Question

1. if one nucleotide is omitted or accidentally repeated in the process of dna duplication, which of the following is most likely to occur? a gene deletion b gene mutation c gene insertion d gene segregation 9. a pea plant with the genotype ttww is crossed with a pea plant with the genotype ttww. how many different genotypes can be expressed in the offspring? a 1 b 2 c 3 d 4

Explanation:

Step1: Analyze question 8

A change in nucleotide sequence during DNA - duplication is a mutation. Omission or repetition of a nucleotide is a type of point - mutation. Gene deletion involves loss of a large segment of DNA, gene insertion is addition of new nucleotides, and gene segregation is related to the separation of alleles during meiosis. So, gene mutation is the correct answer.

Step2: Analyze question 9

For the cross TtWW × ttWw:

• For the T/t gene: Tt×tt gives Tt and tt genotypes.
• For the W/w gene: WW×Ww gives only Ww and WW genotypes.
• By the product rule of probability for independent genes, the possible genotypes of the offspring are TtWW, TtWw, ttWW, ttWw. So, there are 4 different genotypes.

Answer:

1. B. Gene mutation
2. D. 4