final exam test #4
This enzyme catalyzes the reduction of NAD+ to NADH.
6
Which one of the following is formed by the removal of a carbon (as CO2) from a molecule of pyruvate? a) acetyl CoA b) water c) citrate d) ATP
A
A chemical reaction that has a positive ΔG is best described as ________.
C
The mitochondrial ATP synthase consists of several different protein subunits. Which subunit binds ADP and i and catalyzes the synthesis of ATP as a result of conformational change? a) peripheral stalk b) central stalk c) F1 ATPase Head d) transmembrane H+ carrier (rotor ring)
C
Which of the following metabolic processes normally occurs regardless of whether or not oxygen (O2) is present? a) lactate fermentation b) citric acid cycle c) oxidative phosphorylation d) glycolysis
D
Which of the following metabolic processes take place in the cytosol of a eukaryotic cell? a) citric acid cycle b) oxidation of pyruvate to acetyl CoA c) fermentation and chemiosmosis d) glycolysis and fermentation
D
Which of the following statementsdefines metabolism in its entirety in all organisms? a) Metabolism depends on a constant supply of energy from food. b) Metabolism manages the increase of entropy in an organism. c) Metabolism uses all of an organism's resources. d) Metabolism consists of all the energy transformation reactions in an organism.
D
Which of the following statements is true for all exergonic reactions? a) A net input of energy from the surroundings is required for the reactions to proceed. b) The reaction goes only in a forward direction: all reactants will be converted to products, but no products will be converted to reactants. c) The products have more total energy than the reactants. d) The reaction proceeds with a net release of free energy.
d
enzyme in step 9
enolase
NADH undergoes ? to become NAD+
oxidation
This enzyme catalyzes the first 'energy investment' step of glycolysis
1
These enzymes of glycolysis are essentially irreversible (alternate enzymes are used at these steps when glycolysis is reversed during gluconeogenesis).
1, 3, 10
This kinase is named for the product that it produces which can then be either fermented or further oxidized.
10
this enzyme catalyzes the 'cleavage' step of glycolysis
4
Both of these enzymes take a phosphate from a glycolytic intermediate and add it to ADP.
7 and 10
These two enzymes perform 'substrate-level phosphorylation'
7 and 10
Approximately how many molecules of ATP are produced from the complete oxidation of one molecule of glucose (C6H12O6) in aerobic cellular respiration? a) 30-32 b) 18-24 c) 2 d) 4
A
Carbon dioxide (CO2) is released during which of the following stages of cellular respiration? a) oxidation of pyruvate to acetyl CoA and the citric acid cycle b) oxidative phosphorylation and fermentation c) glycolysis and the oxidation of pyruvate to acetyl CoA d) fermentation and glycolysis
A
Energy released by the electron transport chain is used to pump H+ ions into which location in eukaryotic cells? a) mitochondrial intermembrane space b) mitochondrial matrix c) mitochondrial inner membrane d) cytoplasm adjacent to the mitochondrial outer membrane
A
In chemiosmosis, what is the most direct source of energy that is used to convert ADP + i to ATP? a) energy released from movement of protons through ATP synthase, down their electrochemical gradient b) energy released from substrate-level phosphorylation c) energy released as electrons flow through the electron transport chain d) energy released as electrons are transported across the inner mitochondrial membrane
A
The oxygen consumed during cellular respiration is directly involved in which of the following processes or events? a) accepting electrons at the end of the electron transport chain b) glycolysis c) the citric acid cycle d) the oxidation of pyruvate to acetyl CoA
A
What happens to a glucose molecule when it loses a hydrogen atom as the result of an oxidation-reduction reaction? a) The glucose molecule is oxidized. b) The glucose molecule is an oxidizing agent. c) The glucose molecule is reduced. d) The glucose molecule is hydrolyzed.
A
Which electron carrier(s) function in the citric acid cycle? a) NADH and FADH2 c) the electron transport chain b) the citric acid cycle d) glycolysis b) ADP and ATP d) NAD+ only
A
During which of the following metabolic processes is most of the CO2 from the catabolism of glucose is released? a) oxidation of pyruvate to acetyl-CoA c) electron transport
B
The relationship between catabolism and anabolism is most similar to the relationship between which of the following pairs of terms? a) exergonic; spontaneous b) exergonic; endergonic c) free energy; entropy d) work; free energy
B
When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a proton), the molecule becomes ________. a) redoxed b) reduced c) dehydrogenated d) oxidized
B
Which of the following component of the electron transport chain is required to combine electrons with molecular oxygen? a) cytochrome c b) cytochrome c oxidase c) cytochrome c reductase d) NADH dehydrogenase
B
Which of the following events takes place in the electron transport chain? a) the breakdown of an acetyl group to carbon dioxide b) the harnessing of energy from high-energy electrons derived from glycolysis and the citric acid cycle c) the breakdown of glucose into six carbon dioxide molecules d) substrate-level phosphorylation
B
Which of the following processes is driven by chemiosmosis? a) ATP hydrolysis c) reduction of NAD+ to NADH b) oxidative phosphorylation d) substrate-level phosphorylation
B
Which of the following statements about NAD+ is true? a) In the absence of NAD+, glycolysis can still function. b) NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle. c) NAD+ can donate electrons for use in oxidative phosphorylation. d) NAD+ has more chemical energy than NADH.
