Respiration

Question 1

Aerobic Respiration : 4 Stages

Answer 1

Gycolysis, Link reaction, Kreb cycle, Oxidative phosphorylation

Question 2

Glycolysis

Answer 2

Involves splitting one molecule of glucose into two smaller molecules of pyruvate and it happens in the cytoplasm of cells and is the first stage of both aerobic and anaerobic respiration and does not require oxygen

Question 3

Link Reaction

Answer 3

1) Pryuvate is decarboxylated a carbon atom is removed to create CO2
2) NAD is reduced to NADH and it collects hydrogen from pyruvate creating acetate
3) Acetate is combined with coenzyme A to form Acetyl CoA
4) No ATP is produced
Occurs twice for every glucose molecule 2 molecules of acetyl CoA goes into the krebs cycle and takes place in the mitochondrial matrix

Question 4

Krebs Cycle

Answer 4

Takes place in the matrix of the mitochondria and happens once for each pyruvate molecule so goes around twice for each glucose molecule.

1) Acetyl CoA combines with oxaloacetate to from citrate and is catalysed by citrate synthase and coenzyme A goes back to the link reaction.
2) 6C Citrate converted to 5C Molecule, Decarboxylation takes place where CO2 is removed dehydrogenation takes place and the hydrogen removed turns NAD to reduced NAD
3) 5C molecule converted to 4C molecule Decarboxylation and Dehydrogenation occur producing one molecule of reduced FAD and 2 reduced NAD molecules. ATP produced by the direct transefer of phosphate from intermediate to ADP and is called substrate level phosphorylation

Question 5

Oxidative Phosphorylation

Answer 5

Takes place in the inner mitochondrial membrane

Question 6

Oxidative Phosphorylation

Answer 6

H atoms are released from reduced NAD and reduced FAD and they split into protons and electrons. The electrons move along the etc losing energy at each carrier and the membrane is folded into cristae, increases membranes surface area. The energy is used by the electron carriers to pump protons from the matrix into the inner membrane matrix and forms a electrochemical gradient. Protons move down the gradient back into the matrix via atp synthase and the movement drives the synthesis of ATP to ADP and inorganic phosphate and oxygen is the final receptor

Question 7

Lactate Fermentation

Answer 7

Reduced NAD transfers hydrogen to pyruvate to form lactate and NAD and it then can be reused in glycolysis. The production of lactate regenerates NAD and glycolysis needs this to take place which means it can take place even if there is no oxygen around. Cells can tolerate high levels of lactate for short periods off time. The liver takes lactate from the bloodstream and converts it back into glucose (glycogenesis)

Question 8

RQ

Answer 8

Volume of co2 released divided volume of o2 consumed

Question 9

Respiratory substrate

Answer 9

Lipids=0.7
Proteins or amino acids =0.9
Carbs=1

Question 10

Alcoholic fermentation

Answer 10

• C02 removed from pyruvate to create ethanal
• Reduced NAD from glycolysis transfers hydrogen to ethanal to form ethanol and NAD
• NAD then can be used in glycolysis again.

Question 11

Why does Anaerobic respiration release less energy than aerobic respiration?

Answer 11

-Anaerobic respiration only includes one energy releasing stage which only produces 2 ATP per glucose molecule and the other energy releasing reactions require oxygen so cant occur during anaerobic respiration.