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Wilson Bio 1330 Tx State Test 2

Terms in this set (49)

A chemical reaction that has a negative (delta G) is best as described

a. endergonic
b. entropic
c. enthalpic
d. spontaneous
e. EXERGONIC
e. EXERGONIC
When comparing an uncatalyzed reaction to the same direction with a catalyst, the catalyzed reaction will

a. have same rate
b. have the same delta G
c. have the same activation energy
d. consume the catalyst as a reactant
b. have the same delta G
Which of the following occurs in the cytoplasm of a eukaryotic cell?

a. glycolysis and fermentation
b. fermentation and chemiosmosis
c. oxidation of pyruvate to acetyl CoA
d. citric acid cycle
e. oxidative phosphorylation
a. glycolysis and fermentation
The making of ATP by oxidative phosphorylation (chemiosmosis) uses the energy released

a. by the oxidative of NADPH
b. by a phosphoryl transfer reaction from a substrate with higher potential energy
c. by resonance energy of photons that excites electrons
d. by movement of protons across the membrane through a pore in ATP synthase.
d. by movement of protons across the membrane through a pore in ATP synthase.
Chemiosmotic ATP synthesis occurs in ETC

a. all cells but only in the presence of oxygen
b. only eukaryotic cells, in the presence of oxygen
c. only in mitochondria, using either oxygen or other electron acceptors
d. all respiring cells, both prokaryotic and eukaryotic, using oxygen or other terminal electron acceptors
e. all cells, in the absence of respiration
d. all respiring cells, both prokaryotic and eukaryotic, using oxygen or other terminal electron acceptors
What are the input molecules needed for the electron transport chain component of aerobic respiration?

a. oxygen, carbon dioxide, and water
b. NAD+, FAD, electrons and water
c. NADH, FADH2, and protons
d. NADH, FADH2, and O2
e. oxygen and protons
d. NADH, FADH2, and O2
What electrons flow along the electron transport chains of mitochondria, which of the following changes occurs?

a. The concentrations of H+ ions in the matrix decreases
b. ATP synthase pumps protons by active transport
c. The electrons gain free energy
d. The cytochromes phosphorylate ADP to form ATP
e. NAD+ is reduced to NADH
a. The concentrations of H+ ions in the matrix decreases
When a track coach was pushing her runners to the point of pure exhaustion, she was yelling, "feel the fermentation!" What aspect of physiology was she referring to?

a. The muscle cells had shifted to metabolizing mostly protein for energy, which was releasing ammonia into the blood stream.
b. Bacteria in the gut were producing acidic products as a stress-induced response
c. Lactic acid was being produced in the muscles because the work demand exceeded the maximum rate or the aerobic respiration pathway
d. Long-chain fatty acids were being released into the blood stream and this was triggering pain receptors throughout the body.
e. Athletes who had consumed yogurt with live, probiotic cultures before the training session were experiencing an excess build-up of carbon dioxide gas in their intestines
c. Lactic acid was being produced in the muscles because the work demand exceeded the maximum rate or the aerobic respiration pathway
What are the 3 phases of Calvin cycle? (abbreviations= RuBP=Ribulose 1,5 biphosphate, glyceraldehyde 3-phosphate=G3P, 3-Phosphoglycerate=3 PGA.)

a. 1) carboxylation of RuBP into 3-PGA; 2) oxidation of 3-PGA to G3P; 3) fixation of RuBP from G3P
b. 1) decarboxylation of RuBP into 3-PGA; 2) regeneration of G3P from 3-PGA; 3) oxidation of 3-PGA
c. 1) fixation of CO2 into 3-PGA; 2) reduction of 3-PGA to G3P; 3) regeneration of RuBP from G3P
d. 1) decarboxylation of RuBP to form 3-PGA; 2) oxidation of 3-PGA to G3P; 3) regeneration of RuBP from 3-PGA
c. 1) fixation of CO2 into 3-PGA; 2) reduction of 3-PGA to G3P; 3) regeneration of RuBP from G3P
What is the term for metabolic pathways that release stored energy by breaking down complex molecules?

