MB Chapter 6

lactate and NAD+ These are the products of fermentation as it occurs in muscle cells.

In muscle cells, fermentation produces _____.

loses electrons and becomes oxidized In cellular respiration, glucose is oxidized when it loses electrons in hydrogen atoms. Oxygen is reduced as it gains electrons in hydrogen atoms.

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

recycle NADH through fermentation During lactic acid fermentation, pyruvate is reduced directly by NADH to form lactate. This recycles NAD+, so the cycle continues.

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

the pH of the intermembrane space decreases.

As electrons move through the mitochondrial space,

NADH.

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

obligate anaerobes.

Bacteria that are unable to survive in the presence of oxygen are called

found in NADH and FADH2 The energy in these molecules is used to drive the synthesis of ATP in the electron transport chain and chemiosmosis.

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 _____.

. O2 ... CO2

Consider the figure below. __________ is to a mitochondrion as __________ is to a chloroplast. The connection between photosynthesis and cellular respiration.

delivers its electron load to the first electron carrier molecule.

During cellular respiration, NADH

NADH and FADH2 ... intermembrane space The energy released as electrons, which have been donated by NADH and FADH2, is passed along the electron transport chain and used to pump hydrogen ions into the intermembrane space.

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

10 For each glucose molecule that enters glycolosis, a total of 10 NADH are produced -- 2 are produced in glycolysis, 2 are produced in acetyl CoA production, and 6 are produced in the citric acid cycle.

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

2

How many NADH are produced by glycolysis?

carbon dioxide Cellular respiration, or the oxidization of glucose, involves the release of CO2.

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 __________.

oxidative phosphorylation This process utilizes energy released by electron transport.

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

2 It takes 2 ATP to produce 4 ATP.

In glycolysis there is a net gain of _____ ATP.

substrate-level phosphorylation A phosphate group is transferred from glyceraldehyde phosphate to ADP.

In glycolysis, ATP molecules are produced by _____.

ATP Some ATP energy is used to start the process of glucose oxidation.

In glycolysis, what starts the process of glucose breakdown?

these two stages supply the electrons needed for the electron transport chain The main function of glycolysis and the citric acid cycle is to supply oxidative phosphorylation with electrons carried by NADH and FADH2.

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

pyruvate.

The end products of the citric acid cycle include all of the following except FADH2. CO2. ATP. pyruvate.

oxygen Oxygen is combined with electrons and hydrogen to form water.

The final electron acceptor of cellular respiration is _____.

kinetic energy that is released as hydrogen ions diffuse down their concentration gradient Concentration gradients are a form of potential energy.

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

oxygen Oxygen is the final electron acceptor of cellular respiration.

What molecule is indicated by the letter D?

glycolysis Glycolysis occurs in the cytosol.

What process occurs in Box A?

the citric acid cycle The citric acid cycle transfers electrons to NADH and FADH2.

What process occurs within Box B?

The conversion is needed to regenerate the molecules needed for glycolysis.

When an organism such as a yeast lives by fermentation, it converts the pyruvate from glycolysis into a different compound, such as alcohol. Why doesn't it secrete the pyruvate directly?

A compound called coenzyme A binds to a two-carbon fragment. Coenzyme A binds to the two-carbon fragment to form acetyl coenzyme A.

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. Carbon dioxide must be present for pyruvate to enter the citric acid cycle. Oxygen atoms are formed into oxygen gas. Pyruvate is reduced by oxidizing an NAD+ to an NADH.

substrate-level phosphorylation A phosphate group is transferred from GTP to ADP.

In the citric acid cycle (also called the Krebs cycle), ATP molecules are produced by _____.

We would not make enough ATP to meet our energy requirements The electron transport chain accepts electrons from the breakdown products of glycolysis and the citric acid cycle, and it passes these electrons from one molecule to another until they are passed (along with two hydrogen ions) to oxygen to form water.

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

In the reaction that creates acetyl CoA (coenzyme A) from pyruvate Carbon dioxide is produced in the transition between glycolysis and the citric acid cycle when the three-carbon pyruvate is cleaved to a two-carbon acetyl molecule with the remaining carbon of pyruvate released as carbon dioxide.

We inhale O2 and we exhale CO2. Carbon dioxide is produced _____.

energy to make ATP and carbon dioxide

Which of the following are products of cellular respiration? oxygen and carbon dioxide oxygen and glucose oxygen and energy to make ATP energy to make ATP and carbon dioxide

Electrons pass from one carrier to another, releasing a little energy at each step. NADH and FADH2 deliver electrons from the breakdown products of glycolysis and the citric acid cycle to the electron transport chain, which passes these electrons from one molecule to another, releasing a small amount of energy at each step.

Which of the following best describes the electron transport chain? Electrons pass from one carrier to another, releasing a little energy at each step. Hydrogens are added to CO2 to make an energy-rich compound. Acetyl CoA is fully oxidized to CO2. Electrons are pumped across a membrane by active transport.

aerobic respiration

Which of the following processes produces the most ATP per molecule of glucose oxidized? alcoholic fermentation aerobic respiration lactic acid fermentation All produce approximately the same amount of ATP per molecule of glucose.

Photosynthesis occurs in chloroplasts, and cellular respiration occurs in mitochondria.

Which of the following statements regarding photosynthesis and cellular respiration is true? Cellular respiration occurs in mitochondria and in chloroplasts. Photosynthesis occurs in mitochondria and in chloroplasts. Photosynthesis occurs in chloroplasts, and cellular respiration occurs in mitochondria. Photosynthesis occurs in mitochondria, and cellular respiration occurs in chloroplasts.

acetyl CoA Acetyl CoA is a reactant in the citric acid cycle (also called the Krebs cycle).

Which of these enters the citric acid cycle (also called the Krebs cycle)? acetyl CoA glucose NADH + H+ G3P pyruvate

FADH2 FADH2 is a product of the citric acid cycle.

Which of these is NOT a product of glycolysis? water NADH + H+ pyruvate ATP FADH2

acetyl CoA Acetyl CoA enters the citric acid cycle.

Which of these is NOT a product of the citric acid cycle (also called the Krebs cycle)? FADH2 ATP acetyl CoA CO2 NADH + H+

facultative anaerobes

Yeasts can produce ATP by either fermentation or oxidative phosphorylation; thus, they are