5-A respiration

Question 1

equation for aerobic respiration

Answer 1

C6H12O6 + 6O2 —> 6CO2 + 6H2O + energy

Question 2

glycolysis

Answer 2

glucose 6C 
phosphorylation (ATP - Pi = ADP ) x2 
hexose phosphate 6C 
triose phosphate 3C x2 
(4ADP + 4Pi = 4ATP)
oxidised (loses 2 H+) 
2NAD —> 2NADH 
pyruvate 3C x2

Question 3

products of glycolysis

Answer 3

2x NADH - oxidative phosphorylation
2x pyruvate - link reaction
2x ATP ( net gain )

Question 4

link reaction

Answer 4

pyruvate 3C 
decarboxylation ( loses CO2 )
oxidised ( NAD —> NADH ) 
acetate 2C 
\+ CoA 
acetyl CoA 2C

happens twice for every glucose ( one glucose produces one pyruvate in glycolysis )

Question 5

products of link reaction

Answer 5

2x acetyl CoA - krebs cycle
2x CO2 - waste
2x NADH - oxidative phosphorylation

Question 6

krebs cycle

Answer 6

acetyl CoA 2C + oxaloacetate 4C
- CoA 
citrate 6C 
- CO2 
oxidation NAD —> NADH 
5C 
-CO2 
oxidation NAD —> NADH x2
ADP + Pi —> ATP 
oxidation FAD —> FADH
back to oxaloacetate

Question 6

krebs cycle products

Answer 6

1x CoA - link reaction 
oxaloacetate- krebs cycle 
2x CO2 - waste 
1x ATP 
3x NADH - oxidative phosphorylation 
1x FADH - oxidative phosphorylation

Question 7

oxidative phosphorylation

Answer 7

1. H+ from oxidation of NADH + FADH split into electrons and protons
2. electrons move down electron transfer chain which are embedded in cristae membrane ( lose small amount of energy each transfer)
3. energy is used to pump H+ from mitochondrial matrix to inter membrane space
4. conc of H+ is higher in inter membrane space than matrix (conc gradient)
5. chemiosmosis = H+ move down electrochemical conc gradient in mitochondrial matrix via ATP synthase (releases energy to regenerate more ATP)
6. oxygen combines with protons and electrons to form water (oxygen is final electron acceptor)

Question 8

anaerobic respiration in yeast

Answer 8

pyruvate—>ethanal +CO2
ethanal + NADH—>ethanol + NAD

pyruvate from glycolysis is decarboxylated to produce ethanal
ethanol is reduced to ethanol by oxidation of NADH to NAD 

Question 9

anaerobic respiration in animals

Answer 9

pyruvate + NADH —> lactate + NAD

pyruvate from glycolysis is reduced to lactate by the oxidation of NADH to NAD

Question 10

how does anaerobic respiration continue glycolysis? 

Answer 10

The production of lactate or ethanol regenerate NAD meaning glycolysis can continue without much oxygen or ATP continuing respiration