1. Which of the following is NOT needed for DNA replication?

a) ribosomes;     b) DNA;     c) nucleotides;     d) enzymes;     e) all of the above are needed

2. DNA replication is said to be semiconservative. This means that _____.

a) half of the old strand is degraded and half is used as a template for the replication of a new strand

b) one of the two resulting double helices is made of two old strands, and the other is made of two new strands

c) the old double helix is degraded and half of its nucleotides are used in the construction of two new double

helices

d) one strand of the new double helix is made of DNA and the other strand is made of RNA

e) each new double helix consists of one old and one new strand

3. The flow of information in a cell proceeds _____.

a) from RNA to DNA to protein;         b) from protein to RNA to DNA;     c) from DNA to protein to RNA

d) from RNA to protein to DNA;         e) from DNA to RNA to protein

4. The information carried by a DNA molecule is in _____.

a) its amino acid sequence;

b) the sugars and phosphates forming its backbone

c) the order of the nucleotides in the molecule

d) the total number of nucleotides it contains

e) the RNA units that make up the molecule

5. How does RNA polymerase know where to start transcribing a gene into mRNA?

a) It starts at one end of the chromosome.

b) Transfer RNA acts to translate the message to RNA polymerase.

c) It starts at a certain nucleotide sequence called a promoter.

d) The ribosome directs it to the correct portion of the DNA molecule.

e) It looks for the AUG start codon.

6. After an RNA molecule is transcribed from a eukaryotic gene, portions called ____ are removed and the

remaining ____ are spliced together to produce an mRNA molecule with a continuous coding sequence.

a) operators ... promoters;         b) exons ... introns;                 c) silencers ... enhancers;

d) introns ... exons;                  e) promoters ... operators

7. Which of the following processes occurs in the cytoplasm of a eukaryotic cell?

a) DNA replication;                             b) translation;         c) transcription;

d) DNA replication and translation        e) translation and transcription

8. Which one of the following is true of tRNAs?

a) Each tRNA binds a particular amino acid.                     b) tRNAs are extremely small molecules.

c) tRNAs carry special sequences known as codons.         d) There are four types of tRNA.                e) All of the above.

9. A mutagen causes _____.

a) problems with mitosis;                                 b) a change in the base sequence of DNA;

c) blockage of the ribosome-binding sites;         d) decreased permeability of the nuclear envelope

e) a reduction in the number of tRNA molecules available for protein synthesis

10. A gene is usually _____.

a) the same thing as a chromosome

b) the information for making a polypeptide

c) made of RNA

d) made by a ribosome

e) made of protein.

11. Name the enzyme which opens DNA for replication by breaking hydrogen bonds.

a) DNA polymerase;        b) helicase;        c) primase;        d) ligase;        e) none of these.