MOLECULAR GENETICS UNIT TEST-Fall 2009
Name:
Period:
MULTIPLE CHOICE: Circle the best answer.
1. Which of the following pairs are purines? (objective 3, comprehension)
A. Adenine and cytosine
B. Thymine and cytosine
C. Adenine and thymine
D. Adenine and guanine
E. Guanine and cytosine
2. Pyramidines are_________ ring base, and purines are ______ ring bases. (objective 3, comprehension)
A. Single, double
B. Double, double
C. Double, single
D. Single, single
3. The sequence of bases on one strand of DNA is: GGCAGTTCATGC. What would be the sequence of
the bases on the complementary strand? (objective 7, application)
A. CCGUCAAGUACG
B. CCGTCAAGTACG
C. GGCAGUUCAUGC
D. CCCAGTTCATGC
4. Transcription is the process of converting: (objective 12, 14, comprehension)
A. DNA to protein
B. Protein to RNA
C. DNA to RNA
D. RNA to protein
5. A codon is: (objective 10, comprehension)
A. 3 base pair unit that codes for a single protein
B. 3 base pair unit that codes for a single amino acid.
C. 3 base pair unit that codes for a single DNA
D. 3 base pair unit that codes for a single nucleotide
6. Translation is the process of converting: (objective 12, 14, comprehension)
A. RNA to DNA
B. DNA to RNA
C. DNA to protein
D. RNA to protein
7. What would be an example of a point mutation using the sequence, “THE DOG BIT THE CAT”
(objective 16, 17, comprehension)
A.
B.
C.
D.
THE DOG BIT HEC AR
THE EDO GBI THE CAR
THE DOG BIT THE CAR
THH EED OGB ITH ECA
8. The DNA sequence is AGC TAA CCG, therefore the RNA strand would read: (objective 7, application)
A. UCG AUU GGC
B. TCG ATT GGC
C. AGC TAA CCG
D. CGG UUT GCT
9. Which of the following is not a chromosomal mutation (objective 16, knowledge)
A. Deletions
B. Inversions
C. Insertions
D. Point mutation
E. Translocation
10. A mutation in which a single base is added or deleted from DNA is called: (objective 16, knowledge)
A. Frameshift mutation
B. Point mutation
C. Chromosomal mutation
D. Translocation
11. A female is born with a single X chromosome, this is an example of: (objective 20, comprehension)
A. Triploidy
B. Point mutation
C. Monosomy
D. Trisomy
MATCHING
1. Match the following words with their definitions. Write the correct letter on the line in front of the word.
(objective 1, 2, 3, 5, knowledge)
__B___ DNA
__A___ Double Helix
__D___ Replication
__C___ Nitrogen base
__E___ Nucleotide
A. The two twisted, ladder-shaped nucleotide strands held together by hydrogen bonds
between the bases
B. Master copy of an organism’s information code. A complex biological polymer;
deoxyribonucleic acid.
C. Component of DNA of RNA along with a sugar and a phosphate group
D. Process in which the two strands of the double helix separate and bases pair with free
nucleotides to form two molecules of DNA, each identical to the original molecule.
E. Subunits of nucleic acid formed from a simple sugar, a nitrogen base, and a phosphate
group
2. Match the following words with their definitions. Write the correct letter on the line in front of the word.
(objective 1, 13, knowledge)
__B___ tRNA
__A___ mRNA
__D___ rRNA
__C___ RNA
A. Carries protein synthesis information from DNA to the ribosomes
B. Delivers amino acids to the ribosomes for protein synthesis
C. Ribonucleic acid, forms a copy of DNA for use in protein synthesis
D. The RNA that composes ribosomes
TRUE/FALSE Circle the correct answer.
1. True/False: The failure of homologous chromosomes to separate properly during meiosis is nondisjunction (objective 19, knowledge)
2. True/False: A zygote has 47 chromosomes instead of 46, this is an example of the condition trisomy.
(objective 20, comprehension)
3. True/False: Organisms lacking chromosomes often survive, where organisms with extra chromosomes
usually do not survive. (objective 17, comprehension)
4. True/False: A mutation occurs when there is a change in the DNA sequence (objective 15, knowledge)
SHORT ANSWER. Provide as much detail as you find necessary to answer the questions. Partial credit
will be given.
1. Provide the steps that occur during DNA replication. Remember this can be done in four steps.
(objective 9, application)
1. The two strands separate at the base pairs
2. Complementary nucleotides are attracted to those on the strands
3. Enzymes join the new nucleotides to form complementary chains
4. The two chains separate
2. Provide the steps involved in transcription: (objective 12, application)
The enzymes unzip the molecules of DNA, free RNA nucleotides pair with complementray DNA
nucleotides on one of the DNA strands. The mRNA molecule breaks away as the DNA strands
rejoin. The mRNA leaves the nucleus and enters the cytoplasm
3. Provide the steps involved in Translation. (objective 12, application)
The first codon of the mRNA strand attaches to a ribosome. The tRNA molecules (each carrying a
specific amino acide) approaches the ribosome. The tRNA anticodon pairs with the mRNA
codon. The mRNA slides along the ribosomoe and a new tRNA carries another amino acid to the
next mRNA codon. An enzyme joins the amino acids and forms a peptide bond. This process
continues and a chain of amino acids is formed until the ribosome reaches a stop codon on the
mRNA strand.
4. A DNA molecule is often described as a ladder. What components make up this ladder? And what
bonds are present? (objective 6, comprehension)
The side of the ladder is composed of deoxyribse (sugar) and a phosphate group. They
are held together by covalent bonds.
The rungs of the ladder are composed of the base pairs. The bases are held together by
hydrogen bonds.
5. A neighborhood dog looks so different than a lion found in a zoo. A scientist found all four nucleotides
(Thymine, Guanine, Cytosine and adenine) to be present in both animals, but doesn’t understand why they
look so different. Explain why these animals are different. Provide an example of a strand of nucleotides
for the dog and lion to further explain your point. (objective 8, analysis)
The order of the nucleotides in the two organisms are different. For example the dog could have
CTGAGTAACGTA, while the lion has GTTAACAGTAC.
6. What are the three differences that sets RNA apart from DNA? (objective 11, comprehension)
1. RNA is usually composed of a single strand of nucleotides, rather than a double strand in DNA
2. RNA laso contains ribose, instead of deoxyribose in DNA
3. RNA contains uracil instead of thymine in DNA
7. What causes a point mutation? And what causes a chromosomal mutation? (objective 18, knowledge)
A point mutation is caused by a single change on DNA strand, this can change the reading frame.
A chromosomal mutation occurs at the chromosome level. This is caused when parts of the
chromosomes break off and are lost or break and rejoin incorrectly or to the wrong chromosome.