Deck 5: Aerobic Respiration and the Mitochondrion

Question 1

What molecule is responsible for conveying 2 carbons from pyruvate to the Krebs cycle?

A)Coenzyme G
B)Coenzyme A
C)Acetate
D)pyruvate
E)oxaloacetate

Answer 1

B

Question 2

In what ways can pyruvate and NADH be metabolized?

A)fermentation,hydrolysis of PGAL
B)condensation of PGAL and fermentation
C)aerobic processes using Krebs cycle,fermentation
D)anaerobic processing using Krebs cycle,fermentation
E)aerobic processing using Krebs cycle,hydrolysis of PGAL

Answer 2

C

Question 3

What happens to the carbons of pyruvate that do not enter the Krebs cycle?

A)They are converted to carbohydrates.
B)They are converted to CO₂.
C)They are converted to glucose.
D)They are converted to ATP.
E)They are converted to carbon monoxide (CO).

Answer 3

B

Question 4

Which lipid is known for playing an important role in facilitating the activity of proteins involved in ATP synthesis?

A)diphosphatidylglycerol
B)phosphatidyl inositol
C)phosphatidic acid
D)cardiolipin
E)both diphosphatidylglycerol and cardiolipin

Question 5

What is defined as a domain of the inner mitochondrial membrane that is present within the interior of the mitochondrion as a series of invaginated membranous sheets?

A)inner boundary membrane
B)outer boundary membrane
C)cristae
D)matrix
E)pseudopodia

Question 6

To what is the 2-carbon fragment of acetyl CoA added to make citric acid at the start of the Krebs cycle?

A)oxaloacetate
B)citric acid
C)succinate
D)-ketoglutarate
E)isocitric acid

Question 7

What are the two interconnected domains of the inner mitochondrial membrane?

A)inner boundary membrane,cristae
B)central boundary membrane,cristae
C)cristae boundary membrane,outer boundary membrane
D)inner boundary membrane,outer boundary membrane
E)cristae,matrix

Question 8

The inner boundary membrane is particularly rich in which of the following?

A)protons
B)proteins responsible for the import of mitochondrial proteins
C)Krebs cycle enzymes
D)enzymes of the glycolytic pathway
E)glycosaminoglycans

Question 9

What advantage do the cristae confer on the mitochondria?

A)They allow the mitochondria to shrink.
B)They greatly increase the surface area for aerobic respiration machinery.
C)They confer resiliency on the cells.
D)They allow swelling of mitochondria.
E)They activate the matrix.

Question 10

The presence of Ca²⁺ ion transport molecules in the inner mitochondrial membrane is consistent with the mitochondrion's role in _______.

A)muscle contraction
B)regulating cytosolic Ca²⁺ ion concentration
C)ATP manufacture
D)ADP manufacture
E)control of membrane fusion

Question 11

The balance between fusion and fission is likely a major determinant of __________.

A)number
B)length
C)color
D)degree of interconnection
E)number,length and degree of interconnection

Question 12

Which component involved in the Krebs (TCA)cycle is bound to the inner mitochondrial membrane?

A)oxaloacetate
B)acetyl CoA
C)succinate dehydrogenase
D)succinate
E)succinyl CoA

Question 13

Where are most of the enzymes of the Krebs cycle located?

A)in the intercristal space
B)on the cristae
C)on the ribosomes
D)in the soluble phase of the mitochondrial matrix
E)in the intermembrane space

Question 14

How many carbons from 13 original glucose molecules enter the Krebs cycle in the absence of oxygen?

A)0
B)13
C)26
D)52
E)78

Question 15

Which of the following is not found in a reducing atmosphere?

A)H₂
B)NH₃
C)O₂
D)H₂O
E)Both O₂ and H₂O

Question 16

Mitochondria are sites of the __________.

A)synthesis of certain amino acids
B)synthesis of heme groups
C)uptake of Ca²⁺ ions
D)release of Ca²⁺ ions
E)All of these are correct.

Question 17

When fission of mitochondria becomes more frequent than fusion,the mitochondria tend to become __________.

