1. Which is not a role of cell division?
a. Reproduction
b. Growth
c. Repair
d. All of these are roles of cell division
2. What is the advantage of sexual reproduction over asexual reproduction.
Genetic variability is introduced.
3. T/F Binary fission occurs only in prokaryotes and produces two genetically
identical individuals.
False, occurs in mitochondria and other organelles
4. T/F Mitosis is the process of replication used by all organisms to replicate
cells without altering the amount of DNA in the daughter cells (i.e. n-n, 2n2n).
False, mitosis is used only in eukaryotic organisms
5. DNA is replicated during which phase of mitosis?
Not replicated during mitosis, during S phase of interphase
6. T/F Cells spend most of their lives in mitosis.
False, most of time in interphase, some whole lives in interphase
7. Define the following:
a. DNA – double helix single strand of genetic material
b. Chromosome – packaged strand of DNA composed of chromatin
c. Chromatin – DNA strand + associated proteins – not packaged
d. Sister Chromatids – exact copies of a chromosome – genetically
identical – exist in mitotic metaphase, meiosis up to meiosis II
metaphase
e. Homologous Chromosomes – two copies of one chromosome, not
genetically identical, one from each parent
f. Centrosome – organelle containing centrioles
g. Centriole – structure within centrosome responsible for generating
mitotic spindle
h. Centromere – attachment b/w sister chromatids
i. Kinetochore – attachment site of microtubules on chromosomes
8. What phases make up interphase?
a. G1, G2, metaphase
b. G1, metaphase, cytokinesis
c. G1, G2, S phase
d. G1, G2, mitosis
9. In order for cytokinesis to take place:
a. The nuclear envelope must break down
b. The DNA must replicate
c. Microtubules must be generated
d. A and C
e. A and B
f. All of the above
10. T/F Bacteria cells are genetically identical after replication because they
reproduce by binary fission, but eukaryotic cells gain genetic variability and
are therefore not exact replicas.
False, in reproduction eukaryotic cells form genetically new individuals, but
not in replication
11. Is mitosis an infallible process? If not, explain how this is
beneficial/detrimental to the organism.
No, mistakes can hurt an organism, but generally introduce genetic
variability that is helpful
12. Are all cells able to undergo mitosis? Give examples to support your choice.
No, nerve cells cannot, conversely skin cells undergo mitosis continually
13. Mitosis is regulated via the ________ checkpoints.
a. G1, G2, S phase
b. G1, G3, M
c. G1, M
d. G1, G2, M
e. G1, G2, G3
14. Define cancer at the basic level.
a. Uncontrolled cell growth
15. Name 3 external causes of cancer: 1 biological, 1 chemical, and 1
environmental that we talked about in class. How do they work?
a. Oncoviruses – cause a cell to over replicate by inserting themselves
b. Cigarettes – insertion of carcinogens into DNA, cell checkpoint
c. UV – breaks phosphate backbone
16. Transformation is
a.
b.
c.
d.
A mutation that may later cause cancer
When a cell becomes a different type of cell during replication
Loss of cellular control regulating growth
Formation of a tumor from a single cell
17. What is the difference between a benign tumor and a malignant tumor?
a. Benign doesn’t invade, not cancerous, easily removed
b. Malignant, invades, cancerous, hard to remove
18. Why do cancer therapies such as radiation and chemotherapy target cancer
cells and not healthy cells?
a. Do target healthy cells, cancerous cells more affected
i. Replicating faster
ii. Have lost repair machinery
19. What is the major downfall of asexual reproduction?
a. Lack of genetic variability
20. In prophase II (in a human), how many chromosomes are present in the cell?
Are any of these homologs?
a. 46 chromosomes, 26 sets of sister chromatids, no homologs
21. Draw metaphase I. Which of Mendel’s Laws applies to this step of meiosis?
a. Law of independent assortment
b. All homologous pairs of sister chromatids are lined up on the plate
randomly
22. Draw metaphase II. Which of Mendel’s Laws applies to this step of meiosis?
a. Law of segregation
b. Two alleles separate (Meiosis I) AND only one allele per gamete
i. No double copies of an allele in one cell
ii. Sister chromatids will separate so that each gamete is haploid
and contains only one copy
23. How many chromosomes are present when a cell completes the M
checkpoint?
a. 92, 46 sister chromatid pairs
24. Define a chiasma. How does it contribute to the genetic variability? At what
stage of meiosis would you find one?
a. Point where crossing over takes place.
b. Causes genetic recombination
c. Prophase I
25. Use a Punnett square to disprove the blending hypothesis using what you
know about non-Mendelian dominance.
a. Cross of incomplete dominance flowers
b. Self cross of blended flower
c. If blending true, would not get parents back
26. What is the phenotypic ratio when a homozygous dominant individual is
crossed with a heterozygous individual? Assume Mendelian genetics apply.
3:1
27. (a) Assume you have an orange flower and you know that this species
exhibits complete dominance. Design a cross that will allow you to
determine the genotype of the orange flower. What is this type of
experiment called?
Cross against a homozygous recessive (white). If you see whites, it’s
heterozygous. If you see only orange, it’s homozygous dominant. This is
called a test cross.
(b) If you were unsure what type of dominance was behind this phenotype,
what addition experiment would be necessary?
You would need to do a test cross. If you saw three phenotypes, it would be
incomplete dominance.
28. Starting with parents, create a dihybrid cross using self fertilization of the F1
generation. What phenotypic ratio is seen?
Page 11 of L20 Genetics – use the peas dihybrid cross
29. Determine the probability that two parents will have a son with hemophilia.
In one cross, assume a mother with hemophilia and a father without. In the
second, assume a father with hemophilia and a mother without.
a. Mother with hemophilia – 50% chance of having a son with it
i. 100% if I say they have a son, what is the prob he has it
b. Father with hemophilia – 0% chance for either sex
30. If two genes are near each other on a chromosome is there a higher or lower
probability that they will be inherited together? Why?
a. Higher
b. Less likely to separate during crossing over
31. Create a dihybrid cross depicting linked genes.
a. Dominants together, recessives together
32. What is genomic imprinting?
a. Silencing of a gene depending on which parent it came from.
33. Can an organism survive if Mendel’s law of independent assortment is
violated?
a. Yes, trisomy 21, down syndrome