Question

cystic fibrosis affects the lungs, the pancreas, the digestive system, and other organs, resulting in symptoms ranging from breathing difficulties to recurrent infections. which of the following terms best describes this expression of phenotypes?

incomplete dominance
multiple alleles
pleiotropy
epistasis

question 6

characters in humans such as a persons red and white blood cell counts vary quite a bit depending on such factors as altitude and physical activity. traits like this are referred to as ...

polygenic.
completely dominant.
recessive.
multifactorial.

Explanation:

• First question:
• Incomplete dominance is when the heterozygote has an intermediate phenotype. Multiple alleles refer to a gene having more than two alleles in a population. Epistasis is when one gene affects the expression of another. Pleiotropy is when one gene affects multiple phenotypic traits. Cystic fibrosis affects multiple organs (lungs, pancreas, digestive system etc.), so it shows pleiotropy.
• Second question:
• Polygenic traits are controlled by multiple genes. Completely dominant and recessive are related to allele - gene interactions. Multifactorial traits are influenced by both genetic and environmental factors. Red and white blood cell counts are influenced by environmental factors (altitude, physical activity) along with genetic factors, so they are multifactorial.

Answer:

• First question: C. pleiotropy
• Second question: D. multifactorial