Assume that a mutation occurs in the gene responsible for the production of hexosaminidase a, such that only about 50% of the enzyme activity is found in the heterozygote compared with a homozygous normal individual. if heterozygotes are phenotypically normal, we would say that the mutant allele is recessive to its normal allele.

This statement is true.

In the case of autosomal dominant disease, the person is either homozygous (which is very rare) or heterozygous. On the molecular level, either the mutation produced a new deleterious protein for the organism, or the mutation affected an existing protein in the physiological state and that a 50% activity is not enough to compensate for the needs. of the body.

In case of autosomal recessive disease, the sick person is always homozygous. If the two loci each have a different mutant allele, it is called a "composite heterozygote". People with autosomal recessive inheritance disorder have "mandatory heterozygote" parents.

hey, i believe your answer would be d. sugar ribose and the base uracil. i believe this is the answer, because rna consists of sugar ribose, adenine, guanine, cytosine, and uracil.

your first option is incorrect, because that's dna. where it consists of sugar deoxyribose, adenine, guanine, cytosine and thymine.

your second option is also incorrect, this is because sugar deoxyribose is in dna, and uracil is in rna. these two do not make sense together.

your third option being incorrect, because sugar ribose is in rna, but not the base of thymine. rna consists of uracil, not thymine.

lastly your fourth option being correct! this answer is correct, because both sugar ribose, and the base uracil are in rna! ~

answer is d. sugar ribose and the base uracil.