Biology Answers

In peas, a gene for tall plants (T) is dominant over its allele for short plants (t). The gene for smooth peas (S) is dominant over its allele for wrinkled peas (s). The genes are not linked. Determine both phenotypic and genotypic ratios for the results of each of the following crosses:

3.1. heterozygous tall heterozygous smooth x heterozygous tall heterozygous smooth.                                                                                          [26 marks]

In a particular species of plant, tall is dominant to short, and orange petals are dominant to the recessive white colour. Use T and t to symbolize the alleles for height, and F and f to symbolize the alleles for flower colour. A homozygous tall white flower is crossed with a flower heterozygous for both traits.

1.1 List the genotypes of the parents.                                           

1.2 What are the F1 GENOTYPIC and PHENOTYPIC ratios?          [5 marks]

1.3 What are the F2 genotypic and phenotypic ratios?   

In a particular species of plant, tall is dominant to short, and orange petals are dominant to the recessive white colour. Use T and t to symbolize the alleles for height, and F and f to symbolize the alleles for flower colour. A homozygous tall white flower is crossed with a flower heterozygous for both traits.

1.1 List the genotypes of the parents.  

1.2 What are the F1 GENOTYPIC and PHENOTYPIC ratios?  

1.3 What are the F2 genotypic and phenotypic ratios? 

which of the following taxa have mitochondrial DNA?

Ectrodactyly also know as" Lobster claw syndrome" is a recessive disorder in humans. If a phenotypically unaffected an affect offspring, what are the following probilities?

A. Both parents are heterozygotes

B. An offspring is a heterozygotes

C. The next three offspring will be phenotypically unaffected

D. Any two out of three offspring will be phenotypically unaffected.