Nitrogen 2 Flashcards Preview

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Flashcards in Nitrogen 2 Deck (14)
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1
Q

Removal of nitrogen happens mainly in the ______ and only ______ can lose its nitrogen by transamination.

A

liver, glutamate

2
Q

What are the fates of nitrogen in plants, aquatic animals, terrestrial/sharks, birds/reptiles and humans?

A
Conserve almost all
Release ammonium
Excrete through urea
Excrete uric acid
Excrete both urea and uric acid
3
Q

What happens if uric acid crystallises in the joins?

A

Causes inflammation

4
Q

Ammonia is transported through the bloodstream as ______ and excess is processed in the ______, ______ and ______.

A

Glutamine, intestines, kidney, liver

5
Q

Glutamine donates ammonia to pyruvate to make what?

A

Alanine

6
Q

Why are alanine/glutamine used in the glucose-alanine cycle?

A

They have a neutral charge so can pass through membranes easily.

7
Q

Where is excess glutamate metabolised?

A

In the mitochondria of hepatocytes.

8
Q

Describe step 1 of glutamate dehydrogenase.

A

Glutamate - 2 electron oxidation -> intermediate

- hydrolysis -> alpha-ketoglutarate

9
Q

Describe step 2 of glutamate dehydrogenase.

A

Ammonia is recaptured via synthesis of carbamoyl phosphate

10
Q

What enzyme is present in step 2 of glutamate dehydrogenase?

A

Carbamoyl phosphate synthase.

11
Q

Describe step 3 of glutamate dehydrogenase.

A

Nitrogen from carbamoyl phosphate enters urea cycle as aspartate.

12
Q

After removal of amino groups, what happens to carbon skeletons?

A

Converted to glucose or oxidised in the citric acid cycle.

13
Q

What are the 8 essential amino acids?

A
Histidine
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Valine
14
Q

Give the citric acid cycle starting from the addition of Acetyl CoA to oxaloacetate.

A

(Acetyl CoA) -> Oxaloacetate -> citrate -> Isocitrate -> alpha-ketoglutarate -> succinyl CoA -> Succinate -> fumarate -> malate -> (Acetyl CoA)