ATP synthesis

Question 1

WHy is ATP described as the universal energy currency in cells?

Answer 1

• the bond energy in the ATP molecule is used to drive essential metabolic processes

Question 2

How is ATP formed in photosynthesis generally?

Answer 2

• light provides energy needed to build organic molc like glucose
• the energy is used to form chemical bonds in ATP
• then broken to release the energy needed to make bonds as glucose is formed

Question 3

What happens in respiration generally?

Answer 3

• organic molecules are broken down
• energy released is used to synthesise ATP
• ATP then used to supply the energy needed to break bonds in the metabolic reaction of the cell

Question 4

What is chemiosmosis? How does it supply energy?

Answer 4

• process by which ATP is synthesised
• diffusion of H+ from a region of high conc to low conc through a partially permeable process
• movement of H+ as they flow down their conc gradient releases energy

Question 5

What is the energy released in chemiosmosis used for?

Answer 5

• attachement of inorganic phosphate (P_i) to ADP
• forming ATP

Question 6

How is the proton conc gradient created?

Answer 6

• energy to do this comes from high-energy electrons
  
  • excited electrons

Question 7

What is an electron transport chain?

Answer 7

• made up of a series of electron carriers
• each with progressively lower energy

Question 8

How does an electron transport chain supply energy?

Answer 8

• as high energy electrons move from one carrier in the chain to another, energy is released

Question 9

How is the energy released in the electron transport chain used for chemiosmosis?

Answer 9

• used to pump protons across a membrane,
• creating a conc difference across the membrane

Question 10

How is the conc gradient maintained?

Answer 10

• due to the impermeability of the memebrane to hydrogen ions

Question 11

What is the only way for protons to move>

Answer 11

• can move back through the membrane down their conc gradient through hydrophillic membrane channels link to the enzyme ATP synthase
  
  • catalyses the formation of ATP
• flow of protons through this channel provides the energy to combine ADP and P_i
• _{bit like hydorelectric power}

Question 12

What is the function of ATP in respiration and photosynthesis?

Answer 12

• photosynthesis
  
  • USED to synthesise glucose and other organic molc
• respiration
  
  • PRODUCED to provide the energy needed by metabolic processes and reactions essential to life