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CHAPTER 3 : CELL DIVISION

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SUBTOPIC : 3.1 The concept of cell division

LEARNING OUTCOMES : a) Explain cell division (C2)

b) State the importance of cell division in living organism (C1)

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PART A: MULTIPLE CHOICE QUESTIONS

1. The significance of mitosis in human are:

I. Asexual reproduction

II Repair of damaged tissue

III. Growth

IV. Gamete production

A. I only I C. II and III

B. II and III D. I and IV

2. In eukaryotic cell division, the process of cytoplasmic division is called _____

A. cytokinesis. C. cytoplasmosis.

B. cytomeiosis. D. cytomitosis.

3. In animals, somatic cell are produced by mitosis and ____________are produced by meiosis

A. gametes C. zygotes

B. clones D. spores

4. All of the following are functions of meiosis in plants EXCEPT

A. Production of spores

B. Reduction of chromosome number by half

C. Production of identical daughter cells

D. Independent assortment of chromosomes

5. In mitosis, the number of chromosome sets in daughter cells will be ____

A. half the number in the parent cell.

B. twice the number in the parent cell.

C. the same as in parent cell.

D. one fourth the number in the parent cell.

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PART B: STRUCTURED QUESTION

1. FIGURE 1 below shows two cells in the process of division in a diploid organism with four

chromosomes.

FIGURE 1

a) Name the structures labeled A, B and C. [ 3 marks]

A:______________________________________________

B:______________________________________________

C:______________________________________________

b) State the type of cell division and the stage of division in each cell. [ 4 marks]

Cell Type of cell division Stage of division

Cell 1

Cell 2

c) Differentiate the two stages stated in (b). [ 2 marks]

______________________________________________________________

______________________________________________________________

d) What is the importance of cell division in Cell 2? [ 1 mark]

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B

A C

Cell 1 Cell 2

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SUBTOPIC : 3.2 The cell cycle

LEARNING OUTCOMES : a) Explain the stages in cell cycle: Interphase and Mitotic Phase (C2)

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PART A: MULTIPLE CHOICE QUESTIONS

1. “The cell's DNA replicates”. This event occurs in cell cycle during

A. M phase C. S phase

B. G1 phase D. G2 phase

2. Which of the following statement is FALSE about the cell cycle?

A. Development of spindle fibers occur in G2

B. The cell spends the most amount of time in G2 phase

C. G1 is the longest time taken in the cell cycle of most cells

D. G1 is the time when the cell increases in size

3. The events in the cell cycle that are in the CORRECT order is

A. Chromosome align at equator, kinetochores attach at spindle fibers, cytokinesis, new

nuclear membrane form.

B. Interphase, centrioles move to opposite poles, anaphase, chromosome decondense

C. Interphase, sister chromatids completely separated, kinetochores attach to the spindle

fibers, cytokinesis.

D. Chromosomes condense, DNA replication occurs, nuclear membrane breaks down,

telophase.

4. Interphase is the part of the cell cycle when ___________.

A. a cell ceases to function

B. a germ cell forms its spindle apparatus

C. a cell grows and replicates its DNA

D. mitosis proceeds

5. Which of the following is not a stage of mitosis?

A. prophase B. interphase C. metaphase D. anaphase

6. Synthesis of RNA and proteins take place in ______________.

A. G1 phase B. S phase C. karyokinesis D. cytokinesis

7. Which phase comes between G1 and G2 Phase?

A. G0 C. S

B. M D. Prophase

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PART B: STRUCTURED QUESTIONS

1. FIGURE 1 shows the cell cycle.

FIGURE 1

a) i Identify the phases A, D and E.

[3 marks]

Phase A: _________________________________________________________________

Phase D: _________________________________________________________________

Phase E: _________________________________________________________________

ii. State what happens during Phase B? Give TWO significance of the phase.

[3 marks]

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_________________________________________________________________________

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b) What is the function of phase E in mitosis?

[2 marks]

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c) In animal cell, cytokinesis involves the formation of cleavage furrow but not in plant cell.

Explain why?

