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162 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Which of the following is true of a control group in a scientific experiment? (level 1)
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It is treated exactly like the experimental group, except for the one variable being tested.
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What is the main reason for including a control group in the design of an experiment? (level 1)
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To ensure that the results are due to a difference in only one variable.
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When designing his experiments on spontaneous generation, Pasteur repeated his experiments many times. He did this to ...(level 1).
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reduce the likelihood that his results happened by chance.
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Which of the following is a definition of science according to a "scientist"? (level 1).
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Science is a method or way of learning about the natural world.
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People who are uninformed about evolution may state that it is "just a theory." What they often mean is that it is simply a "hunch"; an unproven and little-supported notion about the nature of life on Earth. This statement is not accurate because ...(level 1).
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in science, a theory is a set of principles that is supported by a large body of evidence. Therefore, evolution is more than just a "hunch."
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Which of the following sequences represents the structural organization of an organism? (level 1).
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organelle - cell - tissue - organ - organism
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Which of the following statements might Pasteur have made concerning his experiments on spontaneous generation? (level 2).
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"My experiments support the notion that living organisms only come from preexisting living organisms."
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Which hypothesis concerning Pasteur's work is stated correctly? (level 2)
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If living material fails to grow in the flasks with dust trap necks, then this supports the notion that living material will grow only in the flasks lacking the dust trap necks.
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Probability and statistics are important tools of science because ...(level 1).
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they help scientists distinguish between events that occur by chance versus those that have a definite cause.
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Which of these statements about scientific theories is most accurate? (level 1)
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A scientific theory is supported by many independent observations and experiments.
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Which of these levels of organization WOULD NOT be found in all living things? (level 2).
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tissue
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The term homeostasis refers to ...(level 1)
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the maintenance of a relatively constant body environment.
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A well-controlled experiment will ...(level 2).
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have only one critical variable that is changed over several trials.
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In order for a hypothesis to be valid, it must ...(level 2).
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be falsifiable (open to negation by scientific experiments).
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Why is a "pet rock"--not really a valid pet? (level 2)
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because it does not respond to its environment.
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In the early 1800s, scientists who studied living things changed from being "naturalists," and became more like modern-day "biologists." What was the major factor that determined this change? (level 2).
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Life scientists began to describe the rules of the living world, instead of just describing the forms in the living world.
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Staring out the window one day, you notice a line of ants crawling across the sidewalk. The line leads to a wet spot on the sidewalk and then back to the anthill in the ground. You start to wonder what the ants find so attractive about that wet spot. If you were following the scientific method of investigation, your next step would be to ... (level 1)
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form several possible hypotheses to explain what attracts the ants.
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Which of the following statements best describes the nature of a scientific hypothesis?
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A hypothesis must be testable through experimentation, observation, or mathematical demonstration.
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A theory, as used in scientific discourse, is
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A set of principles, supported by evidence, that explains some aspect of nature
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Pasteur's experiments on spontaneous generation made correct use of a variable in that Pasteur
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held all conditions constant in each test except one
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Evolution is a central, unifying theme in biology because
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The enormously diverse forms of life on Earth have all been shaped by it.
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Biologists generally define life in terms of a group of characteristics possessed by living things. Which of the following is not a characteristic of living things?
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All living things are composed of two or more cells.
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Which of the following is formed by the sharing of electrons between two atoms that do not differ in electronegativities? (level 1).
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a nonpolar covalent bond
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Which of the following is the bond formed between the oxygen atom and the two hydrogen atoms in a molecule of water? (level 1).
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polar covalent bonds
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The drawings of atoms in your text are actually based on the "planetary model" of what an atom looks like. If a three-dimensional model of an atom could be constructed that was as big as the room you are sitting in, most of the atom's volume would be occupied by ...(level 2).
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empty space.
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In an atom that has not undergone any type of chemical reaction, the number of electrons ...(level 2).
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is always equal to the number of protons.
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The primary reason that atoms form chemical bonds is so they can ...(level 2).
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move into a more stable energy state.
