Importance of ATP

Question 1

what is ATP?

Answer 1

ATP is a nucleotide described as the
‘universal energy currency’

Question 2

what are some ATP qualities?

Answer 2

• ATP provides energy in all cells for all reactions.
• ATP releases energy in small, usable amounts.
• ATP is easily hydrolysed, removing the terminal phosphate group to release energy, forming ADP

Question 3

describe the process of chemiosmosis and ATP synthase

Answer 3

ADP is converted to ATP by the enzyme ATP synthetase.
- ATP synthetase spans a membrane
- the energy required to drive the enzyme to phosphorylate ADP
comes from the flow of protons down
an electrochemical gradient by facilitated diffusion.
- This is chemiosmosis

Question 4

describe oxidative phosphorylation in mitochondria

Answer 4

• Hydrogen atoms, from
  dehydrogenation reactions reduce coenzymes (NAD or FAD)
• Reduced coenzymes deliver hydrogen atoms to
  the electron transport chain in the inner mitochondrial membrane
• The proton pumps on the inner mitochondrial membrane are powered
  by high energy electrons and pump protons into
  the intermembrane space where an electrochemical gradient is formed
• Protons flow
  from the intermembrane space through the stalked particles into the matrix
  by chemiosmosis
• they combine
  with the electrons from the chain and oxygen, forming water. Oxygen is the
  final electron acceptor

Question 4

describe photophosphorylation in chloroplasts

Answer 4

• Electrons are excited
  by photons of light and passed along an electron transport chain, powering
  proton pumps to pump protons across the membrane into the thylakoid space
• The thylakoid space is where the protons build up, forming an electrochemical gradient
• protons flow from inside
  the thylakoid back out into the stroma through this enzyme (ATP synthetase) phosphorylating
  ADP to ATP
• Protons re-enter the stroma and combine with the electrons and NADP to form NADPH

Question 5

describe the electron transport chain

Answer 5

• High-energy electrons are delivered to the chain
  = The high-energy electrons power a proton pump to pump the H+ ions through to the membrane-bound space from the matrix or stroma.
  = Electron carriers shuttle these electrons to the next proton pump in the chain.
• This results in a build up of protons on one side of the membrane making an
  electrochemical gradient.
• Protons diffuse back to the matrix or stroma through ATP synthetase.
• Energy is released and used to synthesise ATP.