Unit 9 Test Review
Name _________________________
1. During fertilization, what 2 cells fuse or combine? _____Egg_______ & _____Sperm________
2. During fertilization, are the cells that combine haploid or diploid? ______Haploid_________
3. What is produced at the end of fertilization? ______Zygote_________
4. Is this cell at the end of fertilization haploid or diploid? _____Diploid___________
5. What will this final cell of fertilization become? __________Organism/Embryo___________
6. The exchange of genetic material between arms of homologous chromosomes is called ___Crossing over______
7. The structure where four sister chromatids join together during Prophase I is called a ____Tetrad____
8. Mitosis is _____Asexual______ reproduction whereas meiosis is _____Sexual______ reproduction.
9. Which process Meiosis or Mitosis maintains a constant number of chromosomes in a species? ____Both_____
10. What type of cell Body or Gamete have a diploid number of chromosomes? ______Body_________
11. What type of cell Body or Gamete have a haploid number of chromosomes? _____Sex Cell/Gamete___________
12. NAME three processes that happen during meiosis which result in genetic recombination so that the 4 daughter
cells have different DNA from each other and from the parent cell. Hint: Think Mendel Laws and Prophase I.
a. ____Crossing Over______
b. ____Segregation (law)_____________
c. ____Independent Assortment (law)___________
Complete the following chart on chromosome numbers for the species listed.
Species
Chromosome Number
in body (somatic) cells
(2n)
Number of Homologous
Chromosome pairs in
Body (somatic) cells
Chromosome Number in
gametes (n)
[unique chromosomes; no
pairs]
Homo sapiens
2n = 46
23 pairs of homologous
chromosomes
23 [23 unique, individual
chromosomes]
fruit fly
2n = 8
4 pairs
n=4
leopard frog
2n = 26
13 pairs
n=13
housefly
2n=12
6 pairs
n=6
monkey
2n=42
21 pairs
n=21
bat
2n=44
22 pairs
n=22
chicken
2n=78
39 pairs
n=39
king crab
2n=208
104 pairs
n=104
camel
2n = 70
35 pairs
n=35
goat
2n=60
30 pairs
n=30
armadillo
2n=64
32 pairs
n=32
petunia
2n=14
7 pairs
n=7
rice
2n = 24
12 pairs
n=12
Human
Now answer similar questions by reading carefully whether gamete number, chromosome pairs or
chromosome number is asked for.
____39_____ Dogs have 78 chromosomes in their somatic cells. How many chromosomes are in their gametes?
____39_____ How many pairs of chromosomes do dogs have in their somatic cells?
____19_____ Cats have 38 chromosomes in their somatic cells. How many chromosomes are in their gametes?
____64_____ Horses have 32 chromosomes in their gametes. How many chromosomes are in the somatic cell?
____32_____ How many chromosome pairs does a horse have in its somatic cells?
____21_____ Wheat has 42 chromosomes. How many chromosomes are in the eggs and pollen?
General Comparison of Mitosis and Meiosis.
Each characteristic or event below applies to mitosis, meiosis, or both. Indicate which type of division in the
lines provided.
_____Meiosis_______ One cell divides 2 times to form 4 cells.
_____Meiosis_______ Formation of gametes in eukaryotic cells.
_____Mitosis_______ Zygote (fertilized egg) divides to form the trillion-celled baby.
_____Mitosis_______ daughter cells have the identical chromosomes as the parent cell
_____Meiosis_______ pairing up and crossing over between homologous chromosome pairs occurs at prophase
_____Meiosis_______ daughter cells are genetically different from each other and from the parent cell
_____Both_________ DNA replicates before cell division
_____Mitosis_______ one cell divides to form 2 identical cells
_____Meiosis_______ daughter cells have exactly ½ the number of chromosomes as the parent cell
_____Mitosis_______ cells in our body such as skin cells, blood cells, bone cells divide by this process
_____Meiosis_______ homologous chromosomes end up in different cells
_____Mitosis_______ One division takes place
_____Meiosis_______ Homologous Chromosomes are paired
_____Both _________ Maintains the chromosome number of a species
_____Mitosis_______ diploid cells are formed
_____Meiosis_______ haploid cells are formed
_____Both _________ replicated chromosomes line up in the middle of the cell.
In which phase of meiosis does crossing-over occur? What is the result from crossing-over?
