Meiosis and Homologous Chromosomes
_____1. If the sperm cell of a fruit fly has 4 chromosomes, then the number of chromosomes in each body cell is: a. 2 b. 4 c. 6 d. 8 e. 16
_____2. Of the following cells, the only one to have the haploid number of chromosomes is: a) skin b)muscle c) nerve d) connective e) ovum
_____3. The diploid number is restored as a result of: a) differentiation b) fertilization c) cleavage d) reduction-division e) maturation
_____4. During meiosis, the chromosome number: a) is doubled b) is reduced c) remains the same d) becomes diploid e) becomes tetraploid
5. Prophase I of meiosis (is, is not) similar to prophase of mitosis.
6. The first anaphase of meiosis differs from anaphase of mitosis in that centromeres (do, do not) divide.
7. Oogenesis ultimately gives rise to (one ovum, four ova) with the (haploid, diploid) number of chromosomes.
8. A spermatazoan is a (gamete, zygote), and is (haploid, diploid).
9. An ovum is a (gamete, zygote), and is (haploid, diploid).
10. When a spermatozoan and an ovum merge, they undergo the process of __fertilization____, and give rise to a (gamete, zygote), which is (haploid, diploid).
Questions 11-16. A hypothetical organism has 10 chromosomes for each of its body cells.
11.) Skin cells are continuously being rubbed off and replaced. How many chromosomes will be contained in each new skin cell that is replaced? __10___
12.) This replacement occurs through the process of ___mitosis_______.
13.) The diploid number (2N) for this organism is __10___.
14.) This organism would have how many homologous pairs of chromosomes? ___5__
15.) The female of this organism has an ovary. The number of chromosomes in each of the cells that make up the ovary would be ___10__.
16.) The mature eggs of this female would contain how many chromosomes? __5___
17.) There is an organism whose haploid number is 15. How many chromosomes are found in this organism’s sperm cells? ___15__
_____18.) Crossing-over can be found in the stage of a. Prophase I b) Prophase II c) Interphase d) Anaphase I e) Anaphase II
_____19.) Which of the following process will result in a reduction of the chromosome number by half? a. Mitosis b. Meiosis c. Cytoplasmic division d. DNA replication e. Fertilization
_____20.) The gamete usually has a ___________ chromosome number. a. haploid b. diploid c. triploid d. tetraploid e. polyploidy _____21.) Which of the following best describe the term “crossing over”? a. An exchange of information between two homologous chromosomes b. A molecular interaction between two sister chromatids c. A molecular interaction between two non-sister chromatids d. A separation of two sister chromatids e. None of the above
_____22.) Sexual reproduction requires all of the following except a. meiosis b. mitosis c. gamete formation d. fertilization e. None of the above 23.) What type of cell undergoes meiosis? _____germ cells______
24.) Meiosis produces _haploid_ (#) reproductive cells called ______gametes_______.
25.) Name the 2 human gametes & tell their chromosome number.
Sperm – 23 ; egg - 23
26.) What is the chromosome number for humans in somatic cells? 46
27.) The fusion of a ______sperm______ and an ______egg____ produces a __zygote________ with 46 (2n) chromosome number.
28.) Cells starting mitosis & meiosis begin with a (haploid or diploid) set of chromosomes.
29.) How many times do cells divide during meiosis? twice
30.) What are the stages of meiosis called? Meiosis I: Prophase I, Meta I, Ana I, Telo I, cytokinesis. Meiosis II: Pro II, Meta II, Ana II, TeloII, cytokinesis
31.) What is synapsis & when does it occur?
Point of chromosomal contact among homologous chromosomes
During crossing-over in Prophase I
32.) What is a tetrad?
Aligned homologous chromosomes prior to crossing-over
33.) How are genes aligned on homologous chromosomes?
By tetrad formation
34.) Explain what happens during crossing-over?
Reciprocal exchange of genetic material
35.) What type of material is exchanged during crossing-over? genes
36.) Crossing over results in genetic ___variation_______________.
37-38.) Draw a cell during anaphase I and explain what is occurring.
39.) What is independent assortment & what result does it produce?
-random alignment of homologues at metaphase I plate
- produces variation in gametes
40 and 41.) How many cells are formed at the end of Meiosis I & how many copies of chromosomes does each cell have? ______2______, _____23_______
42.) Is DNA copied before Meiosis II? ___No____
43 and 44.) How many cells form at the end of Meiosis II and how many chromosomes do they contain? _____4________, ______23_______