[2 marks]

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___________________________________________________________________________

___________________________________________________________________________

A

B C

D

E

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2. The graph below shows how the amount of DNA, varies with time during the different phases of the

cell cycle in animal cell.

FIGURE 2

a) Label phases A, B and C. [3 marks]

A : ___________________________

B : ___________________________

C : ___________________________

b) i. Explain what happens to the cell during phase B.

[2 marks]

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ii. State TWO process which occur during phase G2.

[2 marks]

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c) State ONE importance of process in FIGURE 2 above.

[1 mark]

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d) If x is equal to 3; [2 marks]

i. What is the number of chromosome during phase A?

_____________

ii. What is the number of DNA during phase C?

_____________

S T U V

TIME

A B C

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CHECK YOURSELF

List the main events in each phase.

SUBTOPIC : 3.3 Mitosis

LEARNING OUTCOMES : a) Describe the four stages of mitosis (C2)

b) Describe briefly the cytokinesis process in animal and plant cell (C2)

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PART A: MULTIPLE CHOICE QUESTIONS

1. Which of the following is 'the behaviour of the chromosome' during mitosis?

A. Early mitotic spindle formed from the centrosomes

B. Nuclear envelope disappears

C. Sister chromatids separate from each other to the poles of the cells.

D. Two cells formed by formation of cleavage furrow

2. How does mitosis in plant cells differ from that in animal cells?

A. Animal cells form cell plate

B. Animal cells lack cytokinesis

C. Plant cells form cell plate

D. Plant cells lack spindle fibers

G1 phase

G2 phase

S phase

Mitotic phase

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3. Which of the following statements is FALSE about mitosis?

A. Single nucleus gives rise to two

B. Produces identical daughter nuclei

C. The centromeres divide at the onset of anaphase

D. Homologous chromosomes align at the metaphase plate

4. The phase of cell division in which the nuclear envelope and nucleolus are disappearing is called

A. Metaphase B. Telophase C. Anaphase D. Prophase

5. All of the following occur during prophase of mitosis in animal cells EXCEPT

A. The centrioles move toward opposite poles

B. Chromosomes are duplicated

C. The nucleolus can no longer be seen

D. The spindle is organized

6. The significance of mitosis in human are:

I. Asexual reproduction

II Repair of damaged tissue

III. Growth

IV. Gamete production

C. I only I C. II and III

D. II and III D. I and IV

7. Which of the following statements is NOT TRUE?

A. Mitosis produces new nuclei with exactly the same chromosomal number as the parent nucleus

B. Mitosis produces genetically non identical daughter cells as the parent cell

C. Mitosis and cytokinesis are required for asexual reproduction

D. The mitotic spindles in eukaryotic cells are composed of microtubules

8. During prophase a pair of homologous chromosome consist of

A. 4 chromosomes or 4 chromatids

B. 2 chromosomes or 2 chromatids

C. 2 chromosomes or 4 chromatids

D. 1 chromosome or 2 chromatids

9. After mitosis, the chromosome number of a daughter cell is ____________ the parent cell’s.

A. the same as C. rearranged compared to

B. one-half D. doubled compared to

10. Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, taxol distrupts

microtubules formation by binding to microtubules and accelerating their assembly from the protein

precursor, tubulin. Surprisingly, this stops mitosis. Specifically, taxol must affect

A. The fibers of the mitotic spindle

B. Formation of centrioles

C. Chromatid assembly

D. Anaphase

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11. In animal cells, cytokinesis takes place by

A. Cytoplasmic contraction C.Membrane fusion

B. Furrowing process D. Formation of cell plate

12. Cytokinesis usually, but not always, follows mitosis. If a cell completed mitosis but not cytokinesis,

the result would be a cell with

A. A single large nucleus C. Two nuclei

B. High concentrations of actin and myosin D.Two nuclei but with half the amount of DNA

13. How do the daughter cells at the end of mitosis and cytokinesis compare with their parent cell when it

was in G1 of the cell cycle?

