AP Bio Exam Ch. 6

Carbon monoxide is a colorless, odorless, and toxic gas. Theoretically, if you were breathing carbon monoxide, how many ATP molecules could you produce from one glucose molecule?

2 ATP

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

2 ATP, 6 NADH, 2 FADH2

Why is the citric acid cycle called a cycle?

Acetyl CoA binds to oxaloacetate that is restored at the end of the cycle.

When pyruvate is converted to acetyl CoA, _____.

CO2 and NADH are formed

What best describes the electron transport chain?

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

Which of the following serves primarily as a hydrogen-atom carrier molecule in cells?

FAD

An electron carrier, such as _____, acts as an energy-storage molecule when it is _____.

FADH2 ... reduced

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.

Besides sugars and fats, organisms can use other molecules as fuel for cellular respiration. When protein molecules are used, _____ are produced as waste.

amino groups

During aerobic respiration, molecular oxygen (O2) is used _____.

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

Carbon monoxide is a toxic gas because it directly _____.

blocks the transfer of electrons to the final electron acceptor

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

The function of cellular respiration is to _____.

extract usable energy from glucose

The major (but not sole) energy accomplishment of the citric acid cycle is the _____.

formation of NADH and FADH2

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

chemiosmosis

When growing in a nutrient-rich environment, bacteria can use the provided amino acids to synthesize their proteins. However, should the environment change, they can synthesize their amino acids using _____.

citrate

A single glucose molecule produces about 38 molecules of ATP through the process of cellular respiration. However, this only represents approximately 38% of the chemical energy present in this molecule. The rest of the energy from glucose is _____.

converted to heat

In the equation shown below, during cellular respiration _____ is oxidized and _____ is reduced. (C6H12O6 + 6O2 ----> 6CO2 + 6H2O + ATP)

glucose ... oxygen

During cellular respiration, glucose is oxidized. However, an intermediate, _____, can be siphoned off and used to synthesize fats.

glyceraldeyhyde-3-phosphate

Of the metabolic pathways listed below, the only pathway found in almost all organisms is _____.

glycolysis

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

glycolysis

In humans, oxygen and carbon dioxide are exchanged with the atmosphere via the _____.

lungs

In a eukaryotic cell, the electron transport chain is precisely located in or on the _____.

cristae of the mitochondrion

Where in bacterial cells does the citric acid cycle occur?

cytoplasm

What is the mechanism of action for the enzyme ATP synthase? ATP is formed _____.

due to the potential energy of a concentration gradient of hydrogen ions across a membrane

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

electrons

The principal molecules involved in transporting electrons to the electron transport chain are composed of _____.

nucleotides

Bacteria have no membrane-enclosed organelles. However, some still generate ATP through cellular respiration. Where is the electron transport chain found in these organisms?

plasma membrane

In cellular respiration, which of the following is performed directly by the electron transport chain (or its components)?

A proton gradient is formed.

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 efficiency of respiration is approximately _____.

40%

How many kilocalories are captured in ATP from 1.5 moles of glucose?

420 kcal

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.

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

NAD+

Once the citric acid cycle has been completed, most of the usable energy from the original glucose molecule is in the form of _____.

NADH

_____ is to a mitochondrion as _____ is to a chloroplast

O2 ... CO2

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

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

Where does glycolysis occur in a eukaryotic cell?

in the cytoplasmic fluid

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 molecule is oxidized when it _____.

loses an electron

In eukaryotes, most of the high-energy electrons released from glucose by cell respiration _____.

reduce NAD+ to NADH, which then delivers them to the electron transport chain

Muscle tissues make lactic acid from pyruvate so that you can _____.

regenerate (oxidized) NAD+

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

the citric acid cycle

Which of the following directly requires molecular oxygen (O2)?

the electron transport chain

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

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

Rotenone is a poison that blocks the electron transport chain. When it does so, glycolysis and the citric acid cycle eventually halt as well. This is because _____.

they run out of NAD+ and FAD

A gram of fat oxidized by cellular respiration produces approximately _____ as much ATP as a gram of carbohydrate.

twice