Discussion:
Molecular Biology - Multiple Choice
1. Which of the following is an accurate statement concerning the differences between DNA and RNA?
- a. RNA is usually double-stranded, but DNA is usually single-stranded.
- b. RNA has the sugar deoxyribose, but DNA has the sugar ribose.
- c. RNA contains three different nucleotides, but DNA contains four different nucleotides.
- d. RNA lacks the base thymine (which is found in DNA) and has uracil instead.
2. The DNA sequence of a codon in a gene was changed from AAT to AAC. This type of mutation is called a(n) __________.
- a. point mutation
- b. insertion mutation
- c. deletion mutation
3. The cells in your skin have a different shape and different function from the cells in your liver because the two types of cells have different __________.
- a. DNA
- b. proteins
- c. lipids
- d. carbohydrates
4. Genetic recombination (crossing over) produces __________.
- a. new chromosomes
- b. mutations
- c. new combinations of alleles
- d. longer chromosomes
5. Which one of the following statements is true?
- a. An allele is either dominant or recessive, not in between.
- b. A particular gene can have only two alleles.
- c. A single trait can be affected by many different genes.
- d. The environment is irrelevant to gene expression.
6. What is the root cause of sickle-cell anemia?
- a. mutations in the gene that directs the synthesis of the hemoglobin protein
- b. an amino acid substitution in the hemoglobin protein
- c. malaria
- d. abnormally shaped red blood cells
7. What are restriction enzymes?
- a. enzymes that are limited (i.e., restricted) in how big they can become
- b. vitamins such as vitamin A
- c. plasmids
- d. enzymes that cleave through a DNA helix wherever they encounter a specific sequence of nucleotides