Located on the x chromosome of a cat is a gene that codes for deafness. This gene is recessive. A female cat that is heterozygous for deafness is crossed with a male cat that is not deaf. What are the genotypes and phenotypes of the offspring? Genotypes:
Phenotypes:

draw a punnett square to help you

Genotypes: 50% DD 50% Dd

Phenotypes: 50% normal 50% carriers

None of the cats are deaf (unless they are male, they can have a chance of getting it)

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.