Nitrogen Metabolism

Question 1

What is happening to proteins in the body

Answer 1

Continually broken down and re synthesised

Question 2

What is nitrogen a substrate for? (6)

Answer 2

Nucleic acid

Porphryin in heme

Thyroxine hormone

NT

Phospholipids

Coenzymes

Question 3

What happens to AA break down

Answer 3

Energy
Fatty acid and glucose stores - involved in TCA

Production of AA

Question 4

What can phenylalanine be converted to

Answer 4

Tyrosine

Question 5

What is a key function of nitrogen

Answer 5

Enzymes

Question 6

Most important nitrogen enzyme

Answer 6

Glutamate dehydrogenase

Question 7

What does glutamate dehydrogenase do

Answer 7

Detoxifies material

Ammonia

Question 8

Pathway of glutamate dehydrogenase

Answer 8

Ammonia
+
Alpha ketogluterate

To

Glutamate
+ water

NADH H+
Converted to
NAD

Question 9

What 2 enzymes are involved in exertion of urea involving CNS

Answer 9

Glutamine synthase

Glutaminase

Question 10

Pathway of glutamine synthase

Answer 10

Glutamine + NH4 + ATP

Goes to

Glutamate

+ ADP

Question 11

Pathway of glutaminase

Answer 11

Glutamine

To glutamate

And ammonia

Question 12

What is a transaminase

Answer 12

Enzyme which transfers an amine group from AA to an

Keto acid

Question 13

What is a Keto acid

Answer 13

Contain ketone group and carboxylase acid group

Involved in TCA cycle

Question 14

What are common transaminase acceptors/donor

Answer 14

Alanine

And

Alpha ketogluterate

Or

Aspartate

And

OAA

Question 15

How are AA (non essential) formed

Answer 15

Transaminase reactions

May require processing before or after

Question 16

Where do Keto acids derive

Answer 16

Intermediate metabolism

TCA glycolysis

Question 17

What is produced from transaminase reaction when amine group placed on Keto acid

Answer 17

Keto acid converted to another AA

Question 18

Are transaminase enzymes specific to the AA

Answer 18

Yes

Eg
Aspartate transaminase

Question 19

What are common Keto acids

Answer 19

Pyruvate

Oxaloacetate

Alpha ketogluterate

Ribose 5 phosphate

Question 20

What happens to AA when broken down

Answer 20

Amine group removed

Goes into urea cycle

Carbon skeleton reused in metabolism

Question 21

Steps of degradation

Of amino acid

Answer 21

1 removal of amino group
- transaminase

2 amino group on new AA is recycled or goes to urea cycle

3 carbon skeleton enters intermediate metabolism
(TCA)

Question 22

Glucogenic AA

Answer 22

Can be used to produce glucose by gluconeogenesis

Question 23

What can glycogenic

AA intermediates are there for gluconeogenesis

Answer 23

Pyruvate

OAA
Fumarate

Propionyl CoA - succinate

Alpha ketogluterate

Question 24

What do ketogenic AA form

Answer 24

Acetyl CoA

And

Ketones

Question 25

Can acetyl CoA be converted to glucose?

Answer 25

No

Question 26

What happens to ketogenic AA when broken down

Answer 26

Form acetyl CoA - goes to ketones or ATP or fatty acid Ketone bodies form

Question 27

Where are AA stored

Answer 27

They're not

Question 28

Effects of ammonia toxicity

Answer 28

Neurological disease due to build up ammonia | Increased pH causes neuro problems

Question 29

What does high ammonia stimulate Why is this a problem

Answer 29

Glutamate dehydrogenase But removed Alpha ketogluterate Which interrupts TCA cycle ATP reduced Death

Question 30

Why are ammonia levels high in the CNS

Answer 30

Neurotransmission produces | Ammonia as byproduct

Question 31

How is ammonia removed and excreted from CNS

Answer 31

Glutamine synthase And Glutaminase

Question 32

What is important abou glutamine

Answer 32

Can pass through blood brain barrier

Question 33

How are ammonia levels high in muscle after exercise

Answer 33

ATP goes to AMP Which goes to Inosine MP and NH4

Question 34

What enzyme is important in muscles to remove NH4

Answer 34

Glutamate dehydrogenase

Question 35

What happens to lactate from post exercise How is this product removed

Answer 35

Converted to Pyruvate Transaminase reaction takes place See sheets

Question 36

Ammonotelic

Answer 36

Fish release nitrogen into environment Release free ammonia

Question 37

Uricotelic

Answer 37

Bird Nitrogen - produce uric acid Bird poo Insoluble crystals

Question 38

Ureotelic

Answer 38

Urea highly soluble Water loss

Question 39

Urea cycle where

Answer 39

Liver Mitochondria And cytoplasm

Question 40

Does urea cycle need energy

Answer 40

Yes