A)more elongated
B)more interconnected
C)more numerous
D)more distinct
E)more numerous and more distinct

Question 18

When fusion of mitochondria becomes more frequent than fission,the mitochondria tend to become __________.

A)more elongated
B)more interconnected
C)more numerous
D)more distinct
E)more elongated and more interconnected

Question 19

Which of the following regulate intracellular levels of Ca²⁺ ions?

A)Golgi apparatus
B)ribosomes
C)endoplasmic reticulum
D)mitochondria
E)both endoplasmic reticulum and mitochondria

Question 20

How many carbons from 13 original glucose molecules enter the Krebs cycle in the presence of oxygen?

A)0
B)13
C)26
D)52
E)78

Question 21

What is the terminal electron acceptor of the electron transport chain?

A)water
B)O₂
C)CO₂
D)CO
E)glucose

Question 22

What is the name of the process by which the electron transport chain generates the electrochemical gradient that drives ATP production in the mitochondrion?

A)osmosis
B)diffusion
C)facilitated diffusion
D)chemiosmosis
E)frusion

Question 23

What type of electron carrier has a prosthetic group derived from vitamin B₂?

A)flavoproteins
B)cytochromes
C)copper atom containing carriers
D)ubiquinone
E)iron-sulfur proteins

Question 24

How do many potent respiratory poisons exert their effect?

A)They break down oxygen.
B)They bind to electrons.
C)They bind to the cytochrome oxidase catalytic site.
D)They bind to oxygen.
E)They denature the inner mitochondrial membrane.

Question 25

Pathways in which H⁺ ions can "hop" through a channel by exchanging themselves with other protons present along the pathway are called ___________.

A)proton-conduction pathways
B)electrical wires
C)proton wires
D)proton conveyer belt
E)proton-conduction pathways and proton wires

Question 26

What type of electron carrier has a prosthetic group derived from riboflavin?

A)flavoproteins
B)cytochromes
C)copper atom containing carriers
D)ubiquinone
E)iron-sulfur proteins

Question 27

What is formed when electrons reach the bottom of the mitochondrial electron transport chain and bind to the final electron acceptor?

A)water
B)carbon dioxide
C)carbon monoxide
D)hydrogen
E)oxygen

Question 28

Why must the process by which cytochrome oxidase works be efficient?

A)If it is not,mitochondria will shrink.
B)If it is not,mitochondria will swell and burst.
C)The process deals with very dangerous substances,which,if released,could damage virtually every cell macromolecule.
D)If it is not the mitochondria could denature.
E)All of these are correct.

Question 29

Which enzyme of the Krebs (TCA)cycle is different from the others with respect to its location and where is it located?

A)succinate dehydrogenase,mitochondrial matrix
B)malate dehydrogenase,mitochondrial matrix
C)succinate dehydrogenase,inner mitochondrial membrane
D)malate dehydrogenase,inner mitochondrial membrane
E)succinate dehydrogenase,intermembrane space

Question 30

On average,how many ATPs would be made if 4 NADH and 6 FADH₂ molecules donated their high-energy electrons to the mitochondrial electron transport chain?

A)10
B)24
C)12
D)30
E)20

Question 31

Spontaneous oxidation-reduction (redox)reactions are accompanied by ________.

A)a gain of heat energy
B)a loss of free energy
C)a gain of free energy
D)a loss of heat energy
E)a gain of heat loss

Question 32

Electrochemical gradients have both a(n)_________ and a(n)__________ component.

A)concentration,acidic
B)acidic,electrical
C)concentration,basic
D)concentration,electrical
E)acidic,basic

Question 33

How is the energy used to make ATP via the electron transport chain generated?

A)The energy from electrons bound to reduced coenzymes is used to create a steep electrochemical gradient.
B)Electrons bound to NADH are used to generate a H⁺ ion gradient across the inner mitochondrial membrane.
C)Electrons bound to FADH2 are used to generate a proton gradient across the inner mitochondrial membrane.
D)Electrons bound to NADH are used to generate a proton gradient across the inner mitochondrial membrane.
E)All of these are correct.

Question 34

What is unusual about the way that H⁺ ions are transported across the inner mitochondrial membrane as compared to the movement of other ions like Na⁺ and Cl^- ions?

