Amino Acids

Front 1

What are ketogenic and glucogenic amino acids?

Back 1

Glucogenic AA are metabolized to pyruvate, 3-phosphoglycerate -ketoglutarate, oxaloacetate, fumarate or Succinyl CoA

Ketogenic AA are metabolized to Acetyl CoA or acetoacetate.

Front 2

What are essential and non-essential amino acids?

Back 2

Essential AA cannot be synthesized by the body (Pvt Tim Hall acronym)
NO TYROSINE

Front 3

Name the mandatory keto acid and an amino acid in the transanimation reaction.

Back 3

-ketoglutarate is the mandatory keto acid.

Glutamate is the mandatory amino acid.

Front 4

Describe the role of pyridoxal phosphate (vitamin B6) in the transanimation reaction.

Back 4

Pyridoxal phosphate is the coenzyme involved in the transanimation reaction. In this reaction, the amino group is transferred from the amino acid to the coenzyme, which transports it to the -keto acid, forming a new amino acid and regenerating the original coenzyme aldehyde.

Front 5

Describe the role of glutamine with reference to nitrogen catabolism.

Back 5

Glutamine is the transporter of excess nitrogen from the tissues to the liver for the Urea cycle.

Front 6

What are the substrates and products of glutaminase?

Back 6

Glutaminase  Glutamate + Ammonia
(glutaminase)

Front 7

What are the substrates and products of carbamoyl phosphate synthase.

Back 7

NH4+ + HCO3- + 2 ATP 
Carbamoyl phosphate + 2 ADP+Pi

(Carbamoyl phosphate synthase I / CPS-I)

N-acetylglutamate is a positive affector

Front 8

Name the two cellular compartments where the urea cycle operates.

Back 8

Mitochondrial matrix and cytosol

Front 9

Name the allosteric affector of carbamoyl phosphate synthase I

Back 9

N-acetyl glutamate

Front 10

Name a drug that is used for treatment of a urea cycle enzyme deficiency.

Back 10

Carbamoylglutamate

Front 11

In an exercising muscle, name the cycle that utilizes an amino acid and converts it into glucose.

Back 11

Glucose-Alanine cycle

Front 12

Name 2 neurotransmitters that are derived from tyrosine

Back 12

Dopamine
Epinephrine

Front 13

Name 3 types of reactions that are involved in producing a neurotransmitter from an amino acid precursor.

Back 13

Decarboxylation
Hydroxylation
SAM-dependant methylation

Front 14

Name 3 catacholamines

Back 14

Dopamine
Norepinephrine
Epinephrine

Front 15

Name the rate-limiting step in the biosynthesis of catacholamines.

Back 15

Tyrosine + O2 + THB  DOPA + DHB
(Tyrosine hydroxylase)

Front 16

Name the cofactor that is required for tyrosine hydroxylase.

Back 16

Tetrahydrobiopterin

Front 17

Catecholamine release is stimulated by the neurotransmitter ________?

Back 17

Acetylcholine

Front 18

Name two enzymes that are involved in catecholamine catabolism.

Back 18

Catecholamine O-methyltransferase (COMT)
Monoamine oxidase (MAO)

Front 19

Name few functions of catecholamines.

Back 19

TO prepare the body for the “fight or flight” response:

Increase cardiac output, glycogen degradation, triglyceride hydrolysis and release of fatty acids from adipose tissue.

Decrease peripheral resistance to blood flow.

Front 20

Discuss the connection between Parkinson’s disease and dopamine and the drug that is used for patients.

Back 20

Parkinson’s disease is due to a lack of dopamine synthesis. It can be treated by L-DOPA, a precursor of dopamine that can cross the blood-brain barrier.

Front 21

Name 2 neurotransmitter compounds derived from tryptophan

Back 21

Serotonin and melatonin

Front 22

What is the hormone that is involved in circadian rhythms?

Back 22

Melatonin

Front 23

What is the effect of Prozac?

Back 23

Inhibits reuptake process of serotonin.

Front 24

If you suffer from jet lag, what pathway would you target for drug therapy?

