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110 Cards in this Set
- Front
- Back
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What four elements are most abundant in living matter?
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Carbon, oxyben, hydrogen, and nitrogen
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Why is water classified as a compound, but O2 isnt?
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Because water consists of two different elements
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A nitroben atom has 7 protons, and teh most common isotope of nitrogen has 7 neutrons. A radioactive isotope of nitrogen has 8 neutrons. What is the atomic number and mass number of this radioactive nitrogen?
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Atomic number = 7; Mass number = 15
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Why are radioactive isotopes useful as tracers in research on the chemistry of life?
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Organisms incorporate radioactive isotopes of an element into their molecules just as they do the nonraduoactive isotopes, and researchers can detect the presence of the radioactive isotopes.
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Explain what holds together thi ions in a crystal of table salt (NaCl)
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Ionic bonds, the electrical attraction between the Na+ and teh Cl- ions, holds the ions together.
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What is chemically nonsensical about this structure?
H-C=C-H |
Each atom has only three covalent bonds instead of the required four.
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Fill in the blanks with the correct numbers in the followin chemical process:
C6H12O6+_O2 -> _CO2+_H2O |
C6H12O6+6O2 -> 6CO2+6H2O
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Explain why, if you pour very carefully, you can actually "stack" water slightly above the rim of the cup.
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Surface tension due to water's cohesion will hold teh water together until the water it is far enough above the rim for gravity to overcome the cohesion.
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Why is it more dangerous to stay neck-deep in a 105 degree F (41 degree C) hot tub for an hour than it is to sit for an hour outside when the air temperature is 105 degree F (41 degree C)?
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Evaporative cooling in the hot tub is limited to teh skin of teh head and neck
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Explain why ice floats.
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Ice is less dense than liquid water becasue the more stable hydrogen bonds "lock" the molecules in a spacious crystal
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Compared to a basic solution of pH 8, the same volume of an acidic solution at pH 5 has __ times more hydrogen ions (H+)
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1000
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hydroxyl group
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contains OH
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Carbonyl group
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contains C=O
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Amino group
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contains H-N-H
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Carboxyl group
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contains 0=C-OH
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Amino acids contain which functional groups?
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carboxyl and amino groups
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How many molecules of water are required to hydrolyze a polymer that is 100 monomers long?
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99
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Dehydration synthesis
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The adding of a monomer to a polymer chain, releasing one water molecule.
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Hydrolysis
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breaking of a polymer chain by using a water molecule.
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_________ is to polysaccharide as amino acid is to ________
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Monosaccharide (simple sugar); protein (or polypeptide)
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The formula for glucose C6H12)6. What would be the formula for a sugar having just three carbons instead of six?
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C3H6O3
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How do manufactureres produce the high-fructose corn syrup listed as an ingredient on a bottle of soda?
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A commercial process converts glucose in the syrup to the much sweeter fructose.
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Why can't you digest wood?
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Humans lack an enzyme that digests cellulose, the main ingredient of wood.
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On a food package label, what is the meanin of "unsaturated fats"
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Unsaturated fats have less than the maximum hydrogen content. This is because double bonds between carbons in the fatty acids replace some of the bonds between carbon and hydrogen.
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In classifyingthe molecules of life, what do fats and human sex hormones have in common?
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Both fats and sex hormones, which are steroids, are classified as lipids because they are hydrophobic.
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Indicate which of th efollowing is not a protein: an enzyme, hemoglobin, a gene.
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a gene
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In what way id the production of polypeptide similar to the production of a polysacharide?
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Both of these polymers consist of monomers linked by dehydration synthesis
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Why does a denatured protein no longer function?
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Protein function depends on shape, which is altered by denaturation.
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How does an enzyme recognize its substrate?
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The substrate and the enzyme's active site are complementary in shape.
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How does the antibiotic penicillin work?
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It inhibits an enzyme that certain bacteria use to make their cell walls.
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In a double helix, a region along one DNA strand has this sequence of bases: GAATGC. What is the base sequence alon the complementary region of the other strand of the double helix?
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CTTACG
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Which type of microscope would you use to study
(a) the changes in shape of a living human white blood cell; (b) the finest details of surface texture of a human hair (c) the detailed structure of an organelle in the cytoplasm of a human liver cell |
(a)light microscope
(b)scanning election microscope (c)transmission electron microscope |
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Using a light microscope to examine a thin section of a large spherical cell, you find that it is .3 mm in diameter. The nucleus is about one-fourth as wide. What is the diameter of the nucleus in micrometers?
