Strains of E

question 75

Multiple Choice

Strains of E.coli that are defective in mismatch repair have very high levels of spontaneous mutagenesis.Studies have shown that in wild-type strains, A:C and G:T mispairings (as opposed to the normal A:T and G:C pairings) that occur during DNA replication are more likely than other mispairings (A:G, etc.) to be detected and.Which of the following types of base substitutions would you expect to be MOST common among the spectrum of spontaneous mutations created by the mutant mismatch repair-defective strains?

• A)A-to-C
• B)C-to-A
• C)G-to-C
• D)A-to-G
• E)A-to-T

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Definitions:

Carbon-carbon Double Bond

A strong chemical bond involving the sharing of two pairs of electrons between two carbon atoms, characterized by its reactivity and presence in unsaturated compounds.

Unsaturated Fatty Acid

A type of fatty acid that contains one or more double bonds within its hydrocarbon chain, often found in vegetable oils and associated with health benefits.

Hydrolyzed

Refers to the chemical process where a molecule is split into two or more parts by the addition of a water molecule.

Fatty Acid

Carboxylic acids with a long aliphatic chain, which can be either saturated or unsaturated, and are a key component of lipids in the diet.