Component 1.1 - Importance of ATP

Question 1

How is ATP synthesised in chloroplasts and mitochondria?

Answer 1

1) ATP is produced on the internal membranes of mitochondria and chloroplasts
2) When protons flow across these membranes down a concentration gradient through the enzyme ATP synthetase located in the stalked particles, ATP is synthesised.
3) This is called chemiosmosis.

Question 2

Difference between chloroplasts and mitochondria in terms of where ATP synthesis takes place?

Answer 2

1) In mitochondria the protons flow across the inner membrane from the intermembrane space into the matrix.
2) In chloroplasts the protons flow across the thylakoid membrane from the thylakoid space into the stroma.

Question 3

Similarities between mitochondria and chloroplasts in chemiosmosis

Answer 3

1) Involve electron transport chains which excite electrons and produce energy
2) Proton pumps maintain concentration gradient in the inter-membrane and thylakoid space, fuelled by energy from electrons