a. anabolic pathways
b. catabolic pathways
c. fermentation pathways
d. thermodynamic pathways
e. bioenergetic pathways
b. catabolic pathways
Starting with 1 molecule of glucose, the energy-containing products of glycolysis are

a. 2 NAD+,1 Pyruvate, and 2 ATP
b. 2 NADH, 2 Pyruvate, and 2 ATP
c. 2 FADH2, 2 Pyruvate, and 4 ATP
d. 6 CO2, 2 Pyruvate, and 2 ATP
e. 6 CO2, 1 Pyruvate, and approximately 30 ATP
b. 2 NADH, 2 Pyruvate, and 2 ATP
Phosphofructokinase (PTK) is an allosteric enzyme that catalyzes an early step of glycolysis. An increase in the concentration of ATP in a cell wall would be excepted to

a. inhibit PFK and thus slow the rates of glycolysis and the citric acid cycle.
b. activate PFK and thus slow the rates of glycolysis and the citric acid cycle.
c. inhibit PFK and thus increase the rates of glycolysis and the citric acid cycle
d. activate PFK and thus increase the rates of glycolysis and the citric acid cycle
a. inhibit PFK and thus slow the rates of glycolysis and the citric acid cycle.
When a cell catabolizes fatty acids for energy production, the first step is to break down the fatty acids into acetyl-CoA molecules. What happens next to the acetyl-CoA molecules?

a. They directly enter the electron transport chain (ETC)
b. They directly enter the energy-yielding (payoff) stage of glycolysis
c. They are decarboxylated by pyruvate dehydrogenase
d. They directly enter the citric acid cycle
d. They directly enter the citric acid cycle
Carbon dioxide (CO2) is released during which stage of cellular respiration?

a. glycolysis and the oxidation of pyruvate to acetyl CoA
b. oxidation of pyruvate to acetylCoA and the TCA cycle
c. the citric acid cycle and oxidative phosphorylation
d. fermentation and glycolysis
b. oxidation of pyruvate to acetylCoA and the TCA cycle
Which of the following statement is correct about pyruvate dehydrogenase?

a. Its reaction products are Acetyl CoA + NADH + CO2
b. It is the most active when oxygen is absent
c. It is activated when it is phosphorylated
d. It is a small, single-polypeptide enzyme
e. It is located in the cytoplasm
a. Its reaction products are Acetyl CoA + NADH + CO2
The function of complexes 1,2 3, and 4 in the inner mitochondrial membrane is to

a. oxidize NADH to NAD+ so it can be recycled for use in glycolysis
b. split water into oxygen and hydrogen ions
c. reduce NAD+ to NADH and FAD to FADH2 to energize ATP synthesis by phosphorylation
d. release the proton gradient to establish an equilibrium of protons on both sides of the membrane
e. couple the redox energy release from electron transfer with the transfer of protons (H+) ions across a membrane
e. couple the redox energy release from electron transfer with the transfer of protons (H+) ions across a membrane
You have discovered an enzyme that can catalyze 2 different chemical reactions. Which of the following is most likely to be correct?

a. The enzyme lacks a-helices and beta pleated sheets.
b. the enzyme is subject to competitive inhibition and allosteric regulation
c. 2 types of allosteric regulation occur. The binding of one molecule activated the enzyme, while binding of a different molecule inhibits it
d. Either the enzyme has 2 distinct active sites or the reactants involved in the 2 reaction are very similar in size and shape
d. Either the enzyme has 2 distinct active sites or the reactants involved in the 2 reaction are very similar in size and shape
Consider the HIV enzyme called protease. The amino acid residues at the active site are highly hydrophobic. In designing a drug that would bind o the active site and jam it, researchers should use a molecule that is

a. hydrophobic
b. polar
c. charged
d. acidic
a. hydrophobic
For a chemical reaction to happen, it must 1st overcome a thermodynamic barrier known as the reaction's ?

