ATP

Question 1

What does ATP stand for?

Answer 1

adenosine triosephosphate

Question 2

What reaction releases energy from ATP?

Answer 2

hydrolysis of ATP to ADP + Pi

Question 3

Explain why ATP is a suitable energy source for cells.

Answer 3

releases energy in small, manageable amounts, so less energy is wasted as heat

Rapid hydrolysis, so ATP can be broken down in a single step

solubility ATP is water-soluble, so it can be transported around the cell to where it’s needed

Question 4

Describe how light energy is used to generate ATP in the light-dependent reaction.

Answer 4

Light energy is absorbed by photosystems in the thylakoid membrane, which excites electrons to a higher energy level

High-energy electrons are passed around by a series of electron carrier proteins

electrons then lose energy through redox reactions

This energy is used to pump hydrogen ions (protons) from the stroma into the thylakoid lumen, creating a proton gradient.

Proteins flow back into the stroma through the enzyme ATP synthase

providing energy to phosphorilate ADP into ATP