BioSci 110, Fall 08
Exam 1
1. A “gene” is:
a. a protein
b. a chromosome
c. any DNA you inherit
d. something attached to DNA
e. *a section of DNA that codes for a protein
2. A diploid cell that divides by mitosis results in the production of:
a. *2 diploid cells
b. 2 haploid cells
c. 4 diploid cells
d. 4 haploid cells
e. 1 diploid cell
3. In a fruit fly, how would the chromosomes in a cell taken from its wing compare to the
chromosomes taken from a cell in its eye?
a. the wing and eye cells will have different numbers and different kinds of chromosomes
b. the wing and eye cells will have the same number of chromosomes, but they will be different
kinds
c. *the wing and eye cells will have the same numbers and same kinds of chromosomes
d. the wing and eye cells will have some of the same kinds of chromosomes, but some
chromosomes will be different
e. there is no way of knowing how the chromosomes from the eye and wing cells would
compare until lab tests were performed
4. A nucleotide does not contain:
a. phosphate group
b. deoxyribose or ribose sugar
c. nitrogenous base
d. *histone proteins
e. all of the above are components of nucleotides
5. In the model below, which label indicates the physical location of a “gene”?
*B
C
D
AA
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BioSci 110, Fall 08
Exam 1
6. In a double-stranded DNA molecule, the individual strands are held together by:
a. *hydrogen bonds between bases
b. covalent bonds between sugars and phosphates
c. VanderWaals attractions between 3’ and 5’ carbons
d. Winding of strands around histone proteins
r
R
Use the model above to answer questions 7 - 10.
7. The ploidy of the cell above is:
a. 1
b. *2
c. 3
d. 4
e. 6
8. For the cell above, n = ___.
a. 1
b. *2
c. 3
d. 4
e. 6
9. The phase of the cell cycle that best describes the cell above is:
a. *G1
b. G2
c. Metaphase
d. Anaphase
e. Telophase
10. The genotype of the above cell is:
a. A B R
b. a b r
c. *Aa Bb Rr
d. AAaa BBbb RRrr
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BioSci 110, Fall 08
Exam 1
Obj.
Use the representations below to answer the questions 11 – 15 on this page.
MODEL 1:
MODEL 2:
A
T
G G G C T
T T
A
B
11. Model 1 represents a double-stranded DNA molecule. How many double-stranded DNA
molecules would be represented in Model 2?
a. 0
b. 1
c. *2
d. 4
e. 8
12. The sequence of bases that belongs in the blank box in Model 1 is:
a. *T A C C C G A A A
b. A T G G G C T T T
c. G C A A A T C C C
d. U A C C C G A A A
e. bases will not be there since it represents 1 DNA molecule
13. In Model 2, “A” and “B” are:
a. homologous chromosomes that are genetically different
b. homologous chromosomes that are genetically identical
c. sister chromatids that are genetically different
d. *sister chromatids that are genetically identical
14. Model 2 represents:
a. 1 chromosome in the unreplicated state
b. *1 chromosome in the replicated state
c. 2 chromosomes in the unreplicated state
d. 2 chromosomes in the replicated state
15. How many times will you find the base sequence “ATGGGCTTT” (in bold in Model 1)
represented in Model 2?
a. 1
b. *2
c. 4
d. 8
e. 16
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BioSci 110, Fall 08
Exam 1
Bisphenol A (BPA) has been used in the production of a wide variety of plastic products since the 1950’s.
Even under normal conditions, minor changes in pH and/or temperature can cause the BPA to leach out of
plastic containers into food and beverages. Several countries, including the US, have demonstrated that
humans are exposed to low levels of BPA on a continuous basis. The cause for concern over BPA is that it
acts as a “xenoestrogen”. Xenoestrogens are synthetic chemicals that mimic the effects of the female
hormone, estrogen. Some have linked exposure to xenoestrogens to a wide variety of health disorders,
including reproductive problems and cancers, but their effects remain controversial as sufficient data from
humans and primate models is still lacking.
Sex hormones, such as estrogen, play a critical role in brain structure and function, particularly cognition and
mood, through stimulation of synapse formation between neurons. Synapses are regions where neurons
transmit chemical signals. In a study published in last week’s Proceedings of the National Academy of
Sciences, researchers presented the first data from a non-human primate model (African Green monkeys) that
demonstrated the impact of BPA on synapse formation in brain tissue. All monkeys used in the study were
neutered (ovaries and testes removed) in order to prevent effects from naturally-occurring sex hormones.
Monkeys were assigned to 1 of 4 treatments:
1) Control – received a placebo injection containing no hormone and no BPA
2) EB – received injections of estrogen
3) BPA – received injections of BPA
4) EB + BPA – received injections of BPA and estrogen, together
The data below indicate the numbers of synapses counted for 4 different regions in the brains of monkeys at
the end of the experiment (Regions in brain = CA1, CA2, DG, and PFC).
16. In the experiment described above, the
dependent variable is:
a. BPA
b. Estrogen
c. *Number of synapses
d. Cognitive ability of monkeys
e. Number of cancers in monkeys
17. The independent variable/s:
a. BPA
b. Estrogen
c. Number of synapses
d. *A and B
e. All of the above
18. For the PFC region of the brain, the
treatment group that showed the greatest
variability in the number of synapses was:
a. *control
b. EB
c. BPA
d. EB+BPA
19.
a.
b.
c.
d.
A reasonable conclusion from the above study is:
BPA reduces the number of synapses in brain tissue
Estrogen is required for production of synapses in brain tissue
*BPA suppresses the function of estrogen in production of synapses in brain tissue
Using plastics with BPA may reduce cognitive ability and impair mood
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