Multiple Choice
Why are lethal dominant alleles generally rarer in populations compared to lethal recessive alleles?
673
views
12. Meiosis
Genes & Alleles
Multiple Choice
Why are individuals who are heterozygous for the cystic fibrosis allele unaffected by the disease?
A
Heterozygous individuals have a mutation that prevents the disease.
B
They have one normal allele that produces enough functional protein.
C
The cystic fibrosis allele is only expressed in homozygous individuals.
D
The cystic fibrosis allele is dominant, so it does not express the disease.
Verified step by step guidance1
Understand the concept of alleles: Alleles are different forms of a gene. In the case of cystic fibrosis, there are two alleles - one normal and one mutated.
Learn about heterozygosity: A heterozygous individual has two different alleles for a particular gene, one from each parent. For cystic fibrosis, this means having one normal allele and one mutated allele.
Explore protein production: The normal allele produces a functional protein that is necessary for normal cellular function. This protein is called CFTR (Cystic Fibrosis Transmembrane Conductance Regulator).
Consider the effect of the normal allele: In heterozygous individuals, the presence of one normal allele is sufficient to produce enough functional CFTR protein to prevent the symptoms of cystic fibrosis.
Understand expression in homozygous individuals: Cystic fibrosis manifests in individuals who are homozygous for the mutated allele, meaning they have two copies of the mutated allele and no normal allele to produce functional CFTR protein.
Related Videos
Related Practice
