Biology Chapter 6: Cellular Respiration

During glycolysis, a molecule of glucose is partially oxidized. What is the net gain of ATP and NADH for each glucose molecule?

2 ATP and 2 NADH

At the end of the citric acid cycle, most of the energy remaining from the original glucose is stored in

NADH.

What is the role of oxygen in cellular respiration?

Oxygen accepts high-energy electrons after they are stripped from glucose.

How do cells capture the energy released by cellular respiration?

They produce ATP.

Through respiration, humans breathe in O2 and breathe out CO2. However, what would happen if we did not breathe in O2?

We would not make enough ATP to meet our energy requirements

Where does most of the ATP produced in cellular respiration come from?

chemiosmosis

During cellular respiration, NADH

delivers its electron load to the first electron carrier molecule

Which of the following are products of cellular respiration?

energy to make ATP and carbon dioxide

The function of cellular respiration is to _____.

extract usable energy from glucose

During redox reactions,

electrons are lost from one substance and added to another substance.

Which of the following processes takes place in the cytosol of a eukaryotic cell?

glycolysis

During which of the following phases of cellular respiration does substrate-level phosphorylation take place?

glycolysis and the citric acid cycle

Select the correct sequence of steps as energy is extracted from glucose during cellular respiration.

glycolysis → acetyl CoA → citric acid cycle → electron transport chain

Glycolysis is the only stage of cellular respiration that _____.

requires ATP to make ATP

Which step of the citric acid cycle requires both NAD+ and ADP as reactants?

step 3

Cellular respiration accomplishes two major processes: (1) it breaks glucose down into smaller molecules, and (2) it harvests the chemical energy released and stores it in ATP molecules. By the end of _____, the breakdown of glucose is complete; most ATP molecules are produced during _____.

the Citric Acid cycle ... electron transport

The ATP synthase in a human cell gets energy for making ATP directly from _____.

the flow of H+ through a membrane

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

the mitochondrion

Some friends are trying to make wine in their basement. They've added yeast to a sweet grape juice mixture and have allowed the yeast to grow. After several days they find that sugar levels in the grape juice have dropped, but there's no alcohol in the mixture. The most likely explanation is that

the mixture needs less oxygen, because yeast only produce alcohol in the absence of oxygen.

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

NADH and FADH 2 are important in cellular respiration because they deliver high-energy electrons to the electron transport system. Electron transport produces _____ ATP molecule(s) per NADH molecule and _____ ATP molecules(s) per FADH 2 molecule

three ... two

What happens to the energy that is given up by electrons as they move through the electron transport chain?

It pumps H+ through a membrane.

The electron transport chain is, in essence, a series of redox reactions that conclude cellular respiration. During these redox reactions, _____.

NAD+ is reduced, which then oxidizes an electron acceptor in the electron transport chain

Which statement describes the citric acid cycle?

This process produces some ATP and carbon dioxide in the mitochondrion.

Which statement describes glycolysis?

This process splits glucose in half and produces 2 ATPs for each glucose.

Which statement describes the electron transport chain?

This process uses energy captured from electrons flowing to oxygen to produce most of the ATPs in cellular respiration.

Humans use the calories they obtain from ________ as their source of energy.

food

Pyruvate

forms at the end of glycolysis

Cellular respiration completely breaks down a glucose molecule through glycolysis and the citric acid cycle. However, these two processes yield only a few ATPs. The majority of the energy the cell derives from glucose is _____.

found in NADH and FADH2

As a result of glycolysis there is a net gain of ________ ATPs.

2

How many molecules of NADH are produced during glycolysis?

2

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

A compound called coenzyme A binds to a two-carbon fragment.

What is the correct general equation for cellular respiration?

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + ATP energy

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

aerobic respiration

In yeast cells,

alcohol is produced after glycolysis.

In the electron transport chain, the final electron acceptor is

an oxygen atom

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)

By-products of cellular respiration include

carbon dioxide and water.

Cellular respiration requires fuel (glucose) and oxygen gas. The main process that produces these inputs is _____.

photosynthesis

In oxidative phosphorylation, electrons are passed from one electron carrier to another. The energy released is used to _____.

pump protons (H+) across the mitochondrial membrane

In electron transport, high-energy electrons "fall" to oxygen through a series of reactions. The energy released is used to _____.

transport protons into the intermembrane space of the mitochondria, where they become concentrated. They then flow back out into the the inner compartment (matrix) of the mitochodria. On the way back, protons turn ATP synthase turbines and produce ATP.

What is/are the most important output(s) of glycolysis?

two pyruvic acid and two NADH molecules

The energy production per glucose molecule through the citric acid cycle is _____.

2 ATP, 6 NADH, 2 FADH2

Substrate-level phosphorylation directly generates ATP during a chemical reaction. As a single molecule of glucose is completely oxidized, in the presence of oxygen, how many molecules of ATP are gained by substrate-level phosphorylation?

4 ATP

The overall equation for the cellular respiration of glucose is

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + energy.

Which of the following statements regarding cellular respiration is false?

Cellular respiration is a single chemical reaction with just one step

Glycolysis is the multi-step breakdown of _____. Several different _____ play a role in this process.

glucose ... enzymes

In the equation shown below, during cellular respiration _____ is oxidized and _____ is reduced.

glucose ... oxygen

Which of the following options lists the stages in cellular respiration in the correct order?

glycolysis, the citric acid cycle, and oxidative phosphorylation

Unlike the Citric Acid cycle and electron transport, glycolysis occurs _____.

in the cytoplasm

Where does glycolysis occur in a eukaryotic cell?

in the cytoplasmic fluid

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

loses electrons and loses energy

Oxidation is the ________, and reduction is the ________.

loss of electrons . . . gain of electrons

Primarily, cellular respiration serves to _____.

make ATP to power the cell's activities

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

mitochondria

In what organelle would you find acetyl CoA formation, the citric acid cycle, and the electron transport chain?

mitochondrion

Which part(s) of cellular respiration require(s) oxygen gas?

the Citric Acid cycle and the electron transport chain

Which part(s) of cellular respiration take(s) place in the mitochondria?

the Citric Acid cycle and the electron transport chain

Most of the NADH that delivers high-energy electrons to the electron transport chain comes from _____.

the citric acid cycle

The enzyme ATP synthase catalyzes the phosphorylation of ADP to form ATP. In eukaryotic cells, the energy needed for this endergonic reaction is derived from

the movement of hydrogen ions across the mitochondrial membrane