2024\2025 A+ Grade
In DNA, adenine always pairs with ________.
- Thymine
- Guanine
- Uracil
- Cytosine
- correct answer - Thymine
DNA is built from which of the following?
- Nucleosides
- Genes
- Purines
- Nucleotide
- Codons
- correct answer - Nucleotide
The double helix of DNA is stabilized mainly by __________.
- Ionic bonds
- Covalent bonds
- Ion-dipole bonds
- Hydrogen bonds
, - Hydrogen covalent bonds
- correct answer - Hydrogen bonds
Which of the following pentose sugars is a constituent of DNA?
- Xylose
- Ribitol
- 2-deoxyribose
- Arabinose
- Ribose
- correct answer - 2-deoxyribose
Pyrimidines have ________ ring(s), (each) containing ______ nitrogen(s), whereas purines have
________ ring(s), (each) containing ______ nitrogen(s).
- 1; 1; 1; 1
- 1; 2; 2; 2
- 2; 2; 1; 2
- 2; 1; 1; 2
- 2; 2; 1; 1
- correct answer - 1; 2; 2; 2
Identify the base guanine from among the following structures.
- correct answer 5 NH in rings with a double bonded O
Which of the following nucleic acids is responsible for using the encoded genetic information to produce
of proteins found in living organisms?
- Peptide nucleic acid
- Ribonucleic acid
- Ribitol nucleic acid