Name: ________________________________
April 21st, 2009
Dr. Ippolito’s BIO-121 Spring 2009
Test 5 (Chapters 12, 13, 14)
Section MC/SC
1. Who is credited for discovering and publishing the structure of DNA?
a.
b.
c.
d.
e.
Pauling
Watson and Crick
Chase
Franklin
Hershey and Chase
2. What type of chemical bond joins the bases of complementary DNA strands?
a.
b.
c.
d.
e.
ionic
nonpolar covalent
hydrophobic
polar covalent
hydrogen
3. Because one original strand of the double-stranded helix is found in each daughter cell, the replication
process is called
a.
b.
c.
d.
e.
proofreading.
semiconservative.
redundant.
freeing of DNA.
mutation positive.
4. Which of the following human genetic disorders is NOT caused by nondisjunction?
a.
b.
c.
d.
e.
Down's syndrome
Turner's syndrome
Klinefelter syndrome
Fragile X syndrome
Fragile Y syndrome
5. Chorionic villus sampling uses what tissue to analyze the fetal cells and provide a karyotype?
a.
b.
c.
d.
e.
fetal blood tissue
cells floating in the amniotic fluid
a small biopsy from the embryo itself but it readily heals
membrane tissues from the embryo’s side of the placenta
membrane tissues from the mother's side of the placenta
6. Which refers to the movement of a piece of one chromosome to another nonhomologous chromosome?
a.
b.
c.
d.
e.
Inversion
Translocation
Deletion
Duplication
Monosomy
1
7. What additional chromosomal abnormalities will likely result from a chromosomal inversion?
a.
b.
c.
d.
e.
Additional inversions
Deletions only
Duplications only
Duplications and Deletions
Nondisjunction
8. A human female somatic cell has ____ pairs of chromosomes, with ____ unique kind(s) of sex
chromosome(s).
a.
b.
c.
d.
e.
46, 1
46, 2
23, 1
23, 2
46, XX
9. What is the most typical cause of Down’s Syndrome?
a.
b.
c.
d.
e.
The individual has only a single chromosome when they should have two (they are monosomy)
The individual has a small piece of one chromosome attached to another (a translocation occurred)
The individual has two copies of a chromosome when they should have one copy (they are diploid)
They are trisomy for chromosome 21
They are monosomy for chromosome 21
10. Which statement is FALSE about X-linked characteristics?
a.
b.
c.
d.
e.
More males than females are affected.
If a female has the characteristic, all her sons will show it.
Females can be carriers of the gene without showing it.
The characteristic often skips a generation, from a woman's father to her son.
An affected male will have sons also affected.
11. Karyotyping can be used to diagnose which of the following genetic disorders?
a.
b.
c.
d.
e.
Down syndrome
Color-blindness
Muscular dystrophy
Hemophilia
All of the choices.
12. If nondisjunction occurs during meiosis I of spermatogenesis…
a.
b.
c.
d.
e.
the resulting sperm are heterogametes.
one-half of the resulting sperm are n + 1 and the other half are n - 1.
diploid sperm are produced.
The 4 resulting sperm will lack a chromosome and be infertile.
only one half the sperm are affected.
13. Aneuploidy describes all of the following except
a.
b.
c.
d.
e.
Duplication.
Klinefelter syndrome.
Translocation.
XYY.
Down syndrome.
2
14. If a DNA sample contains 13% adenine, what percentage of the sample contains cytosine?
a.
b.
c.
d.
e.
13%
37%
26%
74%
87%
15. A dihybrid cross produces 30 recombinant offspring out of a total of 1,000 offspring. What is the
recombination frequency for the two gene pairs?
a.
b.
c.
d.
e.
