Biochem Continued

Front 1

2,3-bisphosphoglycerate is

Back 1

essential for the efficient release of O2 from hemoglobin

Front 2

A hyperbolic binding curve differs from a sigmoidal binding curve in that the hyperbolic curve

Back 2

has a single equilibrium constant for oxygen binding.

Front 3

A plot of the binding of oxygen to myoglobin as a function of pO2 gives a _____ shape; a similar plot for hemoglobin gives a _____ shape.

Back 3

hyperbolic; sigmoidal

Hint 3

A plot of the binding of oxygen to myoglobin as a function of pO2 gives a hyperbolic shape; a similar plot for hemoglobin gives a sigmoidal shape.

Front 4

ATP nhibits activity of phosphofructokinase (PFK) allosterically

Back 4

ATP nhibits activity of phosphofructokinase (PFK) allosterically

Front 5

Aerobic glycolysis produces a net yield of ______ ATP.

Back 5

2

Hint 5

Aerobic glycolysis produces a net yield of two ATP.

Front 6

All ten steps of the glycolytic pathway must have negative free energies for glycolysis to proceed.

Back 6

False

Front 7

An enzyme not involved in the control of glycolysis is

Back 7

triose phosphate isomerase.

Front 8

Enzymes used in Glycolysis

Back 8

hexokinase

pyruvate kinase

phosphofructokinase

Front 9

Compared to pyruvate, the carbon atoms in lactate

Back 9

are more reduced

Front 10

Conditions in the tissues which enhance the delivery of oxygen by hemoglobin are the presence of

Back 10

carbon dioxide

2,3 BPG

protons

Front 11

Cooperative binding and allosterism of hemoglobin allow oxygen to be unloaded at low partial pressures of oxygen in the tissues

Back 11

True

Front 12

During glycolysis, isomerization occurs during which of the following reactions?

Back 12

Glucose 6- phosphate ----> fructose 6- phosphate

Front 13

During reactions utilizing the enzymes shown below, in which case(s) is ATP produced?

Back 13

2 and 3

Phosphoglycerate Kinase (PGK)

Pyruvate Kinase (PK)

Front 14

Fill in the missing reagents in the following reaction.

Back 14

Reactant: NADH + H(+)

Product: NAD (+)

Front 15

Four molecules of ATP are consumed per glucose during the hexose stage of glycolysis.

Back 15

False

Front 16

Glucose is converted to ______ in skeletal muscle under anaerobic conditions.

Back 16

Lactate

Hint 16

Glucose is converted to lactate in skeletal muscle under anaerobic conditions.

Front 17

Glucose is normally transported into cells by an active transport protein since the concentration of glucose inside cells is normally higher than that in the blood.

Back 17

False

Hint 17

Glucose is not normally transported into cells by an active transport protein since the concentration of glucose inside cells is normally higher than that in the blood.

Front 18

Glyceraldehyde-3-phosphate dehydrogenase oxidizes

Back 18

an aldehyde to a carboxylic acid

Front 19

Glycolysis

Back 19

does not require O2 to generate energy.

Front 20

Glycolysis occurs in the cytosol of eukaryotes.

Back 20

Glycolysis occurs in the cytosol of eukaryotes.

Hint 20

True

Front 21

Hamsters love to run on exercise wheels. Prolonged running at a high rate of speed requires ATP. Could a hamster with a defective gene for the enzyme lactate dehydrogenase meet the extra ATP demand for prolonged, fast wheel-running by maintaining a high rate of glycolysis? Why or why not?

Back 21

No, not enough NAD+ can be regenerated for glycolysis to continue at a high rate

Front 22

Hemoglobin is

Back 22

a dimer of subunits each with two distinct protein chains (alpha and beta).

Front 23

How many ATP molecules are consumed in glycolysis for every one molecule of glucose?

Back 23

Two

Front 24

If glucose labeled at the C-1 position with 14C passes through glycolysis, on which carbon of pyruvate will the radiolabel be found?

Back 24

Carbon 3

Front 25

in glycolysis, the net gain of ATP during the energy investment phase is _____ while the net gain of ATP during the energy payoff phase is _____.

