L6-10- Metabolism overview Flashcards
1
Q
how many stages of catabolism of carbohydrates
A
4
2
Q
stage 1
A
breakdown of carbohydrates into glucose
3
Q
stage 2
A
glycolysis
4
Q
stage 3
A
Kreb cycle/TCA
5
Q
stage 4
A
Electron transport stage
6
Q
outline stage 1
A
Extracellular process
- breakdown of carbohydrates into glucose
- glucose absorbed in the gut
7
Q
outline stage 2
A
cytosolic and mitochondrial
- 1 glucose (C6) –> 2Pyruvtae, 2NADH and 2ATP
8
Q
outline stage 3
A
mitochondrial
- pyruvate loses a CO2 and is converted to Acetyl CoA
- acetyl CoA enters the kerb cycle
- produces NADH, GTP and FADH
9
Q
GTP
A
ATP equivalent in Krebs cycle
10
Q
outline stage 4
A
- mitochondrial membrane
- NADH and FADH from Kreb feeds into the ETC
- Proton motive force is used to power the ATP synthase which synthesises ATP from ADP and Pi
11
Q
stages 1 to 3 are
A
substrate level phosphorylation
12
Q
stage 4 is
A
oxidative phosphorylation
13
Q
which stage produces the most TP
A
ETC
14
Q
during stage 1 proteins are broken down into
A
amino acids
15
Q
during stage 1 CHOs are broken down into
A
monosaccharides
16
Q
name 3 monosaccharides
A
galactose
glucose
fructose
17
Q
during stage 1 lipids are broken down into
A
glycerol and fatty acids
18
Q
all of catabolism of CHOs is
A
oxidation
19
Q
what makes a step irreversible
A
when it loses carbon dioxide
20
Q
glycolysis is a ….. process which produces…. ATP
A
exergonic… 2 ATP
21
Q
name 3 enzymes which control glycolysis
A
1) hexokinase
2) phosphofructokinase
3) pyruvate kinase
22
Q
glycolysis is ….. activated
A
hormonally
- PFK
- pyruvate kinase
23
Q
where does hexokinase work
A
between glucose and glucose-6-phosphatw
24
Q
hexokinase is an example of
A
a negative regulator
25
phosphofructokinase (PFK) is regulated differently by
the liver and the muscles
26
How is PFK regulated in the muscle
allosteric regulation
27
PFK in muscle stimulated by
AMP
28
PFK in muscle inhibited by
ATP
29
PFK in liver stimulated by
insulin
30
PFK in liver inhibited by
glucagon
31
phosphofructosekinase converts what to what
Fructose 6 phosphate to fructose 1,6- bisphopshate
32
pyruvate kinase converts
phosphoenolpyruvate --> pyruvate
33
Pyruvate kinase is inhibited by
phosphorylation- e.g protein kinase A (glucagon)
34
pyruvate is stimulated byq
phosphatase (insulin)
35
stage 3- Krebs cycle takes place in
mitochondrial matrix
36
Krebs cycle known as
hub of metabolsim
37
each pruvate goes round ..... to produce the products of the kreb cycle
2 cycles
38
Krebs cycle is the central metabolism pathway for
- sugar
- fatty acids
- ketone bodies
- amino acids
- alchohol
39
what stimulates the kreb cycle
AMP and NAD+ (low energy signals)
40
what inhibits the kreb cycle
ATP and NADH (high energy signals)
41
products of the Kreb cycle
6 NADH
2 FAD2H
2 GTP
2 CO2 (from Acetyl- CoA)
42
products form the kerb cycle are
precursors for biosynthesis
43
stage 4- the electron transport chain requires
oxygen
44
the ETC is where
most of the ATP is produced
45
where does stage 4 take place
Cristae of the mitochondria
46
outline stage 4
1) electrons from NADH and FADH (from glycolysis and Krebs) are given up to the PTC1
2) electrons from from PTC1 to PTC2 to PTC 3, this releases energy which pumps H+ ions across the membrane
3) At PTC3, oxygen combines with electrons and @H+ ions --> water released
4) high conc of H+ ions in the inner membrane compared to the inside of the mitochondria--> proton motive force
5) H+ ions diffuse through the ATP synthase down the conc. gradient
47
energy released during electron transport
30% pumps H+ across the inner membrane
70% released as heat
48
ATP synthase
ADP --> ATP
| - Protons can only return across the membrane via ATP synthase
49
what can affect ATP synthase production of ATP
uncoupling reactions
50
PTC stands for
proton translocating compelx
51
stage 1 of lipid metbolism
1) TAG broken down to glycerol and fatty acids.
2) fatty acids converted by to TAGa nd stored in adipose
3) Fatty acids released into blood during low blood glucose
4) fatty acid metabolism starts
5) fatty acids activated --> fatty acyl coA
6) carnitine shuffle
7) B oxidation of fatty acyl CoA to acetyl CoA
8) Acetyl CoA enters the kreb cycle and ATP synthase
52
stage 1 of lipid metabolism
- Triglycerides (TAG) eaten and converted to glycerol and fatty acids in the gut
- fatty acids converted back to TAG and absented
- TAG is then transported in the blood to adipose tissue via chylomicrons
- TAG stored in adipose tissue
- released as fatty acids when glucose is low and carried to consumer tissue as albumin-fatty acid complex
53
what transports TAG to adipose tissue from the blood
chylomicrons
54
when are fatty acids released from adipose tissue
when blood glucose is low
55
how are fatty acids carried to consumer tissue
via the albumin-fatty acid complex
56
stage 2 of lipid metabolism
- fatty acid activation --> Acyl CoA
- fatty acyl-Co-A binds to carnitine to produce Acyl carnitine (loses CoA)
- acyl carnitine is then transported across the mitochondrial membrane via the carnitine shuffle transporter
- once within the mitochondria the acyl carnitine lose carnitine loses and recombines with CoA to from Acyl CoA
57
how are fatty acids activated by
combine with Coenzyme A by fatty acyl coA synthase to produce AcylCoA
58
B-oxidation of lipids
when fatty acids chain gets oxidised within B-oxidation cycle
59
every cycle of B-oxidation how many carbons are lost
2 carbons
60
what is released during B-oxidation
FADH and NADH and acetyl coA (2C)
61
FADH and NADH from B-oxidation
used to produce the proton motive force which powers ATP synthase
