Lesson 15 (18/11/14)

Date : 15/11/14

Topic : Mutation

Activities
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Notes

Mutation = any inheritable change in base sequence of DNA ; can be spontaneous or induced

Mutant = a strain carrying the change in base sequence of DNA ; differ from wild (parental) strain
*Selectable : drug resistant (positive or direct selection ; negative selection)
*Nonselectable : loss of colour in pigmented organism

Mutagens = include base analogues, chemical mutagen, radiation and intercalating agents
*Base analogues : compounds sufficiently similar to one of four bases
*Chemical mutagen : substances that can alter a base that is already incorporated in DNA and change its hydrogen bonding specificity
*Radiation : can be ionizing or non-ionizing

Auxotroph = any mutant microorganisms having a nutritional requirement that is absent in the parent

Prototroph = any organism that can synthesize its nutrient from inorganic material

Critical point = protein could be inactive or have reduced activity

Truncated protein = incomplete or shortened protein, usually nonfunctional

Missense mutations : normally due to changes in the first or second base of a codon

Silent mutations : normally due to changes in third base of a codon (except arg- and leu- at first base)

Nonsense mutations : results from stop codon (UAG, UAA, UGA)

Ames test : assume mutant can revert to wild type in the presence of a mutagen (back mutation)

Name of microbes
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Random facts
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Muddiest point
Some of the mechanism is not clear to me because the information is very basic.

My own exploration

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Reflection on this topic

Mutation is also included in one of the topic under Form Six Syllabus. So some of the parts I can understand by revising, but there are some other parts that cover the other aspects which need more understanding.

One thing I realized under this topic is mutation of gene can be very detrimental or beneficial to us, and to maintain the healthy genes is not easy. Most of us are really lucky to be born healthily.