Question

1. What is secreted from both natural killer (NK) cells and cytotoxic T (TC) cells from holes in the cell membranes leading to the eventual destruction of the target?

a) Lysomes

b) Perforin

c) Complement

d) Bacteriocin

2. What is the name for a mutagen that insets itself between 2 base pairs so that an extra base is added during DNA replication? Ethidium bromide DNA  is an example.

1. Base analog
2. Transposon
3. Ionizing
4. Intercalating agent

1. Which of the following is an example of a conditionally lethal mutation?

1. Inversion
2. Temperature-sensitive mutation
3. Translocation
4. Thymine-thymine dimer

1. Insertion equals mutation for all biological mutagens targeting bacteria

1. True
2. False

1. Which term below describes cells that can take up DNA and be transformed? These cells can be generated in the lab using CaCl₂, glycerol, and cold temperature

1. Virulent
2. Competent
3. Reactive
4. Compatible

Answer 1

1.

Perforin, a protein molecule secreted by T-cell and NK cell creates pores in the target cell and kill it eventually. Hence perforin is the correct answer.

2.

Intercalating agents are flat molecules insert between bases and polymerase gets fooled and add a base against these intercalating agents and hence cause mutation. Hence correct option is intercalating agents.

3.

Conditionally lethal mutations are those mutations under certain environmental conditions, there will be mutations leading to death. But under normal conditions cells survive. Example is temperature sensitive mutations. Hence correct option is temperature sensitive mutations.

4.

Transposons are example of biological mutagens which translocate in the DNA and insert itself causing mutation. Hence the statement is true.

5.

Making a cell to take up a surrounding DNA by providing certain environmental conditions such as cold temperature, calcium chloride etc., Known as competent cells. Hence correct option is competent cells.