Basic metabolism Flashcards
What are the two systems in a metabolic pathway
Biosynthesis
Degredation
What is flux
Flux, or metabolic flux is the rate of turnover of molecules through a metabolic pathway. Flux is regulated by the enzymes involved in a pathway. Within cells, regulation of flux is vital for all metabolic pathways to regulate the pathway’s activity under different conditions.
What are short term ways to control flux
Allosteric control (changing enzyme structure by binding)
What are long term ways to control flux
- Covalent modification
- Substrate cycles
- Genetic control
How is there covalent modification
BY phosphatase and kinases
How is there control using substrate cycles
Vary rates of two opposing non-equilibrium reactions
How is there control using genetic control
Affects rate of transcription
What is flux determined by
Rate determining step
What does the slowest step have
The most negative deltaG
What do proteins get hydrolyses into
amino acids
What do polysaccharides get hydrolysed into
Monosaccharides
What do lipids get hydrolyses into
Glycerol and fatty acids
What do amino acids, monosaccharides and glycerol and fatty acids combine to form
Acetyl CoA
Which cycle does Acetyl CoA go into
citric acid cycle
What are the by products of the citric acid cycle
Co2 and ATP
For the digestion of starch, what happens in the mouth
alpha amylase turns carbohydrates to oligosaccharides
For the digestion of starch, what happens in the stomach
Low pH stops the action of amylase
For digestion of starch, what happens in the small intestine
Pancreas releases amylase into small intestine and there’s further digestion
For digestion of carbs, what happens when in contact with mucosal cells
Membrane bound dissacharidases like isomaltase, maltase and lactase turn disaccharides into monosaccharides
Where do the monosaccharides go to after being in contact with the mucosal cells
Liver
What monosaccharides go to liver
Glucose, fracture and galactose
What gets excreted when going to the liver
Cellulose
How does glucose move into cells
- facilitated diffusion
- ATP dependent Na+ monosaccharide transport
What does glucose exist as
D and L enantiomers
When does glucose form pyranase (ring)
IN a solution
What are the two stages of glycolysis
- Energy investment phase
- Energy generation phase
What happens in the glycolytic reaction no.1
Hexokinase phosphorylates glucose so it doesn’t move out of cells and produces glucose-6 phosphate
What does hexokinase do
Phosphorylates and produces Glucose 6-phosphate
What happens in the glycolytic reaction no.2
glucose 6 phosphate is turned into fructose 6 phosphate by phosphoglucose isomerase
What turns glucose 6 phosphate into fructose 6-phosphate
phosphoglucose isomerase
What happens in the glycolytic reaction no.3
Fructose 6-phosphate turns into fructose 1,6 biphosphate by the enzyme phosphofructokinase
What is the enzyme used to turn fructose 6 phosphate into fructose 1,6 biphosphate
Phosphofructokinase
What is added to fructose 6 phosphate to turn it into fructose 1,6 biphosphate and what are the products
ATP added
ADP and H+ are products
Which reaction of glycolysis is irreversible and the rate limiting step and the most important control point
Turning fructose 6 phosphate to fructose 1,6 biphosphate
What does a high conc of ATP do to the third reaction of glycolysis
INhibition
What does a high conc of AMP do to the third reaction of glycolysis
Inhibition
What also inhibits phosphorylation in the third reaction of glycolysis
Citrate
What does phosphorylation require
ATP
What is the fourth reaction of glycolysis called and what is produced
Cleavage
- 2x GAP
- 2x DHAP
both have one phosphate
What is the fifth reaction in glycolysis
Redox
-GAP is turned into BPG
What are the reactants of the fifth reaction glycolysis
add:
- NAD+
- Pi
exit:
- H+
- NADH
What is the sixth reaction of glycolysis
Synthesis
-BPG is turned into 3-phosphoglycerate and ATP is taken out
What is the seventh reaction of glycolysis
3-phosphoglycerate turned into 2-phosphoglycerate
What is the eighth reaction of glycolysis
2-phosphoglycerate turned into phosphoenolpyruvate via the enzyme enolase
-water is taken out
What enzyme is used in the 8th reaction of glycolysis
enolase
What is the final step of glycolysis
PHosphoenolpyruvate turned into pyruvate with the removal of ATP (sub-level phosphorylation)
what is the ATP yield in anaerobic respiration
+2ATP
What is the ATP yield in aerobic respiration
6ATP (includes the additional ATP from the oxidation of 2NADH)
in anaerobic respiration conditions, what cannot be oxidized
Respiratory chain cannot oxides NADH to regenerate NAD+
What will glycolysis do
Converts NAD+ to NADH but NAD+ is needed for glycolysis to continue
What is the yield of water
2xH2O
what is the yield of NADH in glycolysis
2xNADH