Back 25

-2, 4

Hint 25

n glycolysis, the net gain of ATP during the energy investment phase is -2 while the net gain of ATP during the energy payoff phase is 4.

Front 26

In glycolysis, there is a net yield of two molecules of ATP per molecule of glucose.

Back 26

True

Front 27

In skeletal muscle cells, oxidation of NADH generated from anaerobic glycolysis occurs during which of the following reactions?

Back 27

pyruvate → lactate

Front 28

In which of the following metabolic conversions is ATP required during glycolysis?

Back 28

1 & 2

1: fuctose-6-phosphate ---> fructose-1,6-biphosphate

2: glucose ----> glucose-6-phosphate

Front 29

In which reaction above is ATP required?

Back 29

2 only

2: Glucose ---> glucose-6-phosphate (G6P)

Front 30

Mutases are described as

Back 30

isomerases that catalyze the transfer of phosphoryl groups from one part of a substrate molecule to another.

Front 31

Myoglobin and a single chain of hemoglobin have similar ______ structures.

Back 31

Tertiary

Hint 31

Myoglobin and a single chain of hemoglobing have similar tertiary strucutres

Front 32

Myoglobin has a greater affinity for oxygen than hemoglobin.

Back 32

True

Hint 32

Myoglobin has a greater affinity for oxygen than hemoglobin.

Front 33

Myoglobin’s secondary structure is primarily composed of

Back 33

alpha-helices

Front 34

Once inside a cell, glucose is rapidly phosphorylated to glucose-6-phosphate. What is the main purpose of this phosphorylation?

Back 34

to keep glucose inside the cell

Front 35

Phosphofructokinase I deficiency results in

Back 35

an overproduction of Fructose 6-phosphate and fructose 1,6-bisphosphate deficiency only

Front 36

Whate enzyme would catalyze the reaction?

Back 36

hexokinase (HK)

Front 37

The ΔG values for glycolytic reactions at physiological conditions may be exergonic, even though the ΔG°' at "standard" conditions, may be endergonic.

Back 37

True

Front 38

The Bohr effect describes the effect of pH on hemoglobin's ability to bind oxygen. Oxygen binds more tightly at low pH and less tightly at higher pH values.

Back 38

False

Front 39

The Bohr effect refers to

Back 39

the decrease in affinity of Hb for O2 when the pH goes down

Front 40

The central ion of the heme group of hemoglobin is

Back 40

Fe 2+

Front 41

he enzyme responsible for the synthesis of fructose-2,6-bisphosphate is

Back 41

phosphofructokinase-2

Front 42

The enzyme that catalyzes the conversion of pyruvate to lactate is ________.

Back 42

lactate dehydrogenase

Front 43

The enzymes that catalyze glycolysis are located in the

Back 43

cytosol.

Front 44

The equilibrium for isomerization of dihydroxyacetone phosphate to glyceraldehyde-3-phosphate is favored because

Back 44

glyceraldehyde-3-phosphate is being continuously drained off for the subsequent reaction in the glycolytic pathway

Front 45

The equilibrium for the formation of glyceraldehyde-3-phosphate from dihydroxyacetone phosphate is driven by

Back 45

having the product of the reaction continuously consumed

Front 46

The idea that binding of one molecule of oxygen to hemoglobin enhances further binding of oxygen to hemoglobin is called _____.

Back 46

cooperatively

Hint 46

The idea that binding of one molecule of oxygen to hemoglobin enhances further binding of oxygen to hemoglobin is called cooperatively.

Front 47

The main property of myoglobin and hemoglobin that makes them an efficient system for oxygen delivery from lungs to muscles is

Back 47

different binding affinities for oxygen.

Front 48

The most rapid way that erythrocytes adapt to high altitudes is

Back 48

by increasing the intracellular concentration of BPG.

Front 49

The phosphorylation of glucose to glucose 6-phosphate

Back 49

is an endergonic reaction that takes place because it is coupled to the exergonic hydrolysis of ATP.

Front 50

The reaction catalyzed by PFK-1 is metabolically reversible.

Back 50

False

Front 51

The reaction catalyzed by the enzyme aldolase has a ΔG˚' ≈ +23 kJ/mol. In muscle cells, the reaction proceeds in this same, forward direction. How can this occur?

