Practice Test Questions (Cellular Respiration)

Which of the following best describes the electron transport chain?

Electrons are passed from one carrier to another, releasing a little energy at each step.

Which of the following is a correct description of the events of cellular respiration and the sequence of events in cellular respiration?

Oxidation of glucose to pyruvate; oxidation of pyruvate; oxidation of acetyl-coA; oxidative phosphorylation

During the reaction C6H12O6 + 6 O2 → 6 CO2 + 6 H2O, which compound is reduced as a result of the reaction?

Oxygen In cellular respiration, glucose is oxidized to carbon dioxide and oxygen is reduced to water.

In preparing pyruvate to enter the citric acid cycle, which of the following steps occurs?

Pyruvate is oxidized and decarboxylated, and the removed electrons are used to reduce an NAD+ to an NADH.

Most of the electrons removed from glucose by cellular respiration are used for which of the following processes?

Reducing NAD+ to NADH in glycolysis and the citric acid cycle AND producing a proton gradient for ATP synthesis in the mitochondria.

Which part of the catabolism of glucose by cellular respiration requires molecular oxygen (O2) and produces CO2?

The combination of the citric acid cycle and electron transport

Why is the citric acid cycle called a cycle?

The four-carbon acid that accepts the acetyl CoA in the first step of the cycle is regenerated by the last step of the cycle.

Where do the reactions of the citric acid cycle occur in eukaryotic cells?

The matrix of the mitochondrion The citric acid cycle, which takes place in the mitochondrial matrix, completes the degradation of glucose.

If muscle cells in the human body consume O2 faster than it can be supplied, which of the following is likely to result?

The muscle cells will have more trouble making enough ATP to meet their energy requirements.The cells will not be able to carry out oxidative phosphorylation.The cells will consume glucose at an increased rate.

In glycolysis, there is no production of carbon dioxide as a product of the pathway. Which of the following is the best explanation for this?

The products of glycolysis contain the same total number of carbon atoms as in the starting material.

When protein molecules are used as fuel for cellular respiration, __________ are produced as waste.

amino groups

During aerobic respiration, molecular oxygen (O2) is used for which of the following purposes?

at the end of the electron transport chain to accept electrons and form H2O

In an experiment, mice were fed glucose (C6H12O6) containing a small amount of radioactive oxygen. The mice were closely monitored, and after a few minutes radioactive oxygen atoms showed up in __________.

carbon dioxide

Of the metabolic pathways listed below, which is the only pathway found in all organisms?

glycolysis

Which process is the one in which glucose is oxidized to generate two molecules of pyruvate, and in which ATP and NADH are produced?

glycolysis

The function of cellular respiration is to __________.

harvesting usable energy from glucose

During respiration in eukaryotic cells, the electron transport chain is located in or on the __________.

inner membrane of the mitochondrion

Sports physiologists at an Olympic training center wanted to monitor athletes to determine at what point their muscles were functioning anaerobically. They could do this by checking for a buildup of which of the following compounds?

lactate (lactic Acid)

A molecule becomes more oxidized when it __________.

loses an electron

Which of the following substances is/are involved in oxidative phosphorylation?

ADP, oxygen, and ATP.

Which of the following is the source of the energy that produces the chemiosmotic gradient in mitochondria?

Electrons moving down the electron transport chain

After completion of the citric acid cycle, most of the usable energy from the original glucose molecule is in the form of __________.

NADH

Each ATP molecule contains about 1% of the amount of chemical energy available from the complete oxidation of a single glucose molecule. Cellular respiration produces about 32 ATP from one glucose molecule. What happens to the rest of the energy in glucose?

It is converted to heat.

In glycolysis in the absence of oxygen, cells need a way to regenerate which compound?

NAD+

Which of the following statements is the best explanation of what happens to the temperature and carbon dioxide concentration during a one-hour class period in a classroom of 300 students if the heating and air conditioning is turned off and all doors are kept closed?

Temperature and the level of carbon dioxide rise as heat and carbon dioxide are by-products of cellular respiration.

If a compound that allows protons to freely diffuse across membranes is added to cells that are actively metabolizing glucose via cellular respiration, which of the following processes would stop?

The chemiosmotic synthesis of ATP would stop in the mitochondria, but substrate-level phosphorylation could continue.

Most of the NADH that delivers electrons to the electron transport chain comes from which of the following processes?

citric acid cycle

Where do the reactions of glycolysis occur in a eukaryotic cell?

cytosol

Fermentation is essentially glycolysis plus an extra step in which pyruvate is reduced to form lactate or alcohol and carbon dioxide. This last step __________.

enables the cell to recycle the reduced NADH to oxidized NAD+

Which of the following represents the major (but not the only) energy accomplishment of the citric acid cycle?

formation of NADH and FADH2

How many molecules of ATP are gained by substrate-level phosphorylation from the complete breakdown of a single molecule of glucose in the presence of oxygen?

four

In the overall process of glycolysis and cellular respiration, __________ is oxidized and __________ is reduced.

glucose ... oxygen In cellular respiration, electrons and hydrogen are removed from glucose and added to oxygen.

Most of the ATP produced in cellular respiration comes from which of the following processes?

oxidative phosphorylation

Muscle tissues make lactate from pyruvate to do which of the following?

regenerate NAD+