Structure And Function Of Mitochondria

Question 0

How does the structure of the inner membrane enable it to carry out its function

Answer 0

• folded into many cristae –> larger surface area
• lipid composition is different to outer membrane
• impermeable to small ions (H+) –> so they accumulate in inter membrane space, building a proton gradient (source of potential energy)
• electron carriers and ATP synthase enzymes embedded in it

Question 1

How does the structure of the outer membrane enable it to carry out its function

Answer 1

• contains proteins which from channels or carriers to allow the passage of molecules such as pyruvate
• other proteins in the membrane are enzymes

Question 2

How does the structure of electron carriers enable them to carry out there function

Answer 2

• protein complexes are arranged in a chain to carry electrons
• each carrier is an enzyme (oxidoreductase) with a cofactor (non protein with a haem group)

Question 3

How does the structure of ATP synthase enable it to carry out its function

Answer 3

• they are large and protrude from inner membrane into the matrix
• also called stalked particles
• allow protons to pass through down gradient from inter membrane space to matrix (chemiosmosis)
• coenzyme FAD is tightly bound to a dehydrogenase enzyme in inner membrane and becomes reduced during Krebs –> the Hydrogen atoms do not get pumped into inter membrane space but instead pass back into the mitochondrial matrix

Question 4

How does the structure of the matrix enable it to carry out its function

Answer 4

• the matrix is the site of the link reaction and Krebs cycle, it contains

 - enzymes that catalyse the stages of the reactions 
 - molecules of coenzyme NAD 
 - oxaloacetate (4C compound that accepts acetate from link) 
 - mitochondrial DNA (codes for mitochondrial enzymes and other 
   proteins)  
 - mitochondrial ribosomes (where proteins are assembled)