A scientist observes a cell under a microscope. He sees a nucleus, a cell wall,

In codominance, both alleles can be expressed. In these cases, heterozygote individuals instead of showing an intermediate phenotype, express both of the alleles. Their phenotype is an additive expression of their parents' genes.

In cystic fibrosis, there is a gene responsible for coding for a protein named "cystic fibrosis transmembrane conductance regulator, CFTR".

-Most of the people have two copies of the normal allele and produce the functional CFTR protein form.

-Patients with cystic fibrosis have two copies of the mutated allele and so produce the mutated and dysfunctional form for this protein.

-Heterozygote people possess only one normal CFTR allele and a mutated form for the same allele and produce a normal protein and a mutated protein.

In the last case, both alleles are codominant and they express in heterozygote individuals. Given the fact that the normal allele produces enough functional CFTR protein, these individuals do not have any adverse effect and the mutated allele is recessive at a physiological level.

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3 years ago

In order to initiate transcription in eukaryotes, _______. View Available Hint(s) In order to initiate transcription in eukaryot

laila [671]

Answer:

transcription factors bind to the promoter, and RNA polymerase is then recruited to begin transcribing the gene

Explanation:

The transcription process in eukaryotes happens in 3 stages:

Initiation
Elongation
Termination

The initiation of transcription starts when a set of proteins called the transcription binds to the promoter region of a gene on the coding strand of DNA. Thereafter, the RNA polymerase enzyme binds to the promoter region thereby opening up the double helix structure of the DNA in anticipation of transcription.

During elongation, RNA nucleotides are added to the growing RNA strand in 5' to 3' direction with the DNA unwinding and winding back as the polymerase moves along the coding strand in 3' to 5' direction.

Transcription terminates when the RNA polymerase gets to the end of the gene being transcribed signalled by a sequence of DNA known as the terminator.

Hence, in the illustration, the correct answer would be that the transcription factors bind to the promoter, and RNA polymerase is then recruited to begin transcribing the gene.

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2 years ago