A. The daughter cells have half the amount of cytoplasm and half number of DNA

B. The daughter cells have same amount of cytoplasm and half number of DNA

C. The daughter cells have same number of chromosomes and half number of DNA

D. The daughter cells have same number of chromosomes and same number of DNA

14. Where do the microtubules of the spindle originate during mitosis in both plant and animal cells?

A. Centromere C. Centriole

B. Centrosome D. Kinetochore

PART B: STRUCTURED QUESTIONS

1. FIGURE 1 below depict stages in the mitotic division of a cell.

FIGURE 1

(a) Write the letters in the order in which these stages occur. [1 mark]

________________________________________________________________________

(b) Name the structure M and N. [2 marks]

M : ______________________________

N : ______________________________

(c) How many pairs of chromosomes are there in the cell? [1 mark]

________________________________________________________________________

A B C D E

M N

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(d) What is the diploid number of chromosomes in these cells? [1 mark]

________________________________________________________________________

(e) A cell in the basal layer of the skin contains 46 chromosomes and divides by mitosis to produce new

skin cells. After ten successive divisions, how many chromosomes will the basal cell have?

[1 mark]

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(f) An animal has 36 chromosomes in each of its body cell. How many of these chromosomes

came from its male parent? [1 mark]

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(g) Give ONE difference cytokinesis in animal and plant cell.

[1 mark]

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2. The flow chart shows one way in which a chromosome preparation may be obtained from actively

dividing cells.

Sample of cells obtained

Sample incubated for 48 hours

Addition of colchicine and further incubation for 24 hours. Colchicine acts as a

spindle inhibitor

Squash preparation made and chromosomes stained

Chromosomes examined under a microscope

a) Explain why it is necessary to incubate the cells for 48 hours before adding colchicines.

[2 marks]

____________________________________________________________________________

____________________________________________________________________________

b) What is the function of the spindle in mitosis?

[1 marks]

____________________________________________________________________________

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c) If the total number of DNA in the nucleus of the cell immediately before cell division was 8,

how many DNA would there be in this cell after treatment with colchicines? Explain your

answer?

[2 marks]

____________________________________________________________________________

____________________________________________________________________________

3. Read through the following passage about mitosis and then write a list of the most suitable words

to fill the gaps. [10 marks]

During mitosis a cell divides to form …………. daughter cells with ...................... genetic

composition. Replication of DNA occurs during ............................... . The first stage of mitosis is

called.................... in which the chromosomes condense and can be seen to consist of two

.......................... joined together by the ......................... . Then the nuclear membrane disappears

and a ................................ forms in the cell. The chromosomes lined up at the ........................... of

the cell at the stage called ................. . Daughter chromosomes separate and pulled to opposite

poles. Nuclear division is followed by ........................... .

CHECK YOURSELF 1. Name the phases in the diagram.

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Cell Cycle and Mitosis Stages

Stage of cell cycle Events that Occur During this

Phase Sketch of Root tips

Interphase

Prophase

Metaphase

Anaphase

Telophase

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2. Describe briefly the cytokinesis process in animal and plant cell (C2) [10 marks]

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[4 marks]

______________________________________________________________________________________

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[6 marks]

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SUBTOPIC : 3.4 Meiosis

LEARNING OUTCOMES : a) Describe the stages of Meiosis I and Meiosis II (C2)

b) Compare mitosis and meiosis (C2)

