Chapter 02: Genes and Genetic Diseases
Huether: Understanding Pathophysiology, First Canadian Edition
1. A nurse recalls that the basic components of DNA are:
a. pentose sugars and four phosphate bases.
b. a phosphate molecule, deoxyribose, and four nitrogenous bases.
c. adenine, guanine, and purine.
d. codons, oxygen, and cytosine.
The three basic components of DNA are deoxyribose; a phosphate molecule; and four types of
nitrogenous, not phosphate, bases. DNA does not contain condone.
REF: p. 38
2. Which of the following mutations have the most significant effect on protein synthesis?
a. Base pair substitutions
b. Silent mutations
c. Intron mutations
d. Frameshift mutations
The frameshift mutation involves the insertion or deletion of one or more base pairs of the
DNA molecule. This greatly alters the amino acid sequence, which affects protein synthesis.
The base pair substitution is a type of mutation in which one base pair replaces another. Silent
mutations do not change amino acids or protein synthesis. Intron mutations are part of RNA
REF: p. 39
3. The base components of DNA are:
a. A, G, C, and U.
b. P, G, C, and T.
c. A, G, C, and T.
d. X, XX, XY, and YY.
The four base components of DNA are cytosine, thymine, adenine, and guanine, and they are
commonly represented by their first letters (C, T, A, and G). There are no genetic components
identified as P or U. The letters X, XX, XY, and YY are components of human chromosomes.
REF: p. 38
4. A DNA strand has a region with the sequence ATCGGAT. Which of the following would be a