5.2 - Respiration Flashcards
1
Q
- Describe the process of glycolysis and name where it takes place
A
- cytoplasm
- glucose phosphorylated to hexose biphosphate using 2 ATP molecules
- split into 2 x triose phosphate
- converted to 2 x pyruvate using 2 ADP + Pi -> ATP and 2 NAD -> NADH
- anaerobic process
2
Q
- Describe the link reaction
A
- 2 x pyruvate A.T. to mitochondrial matrix
- decarboxylase removes CO2 molecule and H from NADH -> NAD
- acetate formed combines with coenzyme A to form acetyl coenzyme A
3
Q
Per glucose molecule, how many molecules of acetyl coenzyme A are formed in link reaction?
A
2
4
Q
- Describe the Krebs cycle
A
- mitochondrial matrix
- acetate (2C) reacts w/ 4C molecule, releasing acetyl coenzyme A
- 6C molecule formed undergoes series of oxidation-reduction reactions
- starting 4C molecule regenerated to accept another acetate
- generates NADH, FADH2, ATP by substrate-level phosphorylation; CO2 lost
5
Q
- Describe oxidative phosphorylation - stage 1 (sources of electrons)
A
- NADH from Krebs cycle binds to protein complex 1:
NADH -> NAD+ + H+ + e- - FADH2 binds to complex 2:
FADH2 -> FAD+ + H+ + e- - H+ ions move into mitochondrial matrix
- e-s go to ETC
6
Q
Describe oxidative phosphorylation - stage 2 (chemiosmosis)
A
- e-s passed down chain of protein complexes, which go from oxidised -> reduced
- energy released from each movement used to pump H+ ions across inner mitochondrial membrane from matrix to intermembrane space
- creates electrochemical gradient
- H+ ions diffuse (facilitated) back into matrix via ATP synthase
- causes ATP synthase to change in shape, releasing energy used to synthesise ATP
7
Q
Describe oxidative phosphorylation - stage 3 (final acceptor)
A
- oxygen is the final electron acceptor and accepts e-s
H+ + O2 + e- -> H2O
8
Q
State how many turns of the Krebs cycle occur per glucose molecule and how many molecules of each product is produced
A
- 2x per glucose molecule
- 2 ATP
- 6 NADH
- 2 FADH2
- 4 CO2