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Protons and neutrons are said to have a mass of approximately 1 dalton each. Recall that electrons are thought to have virtually no mass. Therefore, a hydrogen atom (with an atomic number of 1) would have a mass of approximately 1 dalton, and an oxygen atom (with an atomic number of 8) would have a mass of approximately 16 daltons. How much mass would one molecule of water have? (level 1).
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18 daltons
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Look carefully at the following chemical equation. What is incorrect about this equation? 3 C + 16 H -----> 3 CH4 (level 2).
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There are 16 H on the left side of the equation and only 12 H on the right side of the equation.
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Nitric oxide is a common type of "free radical" found in human cells. Free radicals are defined as ...(level 1).
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a molecule that contains an atom that has an unpaired electron.
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When you pour salt into water and stir, the salt will disappear. Which of the following statements is true concerning this phenomenon? (level 1).
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Water is a good solvent for polar molecules.
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Before the nature of atoms was known, many men (known as alchemists) tried to turn iron into gold. However, none of them ever succeeded. If you could truly turn iron into gold, how would you do it? (level 2).
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by inserting protons into the nuclei of the iron atoms
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The identity of a chemical element is determined by ... (level 1).
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the number of protons in the nucleus.
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Tritium is an isotope of hydrogen that contains three subatomic particles in its nucleus. The three particles are ... (level 1).
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one proton and two neutrons.
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Salt molecules dissolve in water because ... (level 2).
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they have atoms with charges on them.
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The primary elements that are used to build the human body are ... (level 1).
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carbon, oxygen, and hydrogen.
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If an atom has an atomic number of 7, how many electrons would be in the atom's outer shell? (level 1).
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5
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In the formation of a salt molecule (NaCl) ... (level 1).
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Na loses its outer-shell electron and becomes a positive Na ion.
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Some molecules are known as "signals" because they signal the beginning of certain cellular functions. In order for a signal to do its job though, it must bind to a specific "receptor" on the cell's surface. What is the most critical factor in signal/receptor binding? (level 2).
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The shapes of both the signal and the receptor are critical.
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The following is the chemical formula for the molecule carbon dioxide: O=C=O. The two lines that connect each oxygen atom to the one carbon atom represent ...(level 2).
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two shared pairs of electrons.
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Suppose that you are reviewing for a test, and some fellow students say that the equation for photosynthesis is 6CO2 + H2O → C6H12O6 + 6O2. How would you reply?
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The way this equation is written violates the law of the conservation of matter.
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Neon used to be called an inert gas. Thus it
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has a filled outer shell.
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Oxygen and hydrogen differ in their electronegativity. Thus
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They can share electrons, but unequally.
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A molecule that does not have a net electrical charge at one end as opposed to the other is:
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a nonpolar molecule
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You add sugar to black coffee, and the sugar dissolves. Thus the coffee is the _____ and the sugar is the _____.
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solvent
solute
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The two strands of a DNA molecule are held together because large numbers of hydrogens that are covalently bonded to oxygen or nitrogen in one strand are weakly attracted to oxygens or nitrogens in the opposite strand. Therefore the two strands of DNA are held together by
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hydrogen bonds
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While baking cookies for a friend, you're having a hard time keeping your roommate from eating them because the smell is driving her wild. She is able to smell the cookies because the molecules wafting from them
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have a shape that allows them to bind to receptors in her nose
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The water molecule has the ability to dissolve many substances. What characteristic makes it such a versatile solvent? (level 1).
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The water molecule is polar.
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If three molecules of a fatty acid, each having the formula C16H22O2, were joined to a molecule of glycerol (C3H8O3), the resulting molecule would have the formula ... (level 2)
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C51 H68 O6
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For each chemical reaction linking a fatty acid to a glycerol, a water molecule is lost.
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Which of the following is true of the fatty acid C16H22O2? (level 1).
unsaturated or saturated |
unsaturated
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A 16-carbon fatty acid would have to have 32 hydrogens to be saturated. Remember that carbon always forms four bonds.
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Why are most organic molecules based on the carbon atom? (level 2).