a. entropy
b. activation energy
c. endothermic threshold
d. equilibrium point
e. free-energy content
b. activation energy
Zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as

a. a competitive inhibitor of the enzyme
b. a noncompetitive inhibitor of the enzyme
c. an allosteric activator of the enzyme
d. a cofactor necessary for enzyme activity
e. a coenzyme derived from a vitamin
d. a cofactor necessary for enzyme activity
A researcher studies an enzyme that is normally blocked by a competitive inhibitor, but he discovered a new form of the enzyme that is no longer blocked by the inhibition, even though it still has normal enzymatic activity with its substrates. He guesses correctly, that for this to happen, there must have been a minor change to the enzyme's amino acid sequence. Knowing that the inhibitor worked by competitive inhibition, where in the enzyme will the alteration most likely be found?

a. in or near the active site
b. at an allosteric site
c. at a cofactor binding site
d. in regions of the protein that determine packaging into the virus capsid
e. such mutations could occur anywhere with equal probability
a. in or near the active site
A solution of starch at room temperature does NOT readily decompose into a solution of simple sugars (maltose disaccharides). However, when a small amount of an amylase enzyme is mixed in, the starch rapidly converts to maltose. This happens because...

a. the starch solution has less free energy than the maltose solution
b. the hydrolysis of starch to maltose decreases entropy
c. the activation energy barrier for this reaction cannot easily be surmounted at room temperature
d. amylase changes it from an endergonic reaction into an exergonic reaction
e. amylase is one of the essential reactants
c. the activation energy barrier for this reaction cannot easily be surmounted at room temperature
When oxygen is reduced as the terminal electron acceptor of the ETC in aerobic respiration, it is converted directly into

a. reduced NADPH
b. oxidized NAD+
c. water
d. the electron transfer system of photosystem 1
e. lactic acid or acid alcohols
c. water
Which of the following are products of the light reactions of photosynthesis that are used in Calvin cycle?

