L5+7 Biochem Flashcards

1
Q

also known as Embden-Meyerhof Pathway or Embden– Meyerhof-Parnas Pathway

A

Glycolysis

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2
Q

Aerobic Glycolysis:
1-end product is ___
2-cells have ____ and ___

A

1- Pyruvate

2-mitochondria and oxygen

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3
Q

Anaerobic Glycolysis:
1-end product is ____
2- allows the production of ATP in cells that don’t have ____ and ___
3-e.g happens in ____ and ____

A

1- Lactate
2-mitochondria and oxygen
3-RBC and exercising muscle

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4
Q

entry of glucose into cells happens using carriers:
1-____: for muscle cells, heart cells, adipocytes (insulin-dependent)
2-___ : for liver cells, kidney (insulin-independent)
3-___ : for neurons (insulin-independent)
4-___ : for RBCs, brain (insulin-independent)


all enzymes required for glycolysis are present in the ______

A

1- GLUT4
2-GLUT2
3-GLUT3
4-GLUT1

CYTOSOL

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5
Q

A) Energy investment/Preparatory Phase:
- reactions from 1-5
1- glucose to _________ , __ ATP were invested

B) Energy Payoff Phase:
-reactions from 6-10
1- two glyceraldehyde 3-phosphate molecules to __________ plus ___ ATP molecules.

A

A1- two glyceraldehyde 3-phosphate molecules, two

B1- Two Pyruvate PLUS four ATP

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6
Q
Aerobic glycolysis 
1st reaction:-
1-substrate: glucose
2-****enzyme: \_\_\_\_\_
3-end product: \_\_\_\_\_
4- ATP to \_\_\_
A

2-Hexokinase OR (glucokinase for hepatocytes)
3-Glucose 6-phosphate
4- ADP (energy-consuming)

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7
Q
Aerobic glycolysis 
2nd reaction:-
1- substrate:glucose 6-phosphate (aldose)
2-  enzyme: \_\_\_\_\_
3- end product: \_\_\_\_\_
A

2- Phosphoglucose isomerase

3- Fructose 6-phosphate (ketose)

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8
Q
Aerobic glycolysis 
3rd reaction:-
1-substrate: Fructose 6-phosphate
2- ****enzyme: \_\_\_\_\_ (allosteric/regulatory)
3- end product: \_\_\_\_\_
4- ATP to \_\_\_
A

2- Phosphofructokinase-1
3-Fructose 1-6-bisphosphate
4- ADP (energy-consuming)

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9
Q
Aerobic glycolysis 
4th reaction:-
1-substrate: Fructose 1-6-bisphosphate
2- enzyme: \_\_\_\_\_ 
3- end product: \_\_\_\_\_
A

2- Aldolase
3- one molecule of Glyceraldehyde 3-phosphate
one molecule of Dihydroxyacetone phosphate

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10
Q
Aerobic glycolysis 
5th reaction:-
1-substrate: Dihydroxyacetone phosphate
2- enzyme: Trios phosphate isomerate
3- end product: \_\_\_\_\_
A

Glyceraldehyde 3-phosphate

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11
Q

Aerobic glycolysis
6th reaction:- (substrate-level phosphorylation)
1-substrate: Glyceraldehyde 3-phosphate
2-*** enzyme: ___
this enzyme has 2 functions that are
a. Adding one Pi to C1 (~high energy bond)
b. Oxidation/dehydration (needs H+ carrier called NAD)

3-end product:______ ~high energy~
along with NADH + H

A

2- Glyceraldehyde 3-phosphate dehydrogenase

3- 1,3-Bisphosphoglycerate

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12
Q
Aerobic glycolysis 
7th reaction:- (substrate-level phosphorylation)
1-substrate: 1,3-Bisphosphoglycerate
2- enzyme: \_\_\_\_\_
3-end product: 3-Phosphoglycerate
4- from ADP to \_\_
A

2- Phospho-glycerate kinase

4- ATP (energy releasing)