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Correct: Carbon can form covalent bonds with four other atoms; therefore, organic molecules can be very complex.
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Which level of protein structure is ultimately responsible for the shape of a protein? (level 2).
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Correct: primary
The sequence of amino acids ultimately determines the shape of a protein. |
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Acid rain affects the pH of freshwater streams and creeks far more than it does the saltwater marsh creeks. What might account for this difference? (level 2)
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Correct: the presence of pH buffers in saltwater marshes
Correct. Seawater possesses a buffer (bicarbonate), which prevents drastic fluctuations in pH. |
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What is the highest level of protein structure exhibited by the functional hemoglobin molecule, a molecule composed of four separate protein chains? (level 1).
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Correct: quaternary
Correct. Quaternary structure is seen only in those proteins that combine with other proteins to achieve their full functionality. |
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What complex carbohydrates is a form of stored energy in plants? (level 1.)
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Correct: starch
Correct. Starch is the way that plants store the high-energy molecule glucose. |
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Which of the following lipid molecules is NOT a steroid? (level 1).
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Correct: stearic acid
Correct. Stearic acid is a type of fatty acid, not a steroid. |
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What is NOT part of a nucleotide's molecular structure? (level 1).
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Correct: a buffer
Correct. Buffers are used to maintain proper pH within a solution. |
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What structure refers to a sequence of amino acids coiling into a helix or folding into pleats as a result of electrochemical bonding and repulsion forces operating on the amino acids? (level 1).
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Correct: secondary structure
Correct. Forces acting primarily on the R-groups push the amino acid sequence into these common shapes. |
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Hydrophilic molecules are attracted to water because ... (level 1).
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Correct: they have atoms with charges on them.
Correct. Atoms that have charges are attracted to the partial positive and negative charges found in the water molecule. |
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Which of the major types of biological molecules does NOT consist of monomers and polymers? (level 2).
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Correct: lipids
Correct. Although some lipids are created by the combination of similar molecules (triglycerides), others are not (steroids). |
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When amino acids are joined together to form a polypeptide chain, a waste molecule is given off as a result of this chemical reaction. What is this "waste" molecule? (level 2).
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Correct: water
Correct. One -H and one -OH are removed and combined to form one molecule of water. |
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Why are phospholipids said to have a "dual nature"? (level 2).
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Correct: because they are part hydrophilic and part hydrophobic
Correct. Because they have both natures, they can exist at the border between these two conditions. |
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Nucleotides are used for several functions in cells. Which of the following is NOT a correct function for a nucleotide? (level 1).
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Correct: used to build plant cell walls
Correct. Plant cell walls are built of carbohydrates, not nucleotides. |
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Near an ocean or other large body of water, air temperatures do not vary as much with the seasons as they do in the middle of a continent. This tendency of water to resist changes in temperature is the result of water's
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Your Answer:
high specific heat |
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A frog survives a freezing-cold winter on the bottom of a pond because
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Your Answer:
Ice, which floats on water, insulates the water beneath it. |
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Janine has dry skin, so she uses body oil every morning. The oil seals in some of the water on her skin, so that it doesn't get as dry. This is possible because oils:
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Your Answer:
are hydrophobic |
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Detergent added to water disrupts the network of hydrogen bonds between water molecules. One way entomologists (biologists who study insects) trap bees for population surveys is to place a tray of sugar water in the field to which they add a few drops of detergent. The bees are attracted to the sugar water and they land on its surface. Why do these investigators bother adding detergent when they know its sugar that bees are attracted to?
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Your Answer:
Bees will sink into water with fewer hydrogen bonds, and so cannot escape. |
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When you eat starch such as spaghetti, an enzyme in your mouth breaks it down to maltose. Eventually, the maltose enters your small intestine, where it is broken down to glucose, which you can absorb into your bloodstream. The starch is a _____, the maltose is a _____, and the glucose is a(n) _____.