6%
3%
30%
1.5%
0.5%
16. A general evolutionary trend is that the more complex an organism, the more functional genes they have.
However, chromosome number varies greatly: ants have 2, molds have 8-14, we have 46, potatoes have
100, while crayfish have 200. Some birds and insects have chromosomes that are so short, they are too
small to establish an actual diploid number. This means that….
a. There’s no relationship between the amount of genetic information and complexity.
b. The number of genes per chromosome can vary amongst organisms, which prevents a simple
relationship between chromosome # and complexity to be established.
c. Birds and insects follow different laws of mitosis than other organisms.
d. The more genes an organism has, the more chromosomes it will have.
e. All of these are true
17. Women with X-linked disorders always pass the genes for the disorder to ______, while men with X-linked
disorders always pass the genes for the disorder to _______.
a.
b.
c.
d.
e.
only their daughters; only their daughters
both their daughters and sons; only their sons
both their daughters and sons; only their daughters
both their daughters and sons; their daughters and sons
the answer cannot be determined with the given information.
18. If a woman is a carrier for the color-blind recessive allele and her husband is normal, what are their
chances that a son will be color-blind?
a.
b.
c.
d.
e.
None since the father is normal.
50% since the mother is the only carrier.
100% because the mother has the gene.
25% because the mother is a hybrid.
None since he will also be just a carrier.
19. The X-ray diffraction photography of Rosalind Franklin was essential for…
a.
b.
c.
d.
e.
Indicating that DNA’s structure is a double helix.
Showing equal numbers of purines and pyrimidines.
Showing the bases of DNA were held together by hydrogen bonds.
Revealing the structure of the deoxyribose sugar.
Of the location of each adenine, guanine, cytosine, and thymine.
3
20. DNA was clearly demonstrated to be the transforming factor in bacterial cells in experiments by
a.
b.
c.
d.
e.
Meischer.
Watson and Crick.
Griffith.
Franklin
Hershey and Chase
21. In the Watson and Crick model of DNA, the "steps" of the ladder are composed of
a.
b.
c.
d.
e.
sugars.
one purine and one pyrimidine.
two purines.
two pyrimidines.
a sugar and a phosphate molecule.
22. When we refer to the ‘backbone’ of DNA, what are we referring to?
a.
b.
c.
d.
e.
The repeating nitrogenous bases
The sugar-nucleotide-suger-nucleotide pattern
The sugar-phosphate-sugar-phosphate pattern
The base-pairing of A:T and C:G
The bonds connecting the two strands.
23. RNA utilizes the base ______, whereas DNA contains ______.
a.
b.
c.
d.
e.
Ribose… Deoxyribose
Uracil… Thymine
Cytosine…Guanine
Adenine… Cytosine
Thymine… Uracil
24. Assume DNA replication is NOT semi-conservative. Meselson and Stahl's replication experiment would
have shown different results. After growing the bacteria first on heavy 15N, centrifuged results would have
shown one band of heavy DNA. If then bacteria were allowed to grow on light 14N for a single replication
cycle, the centrifuged results would have shown:
a.
b.
c.
d.
e.
One hybrid band and one light band.
One heavy band.
One hybrid band and one heavy band.
One hybrid band.
One heavy band and one light band.
25. Which of the following statements about DNA replication is FALSE?
a. Unwinding of the DNA molecule occurs as hydrogen bonds break.
b. The process is known as semiconservative replication because one old strand is conserved in the new
molecule.
c. The enzyme that catalyzes DNA replication is DNA polymerase.
d. Replication occurs as each base is paired with another of the same kind.
e. Complementary base pairs are held together with hydrogen bonds.
4
26. Which does NOT describe a function of the DNA polymerase molecule?
a. recognize the free nucleotide that pairs with the base on the template strand of DNA
b. read the strand of template DNA and recognize the specific base at a particular location within the
strand
c. proofread to ensure that the proper base has been incorporated
d. synthesize the proper nucleotide to match with the base read on the template strand
e. cut out an improperly paired nucleotide and replace it with the proper one
27. With your knowledge of Chargaff’s Rules, which of the following mathematical equations must be true?
a.
b.
c.
d.
e.
A + T = G + C.
A + G = T + C.
A = G, T = C.
A = C, T = G.