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About 75 micrometers
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How is the nucleoid region of a prokaryotic cell unlike the nucleus of a eukaryotic cell?
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There is no memberane enclosing the DNA of the nucleoid region
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What is the relationship of chromosomes to chromatin?
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Chromosomes are made of chromatin, which is a combination of DNA and proteins. The chromatin fibers in a cell become more compact and recognizable as individual chromosomes during reproduction of the cell.
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What is the function of ribosomes?
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Protein synthesis
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Which structure includes all others in the list: rough ER, smoothe ER, endomembrane system, the Golgi apparatus?
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Endomembrane system
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What makes rough ER rough?
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Ribosomes attached to teh membranes
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What is th relationship of the Golgi apparatus to the ER in a protein-secreting cell?
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The Golgi receives trasport visicles that bud from the ER and that contain proteins synthesized in the ER. The Golgi finishes processing the proteins and then dispatches transport vesicles that secrete the proteins to the outside of the cell.
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How can defective lysosomes result in excess accumulation of a particular compound in a cell?
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If the lysosomes lack and enzyme needed to break dwon the compound, the cell will accumulate an excess of the compound.
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What does photosynthesis accomplish?
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The conversion of light energy to chemical energy stored in food molecules
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What is cellular respiration?
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A process that converts the chemicla energy of sugars and other food molecules to chemical energy in the form of ATP.
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Which component fot he cytockeleton is most important in
(a) holding the nucleus in place within the cell (b)guiding chromosomes during cell division (c)contracting muscle cells |
(a)intermediate filaments
(b)microtubules (c)microfilaments |
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How do cilia and flagella bend?
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Dynein arms, powered by ATP, slide neighboring doublets of microtubules past one another.
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How are the plasmadesmata of plact cells and communicating junctions of animal cells similar in function?
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They both allow the transport of water and other small molecules between neighboring cells in a tissue
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What polysaccharide is the main component of plant cell walls?
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Cellulose
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plasmodesmata
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channels that pass through cell walls connecting plant cells together
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Why do phospholipids tend to organize into a bilayer in an aqueous environment?
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This structure shields the hydrophobic tails of the phospholipids from water while exposing the hydropholic heads to water.
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Explain why it is not enough just to say that a solution is "hypertonic."
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Hypertonic and hypotonic are relatice terms: A solution that is hypertonic to tap water could be hypotonic to seawater. In using these terms, you muct provide a comparison, as in "The solution is hypertonic to the cell."
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What is the energy source for active transport.
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ATP
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Explain how a protein-secreting cell can synthesize and secrete its product without the protein ever having to cross a membrane.
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From the time the protein is made by rough ER, it is topographically "outside" the cell, first in the ER interior, then within the GOlgi and transport vescicles, and finally outside the plasma membrane as the vesicles release their contents by exocytosis
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Explain how a person can have an excessive cholesterol level in the blood even without producing or eating more cholesterol than otehr people.
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The person may have an impariment in teh ability of cells to remove cholesterol from teh blood becasue of teh absense or shortage fo LDL receptors on liver cell plasma membranes
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The hormone epinephrine can cause a liver cell to break down its stored glycogen and release sugar without the hormone even entering the cell. Explain.
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Epiniphrine binds to a receptor on teh liver cell surface, activating a signal transduction pathway inside the cell that leads to sugar release.
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Rough ER
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Production of new membrane and secretory proteins
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Smooth ER
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Synthesis of lipids, including steroids.Detoxification.
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Golgi Apparatus
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finishes, stores, and distributes chemical products of teh cell.
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What are the chemical ingredients for photosynthesis?
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Carbon dioxide and water
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Why are plants called producers?
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They produce organic molecules by photosynthesis.
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What is misleading about the following statement? "Plants do photosynthesis and animals do cellular respiration."
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it implies that cellular respiration does not occur in plants. It does.
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How can an object at rest have energy?
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It can have potential energy because of its location.
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Describe the energy transformations that occur when you climb to the top of a stairway.
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You convert the chemical energy of food to the kinetic energy of your upward climb. At the top of the stairs, some of the energy has been stored as potential energy becasue of your higher elevation. The rest has been converted to heat.
