Define epistasis and give an example
What will be an ideal response?
ANSWER: In epistasis, two or more genes affect the same phenotype. The phenotypic expression of one
or more alleles of a gene at one locus inhibits or masks the effects of the phenotypic
expression of one or more alleles of a gene at a different locus. An example would be coat
color in Labrador retrievers. In these dogs, the genes for black and brown fur can be silenced
by the expression of a homozygous recessive allele that blocks pigment deposition in fur.
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Which of these time intervals, based on plant fossils, came last (most recently)?
A) extensive growth of gymnosperm forests B) Silurian-Devonian explosion with fossils of plant lineages that contain most of the major morphological innovations C) colonization of land by early liverworts and mosses D) rise and diversification of angiosperms E) carboniferous swamps with giant horsetails and lycophytes
Osmotic pressure of a solution is the amount of pressure exerted on the side of the selectively
permeable containing a higher concentration of solute to prevent diffusion of solute. __________________ Indicate whether the statement is true or false.
What is the fate of metabolites during respiration?
a. They are oxidized completely to carbon dioxide and water. b. They are reduced to from NADH and FADH2. c. They are oxidized completely to form pyruvic acid. d. They are rearranged to form GTP.
What is the connection between sickle-cell anemia and malaria?
A) Both are dominant. B) Both are X-linked. C) Heterozygotes for malaria have some resistance to sickle-cell anemia. D) Heterozygotes for sickle-cell anemia have some resistance to malaria. E) Both are autosomal recessive.