_____________________________________________________________________________________

PART A: MULTIPLE CHOICE QUESTIONS

1. When pairs of homologous chromosomes separate during anaphase I,

A. the maternal chromosomes all move to one daughter cell, and the paternal chromosomes cell. all

move to the other daughter cell

B. the sister chromatids remain linked to one another

C. the genetic composition remain the same

D. the centromere splits

2. Immediately after telophase I of meiosis, the chromosomal makeup of each daughter cell is

A. Diploid, and the chromosomes are composed of a single chromatid

B. Diploid, and the chromosomes are composed of the two chromatids

C. Haploid, and the chromosomes are composed of a single chromatid

D. Haploid, and the chromosomes are composed of two chromatids.

3. All of the following are functions of meiosis in plants EXCEPT

A. Production of spores

B. Reduction of chromosome number by half

C. Production of identical daughter cells

D. Independent assortment of chromosomes

4. How do the cells at the completion of meiosis differ from the parent cell during G2 phase?

A. They have twice the amount of cytoplasm and half the number of DNA

B. They have half the number of chromosomes and half the number of DNA

C. They have the same number of chromosomes and half the number of DNA

D. They have half the number of chromosomes and one-fourth the number of DNA

5. Which of the following statements about crossing over is INCORRECT?

A. Crossing over combines sections of the maternal and paternal chromosomes

B. Crossing over plays a role in both sexual and asexual reproduction

C. There are on average one to three crossover events per chromosome

D. Crossing over increases the extent of genetic variation beyond what is possible through

independent assortment alone

6. When comparing prophase I of meiosis with prophase of mitosis, which of the following occurs only in

meiosis?

A. The chromosomes condense C. The nuclear envelope disassembles

B. Tetrads form D. A spindle forms

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7. Which of these statements is FALSE?

A. In humans, each of the 22 maternal autosomes has a homologous paternal chromosome

B. In humans, the 23rd pair, the sex chromosomes, determines whether the person is female or male

C. Single, haploid set of chromosomes in ovum and sperm unite during fertilization, forming a

diploid, single celled zygote

D. At sexual maturity, ovaries and testes produce diploid gametes by meiosis.

8. Figure below shows an animal cell at the stage of anaphase II.

What is number of chromosomes that are found in the animal’s diploid cell?

A. 3 B. 6 C. 12 D. 24

9. Figure below shows stages of cell division.

Which diagram represents prophase I of meiosis?

A. I C. III

B. II D. IV

10. During meiosis, the formation of four nuclei occurs at

A. Prophase I C. Metaphase I

B. Anaphase II D. Telophase II

11. The following of cell division the chromosome composed of two chromatids,

A. The G1 phase of a mitotic cell cycle

B. Late anaphase of mitosis

C. Late anaphase II of meiosis

D. Telophase I of meiosis

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12. Which the following is TRUE about meiosis?

I. Meiosis occurs to form gametes

II. The genetic constitution of the daughter cells is the same

III. The number of chromosomes is reduced by half

IV. Two daughter cells are formed at the end of the process

A. I, II and III C. II and IV

B. I and III D. IV only

13. Which of the following happens at the completion of meiosis I?

A. Homologous chromosomes are separated

B. The chromosome number is conserved

C. Sister chromatids are separated

D. Four daughter cells are formed

14. Homologous chromosomes separate and end up at the opposite spindle poles

during _______________.

A. prophase I B. prophase II C. anaphase I D. anaphase II

15. Sister chromatids separate and end up at opposite spindle poles during ____________.

A. prophase I B. prophase II C. anaphase I D. anaphase II

16. Meiosis is a division mechanism that produces _________________.

A. two cells B. two nuclei C. eight cells D. four nuclei

17. At what phase of meiosis are there two cells, each with sister chromatids aligned at the spindle equator?

A. metaphase II C. anaphase I

B. metaphase I D. anaphase II

PART B: STRUCTURED QUESTIONS

1. The graph below shows the changes in quantity of DNA within a cell as it goes through a series of

cell division.

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a) What type of cell division is occurring during period A? [1 mark]

____________________________________________________________________________

b) What type of cell division is occurring during period B? [1 mark]

___________________________________________________________________________

c) What event is occurring at the point marked X? [1 mark]

___________________________________________________________________________

d) What do we call the cells produced at the point marked Y? [1 mark]

____________________________________________________________________________

e) What event is occurring at the point marked Z? [1 mark]

___________________________________________________________________________

2. Complete the table below with a tick () if the statement is true or a cross (x) if it is not true.

Centromeres

are split

Spindle fibers

are formed

Homologous

chromosomes

pair up

together

DNA

replication

occurs at the

start of the

division

Crossing over

occurs

Mitosis

Meiosis I

Meiosis II

[3 marks]

3. If 6 chromosomes are observed in a cell at anaphase II of meiosis, work out how many chromosomes the

cell would have contained at metaphase I. [2 marks]

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