Back 51

The concentration of reactant(s) must be significantly greater than product(s) in cells.

Front 52

The reaction of carbonic anhydrase catalyzes

Back 52

the hydration of carbon dioxide, forming bicarbonate and protons.

Front 53

The reduction of pyruvate to lactate

Back 53

allows for recycling of NAD+.

Front 54

Transfer of a high-energy phosphoryl group to ADP, resulting in ATP occurs when:

Back 54

Both 1,3-bisphosphoglycerate 3-phosphoglycerate and phosphoenolpyruvate (PEP) pyruvate

Front 55

Two molecules of ATP are consumed per glucose during the triose stage of glycolysis.

Back 55

False

Hint 55

False

Front 56

Two molecules of ATP are consumed per glucose molecule during the hexose stage of glycolysis.

Back 56

True

Front 57

Two molecules of ATP are produced per glucose during the hexose stage of glycolysis.

Back 57

False

Front 58

Under anaerobic conditions in skeletal muscle, pyruvate is converted into

Back 58

lactate

Front 59

Under what situation might lactic acidosis occur?

Back 59

Oxygen supply to tissues is inadequate.

Front 60

What is the name of the pictured glycolytic intermediate?

Back 60

3-phosphoglycerate

Front 61

What kind of enzyme catalyzes the reaction shown?

Back 61

A dehydrogenase

Front 62

What sort of activity does fructose-1,6-bisphosphate have on pyruvate kinase?

Back 62

feed-forward activator

Front 63

Which enzyme catalyzes the reaction?

Back 63

pyruvate kinase

Front 64

Which enzyme catalyzes the reaction shown?

Back 64

An isomerase

Front 65

Which enzyme is the key regulatory enzyme in glycolysis?

Back 65

phosphofructinase

Front 66

Which group of small molecules best fit the boxes associated with the reaction shown?

Back 66

Four: NAD+ , NADH, Pi

Front 67

Which of the following best describes the control exhibited by phosphofructokinase (PFK)?

Back 67

It is allosterically inhibited by ATP and citrate.

It is allosterically activated by F2,6P

Front 68

Which of the following enzymes catalyzes the transfer of a phosphoryl group from ATP to glucose?

Back 68

hexokinase

Front 69

Which of the following enzymes interconverts an aldose and a ketose?

Back 69

isomerase

Front 70

Which of the following enzymes of glycolysis is not involved in regulation of the pathway?

Back 70

Aldolase

Front 71

Which of the following is not a metabolically irreversible enzymatic reaction of glycolysis?

Back 71

The first irreversible reaction unique to the glycolytic pathway, the committed step, (Section 10.2), is the phosphorylation of fructose 6-phosphate to fructose 1,6-bisphosphate.

Front 72

Which of the following metabolic conversions is considered to be the major control point of glycolysis?

Back 72

fructose-6-phosphate → fructose-1,6-bisphosphate

Front 73

Which of the following terms describes an enzyme that catalyzes electron transfer reactions?

Back 73

dehydrogenase

Front 74

Which substance causes muscles to ache during strenuous exercise?

Back 74

lactic acid

Front 75

While the binding of O2 to myoglobin as a function of pO2 is described by a simple __________ curve, the binding to hemoglobin is described by a more complex ______ curve.

Back 75

hyperbolic, sigmoidal

Hint 75

While the binding of O2 to myoglobin as a function of pO2 is described by a simple hyperbolic curve, the binding to hemoglobin is described by a more complex sigmoidal curve.

Front 76

With a ΔG°′ of -16.7 kJ/mol, the reaction catalyzed by hexokinase is considered to be

Back 76

metabolically irreversible

Front 77

With respect to oxygen saturation, hemoglobin is _____ saturated at the pO2 of the lungs and _____ saturated at the pO2 of the tissue.

With respect to oxygen saturation, hemoglobin is _____ saturated at the pO2 of the lungs and _____ saturated at the pO2 of the tissue.

Back 77

>90%; between 30 and 70%

Hint 77

With respect to oxygen saturation, hemoglobin is > 90% saturated at the pO2 of the lungs and between 30% and 70% saturated at the pO2 of the tissue.