Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

MCBM Exam 4 Kat > Nitrogen Metabolism > Flashcards

Nitrogen Metabolism Flashcards

1
Q

What are some dietary fuels?

A

Carbohydrates (sugars & starches)
Lipids (fats)
Proteins (amino acids)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

When are amino acids oxidized for energy?

A

Normal protein turnover
Starvation
Uncontrolled diabetes mellitus
Protein Rich Diet (Atkin’s)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

N Balance

A

Intake = Loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

(+) N Balance

A

Intake > Loss

Growing children, pregnancy, illness/trauma recovery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

(-) N Balance

A

Loss > Intake

Starvation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is kwashiorkor?

A

Muscle Wasting Metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Define Ureotelic.

A

Beings that excrete Urea like terrestrial animals.

86%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Define Ammonotelic.

A

Beings that excrete Ammonia directly like bony fish

2.8%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Define Uricotelic.

A

Beings that excrete Uric Acid like birds & reptiles

1.5%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where does the other 4.5% of excreted ammonia products come from?

A

Creatin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What do the mucosal cells of the stomach excrete?

A

Gastrin and Histamine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What do the parietal cells of the stomach excrete and what are they activated by?

A

Secretes HCl

Activated by Histamine from the Mucosal Cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does gastrin from the mucosal cells activate?

A

Chief cells which secrete Pepsinogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the action of Atropine and probanthine on the digestive system?

A

Blocks ACh integration with muscarinic receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the action of Cimetidine (Tagamet) and ranitidine (Zantac) on the digestive system?

A

Block histamine interaction with H2 receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What CNS Neurotransmitter initiates secretion in the stomach?

A

Acetylcholine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What two hormones and one enzyme do the intestinal mucosa produce?

A

Cholesistokinin, Secretin, Enteropeptidase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does the pancreas excrete?

A

The secretory cells secrete zymgens and HCO3-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the end result of pancreas excretion?

A

Single Amino Acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What does a deficiency in Neutral amino acids result in?

A

Hartnup’s Disease (NAD def)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Can free amino acids be stored?

A

No, they are catabolized. There is no way to store them.

22
Q

What are the products of amino acid catabolism?

A

Ammonia (NH4+)

Alpha-keto acid carbon skeletons

23
Q

What is ammonia converted into?

A

To Urea for excretion

24
Q

What are alpha-keto acid carbon skeletons converted into?

A

Pyr, AcCoA or TCA cycle intermediates

25
What are the 3 basic processes of nitrogen metabolism?
1) Transport nitrogen to liver 2) Nitrogen removal in liver 3) Production of urea
26
How is nitrogen transported to the liver?
Transamination | Glutamine synthase
27
How is nitrogen removed in the liver?
Glutaminase | Glutamate dehydrogenase
28
What is the Glucose Alanine Cycle in a nutshell?
Pyruvate from skeletal muscle glucose metabolism converted to Ala, sent to liver & converted back to glucose & sent back to muscle
29
What are some major Transaminases?
Glutamate-Oxaloacetate Transaminase (GOT) | Glutamate-Pyruvate Transaminase (GPT)
30
What are some minor transaminases?
Branched chain aminotransferase Tyrosine aminotransferase Ornithine aminotransferase
31
What forms of Vitamin B6 are involved in transamination reactions?
Pyridoxal phosphate | Pyridoxamine phosphate
32
In what cases would serum levels of transaminases go from normally very low to elevated levels?
Heart Attack and Liver Damage | Damaged cells leak enzymes into bloodstream
33
What serum levels should yo check if you think a heart attack may have occurred?
``` SGOT SGPT CK LDH If both CK and LDH raised then 100% diagnostic ```
34
What two intermediate steps are needed for nitrogen transport to the liver?
Transamination | Glutamine synthase
35
What two intermediate steps are needed for nitrogen removal in the liver?
Glutaminase | Glutamate Dehydrogenase
36
Why is the glutamine synthase step of nitrogen transport so important?
It commits the nitrogen to disposal and no other process and is thus highly regulated.
37
What is glutamine important for?
Main repository for NH3
38
What are the functions of glutaminase?
Hydrolytic deamination that uses water to exchange with NH2. Also used in kidneys to supply ammonia for acid neutralization in urine.
39
How much of the bodies nitrogen is excreted as Urea?
80%
40
Where is more ammonia converted to Urea?
In the Liver
41
How energy costly is the urea cycle?
Very | Uses 3 ATP's and 4 high energy bonds
42
What does to much urea in the body mean?
Gout
43
What does increase BUN levels mean?
Kidney problem
44
What does BUN stand for?
Blood urea nitrogen
45
What does increase NH4+ levels mean?
Liver problem
46
What is the committed step (rate limiting step) of the Urea Cycle?
Carbamoyl phosphate synthesis via carbamoyl phosphate synthetase I (an irreversible reaction)
47
Which portion of the urea cycle occurs in the mitochondrial matrix?
The 1st portion
48
What happens when NH4+ is in excess?
alpha-KG is removed from the TCA cycle for transamination to Glu for conversion to Gln for export to liver
49
When would levels of NH4+ increase?
Cirrhosis caused by alcoholism, hepatitis or genetic defects
50
Elevated ammonia levels affects which part of the body profoundly.
The brain Problems include: decreased ATP, depleted Glu and GABA, and brain swelling due to osmotic imbalance.
51
What are some effects of genetic defect in urea metabolism?
Life threatening | Usually cause mental retardation, seizures, and/or coma
52
How are genetic defects in urea metabolism treated?
Requires careful control of diet and administration of detoxifying compounds

MCBM Exam 4 Kat (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions