RNA in cells differs from DNA in that ___________________
(a) it contains the base uracil, which pairs with cytosine.
(b) it is single-stranded and cannot form base pairs.
(c) it is single-stranded and can fold up into a variety of structures.
(d) the sugar ribose contains fewer oxygen atoms than does deoxyribose.
Choice (c) is correct. Choice (a) is untrue because although RNA contains uracil, uracil pairs with adenine, not cytosine. Choice (b) is false because RNA can form base pairs with a complementary RNA or DNA sequence. Choice (d) is false because ribose contains one more oxygen atom than deoxyribose.
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Which of the following represents a sequence located upstream, downstream, within the coding region, or several thousand base pairs away from a gene that increases transcription?
a. promoter b. terminator c. repressor d. enhancer
A male expresses
A. only the homozygous recessive alleles on his X chromosome. B. none of the alleles on his X chromosome. C. only the dominant alleles on his X chromosome. D. both the dominant and recessive alleles on his X chromosome. E. None of the answer choices is correct.
The biological macromolecule that is least soluble in water is a(n):
A. nucleic acid. B. protein. C. carbohydrate. D. lipid. E. enzyme
A mutation in a gene that changes a codon to one that codes for the same amino acid as the original codon; The amino acid sequence of the resulting polypeptide is thus unchanged
What will be an ideal response?