Cell Biology written test Questions & Answerson “Extracellular Matrix and Cell Interactions – Immunoglobulin Superfamily and Cadherins”.
1. Which of the following immunoglobulin is naturally given to the fetus?
A. IgG
B. IgM
C. IgD
D. IgE
Answer: A
Clarification: IgG is the most commonly found immunoglobulin in the serum of humans. It is passed to the fetus from mother through the placenta. It has two antigen binding sites.
2. What is the range of amino acids present in an immunoglobulin molecule?
A. 50-110
B. 70-110
C. 60-10
D. 80-110
Answer: B
Clarification: The immunoglobulin molecules have 70-100 amino acids, which varies according to the functions they are involved in our body. The number of amino acids also depends upon their size.
3. In an immunoglobulin, the heavy chains and the light chains are held together by ____________
A. Diphosphate bond
B. Dichloride bond
C. Disulphide bond
D. Dihydroxide bond
Answer: C
Clarification: The immunoglobulin has two chains, the light chain and the heavy chain. Two light chains and two heavy chains are held together by disulphide bond.
4. What ions is required for the function of cadherins?
A. Ca2+
B. Na+
C. K+
D. H+
Answer: A
Clarification: The cadherins is also known as calcium-dependent adhesion molecule. They require calcium ions for its transmembrane function.
5. Cadherins are 720-750 amino acids long.
A. True
B. False
Answer: A
Clarification: Cadherins contain around 720 to 750 amino acid molecules. These amino acids are synthesized by the posttranslational modifications made to the polypeptide chain.
6. Which of the following has abundant protocadherins?
A. Circulatory system
B. Reproductive system
C. Nervous system
D. Coordination system
Answer: C
Clarification: Protocadherins are abundant in the nervous system. They are present in neurons of our nervous system. A certain gene is present here to express the protocadherin protein.
7. What is epithelial mesenchymal transistion?
A. Loss of adhesion and gain of migration
B. Loss of migration and gain of adhesion
C. Lysis of cell
D. Formation of mesenchymal cells
Answer: A
Clarification: Epithelial mesenchymal transition is the property of cells losing adhesion and gaining migration. It is highly useful in the pluripotency of stem cells in organ development.
8. Where are CDH3 gene found?
A. Bone marrow
B. Lymph nodes
C. Neurons
D. Placenta
Answer: D
Clarification: CDH3 type of cadherin expression gene is present in the placenta. This gene is also responsible for some forms of breast cancer.
9. Which of the following is caused by cadherin disorder?
A. Zellweger syndrome
B. Usher syndrome
C. Bubble boy syndrome
D. Down’s syndrome
Answer: B
Clarification: Usher syndrome is an autosomal recessive genetic disorder caused by mutation. In this disorder the cadherin 23 is responsible for the deafness.
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