MDS PREP
The immunoglobulin secreted in Bile is
1. IgG
2. 1gM
3. IgA
4. IgE
Biochemistry
Answer: 3
The immunoglobulin secreted in Bile is IgA
The biochemical defect in Osteogenesis Imperfecta, type II is:
1. a mutation in the alpha 1 chain of Type I collagen.
2. a deficiency in collagenase.
3. a deficiency in lysyl oxidase.
4. a deficiency in lysyl hydroxylase.
Biochemistry
Answer: 4
The biochemical defect in Osteogenesis Imperfecta, type II is a deficiency in lysyl hydroxylase.
Which of the following enzymes is active in adipocytes following a heavy meal?
1) Glycogen phosphorylase
2) Glycerol kinase
3) Hormone-sensitive triacylglyceride lipase
4) Phosphatidate phosphatase
Biochemistry Answer: 4
The enzyme phosphatidate phosphatase converts phosphatidic acid to diacylglycerol during synthesis of triacylglycerides.
The function of adipose tissue is the storage of fatty acids as triacylglycerols in times of plenty and the release of fatty acids during times of fasting or starvation.
Fatty acids taken in by adipocytes are stored by esterification to glycerol-3-phosphate. Glycerol-3-phosphate is derived almost entirely from the glycolytic intermediate dihydroxyacetone phosphate through the action of glycerol-3-phosphate dehydrogenase. Glycolytic enzymes are active in adipocytes during triglyceride synthesis, but those of glycogen degradation (low levels in adipocytes) and gluconeogenesis (ie, glucose-6-phosphatase) are not.
Glycerol kinase is not present to any great extent in adipocytes, so that glycerol freed during lipolysis is not used to reesterify the fatty acids being released.
The enzyme triacylglyceride lipase is turned on by phosphorylation by a cyclic AMP-dependent protein kinase following epinephrine stimulation.
Aromatic amino acid is:
1. Tyrosine 2. Histidine
3. Arginine 4. Lysine
Biochemistry
Answer: 1
Tyrosine is Aromatic amino acid
The principal role of Vitamin E in the prevention of oxidative damage is to
1. oxidize metals to their less reactive state.
2. potentiate the action of superoxide dismutase.
3. reduce Vitamin C to its active oxidation state.
4. terminate free radical chain reactions in lipid bilayers.
Biochemistry
Answer: 2
The principal role of Vitamin E in the prevention of oxidative damage is to potentiate the action of superoxide dismutase
An enzyme increases the rate of a biochemical reaction by
1. decreasing substrate concentration.
2. decreasing activation energy.
3. increasing Km.
4. increasing Keq.
Biochemistry
Answer: 2
Enzymes are biological catalysts that increase the rate of chemical reactions
by lowering the activation energy required for the reaction to occur.
An alpha helix of a protein is most likely to be disrupted if a missense mutation introduces the following armino acid within the alpha helical structure:
1. Alanine.
2. Aspartic acid.
3. Tyrosine.
4. Glycine.
Glycine and proline introduce a bend in structure of protein, hence alpha helix disrupted
Glycine is a:
1. Glycogenic amino acid, only
2. Ketogenic only
3. Glucogenic and ketogenic
4. Since It Is optically inactive therefore none of the above
Biochemistry
Answer: 1
Glycine is a Glycogenic amino acid, only