Amino acid synthesis and degradation and urea cycle :/

Question 1

How are amino acids obtained

Answer 1

diet
synthesised by body
produced from normal protein turnover (recycled)

Question 2

what happens if aa are not required

Answer 2

degredated

can be used as a source of energy

Question 3

can amino acids be stored or not

Answer 3

cannot be stored

Question 4

List some essential aa from the diet

Answer 4

histidine
isoleucine
leucine
lysine
methaionaine
phenylalanine
threonine
typtophan
valine

Question 5

non essential aa examples

Answer 5

alanine
aspargine
aspartate
glutamate
serine

Question 6

conditionally essential aa examples

Answer 6

arginine
cysteine
glutamine
glycine
proline
tyrosine

Question 7

what is cystinuria

Answer 7

defective carrier system
- leads to aa in urnine
crystals of cysteine form kidney stones

Question 8

what happens when nitrogen is consumed in the diet

Answer 8

usually consumed in a form of protien
- hydrolysed to aa by proteolytic enzymes
aa AT into epithelial cells and enter blood

Question 9

what are the proteolytic enzymes and where are they found

Answer 9

pepsin in stomach

trypsin in pancreas

Question 10

what is required to make aa

Answer 10

carbon

nitrogen

Question 11

what can aa be made from

Answer 11

glucose and nitrogen source) aa or ammonia)

can be made from intermediates of glycolysis and the TCA cyecle

Question 12

what amino acids can be made from aa

Answer 12

non essential amino acids can be made from essential

- donate molecule

Question 13

why would aa be needed to degradate

Answer 13

excess in diet

some no longer needed

Question 14

types of aa

Answer 14

Glucogenic aa

ketogenic aa

Question 15

degredation of glycogenic aa

Answer 15

carbons converted to glucose

Question 16

degradation of ketogenic

Answer 16

converted to acetylene Ca or acetoacetate(ketone bodies)

Question 17

what does the amino acid split into

Answer 17

carbon skeleton

amino acid nitrogen

Question 18

how is nitrogen removed from aa

Answer 18

transamination

- amino group from one aa transferred to another

Question 19

removal of aa nitrogen as ammonia

Answer 19

glutamate can collect nitrogen from other aa
converted to ammonia by glutamate dehydrogenase in the liver
aa enters urea cycle

Question 20

what is removal aa nitrogen as ammonia alllostericaly alters by

Answer 20

allosteric regualtion by :

• ATP and GTP (inhibits)
• ADP and Gdp activates

Question 21

lysosome

Answer 21

protease filled vesicles

Question 22

ubituitin

Answer 22

small protiens that target proteins for degredation

Question 23

proteasome

Answer 23

protease complex
proitne is unfolded and degraded
- easier for the protein to be degredated by proteases

Question 24

what form of nitrogen is not usable in biological systems

Answer 24

NH2

Question 25

nitrogen that is usabel

Answer 25

NH3

Question 26

nitrogen that is toxic

Answer 26

NH4+

Question 27

nitrogen balance

Answer 27

nitrogen ingested (proteins)= nitrogen excreted

Question 28

children and preganen woman nitrogen balance

Answer 28

+

Question 29

disease / starvation nitrogen balance

Answer 29

-

Question 30

nitrogen cycle

Answer 30

5 main steps
1st 2 in mitochondrion
other 3 in cytosol
nitrogen enters as NH4+ and aspartate
ornithine initiates and is regenerated

Question 31

control of the urea cyle

Answer 31

feed forward regulation
allosteric activate of enzymes
high protein diet or fasting induces urea cycle ensymes

Question 32

feed forward urea control

Answer 32

high rate of ammonia production higher rate of urea

Question 33

what enzymes allosterically control the urea cycle

Answer 33

arginine stimulates carbonyl phosphate synthase§

Question 34

what is the glucose alanine cycle

Answer 34

cycling of nutrients between muscles and liver

Question 35

what does the glucose alanine cycle dependon

Answer 35

physiological state i.e. fed or fastine

Question 36

what occurs on fasting

Answer 36

muscle protein broken down to aa
transaminate to form alanine
transported to liver
nitrogen enters urea cycle and pyruvate used to make energy (glucose)

Question 37

what are Ketone bodies

Answer 37

combination of acetoacetate and beta hydroxybutyrate

Question 38

what happens to Ketone bodies when glucose is low

Answer 38

reconverted to acetylene coA

enter TCA cycle for entry

Question 39

what can acetoacetate break down to

Answer 39

acetone spontaneously

Question 40

what is a diagnostic tool for ketonic states

Answer 40

fruity breath

Question 41

Phenylketonuria

Answer 41

mutation in phenylalanine hydroxylate
leads to metal retardation
affects nervous tissue

Question 42

urea cycle disroder

Answer 42

accumulation of ammonia

toxic to NS

Question 43

inborn errors of aa metabolism

Answer 43

deficient enzymes in aa metabolism

leads to accumulation of harmful producs

Question 44

what are some inborn errors in aa metabolism examples

Answer 44

phenylketonura

urea cycle disorders