Flashcards in Biochemistry Deck (56):
Converting glucose to glycogen
Breakdown of glycogen to glucose
What is the purpose of liver glycogen?
To be broken down between meals to provide glucose to blood and brain cells
What is the purpose of muscle glycogen?
Provide energy for glycolysis and the TCA cycle
What is the primary source of glucose through the night (i.e. when the body has no food stores?)
Production of glucose from non-carbohydrate substrates
Name the 2 bonds in glycogen
a 1-4 glycosidic link
a 1-6 glucosidic link
Which glucosidic link makes branches
what is the primer in glycogen attached to?
what are the two options of glucose-6-phosphate?
2. Converted to glucose in the liver
Activated form of glucose
Activated form of phosphate
Activated form of acetate
Name the transporter which gets glucose into the bloodstream
Converts glucose to glucose-6-phosphate
Reversible reaction between Glucose-6-phosphate and glucose 1-phosphate
Glucose-1-phosphate to UDP-glucose
UDP glucose to glycogen
Glycogen to glucose-1-phosphate
glucose-6-phosphate to glucose
Where does energy come from for gluconeogenesis?
Oxidation of fatty acids from adipose tissue
Where does gluconeogenesis occur?
What are the precursors of gluconeogenesis?
What is synthesised to allow gluconeogenesis to continue?
What does glucagon do?
What does insulin do?
Why is fat needed in the body (3 roles)?
For essential fatty acids
Provides fat soluble vitamins
Name the three types of lipids
What are triglycerides made of?
Glycerol + three fatty acids
3 main products of fat digestion
What happens to fatty acids in the mucosa of the intestine (both short and long)?
Short - absorbed into blood stream
Long - resynthesises (along with monoglycerides) back to triglycerides
How are resynthesises triglycerides carried?
What are chylomicrons cleaved by and where?
Lipoprotein lipase in the muscle
Breakdown of lipids
How is ACyl-CoA generated?
CoA + fatty acid
What transports Acyl to the matrix?
Products of B-oxidation in the mitochondria?
1 fatty Acyl-CoA
1 NADH + H+
Total ATP yield from oxidation of one stearic acid?
What are ketone bodies formed from?
Acetyl-CoA from B-oxidation
Why are ketones produced in uncontrolled diabetes?
There is no oxaloaceteate (being used up in gluconeogenesis) so Acetyl-CoA can't enter the TCA cycle to be made into energy
Fatty acid synthesis
What happens to excess carbohydrate?
Converted to fatty acids and triglycerides in the liver
What transports acetyl groups into the cytoplasm?
Citrate (from TCA cycle)
Which enzyme activates Acetly-CoA into Malony-CoA?
Acetyl CoA carboxylase
When is fatty acid synthesis maximal?
When carbohydrates are abundant
What increases the action of Acetyl-CoA carboxylase?
Insulin and citrate
What does glucagon do to the action of Acetly-CoA carboxylase?
What is required for the synthesis of triglycerides?
Glycerol-3-phosphate from glycerol (liver) and glucose (fat)
Are amino acids stored?
No - catabolised in liver mainly
What unwanted product does amino acid break down give?
How are they mainly excreted?
Via urine (produced in liver)
3 stages of urea synthesis
Where does De-amination occur?
In the liver
What is the amino group converted to?
free ammonium ion
3 components of urea
Free ammonium ion