Nitrogen Metabolism
26 Questions
| Attempts: 237
Lecture 63Biochemistry spring 2010SGU
Questions and Answers
- 1.
Compounds that contain nitrogen: proteins, derivatives of amino acids: creatine, ________, purines and pyrimidines, hemeslide 2
- 2.
The most important source of amino acids for the amino acid pool is dietary ____ digestion (60-100 g/day)slide 4
- 3.
Amino acids are used in amino acid catabolism and in the _______ of nitrogen containing compounds.slide 4
- 4.
The rate of tissue protein synthesis is equal to the rate of protein ________. slide 5
- 5.
In a healthy, well-fed adult, input of amino acids = _____ of amino acids. The amino acid pool is in a steady state / equilibrium. 6
- 6.
Damaged or unneeded proteins are degraded by two mechanisms: the lysosomal pathway that degrades extracellular proteins and the ubiquitin-______ pathway that degrades proteins synthesized by the cell 7
- 7.
ATP dependent 8
- A.
Ubiquitin-proteasome pathway
- B.
Lysosomal pathway
Correct Answer
A. Ubiquitin-proteasome pathway -
- 8.
Degrades plasma proteins and proteins taken up by endocytosis 8
- A.
Ubiquitin-proteasome pathway
- B.
Lysosomal pathway
Correct Answer
B. Lysosomal pathway -
- 9.
Non-energy dependent degradative pathway 8
- A.
Ubiquitin-proteasome pathway
- B.
Lysosomal pathway
Correct Answer
B. Lysosomal pathway -
- 10.
Positive nitrogen balance: Intake of dietary nitrogen is ___ the output of nitrogen 11
- A.
Less than
- B.
Greater than
Correct Answer
B. Greater than -
- 11.
Increased tissue protein synthesis
- A.
Positive nitrogen balance
- B.
Negative nitrogen balance
Correct Answer
A. Positive nitrogen balance -
- 12.
Increase in urinary excretion of urea 12
- A.
Positive nitrogen balance
- B.
Negative nitrogen balance
Correct Answer
B. Negative nitrogen balance -
- 13.
Seen in starvation, chronic illness (infections), cancer, uncontrolled diabetes mellitus 12
- A.
Positive nitrogen balance
- B.
Negative nitrogen balance
Correct Answer
B. Negative nitrogen balance -
- 14.
During growth periods during childhood and adolescence, pregnancy 11
- A.
Positive nitrogen balance
- B.
Negative nitrogen balance
Correct Answer
A. Positive nitrogen balance -
- 15.
Which of the following statements is true? 13
- A.
All amino acids are glucogenic
- B.
All amino acids are essential amino acids
- C.
Amino acid catabolism is increased during starvation
- D.
The major excretory end product of amino acid catabolism is ammonia
- E.
Tissue protein synthesis is decreased during periods of growth
Correct Answer
C. Amino acid catabolism is increased during starvation -
- 16.
In infection, the liver synthesizes a group of proteins known as the ____-phase proteins. C-reactive protein, serum amyloid A protein, haptoglobin, ceruloplasmin levels are increased in circulation in any type of inflammation. 15
Correct Answer
acute - 17.
____ is the site where most of the amino acids release their amino groups as ammonia 16
Correct Answer
liver - 18.
____ is the major end product of nitrogen metabolism 16
Correct Answer
urea - 19.
The carbon skeletons of the amino acids are used for __________. 16
Correct Answer
gluconeogenesis - 20.
Urea formed in the liver is transported to the kidneys, where it is excreted in the urine. The kidneys also excrete ammonia as ammonium ions. The other non-protein nitrogenous substances that are excreted by the kidney are creatinine and _____ acid. 17
Correct Answer
uric - 21.
In a patient with renal disease, which of the following parameters would be the best indicators of renal function? 19
- A.
Serum ammonia
- B.
Serum albumin
- C.
Blood glucose
- D.
Serum free fatty acids
- E.
Blood urea nitrogen
Correct Answer
E. Blood urea nitrogen -
- 22.
Tubular reabsorption of cystine is decreased due to an inherited deficiency of the cystine transporter. Cystine is excreted in urine and tends to precipitate in the renal tubules in the renal tract - one of the causes of renal ____ in children 21.
Correct Answer
stones - 23.
Hartnup's disease - inherited defect in the transport of the ___ amino acids like tryptophan 22
Correct Answer
neutral - 24.
_____ supplements can be used as treatment for pellagra 22
Correct Answer
niacin - 25.
Niacin deficiency's 3 d's: dermatitis, diarrhea, and ______. 23
Correct Answer
dementia - 26.
A 12 year old child is suspected of having pellagra because of chronic symptoms including diarrhea, a red scaly rash, and mild cerebellar ataxia. However, his diet is not deficient in protein and he appears to be ingesting adequate amounts of niacin. A sister has a similar problem. Chemical analysis of his urine demonstrates large amounts of free amino acids. Which amino acid do you expect to find in the urine? 23
- A.
Cystine
- B.
Phenylalanine
- C.
Tyrosine
- D.
Tryptophan
- E.
Branched chain amino acids
Correct Answer
D. Tryptophan -
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