BIOC Lecture 6: Nitrogen I Flashcards

1
Q

Can we store nitrogen in our bodies?

A

No, if there is excess it has to be removed

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2
Q

What is the main compound our body uses to get rid of nitrogen?

A

Urea

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3
Q

Where are AA’s obtained from?

A

Dietary protein, body protein degradation or newly synthesised

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4
Q

What are AA’s used for?

A

to synthesise proteins and other Nitrogen containing compounds or generate energy

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5
Q

What happens to excess AA’s?

A

Rapidly degraded

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6
Q

What happens to excess Nitrogen?

A

Needs to be excreted

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7
Q

What are some ways AA’s are used?

A
  • Synthesised into glucose, used to make fatty acids and therefore ketone bodies.
  • Made into body proteins or non-protein N containing compounds
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8
Q

How do AA’s turn into urea?

A

Enzymes remove the ammonia group and this ammonia will end up as urea

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9
Q

What are examples of non-protein nitrogen-containing compounds?

A
  • Pyrimidines
  • Purines (uric acid)
  • Creatine (creatinine)
  • Haem (bilirubin)
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10
Q

What is an important enzyme in protein digestion?

A

Pepsin

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11
Q

Protein digestion summary

A

Stomach: HCl and Pepsin
SI: Pancreatic enzymes

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12
Q

What are the non-essential AA’s?

A
  • Alanine
  • Aspartic acid
  • Asparagine
  • Arginine
  • Glutamic Acid
  • Glutamine
  • Proline
  • Serine
  • Glycine
  • Cysteine
  • Tyrosine
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13
Q

What are the essential AA’s?

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

What AA is on both sides?

A

Arginine

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15
Q

Why is Arginine both essential and non-essential?

A

Under certain physical conditions arginine is required in high amounts and the body can not synthesize enough arginine to keep up with the bodies needs (E.g. when you are young and growing at a high rate)

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16
Q

AA’s are precursors of what?

A

Important regulators of metabolism

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17
Q

What is tyrosine a precursor for?

A
  • Dopamine
  • Adrenaline and noradrenaline
  • Thyroid hormones
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18
Q

What is tryptophan a precursor for?

A
  • Serotonin
  • Melatonin
19
Q

What is histamine a precursor for?

A

Arginine -> Nitric Oxide (allergic reactions)

20
Q

Where does creatine come from?

A

Derived in skeletal muscles by spontaneous cyclisation of creatine and creatine phosphate

21
Q

What are urine creatinine levels proportional to?

A

Muscle mass - high = higher muscle mass

22
Q

What are blood creatinine levels a measure of?

A

Kidney function - High = bad function

23
Q

Where is creatine in its phosphorylated form made?

A

Muscle

24
Q

Creatine acts as a fast supplier of what?

A

Phosphate to make ATP

25
Q

Creatine phosphate in the muscle is involved in what?

A

Energy metabolism

26
Q

What is creatine phosphate made from?

A

Creatine kinase

27
Q

What is creatine kinase?

A

The enzyme that creates creatine phosphate

28
Q

What does creatine kinase in the blood indicate?

A

Muscle damage

29
Q

What are aminotransferases?

A

a group of enzymes that play a crucial role in the metabolism of amino acids

30
Q

What can carbon skeletons be?

A

Glucogenic or ketogenic

31
Q

What decides carbon skeletons class?

A

Whether they can be utilized to make glucose or ketone bodies

32
Q

What is a glucogenic amino acid?

A

Any amino acid that can be broken down into pyruvate or can be used in the TCA cycle (be made into a carbon backbone)

33
Q

What is a ketogenic amino acid?

A

If your amino acid can be directly broken down into acetyl-coA

34
Q

What are the nitrogen containing products excreted in urine?

A
  • Urea
  • Ammonia
  • Uric acid
  • Creatinine
35
Q

How many forms does ammonia come in?

A

2

36
Q

What form is ammonia largely found in?

A

Protonated form - Ammonium Ion (NH4+)

37
Q

What is the other form of ammonia?

A

Ammonia NH3

38
Q

What do elevated blood uric levels indicate?

A

Gout

39
Q

What is nitrogen balance?

A

A measure of N input versus N output

40
Q

What is an individuals nitrogen balance dependent on?

A
  1. Dietary nitrogen intake
  2. Physiological state
41
Q

Where does nitrogen intake come from?

A

Dietary amino acids (nucleotides etc)

42
Q

Where does nitrogen excretion come from?

A
  • Urine, faeces, hair, skin loss and perspiration
  • Obligatory loss
43
Q

What are possible causes of positive nitrogen balance?

A
  • Childhood and adolescent growth
  • Pregnancy
  • Body building
44
Q

What are possible causes of negative nitrogen balance?

A
  • Injury
  • Surgery
  • Infection
  • Starvation