Biology 12
p509-516, p520
Name: ______________
Chap 25 Review Questions
Date: _______________
1. Which of the following cell structures is the site of DNA replication?
A. nucleus
B. ribosome
C. nucleolus
D. rough endoplasmic reticulum
2. Which of the following events occurs during DNA replication?
A. Deoxyribose bonds to phosphate.
B. Hydrogen bonds are formed between the original nucleotides.
C. Bonds form between the DNA nucleotides and RNA nucleotides.
D. Phosphates of the original nucleotides bind to those of the new nucleotides.
Use the following diagram to answer question 3
3. What has occurred to this molecule to cause it to change as shown
A. Ionic bonds have broken between deoxyribose molecules.
B. Hydrogen bonds have been broken between nitrogenous bases.
C. New bonds have formed causing the molecule to change shape.
D. Covalent bonds have been broken between phosphate molecules.
4. In an experiment, a molecule known to be a competitive inhibitor to the enzyme helicase
is added to a culture of actively dividing cells. Which of the following would likely occur?
A. The cells would reproduce more rapidly.
B. The rate of transcription would increase.
C. The rate of DNA production by cells would decrease.
D. The amount of free nucleotide molecules in the cells would decrease.
5. Which of the following molecules contains anticodons?
A. DNA
B. tRNA
C. mRNA
D. amino acid
6. Which molecule is not composed of nucleotides? Use the diagram below
A. W
B. X
C. Y
D. Z
6
7. What event is shown in the diagram to the side
A. Replication B. Translation
C. Transcription
D. mutation
8. A tRNA molecule with the anticodon GCU would be carrying
the amino acid:
 codon would be CGA
A. valine
B. tyrosine
C. alanine
D. arginine
9. Which of the following is NOT a frameshift mutation of the nucleotide sequence
CATUAUCCC? Typo!! No T and U in the same sequence! (& all frameshift mutations)
a) CATTUAUCCC
c) CTUAUCCC
e) CCATUAUCCC
b) ATUAUCCC
d) CATUAUCCGC
10. A strand of DNA has the following bases: C A C G G C C . If a frameshift mutation
occurred & the adenine base was deleted, which amino acids would be coded for?
DNA:
C C G
G
C
C
mRNA:
G G C
C
G
G
amino acid: glycine
arginine
11.
Fill in the following table: (3)
DNA
C
C
A
C
A
T
T
A
A
mRNA
G
G
U
G
U
A
A
U
U
anticodon
C
C
A
C
A
U
U
A
A
amino acid
GLYCINE
VALINE
ISOLEUCINE
12a. What is the difference between a mutagen and a mutation?
A mutagen is a factor that causes a mutation. A mutation is a change in the order
of bases in a sequence of DNA (in a gene)
b. List 2 examples of mutagens & 2 types of mutations.
Mutagens: X-ray radiation or chemicals in cigarettes
Types of Mutations: Frameshift or Point Mutation
13. Put phrases 1 - 6 in the correct order to describe protein synthesis: (1)
1.
2.
3.
4.
5.
6.
mRNA is produced in the nucleus
ribosomes move along mRNA
DNA has a code
polypeptide results
tRNA brings amino acids to ribosomes
mRNA moves to ribosomes
ORDER:
3.
1.
6.
5.
4.
2.
DNA has a code
mRNA is produced in the nucleus
mRNA moves to ribosomes
tRNA brings amino acids to ribosomes
polypeptide results
ribosomes move along mRNA
14. Compare the Structure of RNA to DNA
RNA- ribose sugar, Uracil instead of Thymine, A, G, C bases, single stranded, sugar
phosphate backbone
DNA- deoxyribose sugar, Thymine NOT uracil, A, G, C bases, double stranded,
Sugar phosphate backbone, hydrogen bonding holds 2 strands together, double
helix shape.