Lecture 9a: Bioenergetics- cellular respiration

Question 1

Cellular Respiration

Answer 1

the process by which cells generate ATP through a series of redox reaction; electrons are removed from various molecules such as glucose and passed through intermediate electron carriers to a final electron acceptor

Question 2

Aerobe

Answer 2

organism that grows or metabolizes only in the presence of oxygen (plants and animals)

Question 3

Anaerobe

Answer 3

an organism that grows only in the absence of oxygen (sulphate-reducing bacteria)

Question 4

Facultative anaerobe

Answer 4

organism capable of carrying out aerobic respiration but able to switch to fermentation when oxygen is unavailable (E.coli + yeast)

Question 5

Double-membrane mitochondrion structure

Answer 5

• Outer membrane
• Inner membrane
• Intermembrane space
• Matrix
• Folds (cristae)

Question 6

Aerobic Respiration involves 4 stages:

Answer 6

• Glycolysis
• formation of acetyl-CoA
• Krebs cycle
• Electron transport chain/chemiosmosis

Question 7

Glycolysis

Answer 7

• First stage of cellular respiration for all organisms
• Occurs in cytoplasmic fluid
• produces 2 pyruvate, 2 ATP and 2 NADH

Question 8

Kreb’s Cycle

Answer 8

• 8 steps
• produces citric acid, 2 ATP, 6 NADH, and 2FADH2

Question 9

Electron Transport Chain

Answer 9

the chain contains 3 (4) large enzymes
i: NADH-Q reductase complex
ii: (succinate-Q reductase complex)
iii: Cytochrome b/c1 reductase complex
iv: Cytochrome c oxidase complex

Question 10

oxidative phosphorylation

Answer 10

this exergonic process drives the endergonic reaction, in which ATP is produced by phosphorylating ADP

Question 11

Carbohydrates

Answer 11

Glucose and other sugars. Entering glycolysis

Question 12

Proteins

Answer 12

amino acids e.g. Alanine- pyruvate
glutamate- ketoglutarate
aspartate- oxaloacetate

Question 13

Fats

Answer 13

Glycerol and fatty acids

Question 14

Alcoholic fermentation

Answer 14

yeasts and certain bacteria convert the pyruvate produced by glycolysis to C)2 and ethanol

Question 15

Lactic acid fermentation

Answer 15

in some fungi and bacteria, lactic acid, rather than alcohol, is produced when NADH from glycolysis is oxidized

Question 16

functions of fermentation

Answer 16

• it is an inefficient way to use fuel
• it allows organisms to survive without oxygen
• it removes toxic excess NADH in the cytosol
• it replenishes the supply of NAD+