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Your Answer:
polysaccharide disaccharide monosaccharide |
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In some vintage science fiction movies space travelers find themselves on a planet orbiting a distant star in which there are curious forms of life based on silicon instead of carbon. Although the story clearly is sci-fi, there is an aura of plausibility in the choice of silicon, an atom with 14 protons, in place of carbon as this alien life-form's central atom. This is because silicon:
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Your Answer:
has 4 electrons in its outer-most shell. |
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The myoglobin protein, which carries oxygen in muscle cells, has only the first three levels of protein structure. In other words, it lacks a quaternary level. From this you can conclude that myoglobin
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Your Answer:
is made of only one polypeptide chain |
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You received your genetic information from your parents in the form of DNA. This DNA carried the instructions for making
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Your Answer:
proteins |
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John is lactose intolerant. The -ose ending indicates that John cannot digest a certain
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Your Answer:
sugar |
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Which of the following statements concerning prokaryotes and eukaryotes is probably valid? (level 2).
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Your Answer:
Mitochondria are about the same size as a prokaryotic cell. |
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Which of these organisms usually requires oxygen to live? (level 1).
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Your Answer:
eukaryotes |
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Which were probably the first living cells to appear on Earth? (level 1).
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Your Answer:
prokaryotes |
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Which of these organisms can be unicellular? (level 2).
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Your Answer:
both prokaryotes and eukaryotes |
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Which of the following best summarizes the movement of a protein molecule from the time it is formed until it is secreted from the cell? (level 1).
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Your Answer:
ribosome --> rough ER --> Golgi body --> transport vesicle --> plasma membrane |
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Many antibiotics kill bacteria because they hamper the function of prokaryotic ribosomes. Which of the following cellular processes is directly altered by antibiotics? (level 2).
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Your Answer:
synthesis of proteins |
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The cells of the pancreas secrete large amounts of insulin into the bloodstream. Where are these proteins synthesized? (level 1).
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Your Answer:
rough ER |
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The membrane of which organelle is perforated with pores that regulate the passage of large molecules such as mRNA? (level 1).
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Your Answer:
nucleus |
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Which organelles are very prevalent in cells that secrete steroid sex hormones such as cells of the ovaries and testes? (level 2).
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Your Answer:
smooth ER |
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The primary function of the nucleolus is to ... (level 2).
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Your Answer:
protect the DNA and produce ribosomes. |
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The organelle that is responsible for sorting and shipping proteins to the appropriate places in the cell is the ... (level 1).
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Your Answer:
Golgi apparatus. |
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The organelle responsible for energy production is the ... (level 1).
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Your Answer:
mitochondrion. |
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Which of the following organelles is NOT found in plant cells? (level 2).
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Your Answer:
lysosome |
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Which of the following cell structures is NOT found in animal cells? (level 1).
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Your Answer:
cell wall |
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Which of the following organelles contains digestive enzymes? (level 1).
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Your Answer:
lysosome |
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What is the primary reason that most cells are small? (level 2)
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Your Answer:
to maximize the surface-area-to-volume ratio |
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Which of these molecules is a product of photosynthesis that occurs inside plant chloroplasts? (level 2)
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Your Answer:
oxygen |
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Which of these cytoskeletal filaments is primarily responsible for anchoring the organelles inside the cell's cytoplasm? (level 1).
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Your Answer:
intermediate filaments |
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In the following list, which is the smallest structure? (level 2).
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Your Answer:
protein |
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Evolution is an underlying theme in biology. It ties all other themes in biology together because ... (level 2) [Hint]
1) it explains the diversity of life on this planet. 2)it explains why distantly related organisms sometimes resemble one another. 3) it explains how organisms become adapted to their environment. 4) it explains why related organisms have characteristics in common. 5) All of the above are correct. |
All of the above are correct.
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Which of the following is true of hypotheses? (level 1). [Hint]
1) They are subject to refinement. 2) They must be testable. 3) They are provisional. 4) They should be falsifiable. 5) All of the above are correct. |
All of the above are correct.
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Every person should become more scientifically literate because ... (level 2). [Hint]
1) it could help you make critical decisions concerning you or your family's health. 2) it could help you make informed decisions about public policy. 3) science and technology help us understand our world. 4) science and technology will continue to have a great impact on every person's life. 5) All of these choices are correct. |
All of these choices are correct.