A)Na⁺ and Cl^- ions must traverse the full distance,but H⁺ ions materialize on the other side of the membrane.
B)Na⁺ and Cl^- ions must traverse the full distance,but H⁺ ions can hop through a channel by exchanging themselves with other protons found along the pathway.
C)Na⁺ and Cl^- ions can hop through a channel by exchanging themselves with other similar ions found along the pathway,but H⁺ ions must traverse the full distance.
D)Na⁺ and Cl^- ions must traverse the full distance,but H⁺ ions must only go halfway.
E)Na⁺ and Cl^- ions must traverse the full distance,but H⁺ ions must change into neutrons first.

Question 35

What is another name from for partially reduced ubiquinone?

A)ubiquinone
B)ubisemiquinone
C)ubiquinol
D)ubiquinde
E)ubiquinate

Question 36

How do mitochondria generate and store the energy used to produce most of the ATP made during aerobic respiration?

A)by producing heat
B)by generating a heat gradient
C)by generating an ionic (electrochemical)gradient
D)by generating a Cl^- ion gradient
E)by generating a Na⁺ ion gradient

Question 37

The direct formation of ATP by the transfer of a phosphate group from a donor molecule to ADP is called ________.

A)substrate-level phosphorylation
B)oxidative phosphorylation
C)cyclic photophosphorylation
D)noncyclic photophosphorylation
E)indigenous phosphorylation

Question 38

What is the final electron acceptor in the electron transport chain?

A)water
B)carbon dioxide
C)carbon monoxide
D)hydrogen
E)oxygen

Question 39

You are trying to figure out an electron transport pathway including the following electron transport molecules: B,K,T,Q and X.You do so by employing inhibitors for various steps in the process.When you do,you get the following results: Inhibitor Electron Transport Molecules Trapped in Reduced Form
Ticin Q & K
Digitin K
Estin T,K,Q & B
Lucin Q,K & T
What is the order of the molecules (the pathway)in the electron transport chain suggested by the above data from the most reduced to the least reduced molecule?

A)K -> T -> B -> Q -> X
B)K -> X -> B -> Q -> T
C)K -> Q -> T -> B -> X
D)X -> B -> T -> Q -> K
E)T -> B -> K -> Q -> X

Question 40

___________ exhibit lower electron affinity.

A)Strong oxidizing agents
B)Strong elucidating agents
C)Strong reducing agents
D)Weak reducing agents
E)Weak eliminating agents

Question 41

The energy expended during the formation of ATP by ATP synthase is required to _______.

A)attach the phosphate group to ADP
B)attach the phosphate group to ATP
C)release the tightly bound ATP from the ATP synthase catalytic site
D)attach the tightly bound ATP to the ATP synthase catalytic site
E)move protons against their gradient

Question 42

The three catalytic sites of ATP synthase ___________.

A)have different substrate binding affinities
B)have different product binding affinities
C)at any one time are present in different conformations
D)pass sequentially through their three different conformations
E)All of these are correct.

Question 43

Which molecule below plays a key role in regulating the rate of glycolysis and Krebs cycle by regulating the activity of key enzymes?

A)ADP
B)inorganic phosphate
C)ATP
D)molecular oxygen
E)gaseous nitrogen

Question 44

Electrochemical gradients have both a(n)_________ and a(n)_________ component.

A)concentration,acidic
B)acidic,electrical
C)concentration,basic
D)chemical,voltage
E)acidic,basic

Question 45

Which of the statements below served as evidence that rotational catalysis occurs in ATP synthase?

A)movement was directly observed in the electron microscope
B)a fluorescently labeled actin filament attached to the enzyme's  subunit was seen to rotate when ATP was added to the enzyme which was fixed to a cover slip
C)circular dichroism revealed the movement
D)an inhibitor stopped the enzyme movement
E)atomic force microscopy showed the movement

Question 46

Which molecule below plays a key role in regulating respiratory rate in the mitochondrion?

A)ADP
B)inorganic phosphate
C)ATP
D)molecular oxygen
E)gaseous nitrogen

Question 47

It has been shown that one part of ATP synthase rotates relative to another part of the enzyme.This phenomenon is referred to as ________.

