Respiration

Question 1

Respiration definition:-

Answer 1

The process by which the energy in food molecules is made available for an organism to do biological work. Sometimes called cellular resp.
Only way a cell can obtain energy in a usable form. Occurs in every living cell.

Question 2

Aerobic respiration equation:-

Answer 2

C6H12O6 + 6O2 -> 6CO2 + 6H2O

Question 3

Anaerobic resp in yeast equation:-

Answer 3

C6H12O6 -> 2C2H5OH (ethanol) + 2CO2

Question 4

Anaerobic in animals equation:-

Answer 4

C6H12O6 -> 2C3H6O3

Question 5

Obligate anaerobes:-

Answer 5

Can only respite anaerobically.

Question 6

Falcultative anaerobes:-

Answer 6

Respire aerobically, but can respire anaerobically when no oxygen is present e.g fungi

Question 7

Anaerobic ATP generation:-

Answer 7

Generate ATP by only partly breaking down food molecules rather than breaking them down fully to CO2.

Question 8

Anaerobic breakdown:-

Answer 8

Glucose broken down into pyruvate in a process called glycolysis. Then follows 1 of 2 main anaerobic metabolic pathways. Plants + fungi conv pyruvate to ethanol + CO2 in alcoholic fermentation. Animals conv to lactate in lactate fermentation.

Question 9

Aerobic resp overview:-

Answer 9

Complex process in which food molecules are broken down in a series of steps. During breakdown, energy is released which is used to synth ATP from ADP and Pi.

Question 10

4 stages of aerobic system:-

Answer 10

Glycolysis, link reaction, Krebs Cycle, electron transport system.

Question 11

Glycolysis part 1:-

Answer 11

Glucose given activation energy by 2 molecules of ATP broken down to ADP + Pi. Glucose energised to form glucose phosphate then fructose diphosphate.

Question 12

Glycolysis part 2:-

Answer 12

Fructose diphosphate splits to form 2 GALP molecules.

Question 13

Glycolysis part 3:-

Answer 13

Each GALP conv to Pyruvate by series of reactions, H removed (oxidation) alongside ATP synth and NAD+ reduction to NADH ( + H+).

Question 14

Glycolysis net products:-

Answer 14

2 molecules Pyruvate.
2 NADH
2 ATP

Question 15

Alcoholic fermentation:-

Answer 15

Pyruvate conv to ethanal by decarboxylation(2 x CO2 remove). Ethanal reduced to ethanol using H from NADH.
2NADH-> 2NAD+

Question 16

Glycolysis location:-

Answer 16

Cytoplasm.

Question 17

Lactate fermentation:-

Answer 17

Pyruvate converted to lactate (lactic acid) in a single step. Catalysed by lactate dehydrogenase and requires H from NADH (2NADH -> NAD+)

Question 18

Anaerobic energy budget:-

Answer 18

Anaerobic transfers small proportion of energy in glucose to ATP. Have to satisfy energy needs by glycolysis, despite its low level of ATP production.

Question 19

Aerobic energy budget:-

Answer 19

Can use oxygen to release a much greater proportion of the enegy in glucose to make more ATP molecules via the Krebs cycle and electron transport system.

Question 20

Link reaction location:-

Answer 20

Mitochondria (3c Pyruvate enters by active transport)

Question 21

Link reaction:-

Answer 21

Pyruvate decarboxylised and oxidised (oxidative decarboxylation). The 2c acetyl component of acetyl-CoA diffuses to site of Krebs cycle in mito, coenzyme A helps and is then detached and can be recycled. 2 acetl fragments per glucose molecule enter cycle.

Question 22

Net effects of Krebs cycle:-

Answer 22

In each revolution, 2 CO2 molecules are released, NAD and FAD are reduced and 1 molecule of ATP is generated. Also, Oxaloacetate is regenerated so the cycle can restart if acetyl-CoA is available.

Question 23

Kreb’s cycle (past link reaction entry point) part 1:-

Answer 23

2c acetyl fragment combines w/ 4c oxaloacetate to form 6c compound, citrate. CO2 leaves. NAD+ -> NADH + H+.

Question 24

Kreb’s cycle (past link reaction entry point) part 2:-

Answer 24

5c compound formed, CO2 then leaves cycle and NAD+ is reduced reduced, ATP is synthed.

Question 25

Kreb's cycle (past link reaction entry point) part 3:-

Answer 25

4C succinate formed. FAD -> FADH2. Malate formed (4C). NAD+ reduced. Oxaloacetate formed (4C).

Question 26

ATP synth from Krebs:-

Answer 26

All breakdown = oxidative decarboxylation. Exergonic, releases enough synth 1 ATP molecule. Called substrate-level phosphorylation. Happens twice per molecule of glucose because 2 x acetyl-CoA. Also, H release provides reducing power to generate more in electron transport system.

Question 27

NAD and FAD in Krebs cycle:-

Answer 27

Takes up hydrogen stripped off the organic molecules as they progress around the cycle.

Question 28

Substrate level phosphorylation:-

Answer 28

When the phosphate group is obtained from a substrate (molecule other than ATP,ADP or AMP).

Question 29

Oxidative phosphorylation from NADH:-

Answer 29

3 ATP produced per NADH produced.

Question 30

Oxidative phosphorylation from FADH:-

Answer 30

2 ATP per molecule.

Question 31

Oxidative phosphorylation:-

Answer 31

NADH2/FADH2 bring H to ETC (inner membrane). Oxidised -> NAD/FAD + H. H dissociates, H+ and e-. e- used in etc, releases energy. Energises atp synth.