5.7.2 Structure of the Mitochondrion

Question 1

What are mitochondria?

Answer 1

Rod-shaped organelles 0.5 - 1.0µm in diameter
They are the site of aerobic respiration in eukaryotic cells

Question 2

What is the function of mitochondria

Answer 2

To synthesise ATP
This occurs during oxidative phosphorylation - relies on membrane proteins that make up the ‘electron transport chain; and the ATP synthase enzyme

Question 3

What are the membrane composition of mitochondria

Answer 3

Two phospholipid membranes
Outer membrane is:
- Smooth
- Permeable to several small molecules
Inner membrane is:
- Folded (cristae)
- Less permeable
- Site of electron transport chain (oxidative phosphorylation)
- Location of ATP synthase enzyme (oxidative phosphorylation)

Question 4

Describe the structure of mitochondria

Answer 4

Outer membrane:
Smooth, permeable to several small molecules
Inner membrane:
Folded (cristae), less permeable, site of ETC
Intermembrane space:
Low pH due to high concentration of protons
Proton gradient is formed across the inner membrane is formed during oxidative phosphorylation, and is essential for ATP synthesis
Matrix:
An aqueous solution within the inner membranes of the mitochondrion
Contrains ribosomes, enzymes, and circular mitohcondrial DNA necessary for mitochondria to function

Question 5

What does cristae allow for in the mitochondria

Answer 5

Increased surface area
This allows there to be more elctron transport carriers and ATP synthase enzymes which results in more ATP being produced

Question 6

How does the number of mitochondria in each cell vary

Answer 6

The number of mitochondria in each cell can vary depending on cell activity
Muscle cells are more active and have more mitochondria per cell than fat cells

Question 7

Why do muscle cells have more mitochondria?

Answer 7

As they are more active