exam 3

__ Is a product of glycolysis, pyruvate processing, and the citric acid cycle

NADH

Which process does not occur within a mitochondrion in a eukaryotic cell?

Glycolysis

The glucose molecule has a large quantity of energy in its __

C-H bonds

What is the term for metabolic pathways that release stored energy by breaking down complex molecules?

Catabolic pathways

The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction

Loses electrons and loses potential energy

When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction the molecule becomes

Oxidized

Which of the following statements about NAD+ is TRUE?

NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle

How many oxygen molecules (O2) are required each time a molecule of glucose (C6H12O6) is completely oxidized to carbon dioxide and water via aerobic respiration?

6

What is the major adaptive advantage of cellular respiration?

To produce adenosine triphosphate (ATP)

What kind of molecules serve as electron acceptors in cellular respiration?

Molecules with low potential energy

Which process in eukaryotic cells will proceed normally wether oxygen (O2) is present or absent?

Glycolysis

In addition to ATP, what are the end products of glycolysis?

2 NADH, 2 pyruvate, and 2 ATP

Starting with one molecule of glucose, the energy-containing products of glycolysis are__

2 NADH, 2 pyruvate, and 2 ATP

Why is glycolysis described as having an investment phase and a payoff phase?

It uses stored ATP and then forms a net increase in ATP

Why is glycolysis considered to be one of the first metabolic pathways to have evolved?

It does not involve organelles or special structures, does not require oxygen, and is present in most organisms.

The process of photosynthesis probably originated

In prokaryotes

If photosynthesizing green algae are provided with CO2 containing heavy oxygen (18O), later analysis will show that all of the following molecules produced by the algae contain 18O EXCEPT __

O2

Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?

ATP and NADPH

When oxygen is released as a result of photosynthesis, it is direct by product of __

Splitting water molecules

Which of the following statements best describes the relationship between photosynthesis and respiration?

Photosynthesis stores energy in complex molecules; respiration releases energy from complex organic molecules

In photosynthetic cells, synthesis of ATP by the chemiosmotic mechanism occurs during

Photosynthesis and respiration

Plants photosynthesize

Only in the light but respire in light and dark

Chlorophylls absorb most light in which colors of the visible range?

Violet and red

Which of the following is a difference between chlorophyll a and chlorophyll b

Chlorophyll a and b absorb light energy at slightly different wavelengths

Why are there several structurally different pigments in the reaction center of photosystems

This arrangement enables the plant to absorb light energy of a variety of wavelengths

Glycolysis is active when cellular energy levels are ; the regulatory enzyme, phosphofructokinase, is __ by ATP

High; inhibited

During cellular respiration, acetyl CoA accumulates in which location

Mitochondrial matrix

Even though plant cells photosynthesize, they still use their mitochondria for oxidation of pyruvate. This will occur in

Photosynthetic cells in the light, while photosynthesis occurs concurrently

Pyruvate dehydrogenase activity would be at its lowest when

Pyruvate dehydrogenase is phosphorylated

Following glycolysis and the citric acid cycle, but before the electron transport chain and oxidative phosphorylation, the carbon skeleton of glucose has been broken down to CO2 with some net gain of ATP. Most of the energy from the original glucose molecule at that point in the process, however, is in the form of

NADH

Which electron carrier(s) function in the citric acid cycle

NADH and FADH2

Carbon dioxide (CO2) is released during which of the following stages of cellular respiration?

Oxidation of pyruvate to acetyl CoA and the citric acid cycle

The oxygen consumed during cellular respiration is involved directly in which process or event

Accepting electrons at the end of the electron transport chain

Which of the following events takes place in the electron transport chain

The extraction of energy from high-energy electrons remaining from glycolysis and then citric acid cycle

C6H12O6 (glucose) + 6 O2 → 6 CO2 + 6 H2O. Where is most of the water in this reaction produced

In the electron transport chain

The primary role of oxygen in cellular respiration is to

Act as an acceptor for electrons and hydrogen, forming water

Energy released by the electron transport chain is used to pump H+ into which location in eukaryotic cells

Mitochondrial intermembrane space

Which of the following procedures the most ATP when glucose (C6H12O6) is completely oxidized to carbon dioxide and water

Oxidative phosphorylation (chemiosmosis)

The synthesis of ATP by oxidative phosphorylation, using the energy released by movement of protons across the membrane down their electrochemical gradient, is an example of

An endergonic reaction coupled to an exergonic reaction

When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs

The pH of the matrix increases

The antenna complex in a photosystem:

Captures photons from sunlight

The proteins of the electron transport chain active in the light-dependent reactions

Are membrane proteins present in the thylakoid

What is the difference between NAD+ and NADP

Both function as electron carries, but NADP has a phosphate group and NAD+ does not

As electrons are passed through the system of electron carries associated with photosystem II, they lose energy. What happens to it’s energy

It is used to establish and maintain a proton gradient

Plastoquinone (PQ), an electron carrier of small molecular weight, is found in the electron transport chain associated with photosystem Il. If PQ is not directly anchored to other membrane or cytoplasmic structures, it is probably

Mobile in the thylakoid membrane

The electrons of photosystem Il are excited and transferred to electron carriers. From which molecule or structure do the photosystem II replacement electrons come?

Water

What is the main purpose of light dependent reactions of photosynthesis

To produce NADPH and ATP

Which of the events listed below occurs in the light reactions of photosynthesis

Light is absorbed and funneled to reaction-center chlorophyll a

Which statement describes the functioning of photosystem ll

Light energy excites electrons in they thylakoid membrane electron transport chain

Which of the following is directly associated with photosystem l

Receiving electrons from the thylakoid membrane electron transport chain

Which of the following is an example of potential rather than kinetic energy

A molecule of glucose

Which term most precisely describes the cellular process of breaking down large molecules into smaller ones

Catabolism (catabolic pathways)

Zinc, an essential trace electron for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as

A cofactor necessary for enzyme activity

Anabolic pathways

Consume energy to buildup polymers from monomers

For living organisms, which of the following is an important consequence of the first law of thermodynamics

The organisms ultimately must obtains all of the necessary energy for life from its environment

Which of the following is a statement of the first law of thermodynamics

Energy cannot be created or destroyed

The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway is most precisely described as

Feedback inhibition

When chemical transport or mechanical work is done by an organism, what happens to the heat generated

It is lost to the environment

An allosteric inhibitor decreases the rate of an enzyme reaction by

Changing the shape of the enzymes active site

What is the most common form of kinetic energy that is released from chemical energy in chemical reactions

Thermal