Respiration

Question 1

Why do we need energy

Answer 1

Anabolic processes
Endocytosis + exocytosis
Movement
Active transport
Repair, maintenance + division of cells
Maintaining constant body temp

Question 2

Advantages of ATP

Answer 2

Immediate source of energy
Energy released in small amounts

Question 3

Process of glycolysis + where it occurs + products

Answer 3

Glucose phosphorylated into hexose bisphosphate (use ATP)
Splits into 2 triosephosphate
Oxidised to make 2 pyruvate (use 4ATP + 2NAD)

Cytoplasm

2ATP
2NADH
2Pyruuvate

Question 4

Explain why glucose needs to be phosphorylated at the start of glycolysis

Answer 4

Activates it
Lowers activation energy = more reactive + more likely to split into 2 triose phosphate
Also prevents glucose moving out cell

Question 5

Site of Link + Krebs reaction

Answer 5

Matrix

Question 6

Relate mitochondrial structure to its functions

Answer 6

Matrix
Site of link + krebs
Contains NAD + oxaloacetate

Outer membrane
Proteins in bilayer for transport

Inner membrane
Bilayer has more lips = impermeable to H+
Folding = cristae = inc SA
e- carries + ATP synthase

Question 7

Link reaction + products

Answer 7

Pyruvate = decarboxylated + dehydrogenated
= acetate
CoA joins with acetate
= acetylCoA

2AcetylCoA
2CO2
2NADH

No ATP

Question 8

Krebs cycle + products (1 turn)

Answer 8

CoA leaves acetylCoA
Acetate + oxaloacetate = citrate (6C)
Citrate = decarboxylated + dehydrogenated = 5C
5C = decarboxylated + dehydrogenated = 4C
4C = phosphorylated (makes ATP)
4C = dehydrogenated - FAD
4C = dehydrogenated - NAD
= Oxaloacetate

2CO2
1ATP
1FAD
3NAD
1 glucose = 2 turns

Question 9

Oxidative phosphorylation

Answer 9

NADH + FADH re-oxidised by donating H to ETC
NAD + FAD return back to glycolysis, link or krebs
H atoms split into protons + e-
e- passed along ETC + accepted by O2 (final e- acceptor)
Energy released used to pump H+ into intermembrane space from matrix
H+ accumulated in intermembrane space flow through ATP synthase enzyme
Causing ATP synthesis

Question 10

Anaerobic respiration in mammals + yeast

Answer 10

Pyruvate accepts H from NADH
=Lactate/ lactic acid (lactate dehydrogenase)
NADH = re-oxidised back to NAD
Can enter glycolysis again
if O2 present again
= Lactate converted to pyruvate in liver

Pyruvate decarboxylated = ethanal
Ethanal accepts H from NADH
= ethanol (ethanol dehydrogenase) - ethanol fermentation
NAD used in glycolysis again

Question 11

RQ =

Answer 11

Vol CO2 evolved / Vol of CO2 absorbed

(CO2 produced/ O2consumed)