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13
Q

A- Aerobic glycolysis results in __ ATP, 2 ___ and ___ NADH

B- Anaerobic glycolysis (in RBC/exercising muscle/cornea)
results in :
1- if NO 2,3-BPG is formed: __ ATP
2- if 2,3-BPG is formed: __ ATP

A

A- 8 ATP, 2 pyruvate, 2 NADH

B- 2 , ZERO

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14
Q

Inhibitors of glycolysis:
***1- ____: inhibits glyceraldehyde-3-phosphate by replacing Pi at C1, leads no net production of ATP
2- ____: inhibits glyceraldehyde-3-phosphate
3- ____: inhibits Enolase to decrease dental caries (lactic acid from bacteria)

A

1- Arsenate
2- Iodoacetate
3- Flouride

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15
Q

Regulatory enzymes (glycolysis):
1- Glucokinase/hexokinase
***2-_____
3-pyruvate kinase

A

2-PFK-1

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16
Q
Regulatory Mechanisms (glycolysis):
A) \_\_\_\_\_\_\_\_:
a1-Allosteric
b1-Covalent modifications
B) \_\_\_\_\_\_\_\_:
b1-Induction by \_\_\_\_/repression by \_\_\_\_
A

A- Rapid, short term

B- Slow, long term
b1-insulin (stimulation), Glucagon (inhibition)

17
Q

Effect of hormones on glycolysis:

1) Insulin: ____ the synthesis of the 3 irreversible enzymes.
a. _____ (activates) the enzymes through activation of protein phosphatase

2) Glucagon: ____ the synthesis of the 3 irreversible enzymes.
a. ______ (inactivates) the enzymes mediated by cAMP activation of protein kinase

A

1) Induces
a. dephosphorylates
- -
2) Represses
a. phosphorylates

18
Q

1-_____:
-high affinity (low Km), it is active at low glucose concentration

2-____:

  • low affinity (high Km) only active at high glucose concentration.
  • found in Liver Only
A

1- Hexokinase

2-Glucokinase

19
Q

regulation of PFK-1 ***:

  • inhibited allosterically by ATP and _____
  • stimulated by AMP and ________
A
  • ATP and Citrate

- Fructose 2,6-bisphosphate

20
Q

indicator of high energy state?

A

High citrate (product of citric acid cycle)

21
Q

it is formed from fructose 6-phosphate by phosphofructokinase-2 (PFK-2)

A

Fructose 2-6 bisphosphate

22
Q
  • during well-fed state, elevated levels of ____
A

Insulin

23
Q

regulation of pyruvate kinase (PK)

  • Feedforward regulation by _________ (the product of PFK-1)
  • covalent modification by PK

**Q. if PK was NOT able to function?

A

1- Fructose 1,6- bisphosphate

A. there will be accumulation of PEP (phosphoenolpyruvate)

24
Q

importance of Glycolysis:
1- ___ _____: under aerobic and anaerobic conditions

2-importance of glycolytic intermediates:

2a. pyruvate in making:
- ____(citric acid cycle and gluconeogenesis)
- ____
2b. _____is very important in lipid biosynthesis

3- synthesis of non essential protein

3a. 3-phosphoglycerate—> ___
3b. pyruvate—>___

A

1- energy production

2a.

  • Oxaloacetate (the prime of krebs cycle)
  • Acetyl CoA
  • -
    2b. Dihydroxyacetone phosphate (DHAP)
  • -
    3a. Serine
    3b. Alanine
25
Q

PK deficiency is resricted to RBCs and produces mild to severe _______

A

Chronic hemolytic anemia

26
Q
fate of \_\_\_\_\_ :
1- Lactate
2-Alanine
3-oxaloacetate
4-Acetyl Coa
A

Pyruvate

27
Q

formation of alanine (cytosol)

substrate: Pyruvate
enzyme: ALT (alanine transaminase)
coenzyme: ________

A

PLP: pyridoxal phosphate