Biochem exam 2

Question 1

pyruvate AA (3)

Answer 1

alanine (direct transamination)
cysteine (-NH2, - SH)
threonine (thr aldolase–>Co2 + NH4+ and THFA –> serine)

Question 2

oxaloacetate (2)

Answer 2

aspartic acid/asparagine (transamination)

asparagine (-NH3)

Question 3

alpha ketoglutarate (5)

Answer 3

glutamic acid (ox deamination –NADH)
glutamine (-NH4+)
Arginine, proline, histidine (co2 to histamine)

Question 4

succinyl coA

Answer 4

met, thr, valline, methyl malonyl coa (cofactor is b12)

• ox deamination
• maple syrup urine disease

Question 5

phenylalanine and tyrosine

Answer 5

p 450 to tyrosine and then fumerate–> acetoacetate

Question 6

negative nitrogen balance

Answer 6

nitrogen excretion through urea > nitrogen uptake through AA

Question 7

simple feedback

Answer 7

linear end product negative

Question 8

sequential feedback

Answer 8

fork products inhibit start of fork

Question 9

concerted

Answer 9

fork products inhibit both fork and pre-fork (need both for pre-fork)

Question 10

enzyme multiplicity

Answer 10

X,y and z inhibit fork and also start of fork

ISOENZYMES

Question 11

cumulative feedback

Answer 11

each enzyme can inhibit first step. each enzyme that binds means more increasing inhibition

Question 12

glutamine synthetase

Answer 12

ATP form is less active, AMP form is active

Question 13

7 uses for AA synthesis

Answer 13

proteins, cofactors, hormones, porphyrins and heme, nucleotides, neurotransmitters, pigments

Question 14

heme synthesis

Answer 14

mt of liver. starts with succinyl coa and glycine condensing by pyrodoxal phosphate. get delta amino then condense using NH4

Question 15

RBC degraded in

Answer 15

spleen, 120 days

Question 16

bilirubin

Answer 16

heme is degraded by mixed function oxidase to add OH to get this. this goes to liver and adds sugar to make bile
- causes jaundice

Question 17

porphyria disease

Answer 17

increase levels of delta amino, photosensitivity, red pee, OR enzyme is unstable OR block in enzyme leading to heme so more intermediates (eat liver or blood to get heme)

Question 18

neurotransmitters

Answer 18

diffuse between ells to transfer nerve impulse

Question 19

serotonin

Answer 19

from tryptophan. nneeds pyrodoxal phosphate. something to do with mushrooms

Question 20

dopamine and norepi

Answer 20

tyrosine. using p450 and DOPA and pyrodoxal phosphate and SAM

Question 21

melanin

Answer 21

DOPA makes red pigmennt, then quinoline comes in to make melanin, black pigment

Question 22

PKU

Answer 22

deficency in thing that converts phenylalanine to tyrosine. phe can be converted to phenylpyruvate

• more pp in blood and urine
• pigment issues with no melanin

Question 23

cholesterol cycle

Answer 23

don’t forget reductase, mevalonic acid and negative effector cholesterol

Question 24

sphingolipid cycle

Answer 24

palmitoyl coa + serine, co2 and nadph. sphingosine, ceramide__> cdp choline and sphingomyelin OR udp sugar and cerebrosie

Question 25

inositol cycle

Answer 25

OH and atp

Question 26

neiman pick

Answer 26

high sphingomeylin because can’t do to ceramide and phosphophocholine

Question 27

prostaglandin

Answer 27

arach and prostagalnndin synth

Question 28

bile salts

Answer 28

nadph, p450, co3 and coa

Question 29

FAT and lipid in body

Answer 29

chlomicron to liver to lipase to VLDL to serum to LCAT then HDL then IDL then taken up

Question 30

urea cycle

Answer 30

glu dehydrogenase (- is GTP and ATP). then take nh4 to carbamoyl phosphate and ornithine make citruline, arginosuccinate, argninie (- fumerate), then ornithine
- urea comes from arginine