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Which form of energy is the most randomized and the most difficult to put to useful work?
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Heat energy
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How is your breathing related to your cellular respiration?
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In breathing, your lungs exchange CO2 and O2 between your body and teh atmosphere. In cellular respiration =, your cells consume )2 in extracting energy from food and release CO2 as a waste product.
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In teh following redox reaction, which compound is oxidized and which is reduced?
C4H6O5=NAD+ -> C4H4O5+NADH+H+ |
C4H6O5 is oxidized and NAD+ is reduced
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At the "downhill" end of the electron transport chain, when electrons from NADH are finally passed to oxygen, what waste product of cellular respiration is produced?
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Water
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The oxidation of acetic acid by NAD+ extracts some chemical energy from the acetic acid. How can the cell harness that energy to make ATP?
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The NADH can supply electrons to teh electron transport chain, which generates a hydrogen ion gradient that drives ATP synthesis.
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Of the three stages of cellular respiration, which occurs in teh cytosol, outside mitochondria?
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Glycolysis
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A glucose-fed yeast cell is moved from an aerobic environment to an anaerobic one. If the cell continues to generate ATP at the same rate, how will its rate of glucose consumption compare with its consumption in teh aerobic environment?
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The cell must consume glucose at a rate of about 19 times the consumption rate in the aerobic environment (2 ATPs by fermentation versus 38 ATPs by cellular respiration.)
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_______acid is to human muscle as ethyl _______ is to yeast.
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Lactic; alcohol
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Although they are "self-feeders," autotrophs are not totally self-sufficient. What do they require from the environment in order to synthesize sugar.
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Light, carbon dioxide, and water
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Why are heterotrophs called consumers
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Becasue they must acquire organic material by consuming it rather than making it
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For chloroplasts to produce sugar from CO2 in teh dark, they would require and artificial supply of _____ and ______.
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ATP and NADPH
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For each CO2 molecule it consumes, how many O2 molecules does a plant release to the atmosphere?
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one
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Compared to a solution of isolated cholophyll, why do intact chloroplasts release less heat and fluorescene whe illuminated?
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Int eh chloroplasts, the light-excited electrons are trapped by a primary electron acceptor rather than immediatly giving up all their energy as heat and light.
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Why is water required as a reactant in photosynthesis?
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It is teh splitting of water that provides electrons for converting CO2 to sugar (via electron transfer by NADPH)
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In addition to conveying electrons from teh water splitting photosystem to teh NADPH-producing photosystem, the electron transport chains of chloroplasts also provide the energy for synthesis of ___.
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ATP
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In terms of the spatial organization of photosynthesis within the chloroplast, what is teh advantage of the light reactions producing Nadph and ATP on teh stroma side of teh thylakoid membrane?
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The Calvin cycle, which consumes NADPM and ATP, occurs in teh stroma
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What is the function of NADPH in the Calvin Cycle?
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It provides the high-energy electrons for teh reduction of CO2 to form sugar
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Explain the greenhouse effect.
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Atmospheric carbon dioxide allows sunlight thorugh, which heats Earth's surface, but the carbon dioxide slows the escape of the heat back into space.
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How might the combustion of fossil fuels and wood be contributing to global warming?
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By raising concentrations of atmospheric CO2, and increasing the greenhouse effect.
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Describe the energy transformations that occur when you climb to the top of a stairway.
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You convert the chemical energy of food to the kinetic energy of your upward climb. At the top of the stairs, some of the energy has been stored as potential energy becasue of your higher elevation. The rest has been converted to heat.
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Which form of energy is the most randomized and the most difficult to put to useful work?
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Heat energy
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How is your breathing related to your cellular respiration?
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In breathing, your lungs exchange CO2 and O2 between your body and teh atmosphere. In cellular respiration =, your cells consume )2 in extracting energy from food and release CO2 as a waste product.
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In teh following redox reaction, which compound is oxidized and which is reduced?
C4H6O5=NAD+ -> C4H4O5+NADH+H+ |
C4H6O5 is oxidized and NAD+ is reduced
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At the "downhill" end of the electron transport chain, when electrons from NADH are finally passed to oxygen, what waste product of cellular respiration is produced?
