5. H2 Cell Division Questions

Post-Tutorial Revision Package: Cell Division (H2) 1

POST-TUTORIAL REVISION PACKAGE H2 CELL DIVISION

Multiple-Choice Questions 1 Which of the following best describes the features present in the figure below?

i ii iv v

A Nucleus containing 12 pairs of homologous chromosomes

Homologous chromosomes Centromere DNA double helix

B Nucleus containing 6 pairs of homologous chromosomes

Homologous chromosomes Kinetochore DNA double helix

C Nucleus containing 12 pairs of homologous chromosomes

Sister chromatids Kinetochore

Complementary base pairs

D Nucleus containing 6 pairs of homologous chromosomes

Sister chromatids Centromere

Complementary base pairs


2 During which of the following stages of the cell cycle will a diploid cell contain twice the amount of DNA found in a gamete?

A prophase

B entire S phase

C entire G1 phase

D entire G2 phase

3 The graph shows the mass of DNA present per human cell during sperm production,

fertilization and early development of the embryo.

Which of the following statements about the graph is / are TRUE?

I The cells formed during W and Z are genetically identical to one another as a result of mitosis.

II The cell plate starts to reform during X. III Anaphase II has occurred at X. IV DNA replication occurs during Y.

A I only

B III only

C I and III only

D I and IV only

4 How many different types of gametes would be produced by an organism of genotype

PpqqRrSsTTUu, if all of the genes assort independently?

A 8

B 10

C 16

D 64

X Y

W Z


5 The figure below shows a stage in the division of a cell from an anther of a flower.

Identify the type and stage of nuclear division as shown, as well as the correct diploid number of the plant.

Type of nuclear division Stage of nuclear division Diploid number

A mitosis anaphase 14

B meiosis anaphase I 14

C meiosis anaphase II 28

D meiosis anaphase II 14

6 The following graph represents the changes in the quantity of DNA present in a cell.

At which stage would separation of homologous chromosomes begin?

A I

B II

C III

D IV

7 Which of the following statements about meiosis is false?

A Cells at the beginning of Meiosis II are haploid.

B Homologous chromosomes are paired on the metaphase plate in metaphase I.

C Homologous chromosomes are separated in anaphase I.

D Sister chromatids are separated at anaphase I.


8 The figure shows the life cycle of the water flea, Daphnia. The cells of individual R contain 10 chromosomes. Which of the following are correct?

Individual Ploidy level

Number of chromosomes

Reason for choice

I P 2n 20 The cells of P can undergo both mitosis and meiosis.

II Q 2n 20 P produces eggs Q by mitosis which develop into females.

III S n 10 The gametic cells of P have undergone normal meiosis.

IV T 2n 20 Random fertilisation of haploid gametes from R and S occurred to form zygote T.

A I and II only

B I and III only

C II and IV only

D All of the above

9 If a pair of chromosomes fails to separate during anaphase of meiosis I, what will be the

chromosome number of the four resulting games?

A n+1; n+1; n-1; n-1

B n+1; n-1; n; n

C n+1; n-1; n-1; n-1

D n+1; n+1; n; n


10 D, E, F and G are the four daughter cells resulting when cell A undergoes meiosis. If no

crossing over occurred during the meiotic event, which cells listed below, if any, are

genetically identical?

A B and C

B D, E, F & G

C D & E, F & G

D None

11 Which processes involve mitosis?

A growth, reduction division and asexual reproduction

B growth, repair and asexual reproduction

C growth, repair and semi-conservative replication

D repair, reduction division and asexual reproduction

12 Vinblastine is an anti-microtubule drug used to treat certain kinds of cancer. What is likely

to be its mechanism of action?

A disruption of DNA synthesis

B disruption of mitotic spindle assembly

C inhibition of cleavage furrow formation

D inhibition of kinetochore formation


13 The diagrams represent a pair of chromosomes during prophase I of meiosis. Q and q are alleles of one gene, and R and r are alleles of another gene.

Which diagrams represent situations which would result in the segregation of allele Q from allele q at anaphase I?

A 1, 2 and 3 C 2, 3 and 5

B 1, 2 and 4 D 3, 4 and 5

14 The list below indicates some of the characteristic features of either mitosis or meiosis.

1 Chromosomes always line up along a metaphase plate. 2 Daughter cells contain one of a homologous pair of chromosomes. 3 Centromeres divide in all nuclear divisions. 4 Formation of chiasmata. 5 Daughter chromosomes are identical. 6 Homologous chromosomes associate during synapsis.

Which one of the following shows the correct events specific to each process?

Mitosis Meiosis

A 1 2 5 3 4 6

B 1 3 5 2 4 6

C 2 3 5 1 4 6

D 2 5 6 1 3 4


15 The photographs below show a section of the onion root tip. The cells are at different stages of mitosis.

Which of the following shows the correct sequence of events that occurs in these cells?

A R, T, U, P, S, Q

B T, U, P, S, Q, R

C Q, T, P, S, U, R

D T, R, P, S, U, Q

16 The diagram shows bivalent during prophase I of meiosis.

How many chiasma(ta) must be formed to obtain a gamete with the genotype qRt?

A 0

B 1

C 2

D 3

P S

Q

R

T

U


17 Which pair of statements correctly describes how cellular DNA content and ploidy level change after meiosis I and meiosis II?

A Cellular DNA content is halved after both meiosis I and meiosis II. Ploidy level changes from diploid to haploid only after meiosis II.

