REVISION GUIDE LIVER: NITROGEN Flashcards Preview

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Flashcards in REVISION GUIDE LIVER: NITROGEN Deck (73)
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1

what is the role of amino acids?

they are the building blocks of proteins/peptides

2

what is the structure of amino acids?

have an amino group, a carboxyl group, R-side chain and a carbon backbone

3

what is the role of the R group of amino acids?

they change the amino acid

4

what is the function of amino acid heterogeneity?

it allows proteins to fulfil many different functions

5

what are essential amino acids?

they are amino acids that cannot be produced
they are needed in diet

6

what are non-essential amino acids?

they are simpler amino acids
they body is able to produce them de novo

7

what are conditionally essential amino acids?

under certain circumstances they may need to be consumed in the diet
they may be dependent on the consumption of other amino acids

8

what are the 2 types of amino acids?

glucogenic
ketogenic

9

what are glucogenic amino acids?

the carbon backbone is used in gluconeogenesis or TCA cycle intermediates

10

what are ketogenic amino acids?

the carbon backbone produces acetyl CoA or acetoacetyl CoA

11

which amino acids are solely ketogenic?

leucine
lysine

12

what are amino acids used for?

protein production
production of non-protein molecules

13

which amino acids are essential?

phenylalanine
valine
leucine
isoleucine
tryptophan
methionine
threonine
(histidine)

14

which amino acids are conditionally essential?

arginine
cysteine
glycine
glutamine
proline
tyrosine

15

which amino acids are non-essential?

alanine
glutamate
aspartate
asparagine
serine

16

what type of bonds join together amino acids?

peptide bonds

17

how many amino acids are found in dipeptides?

2

18

how many amino acids are found in polypeptides?

<50

19

how many amino acids are found in proteins?

>50

20

what are the sources of nitrogen?

diet - amino acids from proteins

21

how is nitrogen lost?

via the gut and kidneys (urea)
renal excretion = 70g/day
faecal loss = 10g/day
skin/hair/sweat loss

22

when is nitrogen balance in equilibrium?

when intake/output are equal

23

where does the body maintain a free pool of amino acids?

in the blood

24

what happens to nitrogen during the fasting state?

body protein is used (free or skeletal muscle (80%))

25

what happens to nitrogen during the fed state?

the net contributor is diet

26

what are the different pathways for protein degradation?

lysosomal and ubiquitin-dependent pathways

27

what should nitrogen intake be per day?

0.75g/kg/day (4g/day)

28

what are free amino acids split between in the body?

- free pool in blood
- proteins in the body (~10kg)
- metabolic precursors - loss of amino group and carbon backbone is used in glycolysis and TCA cycle

29

where are amino acids stored?

they are not stored
they always have a function

30

what are the causes of a positive nitrogen balance?

pregnancy
lactation
bodybuilding + steroids
recovery phase