Exam 1 Ch 15 Flashcards
1
Q
What is fermentation
A
anaerobic
breakdown of glucose EtOH & CO 2
2
Q
How many enzymatic reations in glucose metabolism
A
10
3
Q
What does glucose metabolism yield
A
Yields 2 moles ATP & 2 moles pyruvate
4
Q
In glucose metabolism, where is pyruvate reduced to lactate?
A
Anaerobic.
Aerobic: pyruvate is further oxidized
Anaerobic: pyruvate is reduced to lactate
5
Q
In the haworth projection of glucose, when the OH group is up, is it beta or alpha?
A
Beta
6
Q
What are anomers
A
- Stereoisomers of carbohydrates
- Specific type of epimer
7
Q
Where is the anomeric carbon in glucose
A
C1. (the carbon that forms an aldehyde or ketone in the linear form)
8
Q
What’s an alcohol
A
R-OH
9
Q
What’s an aldehyde
A
R-CH=O
10
Q
What’s a ketone
A
R-CR=O
11
Q
Group-transfer reactions
o e.g. kinase
A
Transferases
12
Q
Hydrolysis reactions
o e.g. phosphatase
A
Hydrolases
13
Q
Addition & elimination reactions break bonds
o e.g. aldolase, enolase
A
Lyases
14
Q
isomerization reactions
o e.g. mutase
A
Isomerases (EC 5)
15
Q
Ligation reactions form bonds
o e.g. synthetase, carboxylase
A
Ligases
16
Q
Reduction-Oxidation (redox) reactions
o e.g. reductase, oxidase, dehydrogenase
A
Oxidoreducatses
17
Q
What is the first stage of glycolysis called
A
Preparatory Phase
18
Q
What do you put into the preparatory phase of glycolysis
A
1 molecule of GLO and 2 molecules of ATP
19
Q
What do you get out of the preparatory phase of glycolysis
A
2 molecules of GAP (glyceraldehyde 3-phosphate)
20
Q
What is the second stage of glyclysis called
A
Payoff PHase
21
Q
What do you put into the payoff phase of glycolysis?
A
2 molecules of GAP
22
Q
what do you get out of the payoff phase
A
2 molecules of PYR (main thing. the ATP and NADH are kinda side quests)
4 molecules of ATP
2 molecules of NADH
23
Q
what reactions are in the preparatorty phase of glycolysis
A
1 to 5
24
Q
How many irreversible reations are in the preparatory phase of glycolysis
A
2
25
What happens in the preparatory phase of glycolysis
one molecule of GLO is converted to two molecules of glyceraldehyde e-phosphate (GAP). Two molecules of ATP are used
26
Reaction 1 of glycolysis
phosphorylation. catalyzed by a kinase. GLO to G6P
27
Reaction 2 of glycolysis
Isomerization. catalyzed by isomerase. G6P to F6P
28
Reaction 3 of glycolysis
Phosphorylation by a kinase. F6P to FBP
29
Reaction 4 of glycolysis
Cleavage by and aldolase. FBP to GAP and DHAP
30
Reaction 5 of glycolysis
isomerase. DHAP to GAP
31
What reactions are part of the payoff phase of glycolysis
6 to 10
32
how many irreversible reactions are in the payoff stage of glycolysis and what is it?
1. It's reaction 10. Substrate level phosphorylation by a kinase of PEP (Phosphoenolpyruvate) to PYR
33
What are the two irreversible reactions in the preparatory phase of glycolysis
1 and 3. Phosphorylation of GLO to G6P by a kinase and Phosphorylation of F6P to FBP by a kinase
34
what happens in the payoff phase of glycolysis?
two molecules of glyceraldehyde-3-phosphate (GAP) are converted to two molecules of pyruvate (PYR). It generates 4 molecules of ATP and two molecules of NADH.
35
What is the most abundant stereoisomer of glucose?
D-Glucose
36
Can human metabolize L-glucose?
No
37
If the CH2OH group on C6 is Up is it a D or L sugar
D. For the Haworth ring structure, C6 CH2OH group being Up is D sugar and being Down is L sugar
38
What is the most abundant anomer of glucose at equilibrium?
Beta-D-Glucose because of steric reasons that have to do with stability.