B Cellular DNA content is halved after both meiosis I and meiosis II. Ploidy level changes from diploid to haploid after meiosis I, and remains haploid after meiosis II.

C Cellular DNA content is halved only after meiosis I. Ploidy level changes from diploid to haploid only after meiosis II.

D Cellular DNA content is halved only after meiosis I. Ploidy level changes from diploid to haploid after meiosis I, and remains haploid after meiosis II.

18 How do cells at the completion of meiosis compare with cells that have replicated their

DNA and are just about to begin meiosis?

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

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

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

D They have the same number of chromosomes and half the amount of DNA.


Structured Questions Question 1 Figure 1.1 shows three cells, A, B and C from the same organism. One of the cells is in the first division of meiosis, one is in the second division of meiosis and one is dividing by mitosis.

Fig. 1.1

(a) What is the diploid number of chromosomes in the organism from which these cells were taken? [1]

(b) Complete the table to show which of the cells, A, B or C is in the first division of meiosis

and which is in the second. [1]

Stage of Meiosis Cell

First Division

Second Division

(c) Explain two ways in which meiosis leads to genetic variation in gametes. [4]

1

2


During mitosis chromosomes line up on the equator of the cell. Each chromosome consists of a pair of chromatids. Each chromatid then moves towards a pole of the cell.

The graph shows how the distance between a centromere and the equator of the cell changes during mitosis.

Fig 1.2

(d) Sketch a curve on the graph to show the change in the distance apart of the centromeres

on a pair of chromatids during this mitotic division. [2] (e) (i) What phase of mitosis is represented by stage H on the graph? [1]

(ii) What causes the distance between the centromere and the equator to change during

stage G? [1]

(f) Explain why cells that are produced as a result of mitosis are genetically identical. [3]

[Total: 13]


Question 2

The micrographs shown in Fig. 2.1 are nuclei of cells at successive stages during nuclear division in a flowering plant.

Fig. 2.1

(a) State the type of nuclear division shown in Fig. 2.1. [1]

(b) Explain the importance of this nuclear division in sexual reproduction. [2]

(c) Name stage C and describe the main events that take place during this stage. [3]

(d) Describe two differences between stages B and F. [2]

A B C

EC

DC

FC

G H I


(e) Suggest why the nuclei in stage I are genetically non-identical to one another. [2]

This flowering plant has a diploid number of 24. (f) State the number of possible combinations of chromosomes that can occur in the formation

of gametes. [1]

[Total: 11]


Question 3 The table shows the number of chromosomes and the mass of DNA in different nuclei. All the nuclei come from the same animal.

(a) Complete this table. [2]

nucleus number of chromosomes mass of DNA/arbitrary units

at prophase of mitosis 26 60

at telophase of mitosis

from a sperm cell

Table 3.1

(b) Fig 3.1 shows some cells undergoing mitosis. Each of the cells A, B, C and D is in a different stage of mitosis.

Fig. 3.1

Using the letters provided, write the correct order of the stages in mitosis. [1]

D

B

A

C


(c) The flow chart shows one way in which a chromosome preparation can be obtained.

sample cells obtained

sample cells incubated for 48 hours

colchicine added and further incubated for 24 hours

squash preparation made and chromosomes stained

chromosomes examined under microscope

(i) Explain why it is necessary to incubate the cells for 48 hours before adding colchicine.

[1]

(ii) Suggest why a spindle inhibitor such as colchicine was added in making this

preparation. [1]

[Total: 15]

Question 4 The graph below shows the DNA content during mitosis and meiosis.

(a) State the stages D and E if:

(i) y-axis of graph indicates DNA content per nucleus.[1]

D:

E:


(ii) y-axis of graph indicates DNA content per cell. [1]

D:

E:

The diagrams below show a cell undergoing two different stages of meiosis (to the same scale).

(iii) Identify stages A and B. [1]

(iv) Describe and explain the phenomenon observed in B. [2]

(v) Explain the importance of meiosis to sexually reproducing organisms. [2]

[Total: 7]

A B


Question 5 The micrographs below show the various stages of meiosis in an animal cell.


(a) Micrographs C, H and G show the 5th, 6th and 7th stages in the sequence. In the boxes

below, arrange the other letters shown on the micrographs to indicate the correct

chronological sequence for this type of nuclear division. [1]

C H G

(b) Explain the significance of Stage B. [2]

(c) Describe what happens at Stage D. [2]

(d) Fig. 5.1 shows the attachment of a chromosome during mitosis.

A

B

C Fig. 5.1

(i) Identify the molecules that form structures labelled A to C. [3]

A:

B:

C:


(ii) Explain why the chromosome appears as a doubled armed structure. [2]

(e) Colchicine, an alkaloid drug has a powerful anti-mitotic effect. It inhibits spindle fibre

formation, therefore arresting mitosis at a particular stage. Removal of colchicine is followed by a prompt resumption of mitosis.

Suggest at which stage of mitosis would the cells be arrested in and give an explanation to your answer. [3]

[Total: 14]

Essay Questions Question 1

(a) With the aid of labeled diagrams, describe the changes within the cell associated with the different stages of mitosis. [10]

(b) Compare and contrast the changes described in the section above with those associated with the different stages of meiosis I. [6]

Question 2

(a) Explain how meiosis and fertilization in sexual reproduction lead to variation within a population. [7]

(b) Explain how mitosis produces genetically identical cells. [6]

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5. H2 Cell Division Questions