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When a water molecule is formed ...(level 2). [Hint]
1) two covalent bonds are formed between one oxygen and two hydrogens. 2) the oxygen atom takes on a partial negative charge and the hydrogen atoms take on a partial positive charge. 3) two atoms of hydrogen share electrons with an oxygen atom. 4) All of the above are correct. |
All of the above are correct.
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Free radicals are potentially damaging atoms or molecules that are created in our cells during metabolic processes. They initiate damage to our bodies by ...(level 1). [Hint]
1) damaging the mitochondria in our cells, which may result in the aging of our bodies. 2) producing mutations in our DNA, which can lead to cancer. 3) irritating and scarring artery walls, causing artery-clogging fatty deposits to develop. 4) All of the above are correct. |
All of the above are correct.
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Carbon is an element with an atomic number of 6. Based on this information, which of the following statements is true? (More than one may be true.)
a. Carbon can be broken down into simpler component substances. b. Carbon cannot be broken down into simpler component substances. c. Each carbon atom will always have 6 neutrons. d. Each carbon atom will always have 6 protons. e. Protons + electrons = 6 f. Both b and d are true. |
Both b and d are true.
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Which of the following have the carboxyl (carboxylic acid) functional group as part of their chemical structure? (level 1). [Hint]
a amino acids b fatty acids c acid rain d both A & B e all of the above |
both A & B
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A chemical "buffer" ... (level 2). [Hint]
a is utilized in living systems to maintain correct pH. b can absorb a H+ when the solution becomes too acidic. c can donate a H+ when the solution becomes too basic. d All of the above are correct. |
All of the above are correct.
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Of the following numbers, which would indicate the highest concentration of H+? (level 1). [Hint]
pH 1 pH 7 pH 14 pH 4 pH 10 |
pH 1
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Which of the following cell structures is NOT an extension of the cell's cytoskeleton? (level 1). [Hint]
a flagella b cilia c pseudopodia d All of the above ARE extensions of the cell's cytoskeleton. |
All of the above ARE extensions of the cell's cytoskeleton.
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Jerome has strep throat, a bacterial infection. The cause of the infection is
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Your Answer:
prokaryotic cells |
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Where would you expect to find a cytoskeleton?
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Your Answer:
throughout the cytosol |
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Suppose Dr. Hyde found a cell that had many mitochondria, a nucleus, a cell wall made of cellulose, and an endoplasmic reticulum, as well as many other parts. He might assume that he has found
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Your Answer:
a plant cell |
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Cells in the pancreas manufacture large amounts of protein. Which of these would you expect to find a large amount of, or number of, in pancreatic cells?
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Your Answer:
rough endoplasmic reticulum |
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Suppose that a cell could be seen to lack intermediate filaments. Which of these would be the most likely effect of this condition?
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Your Answer:
a tendency for the nucleus and organelles in the cell to drift around inside the cell |
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Heart muscle cells have a number of gap junctions connecting them to their adjoining cells. From this you can conclude that heart muscle cells
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Your Answer:
communicate frequently |
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Which is the correct ranking of these “small” things, from smallest to largest? (Use typical sizes.)
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Your Answer:
atoms < amino acids < proteins < bacteria < animal cells |
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Cells need large amounts of ribosomal RNA to make proteins. The ribosomal RNA is made in a specialized structure known as _____, which is found in _____.
