Chapter 9: Cellular Respiration and Fermentation

Question 1

fermentation

Answer 1

a catabolic process that makes a limited amount of ATP from glucose, without an electron transport chain and produces a characteristic end product, like ethyl alcohol or lactic acid

Question 2

aerobic respiration

Answer 2

a catabolic pathway for organic molecules, using oxygen as the final electron acceptor in an electron transport chain and ultimately producing ATP. most efficient catabolic pathway and its carried out in most eukaryotic cells and many prokaryotic organisms

Question 3

anaerobic respiration

Answer 3

a catabolic pathway in which inorganic molecules other than oxygen accept electrons at the downhill end of the electron transport chains

Question 4

cellular respiration

Answer 4

the catabolic pathways of aerobic and anaerobic respiration, which break down organic molecules and use an electron transport chain for the production of ATP

Question 5

cellular respiration

Answer 5

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Question 6

redox reactions

Answer 6

a chemical reaction involving the complete or partial transfer of one or more electrons from one reactant to another. Short for reduction-oxidation reaction

Question 7

oxidation

Answer 7

complete or partial loss of electrons from a substance involved in a redox reaction

Question 8

reduction

Answer 8

the complete or partial addition of electrons to a substance involved in the redox reaction

Question 9

reduction agent

Answer 9

the electron donor in a redox reaction

Question 10

oxidizing agent

Answer 10

the electron acceptor in a redox reaction

Question 11

electron transport chain

Answer 11

a sequence of electron carrier molecules (membrane proteins) that carry an electron down a series of redox reactions that release energy used to make ATP

Question 12

citric acid cycle

Answer 12

a chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecules

• begun in glycolysis
• oxidizing the acetyl CoA (which is derived from pyruvate–which is the product of glycolysis) to carbon dioxide
• —occurs within the mitochondrion in eukaryotic cells and in the cytosol of prokaryotes; together with pyruvate oxidation, the second major stage in cellular respiration

Question 13

krebs cycle

Answer 13

the second stage of cellular respiration, aka the citric acid cycle

Question 14

oxidative phosphorylation

Answer 14

3rd major stage of cellular respiration, production of ATP using energy derived from the redox reaction of an electron transport chain

Question 15

substrate-level phosphorylation

Answer 15

the enzyme-catalyzed formation of ATP from a phosphate group directly transferring to ADP from an intermediate substrate in catabolism

(ATP comes from ADP being phosphorylized in an enzymatic reaction)

Question 16

glucose

Answer 16

a six carbon sugar, the molecule energy is harvested from for cellular respiration

Question 17

pyruvate

Answer 17

ionized form of pyruvic acid, formed when the products of glycolysis (2 3-carbon sugars) are oxidized

Question 18

acetyl coenzyme A

Answer 18

the entry compound for the citric acid cycle in cellular respiration, formed from a 2 carbon fragment of pyruvate attached to a coenzyme

Question 19

chemiosmosis

Answer 19

an energy-coupling mechanism

• uses energy stored in the form of a hydrogen ion gradient across a membrane
• drive cellular works, such as the synthesis of ATP.

Under aerobic conditions most ATP synthesis in cells occurs by chemiosmosis.

Question 20

Catabolic pathways and electron transfer play a major role in yielding energy from organic molecules. explain why this is so.

Answer 20

Yielding energy from organic molecules is done by cellular respiration, photosynthesis, and fermentation. All of these processes require molecules to be broken (catabolized/oxidized)
to create new bonds and molecules, and require the transfer of electrons to do so. Glycolysis breaks glucose into and 2 pyruvates, which are fixed into Acetyl CoA. This is catabolic. In the electron transport chain, the transfer of electrons by NADH and FADH2 units allows the protein in the chain to release protons, which are then used to power ATP synthase. Which is what yields energy for the cell

Question 21

Define the areas within the cell that the three steps of cellular respiration occur and dictate the number of ATP produced for each step

Answer 21

Glycolysis: net 2. Happens in the Cytoplasm
Krebs Cycle: net 2. Happens in the Inner membrane of the Mitochondria
ETC: net 34. Happens in the Mitochondria

Question 22

Explain how ATP is called the “energy currency of the cell”

Answer 22

It is the high yield energy molecule all living cells use for energy.
It produces high amounts of energy on its hydrolysis.

Question 23

Compare and contrast obligate anaerobes and facultative anaerobes.

Answer 23

Obligate anaerobes cannot grow in the presence of oxygen.
**They depend on fermentation and anaerobic respiration using a final electron acceptor other than oxygen.
Facultative anaerobes show better growth in the presence of oxygen but will also grow without it.