39
Which form of glycosidic linkages can humans not metabolize? hint: cellulose
B-glycosidic linkages. looks like a squiggly line/hill. humans can metabolize alpha linkages tho. this looks like a scoop and the example is amylose
40
In the chair conformation of glucose, which (alpha or beta) is in the equatorial, more stable position?
beta d glucose
41
input of stage 1 glycolysis
1 glucose and 2 atp
42
output of stage 1 glycolysis
2 glyceraldehyde-3-phosphate and 2 atp
43
input of stage 2 glycolysis
2 GAP, 2 NAD+ and 4 ADP
44
output of stage 2 glycolysis
2 pyruvate, 2 NADH, and 4 ATP
45
What is the cofactor used in reaction 1 and 3 of glycolysis with enzymes hexokinase and phosphofructokinase?
Mg2+. They are phosphorylation reactions which are transferases
46
What is the enzyme classification of reaction 1
Transferase
47
What is the enzyme classification of reaction 2
isomerase
48
What is the enzyme classification of reaction 3
Transferase
49
What is the enzyme classification of reaction 4?
Lyase. It's the cleavage by the aldolase
50
What is the enzyme classification of reaction 5
Isomerase. TIM (triose phosphate isomerase) is the enzyme
51
What type of isomers are the isomers in reaction 5? GAP to DHAP
Structural Isomers (tautomers)
52
Difference between strucutral isomers and sterioisomers
In stereoisomers, the bonds rotate and shift position. In structural isomers the actual structures changes
53
Glycolysis stage 1 review (list all)
1: Phosphorylation (hexokinase)
2: Isomerization (isomerase)
3: Phosphorylation (phosphofructokinase)
4: Cleavage(lyase) (aldolase)
5: Isomerization (isomerase) 6:
54
Review of reaction 1
Glucose becomes phosphorylated at its terminal hydroxide (C6) that produces
a “low energy” intermediate committing it to the pathway.
55
Review of reaction 2
Isomerization moves the terminal carbonyl (C1 C2) yielding a terminal
hydroxide (C1) for subsequent phosphorylation.
56
Review of reaction 3
Phosphorylation at the terminal hydroxide (C1) produces a bisphosphate
compound allowing for the subsequent generation of “low energy”
phosphorylated intermediates.
57
Review of reaction 4
Cleavage between C3 & C4 is facilitated by the C2 carbonyl formed from
reaction 2
58
Review of reaction 5
Isomerization between cleavage products permits use of a single pathway for
subsequent reactions.
59
What is the enzyme in reaction 6 in the payoff phase and what is the enzyme classification?
glyceraldehyde-3-phosphate dehydrogenase (GAPDH). It is a oxidoreductase. NAD+ oxidizes GAP to 1,3-BPG
60
When do you see the first high-energy intermediate in glycolysis?
Reaction 6. 1,3-Bisophosphoglycerate (1,3-BPG)
61
When do we see cofactors used in glycolysis and what are they?
The transferase phosphorylation reactions. Mg2+
62
What happens in reaction 7
!,3-BPT phosphorylates ADP to ATP by phosphoglycerate kinase (PGK)
63
When is the first ATP generated in glycolysis?
Reaction 7. 1,3-BPG phosphorylates ADP to ATP by PGK
64
What is the enzyme classification of reaction 7
transferase. It's phosphoglycerate kinase.
65
What is a special thing about reaction 6 and 7. The oxidoreductase and the phosphorylation (transferase)
They are energetically coupled
66
What happens in reaction 8
3PG isomerizes to 2PG by enzyme PGM. The enzyme is phosphoglycerate mutase (2PG). The enzyme class is isomerase.
67
What type of isomers are 3PG and 2PG in reaction 8?
Structural isomers (not tuatomers)
68
What are tautomers
Tautomers are structural isomers of chemical compounds that readily interconvert. They are constitutional isomers that differ from each other in the locations of a hydrogen atom and one or more double bonds and interconvert rapidly.
69
What happens in reaction 9
2PG dehydrates to PEP by enolase. Classification is lyase. enzyme is enolase. Formation of second high-energy intermediate.
70
What's the second high energy intermeidate in glycolysis is
Phosphoenolpyruvate (PEP). Reaction 9.
71
What is the enzyme classification of reaction 9?
Enolase. Lyase.
72
What happens in reaction 10
PEP phosphorylates ADP to ATP by PK. Enzyme is Pyruvate kinase (PK) and the class is transferase. Generation of second ATP (technically both 7 and 10 produce 2 atp because there are two molecules of the starting material) by substrate-level phosphorylation.