Back 24

Melatonin

Front 25

Name the enzyme that catalyzes the formation of histamine.

Back 25

Histidine carboxylase

Front 26

Name 3 functions of histamines

Back 26

Mediate allergic and inflamatory reactions
Vasodiolation
Constriction of bronchioles
Stimulates excretion of HCl

Front 27

What are the substrates and products of glutamate decarboxylase?

Back 27

Glutamate  GABA
(glutamate decarboxylase)

Front 28

In general, decarboxylases require the coenzyme ________?

Back 28

Pyridoxal Phosphate

Front 29

L-DOPA is used for _______ disease treatment?

Back 29

Parkinson’s

Front 30

Name a synthetic compound that limits serotonin reuptake.

Back 30

Prozac

Front 31

Describe pheochromocytoma.

Back 31

Tumors of chromaffin tissue that produce large amounts of catecholines.

Front 32

Describe the clinical correlation between Huntington’s disease and GABA metabolism.

Back 32

Low levels of GABA and GABAnergic neurons result in the uncontrolled movements of Huntington’s disease

Front 33

Melanins are synthesized in _______?

Back 33

Melanocytes

Front 34

Tyrosinase deficiency causes _____?

Back 34

Albinism

Front 35

Under oxidative conditions, in order to maintain reducing environment inside the cell, which compound is invoked?

Back 35

Glutathione

Front 36

Name the methyl group donor compound that is used in the majority of methyl transfer reactions.

Back 36

S-adenosylmethionene (SAM)

Front 37

Name 2 functions of glutathione.

Back 37

Maintains protein sulfhydral groups in reduced form.
Detoxifies xenobiotics (peroxides and free radicals)

Front 38

Nitric oxide is derived from the amino acid _____?

Back 38

Arginine

Front 39

Name the substrate and products of acetylcholinesterase

Back 39

Acetylcholine + H2O  Acetate + Choline
(Acetylcholine esterase)

Front 40

Explain the action of DIPF on acetylcholinesterase:

Back 40

DIPF is a component of nerve gas. It covalently modifies acetylcholinesterase and knocks the enzyme activity.

[Venk #3, p.4]

Front 41

Name some xenobiotics that inhibit acetylcholinesterase.

Back 41

Physostigmine
Neostigmine

Front 42

Name the channel that is opened up by acetylcholine.

Back 42

Na+ / K+ ion channels

Front 43

Discuss the mechanism of action of nerve gas.

Back 43

DIPF is a component of nerve gas. It covalently modifies acetylcholinesterase and knocks the enzyme activity.

Front 44

Name three excitatory and three inhibitory neurotransmitters:

Back 44

Excitatory:
acetylcholine
aspartate
dopamine
histamine
norepinephrine
epinephrine
glutamate
5-hydroxy tryptamine

Inhibitory:
glycine
taurine
4-aminobutyrate

Front 45

Name three stages of nerve transmission:

Back 45

Resting
Excitation
Termination

Front 46

What is the action GABA?

Back 46

GABA is an inhibitory neurotransmitter. Upon binding to its  subunits, it increases membrane permeability of postsynaptic membranes to chloride ion. This can lead to hyperpolarization and increased threshold of triggering an action potential.

Front 47

What is the function of phenobarbital?

Back 47

Inhibits action potentials when bound to GABA receptors.

Front 48

Name the catabolic products of GABA.

Back 48

Succinate semialdehyde
Succinate

Front 49

What is an ion-gated channel?

Back 49

A channel that allows ions to pass through when a neurotransmitter binds to its receptor.

Front 50

Name two ion channels.

Back 50

Cholingeric nicotinic receptors
GABA receptors
(More generally, Na+ and K+ ion channels)

[Lipp. p.80]

Front 51

Diisopropylphosphoflouridate (DIPF) inhibits the enzyme___________.

Back 51

Acetylcholinesterase

Front 52

Name two inhibitors of the acetylcholine receptor.

Back 52

Tubocurarine
-bungarotoxin
Cobra toxin