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Flashcards in Nitrogen Deck (89)
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1

How do nitrogen fixing bacteria live

anerobically

2

what inactivates nitrogen fixing bacteria

oxygen

3

what do root nodules on legumes contain

Rhizobium bacteria

4

example of nitrogen fixing bacteria

cyanobacteria

5

Why are leguminous plants important for nitrogenous activity

legheamoglobin combines to oxygen making conditions aerobic therefore nitrogenase can work

6

Nitrogen fixing requires

nitrogenase enzyme and a lot of ATP

7

cyanobacteria forms what to prevent oxygen entry

heterocysts

8

example of symbiotic relationship

Leguminous plants and nitrogenase

9

what usable form of nitrogen is taken up by plants

Nitrate

10

Flow of N from NH4+ to other biomolecules occurs through

glutamate

11

Glutamate formed by

ketoglutarate and ammonia

12

what 4 amino acids are held in much higher concentrations

Alanine, glutamine, glutamate and aspartate

13

organisms can fix N2 therefore conserve nitrogen by

Transaminations

14

Whats is transamination

transfer of amino groups between different molecules

15

Taking an amino acid of creates a

ketoacid

16

In transamination one of the two substrates always has to be

glutamate

17

the synthesis and degradation of amnio acids is

reversible

18

what typically accepts amino groups

α-ketoglutarate

19

The enzyme catalysing transamination is

aminotransferases

20

aminotransferases depends on cofactor

pyridoxal phosphate

21

what acts as temporary storage for nitrogen

L glutamine

22

pyridoxal phosphate derive from

vitamin b6

23

If aminotransferase present in plasma indicates

cell damage i.e. liver disease

24

structure of amino acid

NH3 group attached to a carbon which is attached to a COOH

25

structure of a ketoacid

a C double bond O attached to the COOH group

26

amino acid biosynthesis

addition of amino groups to the carbon skeletons of a-keto acids

27

example of a ketoacid

pyruvate

28

Amino acids undergo oxidative catabolism under three circumstances

Left over proteins, degraded
Dietary proteins exceed protein synthesis
Starvation, proteins broken down

29

Whats happens to dietary proteins

enzymatically hydrolysed

30

What enzymes breaks down proteins in the stomach

pepsin

31

trypsin and chymotrypsin cut proteins into further peptides in the

small intestine

32

what does amniopeptidase do to proteins crossing over into in intestine

degrade proteins into amnio acids

33

What can also be targeted for destruction and has same endpoint as dietary proteins

cellualr proteins

34

what pathway is used to digest dietary proteins to amino acids

anabolic (storage energy)

35

What happens to proteins that are ingested exceeding body's needs

Have to be catabolised as no storage facility

36

what does glycolysis yield

pyruvate

37

what it it pyruvate transformed into for transport

alanine

38

What is gout

build up uric acid crystallising in the joints

39

causes of gout

high protein diet

40

where is excess glutaine transported

intestines, kidneys and liver

41

Glutamnine is transformed into alanine for transport of amino group as

alanine has 0 charge so can diffuse across membrane easily compared to glutamines -ve charge

42

what does glutamine add on to alanine

amino group

43

what two reactions happen in Glutamate Dehydrogenase Reaction

Two-electron oxidation of glutamate followed by hydrolysis

44

where does glutamate dehydrogenase occur

mitochondria

45

what is the electron acceptor in glutamate dehydrogenase

NAD

46

Glutamate is broken down into

NH4 and ketoglutarate

47

NH4 is synthesised into what

Carbamoyl Phosphate

48

Carbamoyl Phosphate sythetase enzyme requires

Bicarbonate
ATP

49

Ammonia is recaptured by carbamoyl phosphate in the

mitochondria

50

The carbon skeleton of glutamate is

ketoglutarate

51

what is the first nitrogen to enter urea cycle

carbonyl phosphate

52

Where do products of glutamate dehydrogenase go

Urea cycle

53

what is ketoglurate amino group transferred to

asparate

54

what is the second nitrogen to enter urea cycle

asparate

55

where does urea cycle occur

cytosol

56

what happens to cytoskeleton after removal of amino group

converted to glucose or oxidised as part of the citric acid cycle

57

Carbon atoms of degraded amino acids become

metabolic intermediates

58

Name the 6 metabolic intermediates

acetly coA
pyruvate
oxoacetate
ketoglutarate
Fumarate
succinyl-CoA

59

where is fumarate produced

from urea cycle

60

Metabolic intermediates are

glucogenic or ketogenic

61

metabolic intermediates are found in which cycle

citric

62

what amino acids are with either ketogenic or glycogenic

isoleucine, tyrosine and phenylalanine

63

what metabolic intermediates are not glycogenic

acetyl coA and acetoacetate

64

glucogenesis

glucose produced from non carbohydrate substates

65

why can't acetyl coA go through glucogenesis

as acetyl coA can not be reconverted to pyruvate therefore can produced glucose

66

what is produced in ketogeneisis

ketone bodies

67

where are ketone bodies produced

Liver

68

What doesn't use ketone bodies

liver

69

where are ketone bodies transported

liver to tissue

70

How do ketone bodies fuel the body

reconverted to acetly coA and go through citric cycle

71

Properties of ketone bodies

small, and water soluble

72

what can L glutamine do

synthesize new amino acids, or it can dispose of excess nitrogen as ammonia

73

what catches toxic ammonia

carbonyl phospahte

74

Carbon skeletons of amnio acids are

broken down to give energy

75

what is inherited metabolic disorders usually due to

single gene defect

76

inherited metabolic diseases usually result in abnormal synthesis of

Proteins
Amino acids
Carbohydrate
Lipids

77

effects of enzyme defects

Decreased formation of the product
Accumulation of the substrate
Increased formation of other metabolites

78

Heterozygotes of inherited metabolic disorders are usually

phenotypically normal

79

disorder of urea cycle usually occurs on what enzyme

transcarbamoylase

80

Failure of transcarbamoylase in urea cycle results in

elevated ammonia levels (hyperammonaemia)

81

transcarbamoylase synthesises

carbamyl phosphate into citrulline

82

Treatments of transcarbamoylase defect to reduce ammonia levels

introduction of aginine, Sodium phenylbutyrate, and Sodium benzoate, allows urea to be produced

83

Amino acids disorder results in

Decreased product
Increased precursors
Alternative metabolic products

84

example of amino acid disorder

Phenylketonuria (PKU)

85

what causes PKU

absence of Phenylalanine hydroxylase enzyme, therefore increased levels of Phenylalanine

86

PKU causes

impaired brain development

87

What disorder is PKU

autosomal recessive

88

Diagnosis of PKU

decreased levels of tyrosine

89

Treatment of PKU

low protein diet i.e. with supplement

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