Ch 13 - How Cells Obtain Energy from Food

Question 1

ADP, ATP

Answer 1

nucleoside diphosphate produced by hydrolysis of the terminal phosphate of ATP

Question 1

acetyl CoA

Answer 1

activated carrier that donates the carbon atoms in its readily transferable acetyl group to many metabolic reactions, including the citric acid cycle and fatty acid biosynthesis; the acetyl group is linked to coenzyme A (CoA) by a thioester bond that releases a large amount of energy when hydrolyzed

Question 2

anabolic pathway

Answer 2

series of enzyme-catalyzed reactions by which large biological molecules are synthesized from smaller subunits; usually requires an input of energy

Question 3

catabolism

Answer 3

set of enzyme-catalyzed reactions by which complex molecules are degraded to simpler ones with release of energy; intermediates in these reactions are sometimes called catabolites

Question 4

cell respiration

Answer 4

process by which cells harvest the energy stored in food molecules; usually accompanied by the update of O2 and the release of CO2

Question 5

citric acid cycle

Answer 5

series of reactions that generate large amounts of NADH by oxidizing acetyl groups derived from food molecules to CO2. in eukaryotic cells, this central metabolic pathway takes place in the mitochondrial matrix

Question 6

electron-transport chain

Answer 6

a series of membrane-embedded electron carrier molecules that facilitate the movement of electrons from a higher to a lower energy level, as in oxidative phosphorylation and photosynthesis

Question 7

FAD, FADH2

Answer 7

a molecule that accepts electrons and hydrogen atoms from an electron doner/a high-energy electron carrier produced by reduction of FAD during the breakdown of molecules derived from food, including fatty acids and acetyl CoA

Question 7

fat

Answer 7

type of lipid used by living cells to store metabolic energy. mainly composed of triacylglycerols

Question 8

feedback regulation

Answer 8

process whereby enzymes are either positively or negatively regulated in response to the levels of metabolites that are not their substrates

Question 9

fermentation

Answer 9

the breakdown of organic molecules without the involvement of molecular oxygen. this form of oxidation yields less energy energy than aerobic cell respiration

Question 10

GDP, GTP

Answer 10

nucleoside diphosphate that is produced by the hydrolysis of the terminal phosphate of GTP, a reaction that also produces inorganic phosphate

Question 11

gluconeogenesis

Answer 11

set of enzyme-catalyzed reactions by which glucose is synthesized from small organic molecules such as pyruvate, lactate or amino acids; in effect, the reverse of glycolysis

Question 12

glucose

Answer 12

six-carbon sugar that plays a major role in the metabolism of living cells. stored in polymeric form as glycogen in animal cells and as starch in plant cells

Question 13

glycogen

Answer 13

branched polymer composed exclusively of glucose units used to store energy in animal cells. granules of this material are especially abundant in liver and muscle cells

Question 14

glycolysis

Answer 14

series of enzyme-catalyzed oxidation reactions in which sugar are partially degraded and their energy is captured by the activated carriers ATP and NADH (literally, sugar splitting)

Question 15

NAD+, NADH

Answer 15

a molecule that accepts a hydride ion (H-) from a donor molecule, thereby producing the activated carrier NADH. widely used in the energy-producing breakdown of sugar molecules

Question 16

oxidative phosphorylation

Answer 16

membrane-based process in bacteria and mitochondria in which ATP formation is driven by the transfer of electrons from food molecules to molecular oxygen

Question 17

pyruvate

Answer 17

three-carbon metabolite that is the end product of the glycolytic breakdown of glucose; provides a crucial link to the citric acid cycle and many biosynthetic pathways

Question 18

starch

Answer 18

polysaccharide composed exclusively of glucose units, used as an energy store in plant cells