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AP Biology Genetics Test
Due at the beginning of class _____________________________. NO EXCEPTIONS!
1. When DNA replicates, each strand of the original DNA molecule is used as a template for the synthesis of a
second, complementary strand. Which of the following figures most acutely illustrates enzyme-mediated
synthesis of new DNA at a replication fork?
2. Lactose digestion in E. coli begins with its hydrolysis by the enzyme β-galactosidase. The gene encoding βgalactosidase, lacZ, is part of a coordinately regulated operon containing other genes required for lactose
utilization.
Which of the following figures correctly depicts the interactions at the lac operon when lactose is NOT being
utilized? (The legend below defines the shapes o the molecules illustrated in the options.)
In a transformation experiment, a sample of E. coli bacteria was mixed with a plasmid containing the gene for resistance
to the antibiotic amplicillin (ampr). Plasmid was not added to a second sample. Samples were plated on nutrient agar
plates, come of which were supplemented with the antibiotic amplicillin. The results of E. coli growth are summarized
below. The shaded area represents extensive growth of bacteria; dots represent individual colonies of bacteria.
3. Plates that have only amplicillin resistant bacteria growing include which of the following?
a. I only
b. III only
c. IV only
d. I and II
4. Which of the following best explains why there is no growth on plate II?
a. The initial E. coli culture was not amplicillin-resistant.
b. The transformation procedure killed the bacteria.
c. Nutrient agar inhibits E. coli growth.
d. The bacteria on the plate were transformed.
5. Plates I and II were included in the experimental design in order to
a. demonstrate that the E. coli cultures were viable.
b. demonstrate that the plasmid can lose its ampr gene.
c. demonstrate that the plasmid is needed for E. coli growth.
d. Prepare the E. coli for transformation.
6. Which of the following statements best explains why there are fewer colonies on plate IV than on plate III?
a. Plate IV is the positive control.
b. Not all E. coli cells are successfully transformed.
c. The bacteria on plate III did not mutate.
d. The plasmid inhibits E. coli growth.
7. In a second experiment the plasmid contained the gene for human insulin as well as the ampr gene. Which of
the following plates would have the highest percentage of bacteria that are expected to produce insulin?
a. I only
b. III only
c. IV only
d. I and III
8. The tiny blue-eyed Mary flower is often one of the first flowers seen in the spring in some regions of the United
States. The flower is normally blue, but sometimes a white or pink flower variation is found.
The following data were obtained after several crosses
Which of the following statements best explains the data?
a. The appearance of blue in the F1 generation of the pink and white cross demonstrates that flower color
is not an inherited trait but is determined by the environment.
b. Flower color depends on stages of flower development, and young flower are white, advancing to pink
and then blue.
c. Since the F1 and F2 phenotypes of the pink and white cross do not fit the expected genotypic and
phenotypic rations, blue-eyed Mary must reproduce by vegetative propagation.
d. Flower color is an inherited trait, and the F1 and F2 phenotypes of the flowers arising from the pink and
white cross can best be explain by another gene product that influences the phenotypic expression.
9. The figure above shows several steps in the process of bacteriophage transduction in bacteria. Which of the
following explains how genetic variation in a population of bacteria results from this process?
a. Bacterial proteins transferred from the donor bacterium by the phage to the recipient bacterium
recombine with genes on the recipient’s chromosome.
b. The recipient bacterium incorporates the transduced genetic material coding for phage proteins into its
chromosome and synthesizes the corresponding proteins.
c. The phage infection of the recipient bacterium and the introduction of DNA carried by the page cause
increased random point mutation of the bacterial chromosome.
d. DNA of the recipient bacterial chromosome undergoes recombination with DNA introduced by the
phage from the donor bacterium, leading to a change in the recipient’s genotype.
10. In peas, the trait for tall plants is dominant (T) and the trait for short plants is recessive (t). The trait for yellow
seeds is dominant (Y) and the trait for green seeds is recessive (y). A cross between two plants results in 292 tall
yellow plants and 103 short green plants. Which of the following are most likely to be the genotypes of the
parents?
a. TtYY x Ttyy
b. TTYy x TTYy
c. TTyy x TTYy
d. TtYy x TtYy
11. A child is born with blood type O. All of the following could be the blood type of the parents EXCEPT
a. A and B
b. A and A
c. O and O
d. AB and O
12. ABCDEF  ABEF
A rearrangement in the linear sequence of genes shown above is known as a/an
a. Translocation
b. Deletion
c. Addition
d. Inversion
13. How many autosomes does the human male normally have?
a. 22
b. 23
c. 44
d. 46
14. EcoRI is used to cut DNA at a specific palindrome sequence of DNA nucleotides, EcoRI is a
a. Bacterium
b. Bacteriophage
c. Type of DNA used extensively in research
d. Restriction Enzyme
15. Which of the following is NOT used in the normal replication of DNA?
a. RNA Primer
b. Ligase
c. Restriction enzymes
d. Polymerase
16. What are the regions of DNA called that code for proteins?
a. Introns
b. Exons
c. Anticodons
d. Codons
17. What enzyme permanently seals together DNA fragments that have complementary sticky ends?
a. DNA polymerase
b. Single-stranded binding proteins
c. Reverse transcriptase
d. DNA ligase
18. Which of the following statements about the DNA in one of your liver cells is correct?
a. Your liver cells contain the same DNA as your white blood cells.
b. Most of your DNA in your liver cells will be transcribed but not translated.
c. Most of the DNA in your liver cells will be transcribed in the nucleus and translated in the cytoplasm.
d. DNA in your live cells contains genes unique to storing glycogen, which other cells do not contain those
genes.
