Question

True or False please explain

3. (See the recipe for DNase test agar on page 338.] The purpose of tryptose in DNase test agar is to provide a source of carbon and nitrogen. 4. [See the recipe for DNase agar on page 338.] The purpose of agar in DNase test agar is to solidify the medium for use in Petri dishes. 5. [See the recipe for DNase agar on page 338.] The purpose of methyl green in DNase test agar is to bind to the DNase to make it visible.

Answer 1

Ans.

• Deoxyribonuclease test agar (DNase test agar) is used for the detection of deoxyribonuclease activity of micro-organisms, namely fungi and bacteria.
• DNA is made up of many nucleotides and is way too large to enter the cell membrane in it's polymeric form.
• Bacteria secrate DNase (exoenzymes) outside the cells, which hydrolyzes the DNA into nucleotides which are than transported across the cell through transport proteins.
• Thus, DNase test is used to determine the DNA hydrolizing ability of an organism and to analyze whether it can use those DNA fragments as the energy source.
• Various components of DNase agar test medium and their functions are ;-

1. Typtose - It acts as a source of nitrogen, vitamins, amino acids and other essential growth elements.
2. Agar - It solidify the medium to be used in petri dish.
3. Methyl Green - It acts as an indicator of binding to DNA and make binding to DNA clearly visible.