B
Which of the following statements about anabolic pathways is true? a) They decrease the entropy of the organism and its environment. b) They consume energy to build up polymers from monomers. c) They release energy by degrading polymers to monomers d) They are usually spontaneous chemical reactions.
B
Which of the following statements best describes the primary role played by oxygen in cellular respiration? a) It yields energy in the form of ATP as it is passed down the electron transport chain. b) It serves as the final acceptor for electrons from the electron transport chain. c) It oxidizes glucose to form two molecules of pyruvate. d) It serves as an acceptor for carbon, forming CO2 in the citric acid cycle.
B
Which of the following statements describes a common characteristic of catabolic pathways? a) They combine small molecules into larger, more energy-rich molecules. b) They are exergonic and provide energy that can be used to produce ATP from ADP and i. c) They are endergonic and release energy that can be used for cellular work. d) They require energy from ATP hydrolysis to break down polymers into monomers.
B
Which of the following statements describes a primary function of both alcohol fermentation and lactic acid fermentation? a) reduction of NAD+ to NADH b) oxidation of NADH to NAD+ c) hydrolysis of ATP to ADP + i d) reduction of FAD to FADH2
B
Which of the following supports the 'endosymbiotic theory' of mitochondrial origins? a) unique ribosomes c) mitochondrial DNA b) all of the above d) size of mitochondria
B
Which of the following terms most precisely describes the cellular process of breaking down large molecules into smaller ones? a) metabolism b) catabolism (catabolic pathways) c) dehydration d) anabolism (anabolic pathways)
B
Starting with one molecule of glucose, glycolysis results in the net production of which of the following sets of energy-containing products? a) 6 CO2, 2 pyruvate, and 2 ATP b) 4 NADH, 2 pyruvate, and 4 ATP c) 2 NADH, 2 pyruvate, and 2 ATP d) 2 NAD+, 2 pyruvate, and 2 ATP
C
What happens when electrons are passed from one atom to a more electronegative atom? a) The more electronegative atom is reduced, and energy is consumed. b) The more electronegative atom is oxidized, and energy is released. c) The more electronegative atom is reduced, and energy is released. d) The more electronegative atom is oxidized, and energy is consumed.
C
Where are the proteins of the electron transport chain located? a) mitochondrial outer membrane b) mitochondrial intermembrane space c) mitochondrial inner membrane d) mitochondrial matrix
C
Which of the following components of the electron transport chain does not function as a proton pump? a) cytochrome c reductase c) cytochrome c b) NADH dehydrogenase d) cytochrome c oxidase
C
Which of the following statements about the electron transport chain is true? a) It includes a series of hydrolysis reactions associated with mitochondrial membranes. b) It is driven by ATP hydrolysis. c) It consists of a series of redox reactions d) It occurs in the cytoplasm of both prokaryotic and eukaryotic cells.
C
Which of the following statements describes what happens to a molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction? a) It loses electrons and gains potential energy. b) It gains electrons and loses potential energy. c) It loses electrons and loses potential energy. d) It gains electrons and gains potential energy.
C
Which of the summary statements below describes the results of the following reaction? C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy a) O2 is oxidized and H2O is reduced. c) C6H12O6 is oxidized and O2 is reduced. b) CO2 is reduced and O2 is oxidized. d) O2 is reduced and CO2 is oxidized.
C
A cell has enough available ATP (either stored or from the creatine phosphate pathway) to meet its needs for about 60 seconds. What is likely to happen when an athlete exhausts his or her ATP supply? a) ATP is transported into the cell from the circulatory system. b) Other cells take over, and the muscle cells that have used up their ATP cease to function. c) He or she has to sit down and rest. d) Catabolic processes are activated that generate more ATP.
D
Which kind of metabolic poison would most directly interfere with glycolysis? a) an agent that reacts with NADH and oxidizes it to NAD+ b) an agent that reacts with oxygen and depletes its concentration in the cell c) an agent that binds to pyruvate and inactivates it d) an agent that closely mimics the structure of glucose but is not metabolized
D
Which of the following molecules is most similar in structure to ATP? a) a pentose sugar b) an amino acid with three phosphate groups attached c) a steroid d) an RNA nucleotide
D
enzyme in step 4
adolase
enzyme in step 6
glyceraldehyde 3-phosphate dehydrogenase
human beings are classified as ??? trophs
hetero chemo organotrophs
enzyme in step 1
hexokinase
what enzyme catalyzes the breakdown of pyruvate to lactose?
lactate dehydrogenase complex
enzyme in step 3
phosphofructokinase
enzyme in step 2
phosphoglucoisomerase
enzyme in step 7
phosphoglycerate kinase
enzyme in step 8
phosphoglycerate mutase
enzyme in step 10
pyruvate kinas
pyruvate undergoes ? to become lactate
reduction
what is the most important purpose of the breakdown of pyruvate into lactose?
to regenerate NAD+
enzyme in step 5
triode phosphate isomerase
