Chapter 6 MasteringBiology

In glycolysis, what starts the process of glucose breakdown?

ATP

Why is the citric acid cycle called a cycle?

Acetyl CoA binds to oxaloacetate and this compound is restored at the end of the cycle.

Which of these is NOT a product of glycolysis?

FADH2

Given the relatively modest number of calories burned by anything but the most vigorous activities, why can people consume over 2,000 kilocalories a day, yet maintain a healthy body weight?

Most of the energy consumed in food is spent maintaining the body's functions, so only a fraction of food energy needs to be burned in exercise.

Which of the following processes produces the most ATP per molecule of glucose oxidized?

aerobic respiration

A small amount of ATP is made in glycolysis _____.

by the transfer of a phosphate group from a fragment of glucose to ADP (substrate-level phosphorylation)

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

carbon dioxide

Each turn of the citric acid cycle generates one ATP and ___ additional energy-rich molecules: __________.

four; 3 NADH and 1 FADH2

Arsenic is a poison that binds to a molecule needed to build acetyl CoA. Based on this information, which part of cellular respiration would be stopped if arsenic were ingested?

citric acid cycle

What is the name of the process in which glucose is converted to pyruvate?

glycolysis

Primarily, cellular respiration serves to _____.

make ATP to power the cell's activities

Lungs are to breathing as _____ are to cellular respiration.

mitochondria

The electron transport chain is a series of electron carrier molecules. In eukaryotes, where can this structure be found?

mitochondria

In cellular respiration, most ATP molecules are produced by _____.

oxidative phosphorylation

The final electron acceptor of cellular respiration is _____.

oxygen

The conversion of CO2 and H2O into organic compounds using energy from light is called

photosynthesis

A molecule that functions as the electron donor in a redox reaction __________.

loses electrons and becomes oxidized

For each glucose that enters glycolysis, _____ NADH enter the electron transport chain.

10

How many NADH are produced by glycolysis?

2

In glycolysis there is a net gain of _____ ATP.

2

During electron transport, energy from _____ is used to pump hydrogen ions into the _____.

NADH and FADH2 ... intermembrane space

During fermentation, __________ that was produced during glycolysis is converted back to __________.

NADH; NAD+

What is the purpose of embedding the electron transport chain in the membrane of a cell?

The membrane is impermeable to H+.

What is the ultimate fate of the electrons that are stripped from glucose during cellular respiration?

They are used to form water.

How do cells capture the energy released by cellular respiration?

They produce ATP

A chemist has discovered a drug that blocks phosphoglucoisomerase, an enzyme that catalyzes the second reaction in glycolysis. He wants to use the drug to treat people with bacterial infections. However, he can't do this because _____.

human cells also perform glycolysis; the drug might also poison them

The proximate (immediate) source of energy for oxidative phosphorylation is _____.

kinetic energy that is released as hydrogen ions diffuse down their concentration gradient

In muscle cells, fermentation produces _____.

lactate and NAD+

Sports physiologists at an Olympic training center want to monitor athletes to determine at what point their muscles begin to function anaerobically. They could do this by checking for a buildup of _____.

lactic acid

A muscle cell deprived of molecular oxygen will convert glucose to lactic acid to __________.

recycle NADH through fermentation

In glycolysis, ATP molecules are produced by _____.

substrate-level phosphorylation

Oxidative phosphorylation could not occur without glycolysis and the citric acid cycle, because _____.

these two stages supply the electrons needed for the electron transport chain

Fat is the most efficient molecule for long-term energy storage even compared to carbohydrates because _____.

with their numerous hydrogen atoms, fats provide an abundant source of high-energy electrons