19. Two genes (B and E) determine coat color in Labrador retrievers. Alleles B and b code for how much melanin is
present. The dominant allele B codes for black fur, the recessive allele b codes for brown fur. A second gene
consisting of two alleles E and e, codes for the deposition of pigment in the fur. In this case, the alleles for
pigment deposition (E or e) are said to be epistatic to the gene that codes for black or brown pigment. If the
dominant allele (E) is not present, regardless of the genotype at the black/brown locus, the animal’s fur will be
yellow.
Which of the following statements is correct about the genetics of coat color in Labradors?
a. BBEe will be brown
b. BbEe will be brown.
c. Bbee will be brown
d. BBee will be yellow.
20. Within a cell, the amount of protein synthesized using a given mRNA molecule depends in part on which of the
following?
a. DNA methylation suppresses the expression of genes.
b. Transcription factors mediate the binding of DNA polymerase and the initiation of translation.
c. The speed with which mRNA is degraded will determine how much protein is synthesized.
d. The location and number of ribosomes in a cell will solely determine how much protein is synthesized.
Refer to the codon table for the following questions 21 and 22.
21. Here is a small stretch of mRNA that would be translated at the ribosome:
…AUGCUGAAAUCAGGG…
Suppose a spontaneous mutation altered the boldfaced A and changed it to a U. What effect, if any, would this have
on the protein formed?
a. Because of the redundancy in the code, there would be no change in the protein formed.
b. The amino acid sequence formed from this stretch of DNA would be Met-Leu-Lys-Ser-Gly.
c. The polypeptide would not form because translation would stop at UAA.
d. Translation would continue and a polypeptide would form because AUG codes for start as well as
methionine.
22. Using the following mRNA strand, which of the following mutations would disrupt the amino acid sequence the
most?
…AUGCUGAAAUCAGGG…
a.
b.
c.
d.
A mutation that changed the last G to an A
A mutation that deleted the last G
A mutation that deleted the first G
A mutation that changed the second G to a C
Questions 23 and 24.
Cystic fibrosis is the most common inherited dieses in the US. Among people of European descent, 4% are carriers of the
recessive cystic fibrosis allele. The most common mutation in individuals with cystic fibrosis is a mutation in the CFTR
protein that functions in the transport of chloride ions between certain cells and extracellular fluid. These chloride
transport channels are defective or absent in the plasma membranes of people with the disorder. The result is
abnormally high concentration of extracellular chloride that causes the mucus that coats certain cells to become thicker
and sticker than normal. Mucus builds up in the pancreases, lungs, digestive tract, and other organs. This leads to
multiple effects, including poor absorption of nutrients from the intestine, chronic bronchitis, and recurrent bacterial
infections.
23. Scientific work has been carried out to measure where the relative amounts of CFTR proteins are localized in the
affected cells.
After studying the graph, based on your knowledge of cell organelles and protein synthesis, which of the
following statements about CTRF protein is correct?
a. Transcription is not occurring
b. Translation is not occurring
c. CFTR protein does not fold properly after it is synthesized
d. CFTR protein gets translated but does not get packaged or transported throughout the cell
24. From the description of cystic fibrosis above, which of the following statements is correct?
a. The disease is similar to cancer in that it has both an environmental and a genetic cause.
b. Cystic fibrosis is an example of a genetic disease caused by polygenetic inheritance because several
genes must be mutated in order for the disease to occur.
c. Cystic fibrosis is an example pleiotropy because one mutated gene causes multiple effects.
d. A person who has only one recessive allele for cystic fibrosis will have the disease.
25. The BCL-2 gene codes for a protein that normally inhibits apoptosis. In some cases, the BCL-2 gene is mutated
and becomes activated inappropriately. Cells with this mutated, overexpressed gene fail to undergo apoptosis;
they continue to divide and form cancerous tumors. The mutated gene causes many cancers, including
lymphoma and breast, colon, and prostate cancers. Oblimersen is a drug now in clinical trials that is an antisense
RNA. It binds to BCL-2 mRNA and inactivated it. Which of the following sketches accurately demonstrates the
action of the antisense drug Oblimersen?
Math Portion
1. In a certain species of flowering plant, the purple allele P is dominant to the yellow allele p.
A student preformed a cross between a purple-flowered plant and a yellow-flowered plant. When planted, the
146 seeds that were produced from a cross matured into 87 plants with purple flowers and 59 plants with
yellow flowers.
Calculate the chi-square value for the null hypothesis that the purple-flowered parent was heterozygous for the
flower-color gene. Give your answer to the nearest tenth (Hint the other parent it states in the problem above
was yellow).
(Hint on how to solve, figure out your expected percentages by doing a punnett square, then add up your
population size and use those percentages to find your expected values. I am simply looking for the chi-square
number based on the data observed.)
2. In pea plants tall is dominant to short and round seeds are dominant to wrinkled. How many offspring would
there be of each phenotype (tall and round, tall and wrinkled, short and round, short and wrinkled) would be
expected if two parents are crossed that are heterozygous for both traits? Show your work for full credit (you
may either use a dihyrbid punnett square or solve using percentages).
Short Answer
1. Why is DNA replication semi-conservative?
2. Describe at least two ways that eukaryotic gene expression is controlled.
3. Choose either the lac or trp operon and describe how it functions.