Question

1) Comparing the wild-type and mutated template DNA strand, what kind of mutation is present?:

1) Wild-type template DNA: 3’ -T A C T G A C T G A C G -5’

Mutated template DNA: 3’ -T A C T G A C T A A C G -5’

What kind of mutation is present below?

A) Missense

B) Nonsense

C) silent

D) Frameshift

2) How do B cell and T cell receptors differ?

A. TCRs are only able to interact with protein epitopes, while BCRs are able to recognize more types like polysaccharides and lipopolysaccharides

B. TCRs recognize only recognize MHC II presented antigens, while BCRs recognize only MHC I presented antigens

C. Only T cell receptors are made of an immunoglobulin isotype

D. Multiple TCRs binding to epitopes can activate a T cell in a manner independent of a B cell

3) Yang is dishwasher at a hospital and receives a soiled set of steel surgical tools. What is the first thing Yang

should do?

A. Remove loose soil and debris by washing using a biological detergent

B. Bleach the tools to get rid most of the bacteria

C. Place the tools in an autoclave

D. Apply antiseptic ointment and let it soak

4) What are the kind of cells that can target and process pathogen-associated molecular patterns (PAMPs)?

A. Regulatory T cells

B. Platelets

C. Dendritic cells

D. Erythrocytes

Answer 1

Ans.1) silent mutation

This is point mutation case, in this G is replaced by A. So, the mRNA codon will be GAU instead of GAC, as mRNA is complementary to DNA strand. Both GAU and GAC code for aspartic acid (Asp). As this mutation will not alter the amino acid sequence therefore, it is silent mutation.

If change in nucleotide would have code for stop codon then it would be case of non sense mutation. If it would have code different amino acid then Asp, then it would be the case of missense mutation. If instead of change in single nucleotide their would have insertion or deletion of few nucleotides then it would be the case of frame shift mutation.

Ans. 2) TCR id able to interact with protein epitopes whereas BCarR can recognize peptide, polysaccharides, and lipopolysaccharide.

TCR can only recognize protein which is presented by MHC molecule. There are are two type of T cells, T helper (Th) and T cytotoxic (Tc) cells. Th recognize peptide presented by MHC II and Tc cell recognize peptide presented by MHC I molecules. Whereas B cells do not require antigen presenting cells, it directly interect with antigen by BCR. B cells release antibody which is member of immunoglobulin family, and different isotype.

Ans. 3) he would remove loose soil and debris by washing using a biological detergent.

Firstly soil should be remove soils and then wash with detergent and then it should be autoclaved.

Ans. 4) dendritic cells.

PAMPs are recognized by Toll like receptors of innate immunity cells, like macrophage, Dendritic cells, NK cells etc. They include lipopolysaccharide (LPS) of gram-negative bacteria; lipoteichoic acids (LTA) of gram-positive bacteria; peptidoglycan; lipoproteins generated by palmitylation of the N-terminal cysteines of many bacterial cell wall proteins; lipoarabinomannan of mycobacteria; double-stranded RNA any many more.