A)turning catalysis
B)revolutionary catalysis
C)rotational catalysis
D)rotatalysis
E)revolalysis

Question 48

In the experiment that demonstrated that rotational catalysis occurs,a fluorescently labeled actin filament attached to the ATP synthase enzyme's  subunit was seen to rotate when ATP was added to the enzyme,which was fixed to a cover slip.With each step in the rotational catalysis,how much could the actin filament be seen to rotate?

A)0°
B)360°
C)120°
D)90°
E)3°

Question 49

The L conformation of ATP synthase catalytic sites ________.

A)has a very low affinity for nucleotides
B)loosely binds AMP and an inorganic phosphate group
C)has a very low affinity for proteins
D)binds ATP,ADP and inorganic phosphate groups tightly
E)loosely binds ADP and an inorganic phosphate group

Question 50

What drives the rotation of the F₁ head of ATP synthase?

A)proton movement from intermembrane space to the matrix
B)proton movement from the matrix to the intermembrane space
C)ATP hydrolysis
D)ATP condensation
E)proton movement from the cytoplasm to the intermembrane space

Question 51

Which activity below is not thought to be driven by the proton-motive force?

A)formation of the spindle
B)ADP and inorganic phosphate uptake into the mitochondrion in exchange for ATP and H⁺,respectively
C)uptake of Ca²⁺ ions into the mitochondrion
D)the events of mitochondrial fusion
E)uptake of specifically targeted proteins into the mitochondrion from the matrix

Question 52

An unusual type of phospholipid is found in the myelin sheath that insulates brain axons; abnormalities in the synthesis of this phospholipid can lead to severe neurological dysfunction.What are these phospholipids called?

A)plasmins
B)sphingolipids
C)plasmalogens
D)insulins
E)luciferases

Question 53

What is the purpose of uncoupling proteins in mammalian brown adipose tissue?

A)They give the tissue its color.
B)They help the tissue expand and contract when needed.
C)They function as a source of heat production during exposure to cold temperatures.
D)They allow the production of a larger number of ATPs per glucose.
E)They allow muscles to contract more efficiently.

Question 54

Which of the following is true of peroxisomes?

A)Peroxisomes may contain a dense,crystalline core of oxidative enzymes.
B)Peroxisomes contain more than 50 enzymes involved in diverse activities.
C)Peroxisomes contain enzymes that oxidize very-long-chain fatty acids.
D)Peroxisomes contain the enzyme luciferase,which generates the light emitted by fireflies.
E)All of these are correct.

Question 55

How many catalytic sites does ATP synthase possess?

A)1
B)2
C)3
D)6
E)4

Question 56

Why did DNP kill patients who took the drug to help them lose weight?

A)It caused the patients to oxidize their fat stores in a vain attempt to maintain normal ATP levels.
B)It blocked hemoglobin.
C)It caused an infection.
D)It caused total paralysis.
E)It prevented the patients from breathing.

Question 57

What properties do mitochondria share with peroxisomes?

A)Both form by splitting from preexisting organelles,using some of the same proteins to accomplish the feat.
B)Both import preformed proteins from the cytosol.
C)Both engage in similar types of oxidative metabolism.
D)At least one enzyme is found in the mitochondria of some mammals and the peroxisomes of others.
E)All of these are correct.

Question 58

The F₀ base of ATP synthase serves as a(n)______.

A)enzyme that synthesizes ATP
B)enzyme that hydrolyzes ATP
C)channel that conducts protons from the intermembrane space back to the matrix
D)channel that conducts protons from the matrix back to the intermembrane space
E)proton pump

Question 59

What energy source other than ATP hydrolysis do mitochondria,unlike most other organelles,routinely use to power their activities?

A)ADP hydrolysis
B)proton-motive force
C)Na⁺ ion gradient
D)K⁺ ion gradient
E)Ca²⁺ gradient

Question 60

The energy released by proton movement through ATP synthase ___________.

A)directly phosphorylates ADP to ATP
B)increases the binding affinity of the active site for the ATP product
C)directly phosphorylates ATP to ADP
D)decreases the binding affinity of the active site for the ATP product
E)directly phosphorylates AMP to ATP

Question 61

Where did peroxisomes get their name? How is the toxic hydrogen peroxide generated by these organelles disposed of? What is the specialized type of peroxisome found in plant seedlings and what specialized function do these organelles perform?

