Which of the following statements is incorrect? Down-regulation may occur if a hormone is present in excess. Down- regulation re
1 answer:
You might be interested in
Full Question (figure attached):
Nucleic acid segments and ar
DNA and RNA are nucleic acids that can store biological information based on the sequence of their nucleotide monomers. Figure 1 shows a short segment of each of the two types of nucleic acids. Which of the following best describes a structural difference between DNA and RNA?
A. DNA contains four types of nitrogenous bases, whereas RNA contains only two types of nitrogenous bases
B. The backbone of DNA contains deoxyibose, whereas the backbon e of RNA contains ribose.
C. A DNA molecule is composed of two parallel strands with the same 5'-3' directionality, whereas an RNA molecule is composed of only one strand
D. Phosphate groups provide rigidity to DNA, but RNA is flexible and contains no phosphate groups
Answer:
B. The backbone of DNA contains deoxyibose, whereas the backbon e of RNA contains ribose.
Explanation:
A. DNA contains four types of nitrogenous bases, whereas RNA contains only two types of nitrogenous bases - this is false. Both contain four types of nitrogenous bases. DNA contains cytosine, guanine, adenosine and thymine, whereas RNA contains cytosine, guanine, adenine, and uracil.
B. The backbone of DNA contains deoxyibose, whereas the backbon e of RNA contains ribose. - this is true, each nucleotide in DNA contains a deoxyribose sugar, whereas each nucleotide in RNA contains a ribose sugar
C. A DNA molecule is composed of two parallel strands with the same 5'-3' directionality, whereas an RNA molecule is composed of only one strand - this is false. DNA is composed of 2 strands, and RNA is composed of one, but the DNA strands run in an anti-parallel configuration (one runs 5'-3', the other runs 3'-5')
D. Phosphate groups provide rigidity to DNA, but RNA is flexible and contains no phosphate groups - this is false, both DNA and RNA nucleotides contain phosphate groups
