Lipid Metabolism and Transport

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What is the normal concentration of ketone bodies in the circulation?

1mM (correct)
10mM
0.1mM
100mM

What is required for the synthesis of ketone bodies?

Fatty acids available for oxidation in the liver (correct)
Low plasma insulin only
High plasma insulin/glucagon ratio
Fatty acids available for oxidation in the brain

What is the role of ketone bodies in the body?

They are used by all tissues containing mitochondria (correct)
They are used only by the liver and kidneys
They are not used by any tissues
They are used only by the central nervous system

What is the primary component of cell membrane?

Cholesterol (D) Signup and view all the answers

What is the consequence of a fall in plasma insulin?

It activates the lyase and inhibits the reductase (B) Signup and view all the answers

Where does lipolysis occur in the process of ketone body synthesis?

In adipose tissue (C) Signup and view all the answers

What is the primary function of the enzymes found in the liver and kidney?

To remove the NH2-group from amino acids (C) Signup and view all the answers

What is the usual keto-acid involved in the transamination reaction?

α-ketoglutarate (A) Signup and view all the answers

What is the product of the reaction between glutamic acid and pyruvic acid?

Alanine and α-keto glutarate (B) Signup and view all the answers

What is the product of the reaction between glutamine and glutaminase?

Glutamate and NH3 (D) Signup and view all the answers

What is the purpose of detoxifying ammonia in the body?

To prevent the build-up of toxic compounds (B) Signup and view all the answers

What is the clinical significance of transaminases in the blood?

To assess liver function (A) Signup and view all the answers

Why is early diagnosis of PKU crucial?

To prevent irreversible damage (D) Signup and view all the answers

What is the composition of creatine kinase?

Two subunits of different types (B and M) (A) Signup and view all the answers

What is the byproduct of the deamination reaction?

NH3 (A) Signup and view all the answers

What is the normal blood concentration of ammonia?

Low, around 25-40μM (C) Signup and view all the answers

What is the consequence of a complete loss of an enzyme in the urea cycle?

Fatal (D) Signup and view all the answers

Which of the following is NOT a transaminase of clinical importance?

Glutamate transaminase (GT) (C) Signup and view all the answers

What is the primary purpose of a low-protein diet in the treatment of urea cycle defects?

To restrict the amount of amino acid in the diet (B) Signup and view all the answers

What is the source of ammonia produced during amino acid degradation?

Gut bacteria (D) Signup and view all the answers

What is the enzyme involved in the transamination reaction?

Transaminase (B) Signup and view all the answers

What is the molecular basis of the toxic effect of ammonia?

Its reaction with alpha-ketoglutarate to form glutamate (C) Signup and view all the answers

What is the purpose of replacing amino acids with keto acids in the treatment of urea cycle defects?

To restrict the amount of amino acid in the diet (A) Signup and view all the answers

How is PKU typically diagnosed in newborns in the UK?

Through screening for phenylketones in urine and phenylalanine in blood (A) Signup and view all the answers

Which of the following amino acids is essential and cannot be totally removed from the diet?

Phenylalanine (D) Signup and view all the answers

What is the reaction catalyzed by creatine kinase in muscle cells?

Creatine + ATP → Creatine Phosphate + ADP (D) Signup and view all the answers

What is the consequence of elevated levels of homocysteine and methionine in plasma and the presence of homocystine in the urine?

Homocystinuria (A) Signup and view all the answers

What is the significance of the amount of creatinine in blood and urine?

Indicates kidney function and muscle turnover (D) Signup and view all the answers

What is the toxic compound that accumulates in phenylketonuria?

Phenyl pyrovic acid (D) Signup and view all the answers

What is the significance of the three different enzymes of creatine kinase?

They are isoenzymes with different tissue distributions (B) Signup and view all the answers