Question 62

How many carbons from an original glucose molecule get into the TCA cycle? What happens to the carbons that do not enter the cycle?

Question 63

A preparation of submitochondrial particles is made.The particles are able to oxidize substrates,generate a proton gradient and make ATP.If the particles are treated with urea,what happens? If DNP is added,what happens? How does DNP make the inner mitochondrial membrane permeable to protons?

Question 64

Given the overall equation for respiration: C₆H₁₂O₆ + 6O₂ <-> 6CO₂ + 6H₂O,at what point in respiration are the reactants used up and the products made?

Question 65

You have isolated some muscle cells in a tissue culture system.You are able to get them to contract in culture.If you add an inhibitor of the electron transport system to these cells,they do not contract quite as much,but they still contract noticeably.What kind of muscle fiber type are you employing?

Question 66

You are studying the enzyme kinetics of enzymes in the TCA cycle.You add a molecule to the mixture that appears to act as a competitive inhibitor of one of the enzymes.At first,you cannot tell which enzyme is inhibited,but you can tell that it is bound to the inner mitochondrial membrane.Can you guess which TCA enzyme you have inhibited and how do you know?

Question 67

What are some of the diverse activities in which the enzymes found in peroxisomes are involved?

Question 68

You prepare red blood cell ghosts with a very high internal potassium ion concentration and a very high external sodium ion concentration,higher than normally exists in the body.The red blood cell ghost also contains ADP and inorganic phosphate ions in the interior and the Na⁺-K⁺ pump in the membrane.What happens?

Question 69

Which reaction releases more free energy - the removal of a phosphate group from creatine phosphate or the removal of a phosphate group from ATP?

Question 70

You are a world-wide expert in mitochondria.If an investigator tells you that he wishes to study mitochondrial uncoupling proteins,what kind of organism would you suggest he use as a source of the protein? What is the function of brown adipose tissue? Humans lose brown fat deposits as they age.How does that happen and how do humans maintain body temperature when the brown fat is gone? Uncoupling protein (UCP)isoforms are found in cells of the nervous system.While their roles are debated,what is the most prominent hypothesis that may explain their function?

Question 71

There are four large complexes of electron transport molecules in the inner mitochondrial membrane.There are also two smaller proteins that carry electrons between the complexes.What is a possible reason for the much smaller size of these shuttle proteins,cytochrome c and ubiquinone?

Question 72

You treat some cells with DNP and discover that ATP production ceases.Upon closer examination,you also note that the number of calcium ions sequestered in the mitochondrion decreases.Please explain.

Question 73

Which organelle below is not found in both plants and animals?

A)cell membrane
B)mitochondria
C)peroxisomes
D)glyoxysomes
E)vacuoles

Question 74

How can biologists be sure that the appearance of photosynthetic organisms preceded that of aerobic organisms in the Earth's evolutionary history?

Question 75

In addition to driving the synthesis of ATP,what other processes in the mitochondria are driven by the proton-motive force?

Question 76

Rat liver mitochondria are isolated and placed in an assay medium.What happens to the pH of the medium when the medium is kept anaerobic? What happens when O₂-saturated saline is added to the mixture?

Question 77

What properties do mitochondria and peroxisomes have in common?

Question 78

If fatty acids are a more efficient storehouse of energy than glucose or glycogen,why aren't they used immediately to drive muscle contraction?

Question 79

Observations of two different cell types indicate a couple of differences in their mitochondria.Cell type 1 has 2-3 times the mitochondria of Cell Type 2.The mitochondria in Cell Type 1 are also larger,contain more cristae and the cristae extend farther across the mitochondria than in Cell Type 2.Which cell type is likely to have more extensive energy requirements?

Question 80

A doctor in a hospital emergency room sees an obese patient who has come into the emergency room.He has been losing weight rapidly but complains that he has lost energy and is tired most of the time.During his interview with the patient,the doctor thinks he has discovered what is causing the man's condition.What do you think he has found?