biochem Flashcards
what is glycogenesis
glucose –> glycogen
what is glycogenolysis
glycogen –> glucose
what is gluconeogenesis
precursors–> glucose
where is glucose broken down to maintain blood glucose levels
liver
where is glucose broken down for immediate energy
muscle
in glycogen, what bonds join glucose together
alpha 1,4 glycosidic links
in glycogen, what bond are branches joined in by
alpha 1,6 glycosidic links
what adds branches to glycogen and after how many molecules are they added
transglycosylase, every 10
what is attached to the primer on glycogen
protein glycogenin
can glucose start a new glycogen chain
no, must be pre exsisting
what enzyme adds glucose to glycogen
glycogen synthase
what is the first step of glycogenesis, (what is converted, what is needed if anything, by what enzyme)
glucose –> glucose 6 phosphate, by hexinase, ATP –> ADP
what is the second step of glycogenesis, (what is converted, what is needed if anything, by what enzyme)
glucose 6 phosphate –> glucose 1 phosphate
phosphoglucomutase
what is the third step of glycogenesis, (what is converted, what is needed if anything, by what enzyme)
glucose 1 phosphate –> UDP glucose
UDP glucose pyrophosphorylase
what is the final step of glycogenesis, (what is converted, what is needed if anything, by what enzyme)
UDP glucose –> glucose ready for glycogen
glycogen synthase
ATP–> ADP and UTP –> UDP
what is the RLS of glycogenesis
UDP glucose –> glucose
what are the general steps of glycogenolysis
glycogen –> glucose 1 phosphate –> glucose 6 phosphate – > glucose or for glycolysis
what is the rate limiting step of glycogenolysis and what enzyme is used
glycogen–> glucose 1 phosphate, by glycogen phosphorylase
what converts glucose 1 phosphate –> glucose 6 phosphate
phosphoglucomutase
where can glucose 6 phosphate by dephosphorlayted to glucose
liver
where can glucose 6 phosphate not be dephosphorylated and what happens to it
skeletal, use via glycolysis
in gluconeogenesis, what are the main 3 precursors of glucose
lactate, amino acids, glycerol
what does gluconeogenesis need to proceed
oxaloacetate from TCA cycle
when and where does gluconeogenesis occur
over periods of starvation, in liver
what happens in the cori cycle
blood transfers blood to liver where it can be converted to glucose
what effect does insulin have on glycogen synthase and glycogen phosphorylase
activates glycogen synthase and inhibits glycogen phosphorylase
what effect does glucagon have on glycogen synthase and glycogen phosphorylase
inhibits glycogen synthase and activates glycogen phosphorylase
what happens to amino acids not used for building proteins
broken down in liver by proteolytic enzymes, the products are absorbed into intestinal cells and released to blood
what toxic group do amino acids have
amino - NH4+
how is NH4+ excreted
urea (80%), uric acid, creatinine, ammonium ion
how is urea synthesised
transamination–> deamination–> urea cycle
what happens in transamination
aminotransferase moves amino group from amino acid to keto acids. These produce glutamine and alanine
what do glutamine and alanine do
carry nitrogen in blood to liver
what happens in deamination
in liver, amino acids are separated from NH4+, it then enters urea cycle
what is left of amino acid after amino group is removed
long carbon skeleton
what can ketogenic amino acids give rise too
ketone bodies or fatty acids
what can glucogenic amino acids be converted into
glucose
what does excess carbohydrates lead too
fatty acid and triglyceride synthesis
what is the RLS in fatty acid production and what is the enzyme needed
acetyl CoA –> malonyl CoA by acetyl CoA carboxylase
how are acetyl groups transported into the cytoplasm
citrate
what is needed to catalyse fatty acids
malonyl CoA, acetyl CoA, NADPH
what enzyme synthesises fatty acids
fatty acid synthase
what is the longest chain fatty acid synthase can synthesise
16, palmitic acid
what are the 4 steps of fatty acid synthesis
condensation, reduction, dehydration, reduction and release
what is required for the synthesis of triglycerides and where is it produced
G3P, glycerol –> G3P in liver
what is the main energy store in adipose
triglycerides
how are triglycerides produced
glycerol + 3 fatty acids, esterification
what are saturated fatty acids, what food has them, what is their boiling point like
no double bonds, animal fat, high
what are unsaturated fatty acids, what food has them, what is their boiling point like
1 double bond, plants, low boiling point
what are some fat soluble vitamins
A,D,E,K
what are essential fatty acids
ones the body can’t make
what are the 3 main products of fat digestion and where are they absorbed
glycerol, fatty acids, monoglycerides, intestine
how is absorbed fat converted to lipid
coated with protein, phospholipid, cholesterol and chylomicrons to be transported in lymph
where is fat stored
adipose tissue
what enzyme cleaves it into what for energy
lipase, to fatty acids and glycerol
how are fatty acids oxidised to make the activated
add CoA –> acyl CoA, in cytoplasm, requires 2 ATP
what transports acyl CoA in and out of mitochondria
carnitine shuttle
what happens in the cytoplasm side with the carnitine shuttle
CoA dissociated from acyl CoA to leave acyl carnitine
what happens in the matrix side with the carnitine shuttle
CoA rejoins with acyl carnitine to leave CoA acyl and carnitine
what transports acyl carnitine and carnitine across the membrane
translocase
where does beta oxidation take place
mitochondrial matrix
what does beta oxidation yield
1 of: acetyl CoA, 1 FADH2, 1 NADH + H, 1 fatty acyl CoA
what breaks down glycerol and what is it converted to
glycerol kinase to G3P
where are ketone bodies formed
liver mitochondria, from acetyl CoA during B oxidasation