a. CO2 and glucose
b. H2O and O2
c. ADP, inorganic phosphate. and NADP+
d. electrons and H+
e. ATP and NADPH
e. ATP and NADPH
When oxygen is released as a result of photosynthesis, it is a direct by-product of
a. reducing NADP+
b. splitting water molecules
c. chemiosmosis
d. the electron transfer system of photosystem 1
e. the terminal electron acceptor of the electron transfer chain of photosystem 2
b. splitting water molecules
Which of the following sequence correctly represents the flow of electrons during photosynthesis?
a. NADPH->O2->CO2
b. H20->NADPH->Calvin cycle
c. NADPH->chlorophyll->Calvin cycle
d. H20->photosystem 1->photosystem 2
e. NADPH-> electron transport chain-> O2
b. H20->NADPH->Calvin cycle
Chlorophylls absorb most light in which colors of the visible range?
a. green and blue
b. blue and red
c. yellow and red
d. green and yellow
b. blue and red
Why are there several structurally different accessory pigments in the reaction centers of photosystems?
a. Excited electrons must be filtered pigments before they can be transferred to electron acceptors of the ETC.
b. This arrangement enables the plant to absorb light energy of a variety of wavelengths.
c. They enable the plant to absorb more photons from light energy, all of which are the same wavelength
d. They enable the reaction center to excite electrons to a higher energy level
b. This arrangement enables the plant to absorb light energy of a variety of wavelengths.
What even accompanies photon energy absorption by chlorophyll or other pigment molecules of the antenna complex?
a. ATP is synthesized from the energy absorbed
b. A carboxylation reaction of the Calvin cycle occurs.
c. Electrons are stripped from NADPH
d. An electron is excited
d. An electron is excited
Carotenoids in foods are precursors to the Vitamin A family of compounds, so they can be an important component of healthy human nutrition. According to the WHO, vitamin A deficiency is the leading cause of preventable ___ in children
a. blindness
b. stunted growth
c. diabetes
d. hepatitis
a. blindness
As electrons are passed through the system of electron carriers associated with photosystem 2, they lose energy. What happens to this energy?
a. It excited electrons of the reaction center of photosystem 1
b. It is lost as heat
c. It is used to establish and maintain a proton gradient across a membrane
d. It is used to phosphorylate NAD+ to NADPH, the molecule that accepts electrons from photosystem 1.
a. It excited electrons of the reaction center of photosystem 1
What molecule accepts electrons produced from sunlight-excited chlorophyll and transfers them to the enzyme NADP+ reductase in photosystem 1?
a. ferredoxin
b. Beta carotene
c. pheophytin
d. xanthophyll
c. pheophytin
Where do the enzymatic reactions of the Calvin cycle take place?
a. stroma of the chloroplast
b. thylakoid membranes
c. matrix of the mitochondria
d. cytosol around the chloroplast
e. thylakoid space
a. stroma of the chloroplast
When the herbicide glycolaldehyde is applied to a plant, its cells are unable to undergo the Calvin cycle. Which of the following answer choices best describes the most immediate effect of this herbicide on a plant's cell?
a. The plant's cell cannot produce sugars, such as glucose
b.The plant's cell cannot convert sunlight and water to ATP and oxygen
c.The plant's cell cannot convert ATP and oxygen to sunlight and water
d. Chlorophyll cannot absorb light energy from the sun
a. The plant's cell cannot produce sugars, such as glucose
Which of the following occurs during the light-dependent reactions?
a. blue and red light is absorbed by chlorophyll
b. 3-phosphoglyceric acid (3-PGA) is formed by the enzyme ribulose, 1-5 biphosphate carboxylase/oxygenase (RuBisCO)
c. glyceraldehyde 3-phosphate (G3P) is made using energy from ATP and NADPH
d. A and B are correct
e. A, B, and C are correct
a. blue and red light is absorbed by chlorophyll
Ribulose-1, 5-bisphosphate carboxylase/oxygenase (RuBisCO) is considered the most abundant enzyme on earth. Which of the following is correct about the function of RuBisCO
A, B and C is correct
a. it fixes carbon dioxide and forms two molecules of 3PGA
b. It can use ribulose, 1-5 biophosphate, and either carbon dioxide or oxygen as substrates
c. it has a slow reaction rate, only 3-10 chemical reactions
Which of the following macromolecules leaves the nucleus of a eukaryotic cell through pores in the nuclear membrane?
mRNA
What is the function of the nuclear pore complex found in eukaryotes?
It regulates the movement of proteins and RNAs into and out of the nucleus
The vesicles and organelles produced by the endomembrane system each have their own composition of different lipids and proteins. How is the differentiation of lipids and proteins created?
c. the golgi apparatus sorts and directs membrane components
What is the most likely pathway taken by a newly synthesized protein that will be secreted by a cell?
d. ER --> Golgi ---> vesicles that fuse with plasma membrane
Asbestos is a material that was once used extensively in construction. One risk from working in a building that contains asbestos is the development of asbestosis caused by the inhalation of asbestos fibers. Cells will phagocytize asbestos, but are not able to degrade it. As a result, asbestos fibers accumulate in _____.
lysosomes
Motor proteins provide for molecular motion in cells by interacting with what types of cellular structures?
d. cytoskeletal filaments including microtubules and actin
In receptor-mediated endocytosis receptor molecules initially, project to the outside of the cell. Where do they end up after endocytosis?
c. on the inside surface of the vesicle
Eukaryotic cytoskeletal proteins reside in the cytoplasms and help maintain cell shapes and functions. What would you predict about these proteins?
c. They are manafuctured on free ribosomes, not associated with the endoplasmic reticulum
Flagella and cilia of eukaryotic cells are made of _____________ that produce _________________ movements
c. microtubules and motor proteins/ whip-life or smooth undalatory
The endosymbiont theory helps e xplain the evolutionary origin of eukaryotes. Features of which organelles provide evidence in support of the enosymbiont theory?
a. chloroplast and mitochondrion
The first law of thermodynamics is that energy cannot be created or destroyed. For living organisms, which of the following is an important consequence of the first law of thermodynamics?
b. the organism ultimately must obtain all the necessary energy for the life from its environment
Which of the following statements is consistent with how biology obeys the second law of thermodynamics>
D. cells require an input of energy to maintain their high level of organization
The mathematical expression for the change in free energy of a system is ΔG =ΔH - TΔS. Which of the following is (are) correct?
c. delta G is the change in free energy
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