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Water
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The oxidation of acetic acid by NAD+ extracts some chemical energy from the acetic acid. How can the cell harness that energy to make ATP?
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The NADH can supply electrons to teh electron transport chain, which generates a hydrogen ion gradient that drives ATP synthesis.
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Of the three stages of cellular respiration, which occurs in teh cytosol, outside mitochondria?
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Glycolysis
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A glucose-fed yeast cell is moved from an aerobic environment to an anaerobic one. If the cell continues to generate ATP at the same rate, how will its rate of glucose consumption compare with its consumption in teh aerobic environment?
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The cell must consume glucose at a rate of about 19 times the consumption rate in the aerobic environment (2 ATPs by fermentation versus 38 ATPs by cellular respiration.)
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_______acid is to human muscle as ethyl _______ is to yeast.
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Lactic; alcohol
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Although they are "self-feeders," autotrophs are not totally self-sufficient. What do they require from the environment in order to synthesize sugar.
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Light, carbon dioxide, and water
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Why are heterotrophs called consumers
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Becasue they must acquire organic material by consuming it rather than making it
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For chloroplasts to produce sugar from CO2 in teh dark, they would require and artificial supply of _____ and ______.
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ATP and NADPH
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For each CO2 molecule it consumes, how many O2 molecules does a plant release to the atmosphere?
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one
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Compared to a solution of isolated cholophyll, why do intact chloroplasts release less heat and fluorescene whe illuminated?
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Int eh chloroplasts, the light-excited electrons are trapped by a primary electron acceptor rather than immediatly giving up all their energy as heat and light.
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Why is water required as a reactant in photosynthesis?
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It is teh splitting of water that provides electrons for converting CO2 to sugar (via electron transfer by NADPH)
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Describe the energy transformations that occur when you climb to the top of a stairway.
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You convert the chemical energy of food to the kinetic energy of your upward climb. At the top of the stairs, some of the energy has been stored as potential energy becasue of your higher elevation. The rest has been converted to heat.
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Which form of energy is the most randomized and the most difficult to put to useful work?
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Heat energy
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How is your breathing related to your cellular respiration?
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In breathing, your lungs exchange CO2 and O2 between your body and teh atmosphere. In cellular respiration =, your cells consume )2 in extracting energy from food and release CO2 as a waste product.
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In teh following redox reaction, which compound is oxidized and which is reduced?
C4H6O5=NAD+ -> C4H4O5+NADH+H+ |
C4H6O5 is oxidized and NAD+ is reduced
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At the "downhill" end of the electron transport chain, when electrons from NADH are finally passed to oxygen, what waste product of cellular respiration is produced?
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Water
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The oxidation of acetic acid by NAD+ extracts some chemical energy from the acetic acid. How can the cell harness that energy to make ATP?
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The NADH can supply electrons to teh electron transport chain, which generates a hydrogen ion gradient that drives ATP synthesis.
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Of the three stages of cellular respiration, which occurs in teh cytosol, outside mitochondria?
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Glycolysis
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A glucose-fed yeast cell is moved from an aerobic environment to an anaerobic one. If the cell continues to generate ATP at the same rate, how will its rate of glucose consumption compare with its consumption in teh aerobic environment?
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The cell must consume glucose at a rate of about 19 times the consumption rate in the aerobic environment (2 ATPs by fermentation versus 38 ATPs by cellular respiration.)
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_______acid is to human muscle as ethyl _______ is to yeast.
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Lactic; alcohol
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Although they are "self-feeders," autotrophs are not totally self-sufficient. What do they require from the environment in order to synthesize sugar.
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Light, carbon dioxide, and water
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Why are heterotrophs called consumers
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Becasue they must acquire organic material by consuming it rather than making it
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For chloroplasts to produce sugar from CO2 in teh dark, they would require and artificial supply of _____ and ______.
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ATP and NADPH
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For each CO2 molecule it consumes, how many O2 molecules does a plant release to the atmosphere?
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one
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Compared to a solution of isolated cholophyll, why do intact chloroplasts release less heat and fluorescene whe illuminated?
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Int eh chloroplasts, the light-excited electrons are trapped by a primary electron acceptor rather than immediatly giving up all their energy as heat and light.
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Why is water required as a reactant in photosynthesis?
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It is teh splitting of water that provides electrons for converting CO2 to sugar (via electron transfer by NADPH)
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