Pregunta 1
Pregunta
Testosterone, a lipid-soluble signaling molecule, crosses the membranes of cells throughout the body but affects only target cells because __________.
Respuesta
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only in target cells is testosterone able to initiate the phosphorylation cascade leading to activated transcription factor
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only target cells possess the cytosolic enzymes that transduce signals
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intracellular receptors for testosterone are present only in target cells
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only target cells retain the appropriate DNA segments
Pregunta 2
Pregunta
Chlorophyll molecules are in which part of the chloroplast?
Respuesta
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Thylakoid membranes
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stroma
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thylakoid space
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plasma membrane
Pregunta 3
Pregunta
the concentration of solutes in a particular cell is about 2%, but the cell contains almost no sucrose or urea. Sucrose cannot pass through the membrane of this cell, but water and urea can. Osmosis would cause this cell to shrink the most when immersed in which of the following solutions?
Pregunta 4
Pregunta
starting with one molecule of glucose, the energy containing products of glycolysis are:
Respuesta
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2 NAD+, 2 pyruvate, and 2 ATP
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2 NADH, 2 pyruvate, and 2 ATP
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2 FADH2, 2 pyruvate, and 4 ATP
Pregunta 5
Pregunta
in the absence of oxygen, cells need a way to regenerate which compound following glycolysis?
Respuesta
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NAD+
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ethanol
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carbon dioxide
Pregunta 6
Pregunta
Molecular oxygen (O2) has what role in aerobic cellular respiration?
Respuesta
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it oxidizes pyruvate at the end of glycolysis
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it removes a carbon only from pyruvate, producing CO2
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it is the final electron acceptor at the end of the electron transport chain
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it is the source of oxygen in all of the CO2 molecules produced during cellular respiration
Pregunta 7
Pregunta
Which of the following determines the sign of DELTA G for a reaction?
Respuesta
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the free energy of the reactants and the free energy of the products
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the affinity of the enzyme for the reactants
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the enzyme concentration
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the free energy of the products
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the free energy of the reactants
Pregunta 8
Pregunta
which of the following is a correct description and sequence of events in cellular respiration?
Respuesta
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oxidation of glucose to pyruvate; reduction of pyruvate; TCA cycle; oxidative phosphorylation
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Glycolysis; education of pyruvate; TCA cycle; oxidative phosphorylation
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glycolysis; oxidative phosphorylation; TCA cycles; oxidation of pyruvate
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oxidation of glucose to pyruvate; oxidation of pyruvate; oxidation of acetyl-coA; oxidative phosphorylation
Pregunta 9
Pregunta
how does carbon dioxide enter the leaf?
Respuesta
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stomata
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chloroplasts
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roots
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thylakoids
Pregunta 10
Pregunta
how does a noncompetitive inhibitor decrease the rate on an enzyme reaction
Respuesta
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by binding at the active site of the enzyme
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by changing the shape of the enzyme's active site
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by decreasing the activation energy of the reaction
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by changing the free-energy charge of the reaction
Pregunta 11
Pregunta
which of the following is true for anabolic pathways
Respuesta
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they do not depend on enzymes
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they are usually highly spontaneous chemical reactions
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they consume energy to decrease the entropy of the organism and its environment
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the consume energy to build up polymers from monomers
Pregunta 12
Pregunta
enzyme activity is affected by pH because
Respuesta
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most substrates don't function well at high or low pH
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high or low pH may disrupt hydrogen bonding or ionic interactions and thus change the shape of the enzyme's active site
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the binding of hydrogen ions to the enzyme absorbs energy and thus there may not be enough energy to overcome the activation energy barrier
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changes in pH will cause loss of all cofactors from enzymes
Pregunta 13
Pregunta
when oxygen is released as a result of photosynthesis, it is a direct by-product of
Respuesta
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the electron transfer system of photosystem I
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the electron transfer system of photosystem II
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splitting water molecules
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chemiosomosis
Pregunta 14
Pregunta
approximately how many molecules of ATP are produced from the complete oxidation of one molecule of glucose in aerobic cellular respiration
Pregunta 15
Pregunta
if muscle cells in the human body consume O2 faster than it can be supplied, which of the following is likely to result?
Respuesta
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the muscle cells will have trouble making enough ATP to meet demands
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the cells will not be able to carry out oxidative phosphorylation
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the cells will consume glucose at an increased rate
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the muscle cells will have trouble making enough ATP to meet demands and the cells will not be able to carry out oxidative phosphorylation
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all of the listed events will occur
Pregunta 16
Pregunta
which of the following molecules is most likely to passively diffuse across the plasma membrane?
Respuesta
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glucose
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DNA
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hemoglobin
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carbon dioxide
Pregunta 17
Pregunta
when chemical, transport, or mechanical work is done by an organism, what happens to the heat generated?
Respuesta
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it is used to power yet more cellular work
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it is used to store energy as more ATP
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it is transported to specific organs such as the brain
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it is lost to the environment
Pregunta 18
Pregunta
where do the reactions of the citric acid cycle occur in eukaryotic cells?
Respuesta
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the matrix of the mitochondrion
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the cytosol
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the crustal of the mitochondrion
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the inter membrane space of the mitochondrion
Pregunta 19
Pregunta
most cells cannot harness heat to perform work because
Respuesta
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heat is not a form of energy
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cells do not have much heat; they are relatively cool
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heat can never be used to do work
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temperature is usually uniform throughout a cell
Pregunta 20
Pregunta
which of the following pairs correctly matches a membrane transport process to its primary function?
Respuesta
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pinocytosis; the uptake of water and small solutes into the cell by formation of vesicles at the plasma membrane
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phagocytosis; recreation of large particles from the cell by fusion of vesicles with the plasma membrane
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exocytosis; the movement of water and solutes out of the cell by vesicle fusion with the plasma membrane
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osmosis; passive diffusion of water and small solutes across a membrane
Pregunta 21
Pregunta
in general, the hydrolysis of ATP drives cellular work by __________.
Pregunta 22
Pregunta
some bacteria are metabolically active in hot springs because __________.
Respuesta
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they are able to maintain lower internal temperature
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high temperatures make catalysis unnecessary
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their enzymes are completely insensitive to temperate
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their enzymes have high optimal temperatures
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they use molecules other than proteins or RNAs as their main catalysts
Pregunta 23
Pregunta
in the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of
Respuesta
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ATP, CO2, and lactate
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ATP, CO2, and ethanol (ethyl alcohol)
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ATP, NADH, and pyruvate
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ATP, pyruvate, and oxygen
Pregunta 24
Pregunta
Which of the following statements describes NAD+?
Respuesta
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It has more chemical energy than NADH
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it is oxidized by the action of hydrogenases
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it is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle
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it can donate electrons for use in oxidative phosphorylation
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in the absence of NAD+, glycolysis can still function
Pregunta 25
Pregunta
the electron transport chain involved in cellular respiration is located in/on the ________.
Respuesta
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inner membrane of the mitochondrion
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cytosol
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matrix of the mitochondrion
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inter membrane space of the mitochondrion
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non of the listed responses is corrected
Pregunta 26
Pregunta
which of the following does not occur during the calvin cycle?
Pregunta 27
Pregunta
rubisco is ________.
Respuesta
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the enzyme in C3 plants that first captures CO2 to begin the Calvin Cycle
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the enzyme responsible for splitting H2O to produce O2 in photosynthesis
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the enzyme that forms a 4-carbon compound in CAM photosynthesis
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the 5 carbon sugar molecule that reacts with CO2 to begin the Calvin cycle
Pregunta 28
Pregunta
Do i need to study the matching that is on Test 2?