function of the liver Flashcards
what are some functions of the liver
synthesise bile
detoxifying harmful substances
control blood glucose levels
control amino acid and lipid levels
stores glycogen
liver stores sugar in the form of what?
Glycogen
what percentage of the weight of the liver is glycogen
8% of the weight
how many grams of glycogen can the liver store
120g
how does the storage of glycogen contribute to the control of blood glucose levels
glycogen can be broken down into glucose when required
what is detoxification
rendering a harmful substance/ toxin harmless
what are harmful substances which the liver can detoxify
Hydrogen peroxide
alcohol/ethanol
drugs
what are the two enzymes used in detoxification
Cytochrome p450
Catalase
what is Cytochrome p450
An enzyme used in the detoxification of the liver, can breakdown cocaine or medicinal drugs.
what does catalase do
Breakdown hydrogen peroxide into oxygen and h20
is catalase intracellular
yes
Catalase has a high turnover number what does this mean
it can catalase a lot of hydrogen peroxide in 1 second
what is the turnover number of catalase to hydrogen peroxide
5 million
what are the effects of alcohol in the liver
depresses nerve activity
contains chemical potential energy for respiration
what are the effects of alcohol/ ethanol in the body
depresses nerve activity
how is alcohol detoxified in liver
ethanol is broken down and dehydrogenated by enzyme ethanol dehydrogenase, to produce ETHANAL
this produces 2H which is used to reduce NAD
ETHANAL is then dehydrogenated by ethanal dehydrogenase to produce ethanoate and 2H which again reduces an NAD
ethanoate is then combined with a coenzyme A which produces acetyl coenzyme A which is used in respiration
what two enzymes are used in detoxification of alcohol
ethanol dehydrogenase
ethanal dehydrogenase
what is fatty liver and how is it caused
NAD is also used to break down fatty acids in liver for respiration. therefore a sufficient amount of NAD is needed for both detoxification and fatty acid breakdown
however, if too much alcohol is consumes it uses up the store of NAD, so there isnt enough to breakdown fatty acids..
fatty acids then covert back to lipids and are stored as fat in the liver causing “fatty liver”.
what are the two processes to remove and excrete an amino component
deamination
orthinine cycle
what is deamination
removes amino group from an amino acid to produce ammonia
and a keto acid
what are the products of deamination
keto acid and ammonia
why is it important that ammonia doesnt accumulate
highlt toxic molecule
what does the orthinine cycle do
a cycle made to convert ammonia into urea. as ammonia is very soluble and highly toxic
why is urea better than ammonia
it is less soluble and less toxic therefore can be circulated
summarise the orthenine cycle
ammonia + co2 = urea + water.
why is it important that excess amino acids are excreted
because the amine group on amino acids is toxic when accumulated