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Your Answer:
the nucleolus the nucleus |
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Many antibiotics work by blocking the function of ribosomes. Therefore, these antibiotics will:
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Your Answer:
block protein synthesis |
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Which of the following statements concerning membrane proteins is incorrect? (level 1).
a They often require ATP to actively transport materials across the membrane against a concentration gradient. b They may be receptor proteins that bind specific molecules from the surrounding solution, which triggers endocytosis (i.e., receptor-mediated endocytosis). c They can act as a channel, allowing the transport of ions across the membrane. d They often facilitate diffusion of molecules across the membrane that otherwise would diffuse too slowly to be of use to the cell. e They are usually not particular about what types of chemicals they will allow to cross the membrane. |
Your Answer:
They are usually not particular about what types of chemicals they will allow to cross the membrane. |
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What is the significance of selective permeability to biological membranes?
a Selective permeability allows cells to concentrate particular ions on either side of the membrane. b Selective permeability permits the selective uptake of nutrients and the elimination of wastes. c Selective permeability prevents toxic materials from entering the cell. d Selective permeability allows the plasma membrane to control traffic into and out of the cell it surrounds. e All of the above are correct. |
All of the above are correct.
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The movement of molecules across a membrane against their concentration gradient, at the expense of ATP energy, is called ... (level 1)
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Your Answer:
active transport. |
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Just as with most liquids, the fluid lipid bilayer can solidify and freeze at very cold temperatures. However, there are certain kinds of fish that live in very cold water. The cell membranes of these fish are likely to have more of which of the following membrane components than would a fish that occupies warmer waters? (level 2).
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Your Answer:
cholesterol |
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The activity of the sodium/potassium pump is critically important in maintaining proper ion concentrations across the cell membrane. Which of these steps is necessary in the pumping activity of this protein? (level 2). [Hint]
a The pump changes shape. b The pump releases its energy and changes back to its original shape. c The pump is energized with ATP. d Three sodium ions in the cytoplasm bind with the pump. e Two potassium ions in the extracellular fluid bind with the pump. f All of the above are critical steps in the activity of the pump. |
Your Answer:
All of the above are critical steps in the activity of the pump. |
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Which of the following types of transport does NOT require the use of a transport protein? (level 1).
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Your Answer:
simple diffusion |
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What do you think would happen to an animal cell that was placed into a drop of 100% pure water? (level 2)
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Your Answer:
The cell will swell up and eventually burst. |
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In the process of diffusion ... (level 1).
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Your Answer:
molecules move from an area of greater concentration to an area of lesser concentration. |
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Materials that are too large to move out of the cell through either the lipid bilayer or a transport protein must be moved out through the process of ...(level 1).
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Your Answer:
exocytosis. |
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Large food particles, or perhaps whole organisms, can be engulfed and pulled into the cell by the process of ... (level 1).
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Your Answer:
phagocytosis. |
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Many of the proteins that are associated with the cell membrane are said to be "integral" proteins. An integral protein is defined as a protein that is ... (level 1).
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Your Answer:
bound to the hydrophobic portion of the lipid bilayer of the membrane. |
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Of the four primary functions of membrane proteins, which one does NOT require that the protein be in contact with the extracellular fluid? (level 1). [Hint]
a communication proteins b transport proteins c recognition proteins d structural proteins |
Your Answer:
structural proteins |
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Which of the following molecules or ions would normally need to use a membrane protein in order to move through the cell membrane? (level 2).
a CO2 b O2 c H+ d H2O |
Your Answer:
H+ |
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Which of the following processes uses a difference in concentration (or concentration gradient) to transport molecules across the cell membrane? (level 2) [Hint]
a osmosis b simple diffusion c facilitated diffusion d all of the above |
all of the above
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If the plasma membrane lacked a glycocalyx, the cell would have difficulty
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Your Answer:
adhering to other cells |
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You eat spaghetti for dinner and digest the starch in it to glucose. The glucose is now in high concentration in the cells of your small intestine, relative to its concentration in your bloodstream. Predictably, the glucose diffuses across the plasma membrane of your intestinal cells, into your bloodstream.
a true b false |
true
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When a human cell is placed into water, it swells. This is said to be due to osmosis. What's happening to make the cell swell?
