Chapter 6

Question 1

Cellular Respiration

Answer 1

the aerobic harvesting of energy from food molecules;the energy-releasing chemical breakdown of food molecules, such as glucose and the storage of potential energy in a form that cells can use to perform work; involves glycolysis, the citric acid cycle, and oxidative phosphorylation (the electron transport chain and chemiosmosis)

Question 2

Kilocalories (kcal)

Answer 2

a quantity of heat equal to 1,000 calories. used to measure the energy content of food, it is usually called a “Calorie”

Question 3

Redox Reaction

Answer 3

short for reduction-oxidation reaction. a chemical reaction in which electrons are lost from one substance (oxidation) and added to another (reduction)

Question 4

Oxidation

Answer 4

the loss of electron from a substance involved in a redox reaction; always accompanies reduction

Question 5

Reduction

Answer 5

the gain of electrons by a substance involved in a redox reaction; always accompanies oxidation

Question 6

NAD+

Answer 6

Nicotinamide adenine dinucleotide; a co-enzyme that can accept electrons during the redox reactions of cellular metabolism. it cycles between oxidized (NAD+) and reduced (NADH) states

Question 7

Electron Transport Chain

Answer 7

a series of electron carrier molecules that shuttle electrons during a series of redox reactions that release energy used to make ATP; located in the inner membrane of mitochondria, the thylakoid membranes of chloroplasts, and the plasma membranes of prokaryotes

Question 8

Glycolysis

Answer 8

a series of reactions that ultimately splits glucose into two molecules of pyruvate; the first stage of cellular respiration in all organisms.occurs in the cytosol

Question 9

Citric Acid Cycle

Answer 9

the chemical cycle that completes the metabolic breakdown of glucose molecules begun in glycolysis by oxidizing acetyl CoA (derived from pyruvate) to carbon dioxide. they cycle occurs in the matrix of the mitochondria and supplies most of the NADH molecules that carry electrons to the electron transport chains. with pyruvate oxidation the second major stage of cellular respiration

Question 10

Oxidative Phosphorylation

Answer 10

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

Question 11

Chemiosmosis

Answer 11

an energy-coupling mechanism that uses the energy of hydrogen ion (H+)gradients across membranes to derive cellular work, such as the phosphorylation of ADP; powers most ATP synthesis in cells.

Question 12

Substrate Level Phosphorylation

Answer 12

the formation of ATP by an enzyme directly transferring a phosphate group to ADP from an organic molecule

Question 13

Intermediate

Answer 13

one of the compounds that form between the initial reactant and the final product in a metabolic pathway eg. between glucose and pyruvate in glycolysis

Question 14

Acetyl CoA

Answer 14

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 15

ATP Synthase

Answer 15

a cluster of several membrane proteins that function in chemiosmosis with adjacent electron transport chains, using the energy of a hydrogen ion concentration gradient to make ATP

Question 16

Lactic Acid Fermentation

Answer 16

glycolysis followed by the reduction of pyruvate to lactate, regenerating NAD+

Question 17

Alcohol Fermentation

Answer 17

glycolysis followed by the reduction of pyruvate to ethyl alcohol regenerating NAD+ and releasing carbon dioxide