Metabolic Pathways Flashcards
Give the location and O2 needs of the following processes:
1. glycolysis
2. PDC/Kreb’s Cycle
3. ETC/Oxidative Phosphorylation
- glycolysis: cytosol, anaerobic
- PDC/Kreb’s cycle: matrix of mitochondria, indirect O2
- ETC/Oxidative Phosphorylation: inner membrane of mitochondria; aerobic, directly
Run through the glycolysis process with the enzymes used:
1. Give ATP & NADH values when needed
2. Any feedback inhibition? :/
3. Which steps are veryyyYYY spontaneous? [x]
4. Indicate net energy at end
[1. glucose 6C
-hexokinase + ATP->ADP
hexokinase inhibited by 6CP
2. 6C-P. ]
(isomerization)
3. fructose 6-phosphate 6C-P
-phosphofructokinase + ATP->ADP
PFK inhibited by ATP
4. fructose 1,6-bisphosphate P-6C-P
5. glyceraldehyde 3 phosphate 2 3C-P (GAP)
[6. phosphoenolpyruvate (PEP) + 4 ATP + 2NADH
-pyruvate kinase
7. pyruvate 2 3C]
Net: 2 ATP and 2 NADH per glucose
Run through PDC/Kreb’s Cycle:
1. Give ATP, NADH, FADH2 values when needed
2. Indicate net energy at end (assuming ONE glucose molecule)
1) PDC:
pyruvate (3C) -> acetyl CoA (2C)
Net: 2 NADH
2) Kreb’s Cycle
a. 2C + oxaloacetate (4C)
b. 6C
c. 5C + NADH
d. 4C + NADH
e. isomerization of 4C back into oxaloacetate
this step causes release of 1GTP, 1FADH2,
1NADH
Net: 6NADH, 2FADH2, 2GTP
What are other names for the Kreb’s Cycle?
citric acid cycle, TCA cycle (tricarboxylic acid cycle)
What is the net ATP difference between prokaryotes and eukaryotes for the 3 metabolic processes, glycolysis, Krebs, ETC combined? Why?
32 ATP for prokaryotes, 30 ATP for eukaryotes. All processes occur in the cytosol for prokaryotes.
Gluconeogenesis steps
- 2 pyruvate (2 3C)
pyruvate carboxylase + 2ATP - 2 oxaloacetate (2 4C)
PEPCK (pep carboxykinase) + 2GTP - 2 phosphoenol pyruvate (2 3C-P)
2 ATP + 2 NADH - 2 glyceraldehyde phosphate (2 3C-P)
- fructose 1,6-bisphosphate (P-6C-P)
fructose 1,6 bisphosphatase - fructose 6-phosphate (6C-P)
glucose-6-phosphatase - glucose (6C)
Glycogenesis/Glycogenolysis when does it occur and what are the enzymes involved?
- glycogenesis: formation of glycogen
6C + hexokinase +ATP -> 6C-P +
phosphoglucomutase -> glucose 1P + UTP —
glycogen synthase (removes UTP) —>
glycogen - glycogenolysis: breakdown of glycogen
glycogen + glycogen phosphorylase -> glucose
1P + phosphoglucomutase -> glucose 6P +
glucose-6-phosphatase-> glucose 6C
What are the two phases of the pentose phosphate pathway (peepeepee 😼)
- Oxidative phase
6C –> 6C-P + glucose-6-P dehydrogenase(G6PDH) + 2NADP+ –> Ribulose-5-phosphate + 2NADPH
* NADPH can inhibit G6PDH* - Non-oxidative phase
Ru-5-P -> glycolytic intermediates (GAP, F6P)
What are the ATP equivalents for 15 NADH, 15 FADH2, and 8 GTP
1 NADH = 2.5 ATP
1 FADH2 = 1.5 ATP
1 GTP = 1 ATP
SO……
15 NADH = 37.5
15 FADH2 = 22.5
8 GTP = 8 ATP
TOTAL: 68 ATP
What are the starting materials for fatty acid synthesis?
acetyl-CoA and malonyl Co-A
Where does FA oxidation occur, what it’s linked to, electron carriers that get reduced, and does it generate energy?
-mitochondrial matrix
-coenzyme A
-NAD+ and FADH get reduced
-generates ATP
Where does FA synthesis occur, what is it linked to, what are the electron carriers used, and does it generate energy?
-cytosol
-acyl carrier protein
-NADPH (from PPP)
-no, requires ATP
When does ketogenesis occur?
when the blood glucose levels in the body are low, fatty acid oxidation begins, acetyl-CoA levels rise, ketone bodies are made
What are 3 different ketone bodies?
acetoacetate (made from 2 acetyl-CoAs), acetone & hydroxybutyrate (last 2 are created from acetoacetate)
When does ketoacidosis occur?
when there is an accumulation of ketone bodies, this causes a drop in blood pH and thus ketoacidosis
