Variation and Evolution

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 on the internal membranes of mitochondria and chloroplast

Question 3

describe how ATP is synthesised

Answer 3

involves ATP synthase, and enzyme found embedded in cellular membrane
ATP synthase phosphorylates ADP to form ATP as protons flow through it

Question 4

compare the flow of protons across the mitochondrial and chloroplast membranes

Answer 4

Mitochondrial membrane: H+ flow from the intermembrane space into the matrix, across the inner membrane.
Chloroplast membrane: H+
flow from the thylakoid space into the stroma, across the 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 proton gradient maintained during chemiosmosis

Answer 6

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

Question 7

what is an electron transport chain

Answer 7

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

Question 8

how can dehydrogenase activity be investigated

Answer 8

Investigated using artificial hydrogen acceptors such as DCPIP, methylene
blue and tetrazolium compounds

Question 9

what colour change is observed when DCPIP is reduced

Answer 9

dark blue to colourless

Question 10

what colour change is observed when methylene blue is reduced

Answer 10

dark blue to colourless