1. What is cell division?
The process of one cell (mother cell) dividing into two or above new cells (daughter cell).
2. What is the difference between chromosome and chromtin?
When a cell is not dividing, chromosomes exist as a mass of long and thing fibres called chromatin.
At the beginning of cell division, the chromatin will become thicker and become clearly visible chromosomes.
3. What are chromatid and sister chromatids?
When one chromosome duplicates, two chromatids will be formed. They are joined at a point called the centromere on the chromosome. These two chromatids are called sister chromatids.
4. What are homologous chromosomes?
Chromasomes exist in pairs in body cells. These pairs of chromosomes are called homologous chromosomes.
5 What is a diploid cell?
A cell with two sets of chromosomes.
6. What is a haploid cell? What kind of cells belongs to haploid cells?
Cells with a single set of chromosomes are called haploid cells. A gamete is a haploid cell.
7. What are the two types of cell division.
(1) mitotic cell division
(2) meiotic cell division
8. What are the main stages of cell division of body cells?
(1) Interphase: cell growth phase
(2) Mitotic cell division
It consists of nuclear division and cytoplasmic division
9. What kind of activities are being carried out during interphase?
(1) new organelles and protein are being synthesized
(2) DNA replication
(3) cell grow to its maximum size
10. What are the process of mitotic cell division?
(1) nuclear division: including prophase, metaphase, anaphase and telophase\
(2) cytokinesis
11. What are the characteristics of prophase of the nuclear division of mitotic cell division?
(1) Chromosome shorten and thicken. They become visible.
(2) nuclear membrane breaks down.
12. What are the characteristics of metaphase of the nuclear division of mitotic cell division?
(1) Chromosomes line up in the middle of the cell (equator).
(2) Spindles fibres attach to the chromosome.
13. What are the characteristics of anaphase of the nuclear division of mitotic cell division?
(1) Spindle fibres contract. The sister chromatics separates and move to opposite poles of the cell.
(2) Cytoplasm starts to divide.
14. What are the characteristics of Telophase of the nuclear division of mitotic cell division?
(1) formation of new nuclear membrane
(2) chromosomes uncoil to become chromatin.
15. What is the difference in cytokinesios between the animal cell and the plant cell?
Animal cell: cell membrane constricts inwards
Plant cell: cell plates grows outwards
16. What is the significance of mitotic cell division?
(1) Growth: provide new cells
(2) repair damaged tissues, replace dead cell.
(3) asexual reproduction
17. What are the processes of meiotic cell division?
(1) First meiotic division: prophase, metaphase, anaphase and telophase
(2) Second meiotic division: prophase, metaphase, anaphase and telophase
18. What are the features of prophase of the first meiotic division?
(1) chromosomes shortens
(2) members of each pair of homologous chromosomes pair up
(3) nuclear membrane breaks down.
19. What are the features of metaphase of the first meiotic division?
(1) Pairs of homologous chromosomes line up along the equator
(2) Spindle fibres attach to the chromosomes
20. What are the features of anaphase of the first meiotic division?
(1) Spindle fibres contract. The two members of each homologous pair separate and move to opposite poles of the cell.
(2) cytoplasm starts to divide
21. What are the features of telophase of the first meiotic division?
(1) New nuclear membranes form around each group of chromosomes
(2) to become 2 daughter cells.
22. What are the features of prophase of the second meiotic division?
(1) nuclear membrane breaks down again
23. What are the features of metaphase of the second meiotic division?
(1) chromosome line up along the equator
(2) new spindle fibres attach to the chromosomes.
24. What are the features of anaphase of the second meiotic division?
(1) The spindle fibres contract. The sister chromatids separate and move to opposite poles of the cells.
(2) The cytoplasm starts to divide.
25. What are the features of telophase of the second meiotic division?
(1) New nuclear membranes form around each group of chromosomes.
(2) The chromosomes uncoil to become chromatin again.
26. How many cells are there at the end of meiotic cell division?
4
27. What is the significance of meiotic cell division?
1. Produce haploid gametes for sexual reproduction. When the male gamete and the female gamete fuse at fertilization to form a zygote, the diploid
number of chromosomes can be restored. This allows a species to preserve
a constant number of chromosomes from generation to generation.
2. Increasing the variations between gamates.
28. How does the process of meiotic cell division produce genetic variations in the next generation?
(1) Independent assortment of chromosomes
(2) crossing over
29. At which stage of meiotic cell division does independent assortment of chromosomes happens?
At metaphase and anaphase of the first meiotic division, homologous chromosomes pairs line up in a random way.
30. At which stage of meiotic cell division does crossing over happens?
At metaphase of the first meiotic division. When a pair of homologous chromosome line up at the equator. Happens between non-sister chromatids of homologous chromosomes.