Nitrogen Metabolism

Question 1

How is nitrogen fixation carried out

Answer 1

By an enzyme complex called bacterial nitrogenases forming reduced nitrogen, NH4+, can be used by all organisms to form amino acids.

Question 2

What are the three components used for nitrogen fixation?

Answer 2

1. An enzyme systems- nitrogenase complex

2.A strong reducing agent- dinitrogenase reductase

3/ATP to transfer hydrogen atoms to dinitrogen

Question 3

information about Amino acid?

Answer 3

1.Building blocks of proteins

2. Serve as precursors for active molecules, such as neurotransmitters, local mediators, energy-related metabolites, the oxygen-binding molecule ‘heme‘, and DNA bases called purines

3.They serve as an energy source during prolonged fasting, diabetes, and when the diet is rich in proteins

4. Some act as regulators of gene expression and cellular signalling

Question 4

What are the three classified groups of amino acid?

Answer 4

– Essential amino acids
– Nonessential amino acids
– Conditional amino acids

Question 5

What are the types of essential amino acid?

Answer 5

Valine
Methionine
Histidine
Leucine
Phenylalanine
Threonine
Isoleucine
Lysine
Tryptophan

Question 6

What are the types of non-essential amino acid?

Answer 6

Alanine
Asparagine
Aspartate
Glutamate

Question 7

What are the types of conditional amino acid?

Answer 7

Arginine
Cysteine
Glutamine
Glycine
Proline
Serine
Tyrosine
Ornithine

Question 8

What are the Dietary Sources of Amino Acids?

Answer 8

Animal : meats, dairy products, fish and eggs

Vegan: whole grains,pulses, legumes, soy, and nuts

Question 9

What is the structure of an amino acid and what is the smallest AA?

Answer 9

All amino acids found in proteins have this basic structure, differing only in the structure of the R-group or the side chain

The simplest, and smallest, amino acid found in proteins isglycine for which the R-group is a hydrogen

Question 10

What is the nitrogen balance and what sources of nitrogen?

Answer 10

Nitrogen Balance = Nitrogen intake - Nitrogen loss.

Sources of nitrogen intake- Meat, Dairy, Eggs,Nuts and Legumes, and grains and cereals.

Examples of nitrogen losses: urine, faeces, sweat, hair, and skin

Question 11

What is Kwashiorkor, what are the symptoms& Treatment?

Answer 11

Form of severe protein–energy malnutrition

– Sufficient calorie intake, but with insufficient protein consumption, distinguishes it from marasmus

Symptoms- Oedema of the hands and feet, irritability, anorexia, rash, hair discolouration, and a large fatty liver.

Treatment-protein into diet gradually

Question 12

Why do people take Amino Acid Supplements?

Answer 12

–Protein supplements are often consumed by body builders
– Improvements in performance and training
– Muscle Growth
– Reduced muscle breakdown
– Resistance to fatigue during exercise
– Fat loss

Question 13

What are the fate of amino acid?

Answer 13

Glucogenic- Alanine, Asparagine, Aspartate, Cysteine & Glutamate

Ketogenic-Leucine & Lysine

Glucogenic and ketogenic- Isoleucine, Threonine, Tyrosine & Tryptophan

Question 14

What is the genetic errors of amino acid catabolism disorder?

Answer 14

Phenylketonuria- caused by a block in the conversion of phenylalanine into tyrosine
– Readily diagnosed
– Treated by removing phenylalanine from the diet.

Question 15

What is urea cycle disorder (UCDs) & its symptoms?

Answer 15

-Is a genetic disorder caused by a mutation that results in a deficiency of one of the enzymes in the urea cycle

-In milder/partial urea cycle enzyme deficiencies, ammonia accumulation may be triggered by illness or stress , resulting in multiple mild elevations of plasma ammonia concentration; the hyper ammonia is less severe and the symptoms may be subtle

-Symptoms- Hyperventilation,vomiting, poor feeding and hyper ammonia leading to a coma or death

Question 16

What are the different deficiency for urea cycle disorder?

Answer 16

• N-Acetylglutamate synthase deficiency- Mitochondria
  -Carbamoyl phosphate synthetase I deficiency-Mitochondria
  -“AL deficiency” orargininosuccinicaciduria (ASA)- Cytosol

Question 17

What does low and high levels of urea suggest?

Answer 17

Low levels- malnutrition, too little protein in the diet & kidney issues

High levels – too much protein in the diet, too much protein breakdown in the body

Question 18

What is the synthesis of amino acid?

Answer 18

1) AminationIn this process, ammonia reacts with a-ketoglutaricacid to form glutamic acid

2) Transamination– Glutamic acid is the main amino acid from which other 17 amino acids are formed through transamination– amino acid is made of a carboxyl group (-COOH) andone or more amino groups (-NH2)– Transamination involves the transfer of amino group from oneamino acid to the keto group of keto acid. The enzyme responsiblefor transamination is transaminase

Question 19

What happens in the amino acid metabolism?

Answer 19

Phase I: removal of α-amino group and forming NH4+ and α-keto acid

Disposal of nitrogen - NH4 is recycled in biosynthesis or excreted in urine

Question 20

What happens in Amino Acids Metabolism: Oxidative Deamination

Answer 20

-α-amino groups of amino acids is transferred α-keto acids catalysed by transaminases.

– The reaction is catalysed by glutamate dehydrogenase and NAD+ and NADP+ are cofactors

Question 21

What happen in Amino Acids Metabolism: Disposal of Nitrogen Phase 2

Answer 21

1. Phase II: is carbon skeleton of the α-ketoacids are converted into common intermediates of energy producing metabolic pathway. can be metabolized into CO2, H2O, glucose, fatty acids,
2. The carbon skeletons of amino acids are transformed into acetyl CoA, acetoacetyl CoA, pyruvate or one of the intermediates of the citric acid cycle.–
3. Fatty acids, ketone bodies, and glucose can be formed from amino acids

Question 22

Where does amino acid catabolism take place?

Answer 22

In the liver or muscles for long excursuses and fasting