Chapter 6 (How Cells Harvest Chemical Energy)

Front 1

What is cellular respiration?

Back 1

- aerobic harvesting of energy from food molecules
- 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 (electron transport chain & chemiosmosis)

Front 2

- in breathing, CO2 and O2 are exchanged between your lungs and the air
- in cellular respiration, cells use O2 obtained through breathing to breakdown fuel, releasing Co2 as a waste product

Back 2

How is your breathing related to cellular respiration?

Front 3

demand for ATP is supported by an increased rate of cellular respiration, but about 66% of the energy fro food produces heat instead of ATP

Back 3

Why is sweaty and other body-cooling mechanisms necessary during vigorous exercise?

Front 4

What is a kilocalorie?

Back 4

- quantity of heat equal to 1000 calories
- used to measure the enrgy content of food

Front 5

What is a redox reaction?

Back 5

- chemical reaction in which electrons are lost from 1 substance and added to another

Front 6

What is oxidation?

Back 6

loss of electrons from a substance involved in a redox reaction, always accompanies reduction

Front 7

What is reduction?

Back 7

gain of elctrons by a substance involved in a redox reaction, always accompanies oxidation

Front 8

What is NAD+?

Back 8

- coenzyme that can accept electrons during the redox reaction of cellular metabolism
- plus sign indicates that the molecule is oxidized and ready to pick up hydrogens
- reduced, hydrogen (electron) - carrying form is NADH

Front 9

What is electron transport chain?

Back 9

- series of electron carrier molecules that shuttle electrons during the redox reaction 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

Front 10

oxygen is very electronegative making it very powerful in pulling elctrons down the electron transport chain

Back 10

What chemical characteristic of the element oxygen accounts for its function in cellular respiration?

Front 11

1. glycolysis
2. pyruvate oxidation and citric acid cycle
3. oxidative phosphorylation

Back 11

What are the main stages of cellular respiration?

Front 12

What is chemiosmosis?

Back 12

- energy coupling mechanism that uses the energy of hydrogen ion gradients across membranes to drive cellular work, such as the phosphorylation of ADP
- powers most ATP synthesis in cells

Front 13

oxidative phosphorylation, using the electron transport chain, which eventually transfers electrons to oxygen

Back 13

Of the 3 main stages of cellular respiration, which one uses oxygen to extract chemical energy from organic compounds?

Front 14

What is substrate level phosphorylation?

Back 14

- formation of ATP by an enzyme directly transferring a phosphate group to ADP from an organic molecule
EX: (intermediates in glycolysis or citric acid cycle)

Front 15

What are intermediates?

Back 15

- 1 of the compounds that form between the initial reactant and the final product in a metabolic pathway
EX: the one between glucose and pyruvate in glycolysis

Front 16

- two molecules of pyruvate, two molecules of ATP, and two molecules of NADH

Back 16

For each glucose molecule processed, what are teh net molecular products of glycolysis?

Front 17

What is actyl COA?

Back 17

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

Front 18

What is ATP synthase?

Back 18

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

Front 19

What is lactic acid fermentation?

Back 19

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

Front 20

What is alcohol fermentation?

Back 20

glycolysis followed by the decrease of pyruvate to ethyl alcohol, regenerating NAD+ and releasing CO2

Front 21

glycolysis occurs univerally functioning in both fermentation and respiration, doesn't require oxygen, and doesn't occur in membrane bounded organelle

Back 21

What are the characteristics of glycolysis that indicate that it's an ancient metabolic pathway?