Prophase I, Genetic Variation amongst daughter cells (4 genetically unique daughter cells)
Describe the activity of chromosomes in anaphase 1. How does this activity differ from the activity of the
chromosomes in anaphase II? (In other words, what separates during anaphase I and what separates during
anaphase II?)
During anaphase I the tetrad from prophase I is being pulled apart, during anaphase II, the
chromosome pairs are separating into sister chromatids and being pulled to opposite ends of the
cell.
Explain why mitosis could not be used for the sexual reproduction of offspring that contain the same number of
chromosomes as the parents.
If mitosis were used for sexual reproduction, the daughter cells would end up with double the
number of chromosomes which would cause the cell to most likely die (if an animal).
Define Homologous Chromosomes.
Chromosomes that are the same size and code for the same genes (does not mean same alleles, they
could be “A” and “a” but they both need to be matched up at the A gene.
Define Sister Chromatids.
Sister chromatids are identical copies of each other, made during interphase before meiosis
occurs.
Mitosis is a process of cell replication. Explain what this statement means.
Mitosis creates two daughter cells that are exact replicas of each other. They are the same in every
way including the number or chromosomes. This is why it is called replication.
Meiosis is a process of cell reduction. Explain what this statement means.
Meiosis is called cell reduction because there is a reduction (decrease) in the number of
chromosomes from the original parent cell. Starts with 46 chromosomes in humans and forms
haploid cells of 23 chromosomes.
Which part of Meiosis is similar to mitosis?
____Meiosis II_______
20
10
No
23 pairs
Mitosis and Meiosis
Interphase
Prophase I
Metaphase I
Prophase II
Metaphase II
Anaphase I
Anaphase II
Telophase I
Telophase II
Which picture from the above diagrams shows where crossing-over would occur? ___7___
Which picture from the above diagrams shows 4 haploid daughter cells? __14____
Which picture from the above diagrams shows the sister chromatids separating? ___13___
Metaphase I
3
1
Interphase
Anaphase I
4
Prophase I
2
5
Telophase I
Fix underlined word if False.
True
True
False; Independent Asst.
False; Sometimes (does not occur in monosomy)
False; Trisomy
True
False; Meiosis
________________ 26. Mitosis is represented by
23
46
23
True
_________________ 27. Sperm and eggs are produced through meiosis.
True
_________________ 28. A karyotype shows the number of chromosomes and gender of a person.
True
_________________ 29. A zygote results from the following:
False; Monosomy - 19
23
+
23
=
46
_________________ 30. A nondisjunction where one chromosome on the 19th pair is missing is
called trisomy - 19.
False; Plants.
_________________ 31. Animals benefit often from polyploidy by being healthier.
Karyotypes show pairs of homologous chromosomes. Draw a pair of homologous chromosomes.
B
b
Have to be same size and code for same genes (both have to be same letter)
Examine the pair of homologous chromosomes. Are they homozygous dominant or recessive?
a
a
A
a
Using the chromosome pair from above, draw the same pair above but with heterozygous alleles.
What is polyploidy? What organisms benefit from polyploidy? Which ones do not benefit?
Polyploidy is the complete failure of chromosomes to separate causing some daughter cells to
have two complete sets of chromosomes and others with no chromosomes. Plants benefit by being
healthier and producing larger fruits and flowers whereas animals die from it.
What is a non-disjunction?
Any failure in the separation of chromosomes during cell division causing daughter cells to have
abnormal chromosomal numbers.
For each karyotype determine the sex of individual and state whether or not there is a disorder present.
If there is a disorder, circle the chromosomal mistake and name the disorder.
Normal female
Intersex Klinefelter Syndrome
A
B
C
Normal Male
D Male with Down Syndrome