Topic 3.7: Cell Respiration

Question 1

What is cell respiration?(5)

Answer 1

controlled release of energy from organic compounds in cells to form ATP; organic compounds contain stored chemical potential energy in their bonds; when that energy is released, cells can use it for metabolism; glucose (from glycogen stores) typically used first as the source of energy; if there is no glucose then lipids then amino acids/proteins and in extreme cases startvation

Question 2

What is ATP? (4)

Answer 2

synthesized in mitochondria; energy “currency” of life; high energy molecule that stores energy for just about every cellular process we need; found in the cytoplasm and nucleoplasm

Question 3

What is glycolysis?(5)

Answer 3

glucose enters the cell via the cell membrane and stays in the cytoplasm; after a few modifications and a handful of reactions, glucose is eventually cleaved into 2 pyruvate(3-carbon compound); 2 ATP molecules needed to start; 4 ATP molecules produced; net gain of 2 ATPs

Question 4

What is anaerobic respiration? (5)

Answer 4

occurs in the cytoplasm; only needs ATP from glycolysis to begin; breakdown of organic molecules for ATP without using oxygen; organisms that do this only are called anaerobes; fermentaion is another word for this; two main pathways in alcoholic fermentation and lactic acid fermentation

Question 5

What is lactic acid fermentation?(7)

Answer 5

type of anaerobic respiration; occurs in humans which is why muscles burn after a workout; normally occurs in aerobic organisms when they are in a situation where it is hard to receive oxygen which is why you breathe harder when working out; pyruvate converted to lactate(3-carbon compound); no CO₂ produced; no ATP is produced; when O₂ becomes available, lactate is converted back into pyruvate and then pushed through the aerobic pathway

Question 6

What is alcoholic fermentation?(4)

Answer 6

type of anaerobic respiration; occurs in yeast cells; pyruvate converted to ethanol (2-Carbon compound); CO₂ is released

Question 7

What is aerobic respiration?(5)

Answer 7

occurs in mitochondria; most efficient way to produce ATP; pyruvate loses a Carbon as CO₂ and becomes acetyl-CoA; Acetyl-CoA enters Kreb’s cycle where two more CO₂ molecules are produced, as well as some ATP; byproducts of Kreb’s cycle move onto electron transport chain where most ATPs are produced

Question 8

What is the importance of the cristae in the mitochondria for aerobic respiration?

Answer 8

folds of the mitochondrial cristae provide huge surface area which equals a high efficiency/production