All of these are true.
28. Which of the following is/are NOT true about mutations?
a. Damage to DNA results after exposure to environmental factors such as sunlight or chemicals such as
pesticides.
b. Mutations can often be repaired by cellular enzymes.
c. Mutations to DNA typically result in lethal effects and therefore death of a cell.
d. Variations in DNA and mutations are essential for evolution to occur.
e. All of these statements are true of DNA.
29. Which is NOT a difference between prokaryotic and eukaryotic DNA replication?
a.
b.
c.
d.
e.
Prokaryotic DNA replication can be unidirectional; eukaryotic is bidirectional.
Prokaryotic DNA lets U pair with A; eukaryotic DNA lets A to pair with T.
Prokaryotic DNA polymerase is faster at replicating DNA than eukaryotic DNA polymerase.
Prokaryotic DNA replication is much more error prone than Eukaryotic DNA replication
All of these are differences between prokaryotic and eukaryotic DNA replication.
30. Which of the following are TRUE statements about the nature of DNA structure and function?
a.
b.
c.
d.
e.
DNA is replicated from the 3’ to the 5’ end, with new nucleotides added to the 5’ end.
DNA is replicated from the 5’ to the 3’ end, with new nucleotides added to the 3’ end.
DNA replication results in two DNA double helices made of completely new material.
Two of the above are correct.
None of the above are correct.
31. Consider the case of a lethal recessive gene located on the human X-chromosome; it is therefore sexlinked. Its effect is to prevent the full development of the embryo, which therefore is reabsorbed by the
body at an early stage. Beginning with a female who carries this gene in a heterozygous state, what
proportion of the viable (living) offspring will be female?
a.
b.
c.
d.
one-half
two-thirds
three-fourths
all, because the lethal recessive gene will express itself in the absence of any genes on the short Y-arm
for the XY male embryos
e. No offspring will be produced at all.
5
32. Which “inconvenience” prevents DNA replication from looking like a well-designed mechanism?
a. The strands are arranged parallel to each other – The end of each strand would have the 5’ carbons
next to each other, and at the other end, the 3’ carbons next to each other.
b. The strands are arranged anti-parallel to each other – the 5’ and 3’ ends of each strand face opposite
directions
c. DNA polymerase moves very, very slowly
d. DNA polymerase has the ability to proofread, allowing the error rate to be as low as 1 in a billion under
standard conditions
e. DNA replication is semi-conservative.
33. Which of the following is/are true about introns?
a.
b.
c.
d.
e.
Introns are sections of nucleotides found on mRNA transcripts.
RNA splicing usually removes introns from a mRNA molecule.
Introns can function to regulate gene expression.
The sequence of nucleotides found in introns is not known to represent anything usable by the cell.
All the choices are true except for saying that introns do not represent anything usable by the cell.
34. Which of the following undergoes transcription to create a new strand of RNA?
a.
b.
c.
d.
e.
a noncoding gene
a protein-coding gene
a promoter
a ribozyme
Two of these are correct.
35. Which of the classes of RNA molecules carries the amino acids that are added to the growing polypeptide
chain?
a.
b.
c.
d.
e.
ribosomal RNA
transfer RNA
messenger RNA
primary mRNA transcript
None of the above.
36. In the Beadle and Tatum experiment, mutated Neurospora were unable to grow on minimal media plus
metabolites A or B, but did grow on minimal media plus metabolites C and D, indicating enzyme 2 is
missing from the hypothetical pathway. Which of the following statements is therefore true?
a. If only enzyme 1 were missing, then growth would occur with just metabolite B.
b. From the limited data given here, enzyme 1 could also be missing from the original experiment.
c. Any minimal media with metabolite D should grow the Neurospora without revealing if the strain
contains or lacks enzymes 1, 2 or 3.
d. Failure to grow on minimal media lacking metabolites A, B and C reflects lack of enzyme 3.
e. All of the choices are correct.
