5.7.3 structure of mitochondrion

Question 1

cristae

Answer 1

inner highly-folded mitochondrial membrane

Question 2

mitochondrial matrix

Answer 2

fluid-filled inner part of mitochondria

Question 3

structure of mitochondria

Answer 3

• inner & outer phospholipid membrane = envelope
• outer membrane = smooth
• inner membrane = folded into cristae (large SA)
• proteins embedded in inner membrane & protein channels
• inter-membrane space between
• mitochondrial matrix = enclosed by inner membrane, semi-rigid & gel-like

Question 4

what does the mitochondrial matrix contain

Answer 4

• mitochondrial ribosomes
• looped mitochondrial DNA
• enzymes for link reaction/Krebs cycle

Question 5

what does the matrix contain? - link to function

Answer 5

1. enzymes - catalyse stages of respiration reactions
2. molecules of coenzymes NAD & FAD
3. oxaloacetate - 4 carbon compound which accepts acetyl group from link reaction
4. mitochondrial DNA - code for enzymes & other proteins
5. mitochondrial ribosomes - proteins are assembled

Question 6

structure of outer membrane - link to function

Answer 6

• phospholipid composition
• contain proteins = some form channels/carrier proteins allowing passage of molecules (eg, pyruvate) into mitochondrion

Question 7

structure of inner membrane - link to function

Answer 7

• lipid composition
• less permeable than outer membrane to small ions (eg. hydrogen ions - protons)
• folds (cristae) give large SA for electron carriers & ATP synthase enzymes embedded

Question 8

describe electron carriers (inner membrane)

Answer 8

protein complexes arranged in electron transport chains (involved in oxidative phosphorylation)

Question 9

structure of intermembrane space (relate to function)

Answer 9

• between outer/inner layers of mitochondrial envelope
• involved in oxidative phosphorylation
• inner membrane in close contact with matrix = NADH & FADH can easily deliver hydrogens to electron transport chain

Question 10

what does each electron carrier protein contain

Answer 10

cofactor = non-protein haem group containing an iron ion

Question 11

what is the role of the cofactor on the electron carrier protein

Answer 11

accept/donate electrons, as becomes reduced (Fe2+) by gaining electron & becomes oxidised (Fe3+) when donating electron to next electron carriers

= oxido-reductase enzymes

Question 12

describe the role of coenzymes on the electron carriers

Answer 12

uses energy released from electrons to pump protons from matrix to intermembrane space

Question 13

describe the ATP synthase enzyme

Answer 13

• large
• protrude from inner membrane into matrix
• protons pass through them