Nitrogen 1-3

Question 1

How does Nitrogen enter the body ?

Answer 1

Through diet

Question 2

How many covelant bonds does Nitrogen have ?

Answer 2

Three

Question 3

What is the name of the enzyme that bacteria use to break the bonds found in Nitrogen & what affects this enzyme ?

Answer 3

Nitrogenase

Inactivated by Oxygen: Live anaerobically

Question 4

What kind of bacteria can form structures that resemble cell walls ?

Answer 4

Cynobacteria

Question 5

What do leguminous plants contain that assist in Oxygen binding ?

Answer 5

They produce hemoglobin

Question 6

What form must Nitrogen be before it is taken up by bacteria & plants ?

Answer 6

Nitrate (NO3)

Question 7

What is the product of Alpha-Ketogluterate + Ammonium ?

Answer 7

Glutamate

Question 8

Alpha-Ketogluterate is an intermediate from which other biochemical cycle ?

Answer 8

CAC

Question 9

What Amino Acid is crucial for Nitrogen to enter the cells of the body ?

Answer 9

Glutamate

Question 10

What 2 Amino Acids also act as excitatory neurotransmitters ?

Answer 10

Glutamate and Aspertate

Question 11

Define transamination?

Answer 11

An amino acid giving up an amino acid group to form a Keto-acid and an amino acid

Question 12

Why is transamination used ?

Answer 12

To conserve Nitrogen in an organism

Question 13

What co-factor do Amino Transferases rely on & where does this originate from ?

Answer 13

Pyridoxal Phosphate Co-factor and it is derived from Vitamin B6

Question 14

What does L-Glutamine do ?

Answer 14

Acts as a temporary storage for Nitrogen in the body

Question 15

Amino acids undergo oxidative catabolism under what three conditions ?

Answer 15

1: Leftover A.A. from normal turnover and degradation
2: When there is an excessive amount of dietary A.A that exceed the body’s protein synthesis.
3: During starvation protein is broken down due to the lack of carbohydrates

Question 16

What cuts protein into peptides in the stomach ?

Answer 16

Pepsin

Question 17

What acts in the small intestine to cut down proteins & larger peptides into smaller peptides ?

Answer 17

Trypsin and Chymotrypsin

Question 18

What acts in the small intestine to degrade peptides into amino acids ?

Answer 18

Aminopeptidase and Carboxypeptidases A and B

Question 19

How are active proteases stored in the small intestinal cells ?

Answer 19

Zymogens

Question 20

What happens to defective proteins ?

Answer 20

They are regulated and broken down by proteosome into peptide fragments and Released Ubiquitin

Question 21

How is Nitrogen excreted from the body ?

Answer 21

As urea

Question 22

Properties of urea

Answer 22

Highly soluble and non-toxic

Question 23

What are the properties of ammonia that have to be considered when transporting through the body ?

Answer 23

Highly toxic

Question 24

how is Ammonia transported through the bloodstream ?

Answer 24

As Alanine

Question 25

What is the name of the cycle that carries Alanine from muscle to the liver via the bloodstream ?

Answer 25

Glucose-Alanine Cycle

Question 26

When would the body utilize the Glucose-Alanine Cycle ?

Answer 26

During starvation

Question 27

What other cycle is much like the Glucose-Alanine cycle and when would it be utilized ?

Answer 27

The cori cycle - during exercise.

Question 28

What kind of charge does Glutamate have ?

Answer 28

-ve charge

Question 29

What kind of charge does Alanine and Glutamine have and what does that mean with regards to membranes ?

Answer 29

No charge - easier to pass through membranes

Question 30

Where is excess Glutamate metabolized ?

Answer 30

The mitochondria of the hepatocytes

Question 31

What does Oxaloacetate get metabolized into once combined with alpha-ketogluterate in the Mitochondria ?

Answer 31

Aspertate

Question 32

What is the first Nitrogen Acquiring reaction in the Mitochondria ?

Answer 32

Glutamate -> Carbomyl Posphate

Question 33

What does Carbomyl Phosphate turn into before it leave the Mitochondria ?

Answer 33

Citruline

Question 34

What also leaves the Mitochondria to meet up with Citruline in the Cytoplasm and what does this create ?

Answer 34

Aspertate meets with Citruline in the cytoplasm to form Arginosuccinate & this is the 2nd nitrogen acquiring reaction

Question 35

What is the order of events from Arginosuccinate to urea production ?

Answer 35

Arginosucinate -> Arginine -> H2O = Urea

Question 36

What are the two broad classes of Amino Acid ?

Answer 36

Glucogenic and Ketogenic

Question 37

What do Glucogenic amino acids generally go on to become ?

Answer 37

Oxaloacetate -> Glucose

Question 38

What do Ketogenic amino acids generally go on to become ?

Answer 38

Ketone Bodies

Question 39

How many disorders of the urea cycle are there ?

Answer 39

there are 6

Question 40

What is the most common disorder of the urea cycle ?

Answer 40

The most common is an ornitine transcarbamoylase (OTC) deficiency.

Question 41

What is the purpose of OTC ?

Answer 41

Turns Ornitine back into Citruline in the urea cycle

Question 42

How is OTC deficiency inherited ?

Answer 42

It is an x linked inheritance

Question 43

How is OTC deficiency usually characterized ?

Answer 43

By hyperammonaemia (abnormally high levels of ammonia in the blood) which can be toxic

Question 44

In what age bracket does OTC deficiency usually present ?

Answer 44

New born

Question 45

In which cycle is OTC deficiency disorder found ?

Answer 45

The urea cycle

Question 46

In amino acid disorders decreased enzyme activity will do what to the product and the precursors ?

Answer 46

Decrease the product and increase the precursors

Question 47

What is one of the most common amino avid disorders ?

Answer 47

Phenylketonuria (PKU)

Question 48

How is PKU defined ?

Answer 48

as an absence or deficiency of Phenylalanine Hydroxylase (PAH)

Question 49

What is the purpose of the enzyme PAH ?

Answer 49

It catalyses the reaction of Phenylalanine to Tyrosine

Question 50

What occurs in this pathway when PAH is not present ?

Answer 50

There is a build up of Phenylalanine and Phenylalanine turns into Phenylpyruvate and then phenylacetate

Question 51

What occurs in an individual who has not been treated for PKU ?

Answer 51

Impaired brain development

Question 52

How is PKU treated ?

Answer 52

Decreased amounts of dietary protein and tyrosine supplements

Question 53

What is generated from Tyrosine ?

Answer 53

Thyroxine & L-DOPA

Question 54

When is PKU usually first spotted in babies ?

Answer 54

Once they start feeding phenylalanine levels will rise