Cellular Respiration

Question 1

What are the major energy requirements of a cell

Answer 1

For mechanical work (motor proteins)
Making of new materials (growth and replacement)
For transport (active transport)
To maintain order

Question 2

What is the chemical equation for cellular respiration

Answer 2

C6H12O6 + 6O2 —> 6CO2 + 6H2O + Energy (ATP)

Question 3

What are the two important compartments for cellular respiration

Answer 3

Mitochondrial matrix
Mitochondrial inner membrane

Question 4

What is the approx size of mitochondria and how many in cell

Answer 4

1-10 micrometers long
1-1000s per cell (depends on energy demand)

Question 5

Outline the structure of the mitochondria

Answer 5

Has two membranes - inner and outer
Mitochondrial matrix inside the inner membrane
Inner membrane highly folded (cristae)
Has an inter membrane space

Question 6

What are the 4 overarching steps of cellular respiration

Answer 6

Glycolysis
Pyruvate oxidation
Citric acid cycle
Oxidative phosphorylation

Question 7

Outline glycolysis

Answer 7

Occurs in cytosol
Glucose is converted into 2 smaller pyruvate molecules
Generates 2 ATP
Electrons are transferred to the high energy electron carrier NAD+ (making 2 NADH)
Net yield: 2 ATP, 2 pyruvate, 2 NADH

Question 8

Outline pyruvate oxidation and the citric acid cycle

Answer 8

2 pyruvate are oxidised into 2Acetyl CoA
Acetyl CoA enters the citric acid cycle
Output is 2 ATP, 6 NADH, and 2 FADH2
Co2 is released

Question 9

Summarise stages 1 & 2 of cellular respiration

Answer 9

Glucose converted into 2 pyruvate molecules, converted into 2 Acetyl CoA. Output is ATP, NADH, FADH2, CO2

Question 10

What are the 2 parts of the 3rd stage of cellular respiration (oxidative phosphorylation

Answer 10

Electron transport
Chemiosmosis

Question 11

Outline the electron transport chain

Answer 11

Electron Carriers (NADH & FADH2) shuttle high energy electrons to the inner mitochondrial membrane
These electrons move through protein complexes embedded in the inner membrane
As the electrons move, protons (H+) are pumped across the membrane
H+ accumulate in intermembrane space making proton concentration different either side of membrane (higher in intermembrane space)

Question 12

Outline chemiosmosis

Answer 12

The inner mitochondrial membrane contains ATP Synthase protein complex (spans across membrane from intermembrane space to mitochondrial matrix)
Movement of H+ through ATP synthase from high to low conc (intermembrane space to mitochondrial matrix) powers ATP synthase
ATP synthase converts ADP+Pi to ATP (oxidation phosphorylation reaction)

Question 13

Outline the hydrolysis of ATP

Answer 13

ATP goes to ADP (adenosine diphosphate) and Pi (inorganic phosphate). Hydrolysis of ATP occurs by the addition of water

Question 14

Explain the continuous regeneration of ATP

Answer 14

Cell continuously uses and regenerates ATP
Energy from catabolism (breakdown of complex molecules) powers formation of ATP (ADP + Pi)
ATP hydrolysis (ATP to ADP + Pi) releases cellular energy (endergonic energy consuming processes)