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Your Answer:
Water is diffusing across the plasma membrane from a region of lower solute concentration (outside the cell) to a region of higher solute concentration (inside the cell). |
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Tyrone gave Lakeisha a rose for the anniversary of their first date. Now the rose has wilted, because
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Your Answer:
The plant's cells have insufficient water in them to push against their cell walls. |
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The protein that functions in the sodium-potassium pump is an integral protein. The word integral tells you that this protein
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Your Answer:
is connected to the hydrophobic interior of the plasma membrane |
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You get a cut on your finger and some bacteria enter. Your immune-system cells kill off the invaders by ingesting them. This is an example of
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Your Answer:
phagocytosis |
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According to the fluid-mosaic model of membrane structure, the membrane is made up of a
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Your Answer:
bilayer of phospholipids with proteins interspersed in it that have fairly free lateral movement |
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Calcium ions (Ca++) are present in the endoplasmic reticulum at 1000-fold higher concentrations than in the cytosol (the gel-like material of the cell outside of organelles). One protein on the endoplasmic reticulum membrane is devoted to allowing Ca++ to move from the endoplasmic reticulum to the cytosol and another protein moves Ca++ from the cytosol to the endoplasmic reticulum. These processes are not trivial, as Ca++ released into the cytosol allows such things as muscle contraction and communication between nerve cells. In this pair of Ca++ transport proteins, you would predict that the protein moving Ca++ from the endoplasmic reticulum to the cytosol _____ and the protein that moves Ca++ from cytosol to the endoplasmic reticulum _____.
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Your Answer:
works without ATP; requires ATP |
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Endocytosis and exocytosis are similar in that both involve the use of
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Your Answer:
vesicles that carry materials into and out of the cell |
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Osmosis refers to the net movement of _____ across a _____
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Your Answer:
water semipermeable membrane |
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The hypothetical biochemical reaction A + B --> C + D requires 7.2 kcal/mole of energy to proceed. Could this reaction be coupled with the reaction ATP --> ADP + P (releases 7.2 kcal/mole of energy)? (level 2).
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Correct: No, because some of the energy liberated in the reaction involving ATP is released as heat.
Correct. This is the second law of thermodynamics. |
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Cells probably regulate enzyme activity in all of the following ways except ... (level 2).
a producing two or more molecules that compete with the substrate for the active site on a given enzyme, thereby blocking or slowing down enzyme activity. b denaturing an enzyme, thereby slowing down or stopping enzyme activity. c utilizing the end product of the biochemical pathway in which the enzyme is involved to inactivate an enzyme. |
Correct: denaturing an enzyme, thereby slowing down or stopping enzyme activity.
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Which of the following is important in determining enzyme function? (level 2).
a its amino acid sequence b its surface geometry c temperature d the chemical makeup of the active site e All of the above are important in determining function. |
Correct: All of the above are important in determining function.
Correct. All of the above play a significant role in the functions of an enzyme. |
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As biological catalysts, how do enzymes lower the activation energy of a reaction? (level 1)
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Correct: by bringing the reactants into proper orientation for the reaction to take place
Correct. Enzymes allow for the electron clouds of molecules to be brought together in the right orientation for them to react. |
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The inhibitor of an enzyme is frequently a molecule that is produced at the end of a biochemical pathway in a cell. This inhibitor binds to the inhibitor site on an enzyme with several active sites, causing a change in the shape of the enzyme. This prevents the normal substrate from binding to all active sites. What process does this describe? (level 2)
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Correct: allosteric regulation
Correct. Allosteric regulation involves changing the shape, and therefore the activity, of an enzyme. |
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According to the laws of thermodynamics, which of the following is NOT possible? (level 2)
a the creation of a system that is 100% energy efficient b the creation of an isolated system whose entropy decreases c the creation of a system that couples an endergonic reaction to an exergonic reaction d the creation of a system that requires a catalyst |
Correct: the creation of a system that is 100% energy efficient
Correct. The second law of thermodynamics states that energy conversions always result in the loss of heat. |
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In any system, what is the term for energy that is not available for doing useful work? (level 1).
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Correct: heat
Correct. Heat is random molecular motion that dissipates to the surroundings. |
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The hydrolysis of ATP is probably coupled to all of the following except ... (level 2).
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Correct: osmosis.
Correct. Osmosis is a passive process. Review Section 5.4. |
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According to the first and second laws of thermodynamics, if the entropy in the universe has increased, then what has happened? (level 2).
