Biology 108: Chapters 9/10

The ΔG for hydrolysis of ATP to ADP and Pi is _______ kcal/mole.

-7.3

Glycolysis yields a net gain of _______ ATP molecules per molecule of glucose.

2

In aerobic cells, the complete oxidation of glucose via glycolysis and the citric acid cycle yields _______ molecules of ATP per molecule of glucose.

32

What does the alcoholic fermentation pathway have in common with the oxidation of pyruvate under aerobic conditions?

CO2 is a product of each reaction

The mobile carrier that transfers electrons from Complex I or II to Complex III of the electron transport chain is called _______.

CoQ, or enzyme Q

In addition to the three molecules of NADH produced per molecule of acetate introduced into the citric acid cycle, one molecule of an additional reduced cofactor called _______ is produced.

FADH2

T/F: Approximately 50 percent of the chemical reactions in cells are catalyzed by enzymes.

False

T/F: Glucose is synthesized by chemical reactions that are the reverse of glycolysis.

False

T/F: Glycolysis starts from glucose or fatty acids.

False

T/F: Most of the ATP derived from the breakdown of glucose in aerobic cells is derived from glycolysis.

False

In the light reactions of photosynthesis,

H2O is converted to O2 and NADP+ is reduced to NADPH.

The ultimate acceptor of electrons from the electron transport chain is _______.

O2

T/F: ATP serves to transfer energy from energy-producing to energy-requiring reactions.

True

T/F: Coenzymes function in conjunction with enzymes to carry chemical groups between substrates.

True

T/F: In photosynthesis, energy from sunlight is used to drive the synthesis of ATP and NADPH.

True

T/F: Most of the ATP derived from the breakdown of glucose in anaerobic cells is derived from glycolysis.

True

T/F: Some enzymes participate directly in the chemical reactions they catalyze.

True

T/F: The activity of enzymes can be controlled by the binding of small molecules, by interaction with other proteins, and by covalent modifications.

True

The citric acid cycle involves the addition of two carbons from the compound _______ to the four-carbon oxaloacetate to produce the six-carbon compound _______.

acetyl CoA; citrate, or citric acid

A reaction in which the substrate glucose binds to the enzyme hexokinase and the configuration of both molecules changes is an example of

an induced fit mechanism

During oxidation of a fatty acid, the fatty acid is joined to the molecule _______ and is broken down by stepwise removal of _______-carbon units as part of the molecule _______, which can then enter the citric acid cycle to be metabolized.

coenzyme A; two; acetyl CoA

In eukaryotic cells, glycolysis takes place in the

cytosol

Enzymes act by

decreasing the activation energy

How many electron pairs are removed from carbohydrate intermediates within the Krebs Cycle per molecule of glucose undergoing oxidation?

eight

In allosteric regulation, binding of a small, regulatory molecule to an enzyme _______ the enzyme activity.

either stimulates or inhibits

The hydrolysis of ATP to ADP and phosphate allows glucose-6-phosphate to be synthesized from glucose and phosphate because the

enzymatic coupling of these two reactions allows the energy of ATP hydrolysis to drive the synthesis of glucose-6-phosphate

Under anaerobic conditions, the NADH produced by glycolysis is recycled by a reaction that produces NAD+ and

ethanol or lactate

How many redox reactions occur in one turn of the Citric Acid Cycle?

four

How many total electron pairs are accepted by NAD+ , the oxidant form of the coenzyme, in the oxidation of glucose through acetyl-CoA?

four

Glycolysis produces four molecules of ATP from each molecule of fructose-1,6- bisphosphate because

fructose-1,6-bisphosphate is converted into two molecules of 1,3-bisphosphoglycerate, each of which produces two ATPs in being metabolized to pyruvate.

The Calvin cycle (dark reactions) can occur

in the absence of light.

Like other catalysts, enzymes

increase the rate of reactions without being consumed in reactions do not alter the chemical equilibrium between reactants and products

Which statement below best describes the usual relationship of the inhibitor molecule to the allosteric enzyme in feedback inhibition of enzyme activity?

inhibitor is final product of metabolic pathway

The free-energy change of a reaction is determined by the

intrinsic properties of the reactants and products concentrations of the reactants and products temperate of the reactants and products

Under anaerobic conditions, pyruvate is converted to either _______ or _______.

lactate; ethanol

In eukaryotic cells, the citric acid cycle occurs in the

mitochondria

Many coenzymes are vitamins because vitamins are

necessary components in the human diet

ATP is produced in mitochondria by a process called _______.

oxidative phosphorylation

In glycolysis, the key control enzyme that is inhibited by excess ATP is

phosphofructokinase

Under aerobic conditions, the end product of glycolysis is

pyruvate

Under anaerobic conditions, the end product of glycolysis is

pyruvate

Coenzymes are

small molecules that work with an enzyme to enhance reaction rate

Fatty acids are broken down in a stepwise process, _______ carbons at a time.

two

Glycolysis produces _______ molecules of ATP per molecule of glucose.

two

How many total Redox reactions occur when glucose is converted to pyruvate?

two

In anaerobic cells, the complete oxidation of glucose via glycolysis and the citric acid cycle yields _______ molecules of ATP per molecule of glucose

two