[7] Vocabulary - Cellular Respiration and Fermentation

Question 1

acetyl CoA

Answer 1

Acetyl coenzyme A; the entry compound for the citric acid cycle in cellular respiration, formed from a two-carbon fragment of pyruvate attached to a coenzyme

Question 2

aerobic respiration

Answer 2

a catabolic pathway for organic molecules, using O2 as the final electron acceptor in an electron transport chain and ultimately producing ATP. This is the most efficient catabolic pathway and is carried out in most eukaryotic cells and many prokaryotic organisms.

Question 3

alcohol fermentation

Answer 3

glycolysis > reduction of pyruvate to ethyl alcohol > regenerates NAD+, releases CO2

Question 4

ATP synthase

Answer 4

a complex of several membrane proteins that functions in chemiosmosis with adjacent electron transport chains, using the energy of a hydrogen ion (proton) concentration gradient to make ATP. ATP synthases are found in the inner mitochondrial membranes of eukaryotic cells and in the plasma membranes of prokaryotes.

Question 5

ATP synthase

Answer 5

a complex of several membrane proteins that functions in chemiosmosis with adjacent electron transport chains, using the energy of a hydrogen ion (proton) concentration gradient to make ATP. ATP synthases are found in the inner mitochondrial membranes of eukaryotic cells and in the plasma membranes of prokaryotes.

Question 6

beta oxidation

Answer 6

a metabolic sequence that breaks fatty acids down to two-carbon fragments that enter the citric acid cycle as acetyl CoA (Coenzyme-A)

Question 7

cellular respiration

Answer 7

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

Question 8

chemiosmosis

Answer 8

an energy-coupling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work, such as the synthesis of ATP. Under aerobic conditions, most ATP synthesis in cells occur by chemiosmosis.

Question 9

citric acid cycle

Answer 9

a chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecule begun in glycolysis by oxidizing acetyl CoA (derived from pyruvate) 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 10

cytochrome

Answer 10

an iron-containing protein that is a component of electron transport chains in the mitochondria and chloroplasts of eukaryotic cells and the plasma membranes of prokaryotic cells

Question 11

electron transport chain

Answer 11

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

Question 12

facultative anaerobe

Answer 12

an organism that makes ATP by aerobic respiration if oxygen is present but that switches to anaerobic respiration or fermentation if oxygen is not present

Question 13

fermentation

Answer 13

catabolic process that makes 2 ATP from glucose (or other organic molecules) WITHOUT an electron transport chain, and that produces a character end product, such as ethyl alcohol or lactic acid

SUMMARY: catabolic, makes 2 ATP from organic molecules

Question 14

glycolysis

Answer 14

a series of reactions that ultimately splits glucose into pyruvate. Glycolysis occurs in almost all living cells, serving as the starting point for fermentation or cellular respiration.

Question 15

lactic acid fermentation

Answer 15

glycolysis > reduction of pyruvate to lactate > regenerates NAD+ without releasing CO2

Question 16

NAD+

Answer 16

the oxidized form of nicotinamide adenine dinucleotide, a coenzyme that can accept electrons becoming NADH. NADH temporarily stores electrons during cellular respiration.

Question 17

NADH

Answer 17

the reduced form of nicotinamide adenine dinucleotide, which temporarily stores electrons during cellular respiration. NADH acts as an electron donor to the electron transport chain.

Question 18

obligate anaerobe

Answer 18

an organism that only carries out fermentation or anaerobic respiration. Such organisms cannot use oxygen and in fact may be poisoned by it.

Question 19

oxidation

Answer 19

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

Question 20

oxidative phosphorylation

Answer 20

production of ATP using energy derived from redox reactions of an electron transport chain; the third major stage of cellular respiration

Question 21

oxidizing agent

Answer 21

electron acceptor in redox reaction

Question 22

proton-motive force

Answer 22

the potential energy stored in the form of a proton electrochemical gradient, generated by the pumping of hydrogen ions (H+) across a biological membrane during chemiosmosis.

Question 23

redox reaction

Answer 23

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

Question 24

reducing agent

Answer 24

the electron donor in a redox reaction

Question 25

reduction

Answer 25

addition of electrons to substance involved in redox reactions

Question 26

substrate-level phosphorylation

Answer 26

the enzyme-catalyzed formation of ATP by direct transfer of a phosphate group of ADP from an intermediate substrate in catabolism