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Phase 1 > liver > Flashcards

liver Flashcards

1
Q

how are lipoprotiens made?

A

apoprotien a is synthasised in teh RER
• Microsomal TAG transfer protien adds the lipid to the ApoB proten to make a lipoprotien
• These are transported to the golgi aperatis where the protien part is glycosated

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2
Q

how are lipids brought to the liver

A

tryglycerides and lipoprotiens

Sometimes they are brought in as fatty ascids bounf to albumin

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3
Q

how to triglycerides move into cells

A

broken down by lipoprotein lipase into glycerol and fatty acids which can differ though

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4
Q

what are chylomicrons

A

chylomicrons are emulsification fo fat made by bile that can bipass the liver when it is overloaded

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5
Q

how are ketones made?

A

• When there is an abundance of acetyl CoA due to fatty acid catabolism
• 2 Acetyl CoA molecuels are bound together to form acetoacetyl CoA
• The CoA groups are then removed which makes acetoacetate
• This can be converted into betahydroxybuterate
This is used by the brain for fuel when there is no glucose left

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6
Q

How are ketones used as fuels?

A

converted into teh ketone acetoacetate
then succincyl CoA donates its CoA and becomes succinate, making Acetoacetate CoA
thsi can then be cleaved into two acetyl Co A molecuels that can go striaght into the krebbs cycle

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7
Q

where are ketones used as fuels

A

predominatly the brain when tehre is no glucose left, cant be used in the liver as it lacks the enzyme succinyl CoA transferase to make the Acetyl CoA, however the liver does make the ketone bodies

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8
Q

how do fatty acids get into the mitochondrial membrane?

A
  • Fatty acids longer than 12 cant diffuse across the mitochondial membrane son have to use the carnitine shuttle
    • The chains are broken down into ACYL CoA
    • This is converted to ACYL carnitine (by carnatineacyl transferase 1 enzyme) and moved acorss the membrane
    • Then it is reformed by carnatineacyltransferase 2 into ACYL CoA
    • Carnitine can go back and shuttle more though
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9
Q

how are fatty acids metabolised inside of the mitochondria?

A

s the sequential removal of 2 carbon units by
oxidation – the second (hence beta) carbon is cleaved
• Each round of beta oxidation produces 1NADH, 1FADH2 and 1 acetyl coA
There can then do into the krebbs cycle or oxidative phosphorilation

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10
Q

what is transaminiation

A

the amino group being removed from an amino acid and added to another

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11
Q

what is an example of transaminiation

A

alphaketogluterase accepts the amino group from alanine to form glutamate (AKG) and pyruvate (from the alanine).

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12
Q

what is oxidative deaminiation

A

when the amino group is hydrolysed to form NH3 and a deaminiated amino acid

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13
Q

what is an example of oxidative deaminiation

A

glutamate is hydrolysed (water is added) to form alpha ketogluterase and NH3 (amonia)

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14
Q

what is the citric acid cycle

A

citrulline (in NH3), arginine (out urea), ornithine (in NH3 +CO2)

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15
Q

how much albmunin is made a day

A

9-12g

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16
Q

what are the two ways protines are degraded

A

protasomeal - in the cell cytoplpams and smalll proties bind to the protine and signal that it needs to be broken down then enzymes come and break it down

Lysosomal - lysosome vesticles fusing with it and breaking ti down

17
Q

what is the glucose alanine cycle

A

• IN the muscle cell, the glucose is broken down into pyruvate via glycolysys
• The pyruvate is then converted into the amino acid alanine via transamination from glutame (which then turns into alpha ketogluterate - AKG)
• The alanine can then travel to the liver
• At the liver alanine is reconverted into pyruvate via transamination of AKG
The pyruvate then can be converted into glucose
• The Glutamate formed in the liver can undergo deaminiation to form urea and AKG

18
Q

what is teh purpose of teh glucose alanine cycle

A

to make glucose

to get rid of excess amonia

19
Q

what are xenobiotics

A

forign suubstances with no nutritional value that need to be excreted, for exapmle durgs

20
Q

what are two ways xenobiotics can damage the body?

A

• They cane cause damage to protiens and act as carciogens by binding to DNA
They can react with O2 and release free oxygen radicals

21
Q

how are xenobiotics excreted

A

they are made more soluble so they can be peed out. this happens through phase 1 and then 2 reactions

22
Q

what is a phase 1 reaction

A

addiing a hydrophillic group such as OH, amine and carboxyl groups
• There are three tyoes of phase one reactions:
- Oxidation, which is addign OH groups, remocing hydrophobic side
- Reduction - adding H groups to make unsatureated bonds saturated
- Hydrolysis - splitting up amide and ester bonds to make the melecles smaller

23
Q

what is a phase two reaction?

A

phase 2 involves conjugation of froming hydophillic metabolites
• This is by adding molecules to the xenobiotic such as sulphate, gluceronic acis
• This causes a large increase in hydrophilicity

24
Q

what are the 4 steps of pharmakokinetics

A

absprption, distrabution, metabolism and elimination

25
Q

where do microsmal reactions take place

A

the smooth endoplasmic reticulum

26
Q

what are Cytochrome P450’s?

A

microsomla enzymes that are important for biotransformation

• There are 10 main groups

27
Q

what does inducible mean?

A

can be promoted to work if people take certain drugs

28
Q

are Cytochrome P450’s inducible?

A

yes!

29
Q

how do cytochrome P450’s work?

A
  • The cytochrome P450s all contain a heam group which is used to oxidise the substrate
    • They generate a reactive free radical compound
30
Q

what is the most common cytochrome P450 enzyme

A

• The most commen cytochrome enzype is the CYP3A4

•

31
Q

do Cytochrome P450’s do mainly phase 1 or 2 reactions?

A

in phase 1 they do - oxidation, reduction, hydrolysis

in phase 2 they only do glucoronide conjugation

32
Q

what enzyme breaks alcohol down

A

alcohol dehydrogenase

33
Q

what makes up bile

A

Water, bile salts, billirubin, cholesterol, protiens

34
Q

how much bile s produced a day

A

500-600ml a day

35
Q

how many times a bile recycled

A

• 2-3 cycls per meal

36
Q

how is bile release regulated

A

• When tehre is toomuch bile presant, the bile salts act as a ligend for a receptor that releases a protine that helps to inhibit bile production

37
Q

what is special about bile salts

A

It has bile salts which are amiohatc so have both hydrophobic and hydrophillic part

38
Q

what do bile salts and fats combine to form

A

emulsion droplets, then once broken down further it form micells

39
Q

what are teh three main ligamnets of teh liver

A

falciform - between left and right anatomical lobe
ligamentum teres - reminant of teh umbilical vein
ligamentus venosus - remenant of the ductus venosus that helps bypass the liver (comes out the top)

Phase 1 (11 decks)

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