Unit 3.1 - Importance of ATP

Question 1

What is chemiosmosis

Answer 1

The flow of electrons down an electrochemical gradient, through ATP synthase with the synthesise of ATP (from ADP + Pi) following the creation of an electrochemical gradient

Question 2

Where is ATP synthesised?

Answer 2

In the mitochondria - using oxidative phosphorylation

Question 3

What is oxidative phosphorylation?

Answer 3

The addition of a phosphate that requires oxygen

Question 4

Why is ATP described as a universal energy currency?

Answer 4

ATP is used in all organisms for all/most reactions

Question 5

Why is ATP an important molecule? (4 points)

Answer 5

• It is readily formed by phosphorylation
• One step required to release energy
• One enzyme to catalyse the release
• Releases energy in small amounts

Question 6

What is the catalyst for the synthesis of ATP?

Answer 6

ATPsynthase

Question 7

What happens during the reaction of ATP –> ADP + Pi + 30.6kJmol-1 (3 points)

Answer 7

• When the terminal bond between phosphates is hydrolysed, ADP + Pi is produced releasing
  30.6kJmol-1 of energy.
• The enzyme used is ATPase
• This reaction is exothermic

Question 8

What happens during the reaction ADP + Pi + 30.6kJmol-1 –> ATP (3 points)

Answer 8

• This is the synthesis of ATP
• Condensation reaction
• Catalysed by ATPsynthase
• Endothermic reaction

Question 9

Uses of ATP in the cells (4 points)

Answer 9

• Muscle contraction
• Protein synthesis
• Cell division
• Active transport
• Endo/Exocytosis

Question 10

How is ATP suited to its role?

Answer 10

• Inert (not very reactive)
• 1 step reaction, 1 enzyme (can break and form energy in 1 step and use 1 enzyme)
• Universal energy currency
• The phosphodiester bonds are high energy bonds