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Correct: A transfer or transformation of energy has occurred.
Correct. Energy transformation always results in the loss of some energy as random molecular motion (heat). |
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When energy changes from one form to another, some of the energy that can be used to do work is always lost. The loss of this energy is mostly in the form of ...(level 1).
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Correct: heat energy.
Correct. Although heat energy can be used to do work, more often than not it is simply dissipated away. |
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Many types of "perpetual motion machines" have been invented; however, none of them have ever worked. An example of a simple perpetual motion machine might be as follows: a battery is hooked up to an electrical engine, causing the engine to turn a generator, which recharges the battery. In theory, the machine could be turned on, and it would run forever; however, in reality, it will not. Why? (level 2).
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Correct: Some of the energy will be lost in all of the energy transformations; thus, the battery will eventually run down.
Correct. This is what the second law of thermodynamics makes clear. |
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Which kind of work is exemplified by the contraction of skeletal muscles? (level 1).
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Correct: mechanical work
Correct. Muscle contractions move objects (such as ourselves). This is mechanical work. |
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What type of chemical reaction is correct?
ADP + P + energy --> ATP (level 2). |
Correct. This is most definitely an endergonic reaction.
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Enzymes are critical to life. What is it that enzymes do that is so important? (level 1).
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Correct: Enzymes cause chemical reactions to occur quickly, so that necessary products are available to living things.
Correct. Without enzymes, a living organism would perish waiting for reaction products to be produced. |
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Some enzymes need assistance from other molecules (such as vitamins) in order to facilitate the transformation of chemical reactants into products. These other molecules are collectively referred to as ... (level 1).
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Correct: coenzymes.
Correct. Vitamins are an important kind of coenzyme; however, there are other types. |
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Living things rely on a constant input of energy in order to sustain life. What is the ultimate source of energy for living things on Earth? (level 1).
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Correct: the Sun
Correct. All of Earth's energy supplies have been, and will continue to be, supplied by the Sun. |
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What is activation energy? (level 1).
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Correct: the energy required to initiate or begin a chemical reaction
Correct. Enzymes function by lowering this activation energy, thereby making reactions occur that much faster. |
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Which of the following statements concerning metabolic pathways is correct? (level 2).
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Correct: The product of one enzyme reaction becomes the substrate of the next enzyme in the metabolic pathway.
Correct. This allows for a rapid enzymatic transformation from beginning substrate to final end product. |
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According to the first law of thermodynamics, energy
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Correct: is never lost or gained, but is only transformed
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Each time there is a chemical reaction, some energy is exchanged. According to the second law of thermodynamics, with each exchange
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Correct: Some energy is transformed into heat.
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Your car uses gasoline to fuel the engine. Can you explain why you need a coolant system for you car?
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Correct: it is required to absorb the heat energy when the fuel is combusted
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ATP stores energy in the form of
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Correct: chemical bond energy
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People who are lactose intolerant lack a compound called lactase in their digestive tract. You know that this compound, lactase, is probably a(n)
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Correct: enzyme, because its name ends in -ase.
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Each molecule of ATP stores a good deal of energy because
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Correct: ATP’s third phosphate group exists in a highly energetic state
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Which of the following will lower the activation energy of a reaction in a cell?
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Correct: using an enzyme
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The active site of enzyme A is occupied by a molecule other than its substrate. Enzyme B has had its activity reduced by means of a molecule binding to it at a site other than its active site. What is taking place in connection with enzyme A and then enzyme B?
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Correct: competitive inhibition, allosteric regulation
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Glycolysis is a metabolic pathway that helps living things extract energy from food. From this we know that glycolysis
a proceeds by means of each enzyme leaving a succeeding reaction to a different enzyme b uses a number of enzymes c involves the modification of a series of substrates d consists of a series of chemical reactions e all of the above |
all of the above
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Enzymes
a are not chemically altered by binding with a substrate b lower the activation energy of specific chemical reactions c accelerate specific chemical reactions d a and c only e all of the above |
all of the above
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