3.1: ATP 1

Question 1

What is ATP?

Answer 1

Adenosine Triphosphate, the universal energy carrier found in all living cells

Question 2

Where is ATP produced?

Answer 2

ATP is synthesised in the internal membranes of mitochondria and chloroplasts

Question 3

Describe how ATP is synthesised

Answer 3

Involves ATP Synthase an enzyme embedded in cell membranes, ATP Synthase phosphorylates ADP to form ATP as protons flow through it

Question 4

Compare the flow of protons across mitochondrial and chloroplast membranes

Answer 4

Mitochondrial membrane: H+ flow from the intermembrane space into the matrix across the inner membrane
Chloroplast membrane: H+ flows from thylakoid space into stroma across thylakoid membrane

Question 5

Define chemiosmosis

Answer 5

The synthesis of ATP through the movement of protons down their electrochemical gradient across a semi-permeable membrane catalysed by ATP Synthase

Question 6

How is the proton gradient maintained during chemiosmosis?

Answer 6

Potential energy associated with exited electrons is coupled to the active tranport of H+ across the membrane by proton pumps.

Question 7

What is the electron transport chain?

Answer 7

A series of electron carrier proteins that transfer electrons in a series of oxidation-reduction reactions releasing energy

Question 8

How can dehydrogenase activity be investigaetd?

Answer 8

Investigated using artificial hydrogen acceptors like DCPIP, methylene blue and tetrazolium compounds.

Question 9

Colour change observed when DCPIP is reduced?

Answer 9

Dark blue to colourless

Question 10

Colour change observed when methylene blue is reduced?

Answer 10

Dark blue to colourless