6
37. The idea that a single gene coded for a polypeptide rather than an enzyme was evident from the…
a.
b.
c.
d.
e.
use of X rays to make nutritional mutants in bread mold.
transformation of bacteria from rough and non-virulent to smooth and virulent.
presence of a mutation in one chain of hemoglobin but not in the other.
discovery that mutated genes changed enzymes in a biochemical pathway.
finding that some genes in eukaryotes are split by introns.
38. On a hypothetical planet, life evolves based on a DNA-like molecule with six rather than four nucleotides.
Which table reflects the number of bases per codon and the number of different amino acid combinations
that could be specified?
a.
b.
c.
d.
e.
A
B
C
D
Two of the above
39. Prior to protein synthesis, the DNA
a.
b.
c.
d.
e.
attracts tRNAs with appropriate amino acids.
must first undergo replication.
contains anticodons that must become codons.
serves as a template for the production of mRNA.
adheres to ribosomes for protein synthesis.
40. Which of the classes of RNA molecules is never found in the cytosol?
a.
b.
c.
d.
e.
ribosomal RNA
transfer RNA
messenger RNA
primary mRNA transcript
None of the above.
41. Transcription of a part of a DNA molecule with a nucleotide sequence of A-A-A-C-A-A-C-T-T results in a
mRNA molecule with the complementary sequence of
a.
b.
c.
d.
e.
G-G-G-U-G-G-U-C-C
U-U-U-G-U-U-G-A-A
T-T-T-G-T-T-G-A-A
C-C-C-A-C-C-A-C-C
none of the choices are correct.
42. Which is the process that synthesizes mRNA, tRNA, or rRNA?
a.
b.
c.
d.
e.
translation
transcription
transposition
transformation
none of the above
7
43. A cell with many complex proteins shelters and supports the DNA genetic coding, and the coding is the
blueprint for the cell proteins; thus is set the "chicken-or-the-egg" dilemma of which came first. This can
be solved by the discovery that
a. RNAs called ribozymes have enzyme functions and could have served as both genetic matter and
enzymes.
b. reverse transcriptase can convert RNA back into DNA.
c. all DNA and protein can be distributed evenly inside and outside the nucleus.
d. some proteins are simply assemblages of guanine, cytosine, thymine and adenine.
e. viruses can give rise to all of the cell molecules.
44. Today, it is most appropriate to state that a gene controls
a.
b.
c.
d.
e.
one enzyme.
one protein.
one polypeptide chain.
one amino acid.
one starch, amino acid or lipid molecule.
45. mRNA production is essential for protein synthesis because…
a.
b.
c.
d.
e.
without transcription, translation cannot occur
without translation, transcription cannot occur
transcription is impossible without an RNA template to read from
two of the above are correct
none of the above are correct
46. In order to produce many copies of a protein fast, the cell uses…
a.
b.
c.
d.
e.
DNA replication.
intron self-splicing.
single-unit ribosomes for high speed translation.
codon-anticodon reciprocal duplication.
many RNA polymerase molecules to produce mRNA transcripts at the same time.
47. Which is MOST directly responsible for the sequence of amino acids in a protein?
a.
b.
c.
d.
e.
the sequence of the anticodons
the number of codons in mRNA
the enzyme that attaches the amino acid to tRNA
the proteins associated with rRNA
the sequence of codons in mRNA
48. Which is NOT true about the genetic code?
a.
b.
c.
d.
e.
It is composed of a triplet code of three bases per codon.
It produces 64 different possibilities of base sequences.
It was cracked through the use of a cell-free system of enzymes.
It contains start and stop codons as instructions.
The proportions of all 4 nucleotides are the same in every species.
8
49. For translation to take place, which of the following would NOT be required to be present?
a.
b.
c.
d.
e.
DNA
mRNA
tRNA-amino acid complex.
rRNA
ribosome
50. An unknown chemical is analyzed and found to contain the bases thymine and guanine. This chemical is
most likely
a.
b.
c.
d.
e.
tRNA
mRNA
DNA
rRNA
ATP
9