Biochemistry: Catabolism of Glucose Flashcards Preview

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Flashcards in Biochemistry: Catabolism of Glucose Deck (19)
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1
Q

which is a reduction/oxidation reaction

  • anabolism
  • catabolism
A
  • anabolism, reductive

- catabolism, oxidative

2
Q

what type of molecules are (mono/di/polysaccharides)

  • glucose
  • glycogen
A
  • monosaccharides

- polysaccharides

3
Q

what are the 4 fates of glucose

A
  • storage
  • pyruvate
  • lactate
  • ribose - 5 - phosphate
4
Q

what is glucose stored as

A
  • starch
  • glycogen
  • converted to lipids
5
Q

how is glucose made in ribose - 5 - phosphate and what is it used for

A
  • oxidation via pentose phosphate pathways

- precursor for nucleotide synthesis, cell growth

6
Q

how is glucose made into lactate and what is it used for

A
  • fermentation via anaerobic glycolysis

- inefficient but rapid ATP synthesis

7
Q

how is glucose made into pyruvate and what is it used for

A
  • oxidation via aerobic glycolysis

- efficient ATP synthesis via TCA cycle

8
Q

types of glucose transporters

A
  • Na+/glucose symport

- GLUT 1-5

9
Q

where are each of the GLUT transporters

A
  • 1, brain
  • 2, liver and B cells
  • 3, brain
  • 4, muscle and adipose tissue
  • 5, gut
10
Q

how do the GLUT transporters work

A
  • glucose binds and a conformational changes faces the binding site inward
  • gluce is released in side the cell and another conformational change faces the binding site outwards
11
Q

draw the diagram for glycolysis

A

**

12
Q

what are the 3 control points of glycolysis

A
  • hexokinase - substrate entry
  • phosphofructokinase - rate of flow
  • pyruvate kinase - product exit
13
Q

what is the rate-limiting enzyme of glycolysis

A

phosphofructokinase

14
Q

what does each enzymes do

  • hexokinase
  • phosphofructokinase
  • pyruvate kinase
A
  • phosporylates glucose
  • phosphorylates fructose - 6 - phosphate
  • phosphorylates ADP to make pyruvate and ATP
15
Q

how does phosphofructokinase slow glycolysis

A
  • ATP, citrate and H+ inhibit glycolysis
  • ATP as there is excess energy so slows
  • citrate is a TCA cycle intermediate and slows pyruvate entry as excess energy
  • H+ too much lactate and so slows
16
Q

how does phosphofructokinase speed up glycolysis

A
  • AMP and fructose 2, 6 bisphosphate

- as energy is required

17
Q

how does AMP control phosphofructokinase activity

A

via the ATP/AMP ratio

  • adenylate cyclase tries to salavge energy from excess ADP via 2ADP -> ATP + AMP
  • if there is an excess of AMP present energy is needed therefore glycolysis is sped up
18
Q

what is the Warburg effect

A

cancer cells make energy via anaerobic oxidation which is ineffective (lactate) and needs excess glucose in order to continually create energy for cell growth

  • leads to cachexia
  • H+ and lactate are produced in high volume but supports alt pathways for nucleotide synthesis
19
Q

what are the MoAs of treating cancer via glycolysis

A
  • 2, deoxyglucose and 3, Bromopyruvate competitively inhibit glycolysis intermediates
  • 2 deoxy glucose blocks metabolism of an intermediate whereas 3, bromopyruvate inhibits the production of one
  • dichloroacetate slows glycolysis by promoting the conversion of lactate to pyruvate, this means nucleotide synthesis isn’t sustained and cell growth cannot continue

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