73
When is the second atp generated?
reaction 10
74
GLycolysis stage II Review
6: Oxidation (dehydrogenase)
7: Substrate-level phosphorylation (kinase) (first ATP)
8: Isomerization of phosphoryl group (mutase)
9: Elimination of waters (enolase)
10: Substrate-level phosphorylation (kinase)
75
How many irrevsersible reactions in second stage of glycolysis
1. Number 10
76
Review of reaction 6
oxidation (dehydrogenase) followed by subsequent phosphorylation
Oxidation coupled to phosphorylation at C1 produces first “high energy” compound.
77
Review of reaction 7
High C1 phosphoryl group transfer potential drives substrate-level phosphorylation
yielding ATP
78
Review of reaction 8
Intramolecular transfer of phosphoryl group from C3 to C2 produces another “high
energy” compound.
79
Review of reaction 9
Dehydration at C3 raises C2 phosphoryl group transfer potential.
80
Review of reaction 10
High C2 phosphoryl group transfer potential drives substrate-level phosphorylation
yielding ATP.
IRREVERSIBLE
81
Stage I (Investment Phase)
1. Glucose phosphorylation (−1 ATP)
2. G6P isomerization to F6P
3. F6P phosphorylation (−1 ATP)
4. FBP cleavage into GAP & DHAP
(Hexose 2× Triose)
5. Triose isomerization
82
Stage II (Payoff Phase)
6. GAP oxidation & phosphorylation
(+2 NADH)
7. 1,3-BPG substrate-level
phosphorylation (+2 ATP)
8. 3PG isomerization to 2PG
9. 2PG dehydration to PEP
10. PEP substrate-level
phosphorylation (+2 ATP)
83
After you create pyruvate in glycolysis, it's got to go somewhere. In anaerobic, it becomes lactate (homolactic fermentation) and Co2 +Ethanol (alcoholic fermentation). What happens to it in Aerobic?
Oxidative phosphorylation. THe citric acid cycle. It becomes Co2 and H2O.
84
What does LDH (lactate dehydrogenase) do
lactate dehydrogenase is an enzyme that converts pyruvate to lactate in anaerobic ferm. H subunits are aerobic tissues and have low rates. M subunits are anaerobic tissues and have high reates
85
What is pyruvate decarboxylase's cofactor?
Thiamine pyrophosphate (TPP). I't sstrongly bound (prosthetic group) and a coenzyme
86
What percent efficiency does homolactiv ferm and alcoholic ferm have?
30% and 26 %. Very inefficient. both -196 and -2235 kj/mol. Oxidative phosphorylation is like 80-90% though
87
Which is faster, ferm or oxidative phosph
Ferm. 100x faster. Fast-twitch muscle fiber is devoid of mitochondria and uses anaerobic glycolysis to get ATP
88
List the glycolysis enzymes in order
Hexokinase, PGI, PKF, Aldolase, TIM, GAPDH + PGK, PGM, Enolase, PK
89
What is the major flux-controlling enzyme of glycolysis
PFK. At equilibrium between R and T state.
90
In PFK, is T inactive for active form
Inactive
91
What regulates PFK?
Substrate cycling
92
What does fermentation do?
Restores NAD+ at the expense of Pyruvate
93
What enzyme does the homolactiv pathway use?
Lactate dehydrogenase
94
What enzymes does alcoholic pathway use
pyruvate decarboxylase and alcohol dehydrogenase
95
What does phosphofructokinase do?
Regulates glycolysis
96
What regulates PFK?
ATP amount. When ATP is high, it inhibits PFK so glycolysis doesn't occur but when it's low and ADP and AMP are around, PFK is activated and glycolysis happens.
97
By what type of regulation is PFK regulated in R and T state?
Allosteric modulation by ATP and ADP/AMP. T state is inactive. R state is active.
98
Which state of PFK promotes glycolysis?
R
99
What also regulates PFK besides ATP?
Fructose-1,6-bisphosphatease (FBPase). This is through substrate cycling.
100
Epimers
Epimers: one different
stereocenter
101
Diastereomers
Diastereomers: more than
one different stereocenter
102
Enantiomers
Enantiomers: all different
stereocenters
103
By what pathway is NADPH generated?
Pentose phosphate pathway
104
What is NADPH used for?
Reducing agent
105
What is NAD+ used for
oxidizing agent
106
What are the products of pentose phosphate pathway
NADPH and R5P
107
What is excess R5P converted to?
Glycolysis intermediate
108
How is flux of pentose phosphate pathway regulated by?
rate of G6P. Rate of this is high when NADP+ is high.
