Biochemistry: Catabolism of Glucose Flashcards
which is a reduction/oxidation reaction
- anabolism
- catabolism
- anabolism, reductive
- catabolism, oxidative
what type of molecules are (mono/di/polysaccharides)
- glucose
- glycogen
- monosaccharides
- polysaccharides
what are the 4 fates of glucose
- storage
- pyruvate
- lactate
- ribose - 5 - phosphate
what is glucose stored as
- starch
- glycogen
- converted to lipids
how is glucose made in ribose - 5 - phosphate and what is it used for
- oxidation via pentose phosphate pathways
- precursor for nucleotide synthesis, cell growth
how is glucose made into lactate and what is it used for
- fermentation via anaerobic glycolysis
- inefficient but rapid ATP synthesis
how is glucose made into pyruvate and what is it used for
- oxidation via aerobic glycolysis
- efficient ATP synthesis via TCA cycle
types of glucose transporters
- Na+/glucose symport
- GLUT 1-5
where are each of the GLUT transporters
- 1, brain
- 2, liver and B cells
- 3, brain
- 4, muscle and adipose tissue
- 5, gut
how do the GLUT transporters work
- 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
draw the diagram for glycolysis
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what are the 3 control points of glycolysis
- hexokinase - substrate entry
- phosphofructokinase - rate of flow
- pyruvate kinase - product exit
what is the rate-limiting enzyme of glycolysis
phosphofructokinase
what does each enzymes do
- hexokinase
- phosphofructokinase
- pyruvate kinase
- phosporylates glucose
- phosphorylates fructose - 6 - phosphate
- phosphorylates ADP to make pyruvate and ATP
how does phosphofructokinase slow glycolysis
- 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
how does phosphofructokinase speed up glycolysis
- AMP and fructose 2, 6 bisphosphate
- as energy is required
how does AMP control phosphofructokinase activity
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
what is the Warburg effect
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
what are the MoAs of treating cancer via glycolysis
- 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
