin cycle and will eventually reduce the carbon in CO2. |
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The enzyme rubisco is important to the process of catabolism. fermentation. glycolysis. carbon fixation. |
carbon fixation. |
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The three stages of aerobic catabolism are photosynthesis, glycolysis, and oxidative phosphorylation. glycolysis, the Krebs cycle, and oxidative phosphorylation. glycolysis, fermentation, and the Krebs cycle. photosynthesis, the Krebs cycle, and fermentation. |
glycolysis, the Krebs cycle, and oxidative phosphorylation. |
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The Krebs cycle takes place in the mitochondrial matrix. cytosol. thylakoid membrane. outer mitochondrial membrane. |
mitochondrial matrix. |
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Biologists believe that Earth’s early life-forms were exposed to an atmosphere with no molecular oxygen and had not yet evolved the Krebs cycle. If so, alcoholic fermentation would have been particularly critical to life because without the pathway ethanol would not be available as a nutrient for other consumers. lactic acid would accumulate and disable prokaryotic muscle cells. carbon could not be recycled back into the biosphere for use by producers. the only source of NADH for electron transport would be from glycolysis and ATP production would be greatly reduced. |
carbon could not be recycled back into the biosphere for use by producers. |
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What is the importance of photosynthesis to organisms other than plants? All other organisms require oxygen for life processes. The sugars made during photosynthesis are building blocks of DNA. All cells must have chloroplasts in order to survive. Photosynthesis captures energy that other organisms access when they eat either plants or organisms that eat plants. |
Photosynthesis captures energy that other organisms access when they eat either plants or organisms that eat plants. |