Download SBI3U TGT - Chapter 3

Chapter 3 Review Questions:
1.
What are the 2 strands of a double-stranded chromosome
called?
2.
Describe what happens during Anaphase I of meiosis.
3.
Describe what happens during Metaphase of mitosis.
4.
Is Metaphase of mitosis more similar to Metaphase 1 or
Metaphase 2 of meiosis?
5.
Explain.
What are 2 purposes for cells in an organism to undergo
mitosis?
6.
Define and contrast diploid and haploid.
7.
What is the only type of cell that could not be used for
cloning an individual organism?
8.
Name the only type of cell that undergoes meiosis in a human
male.
9.
What is synapsis and when does it occur during meiosis?
10. What is crossing over and when does it occur during meiosis?
11. If an oocyte undergoes meiosis, what does it produce?
(Be
specific about the number and type of cells it produces)
12.
A cat has 38 chromosomes in its muscle cells.
How many
chromosomes does it have in its heart cells?
13.
What do "2n" and "n" refer to?
14.
What is a karyotype?
15.
How many autosomes are there in a normal human sperm cell?
16.
What is nondisjunction?
17.
Name a nondisjunction disorder, and describe its karyotype.
18.
Explain how a trisomic female (XXX) would be produced.
19.
What are 2 events that occur during interphase?
20.
What is amniocentesis and what is it used for?
Chapter 3 Review Answers:
1. sister chromatids
2. spindle fibres contract, separating homologous pairs of
chromosomes
3. spindle fibres pull choromosomes into a single line along the
equatorial plate.
4. Metaphase of mitosis is more similar to Metaphase 2 of
meoisis. In both, chromosomes line up in a single line along
the equatorial plate. (In meiosis 1 chromosomes line up in
homologous pairs, i.e. a double line)
5. growth, repair (replacement of damaged or dead cells)
6. diploid describes a cell with 2 sets (or the full set) of
chromosomes
haploid describes a cell with 1 set (or half of the full set) of
chromosomes
7. a gamete because it doesn't contain the full set of an
organism's chromosomes
8. spermatocytes (in the testes of the human male)
9. synapsis is the pairing of homologous chromosomes; it occurs
during Prophase 1 of meiosis
10. crossing over is the exchange of genetic material between 2
homologous chromosomes; it occurs during Prophase 1 of meiosis
(but it is possible that it might still occur during early
Metaphase 1)
11. meiosis of an oocyte will produce 3 nuclei (polar bodies)
and 1 immature egg cell (ootid)
12. 38 (muscle cells and heart cells are both diploid)
13. "2n" refers to the diploid number, and "n" refers to the
haploid number
14. a karyotype is a picture of a cell's chromosomes
15. there are 22 autosomes (and 1 sex chromosomes) in a normal
human sperm or egg cell
16. nondisjunction is when homologous pairs do not split during
Anaphase 1 of meiosis (it can also describe when sister
chromatids do not separate during Anaphase of mitosis or
Anaphase 2 of meiosis)
17. Down syndrome: trisomy 21
Klinefelter's syndrome: trisomy 23, XXY
Turner syndrome: monosomy 23, XO
Trisomy 13: trisomy 13
etc...
18. nondisjunction would have caused the egg cell to have 2 X
chromosomes; when it was fertilized by a normal sperm cell,
there would be 3 X chromosomes in the zygote.
19. cell growth, repair, normal cell functions, DNA replication
20. amniocentesis is the extraction of a sample of the amniotic
fluid of an unborn fetus; it can be used to screen for genetic
disorders such as Down Syndrome in a fetus