CIE A Level Biology

Topic Questions

A LevelBiologyCIETopic Questions5. The Mitotic Cell Cycle5.2 Chromosome Behaviour in Mitosis

Syllabus Edition

First teaching 2020

Last exams 2024

|

5.2 Chromosome Behaviour in Mitosis

DownloadView
Easy
Medium
Hard
Easy
Medium
Hard
1a
Sme Calculator3 marks

Identify the different stages of mitosis by completing Table 1.

Table 1

Description of stage Name of stage
Two nuclear envelopes form within the cell  
After this stage is complete the chromatids are referred to as chromosomes  
The nuclear envelope disappears  

How did you do?

1b
Sme Calculator1 mark

Fig. 1 shows a cell undergoing mitosis.

4pikB79F_5-2q2b

Image courtesy of Doc. RNDr. Josef Reischig, CSc. Licensed under Creative Commons Attribution-Share Alike 3.0 Unported License. Reused and distributed under conditions found at: https://creativecommons.org/licenses/by-sa/3.0/

Fig. 1

Identify the stage of mitosis that is visible in Fig. 1.

How did you do?

1c
Sme Calculator3 marks

Describe the main events that occur during the stage of mitosis shown in Fig. 1.

How did you do?

Did this page help you?

2a
Sme Calculator2 marks

Mitosis plays an important role in living organisms.

Define the term mitosis.

How did you do?

2b
Sme Calculator3 marks

The nucleus of a cell contains 27 chromosomes as it enters prophase. Each chromatid contains one DNA molecule.

State the number of DNA molecules found in the cell at the end of each of the following:

(i)

Metaphase.

[1]

(ii)

Anaphase.

[1]

(iii)

Cytokinesis.

[1]

How did you do?

2c
Sme Calculator4 marks

Identify the missing words from the following paragraph describing anaphase by choosing from the words below:

centromere             centrosome                 shorten                chromosomes

opposite                 microtubules                     extend

Each word may be used only once or not at all.

The sister chromatids separate at the ........................................ Spindle fibres

begin to ............................ and the ......................................... are pulled to

................................ poles.

How did you do?

2d
Sme Calculator1 mark

State the stage of mitosis where the chromosomes decondense into chromatin.

How did you do?

Did this page help you?

3a
Sme Calculator1 mark

Fig. 1 below shows the stages of mitosis in the incorrect order.

PDxg6IV7_2

Fig. 1

Place the letters (A to D) in the correct order in which they would occur during mitosis.

How did you do?

3b
Sme Calculator3 marks
(i)
Identify stage C shown in Fig. 1 .

[1]

(ii)
State two events that occur during stage C.    

[2]

How did you do?

3c
Sme Calculator2 marks

A student wanted to observe cells during mitosis and decided to follow the method described below:

  1. Cut 1 cm from the tip of a growing root.
  2. Place the cut root tip in a test tube containing 1 M hydrochloric acid and place in a water bath at 60°C for 5 minutes.
  3. Remove the root tip from the test tube and rinse with distilled water. Dry carefully with a paper towel.
  4. Remove 2 mm from the very tip of the root sample and place on a microscope slide.
  5. Break the 2 mm root tip apart and spread the cells out using a mounted needle.
  6. Add a few drops of toluidine blue stain.
  7. Lower a cover slip over the root tip sample. Place a paper towel over the cover slip and press down gently, being careful not to break the cover slip or move it sideways.
  8. Observe the slide using an optical microscope.

Explain the reason for steps 1 and 6.

How did you do?

3d
Sme Calculator1 mark

One of the root tip samples observed by the student is shown in Fig. 2 below.

wLyLFjlJ_3

Fig. 2

State the number of cells in the sample shown in Fig. 2 that are undergoing metaphase.

How did you do?

Did this page help you?

1a
Sme Calculator2 marks

Hepatic stem cells divide by mitosis to form new liver cells. Each time a stem cell divides it forms a replacement stem cell and a cell that will specialise to become a liver cell.

Fig. 1 shows changes in the mass of DNA in a human hepatic stem cell during four cell cycles..

5-2-fig-4-1
Fig. 1

Identify the processes taking place at the points marked A and B in Fig. 1 that bring about changes in the mass of DNA per cell.

How did you do?

1b
Sme Calculator2 marks

Describe what happens to the number of chromosomes in the hepatic stem cells of Fig. 1.

How did you do?

1c
Sme Calculator3 marks

Colchicine is an alkaloid drug extracted from the corm of the autumn crocus (Colchicum autumnale). It is often used as a treatment for gout and other inflammatory diseases. Colchicine binds to a protein called tubilin and prevents the elongation of microtubules in a cell.

Explain why anaphase would not be able to occur in the presence of colchicine.

How did you do?

1d
Sme Calculator5 marks

Outline what happens to a chromosome between the beginning of telophase and the start of the next round of mitosis.

How did you do?

Did this page help you?

2a
Sme Calculator1 mark

Fig. 1 below shows a drawing of an electron micrograph of a cell undergoing mitosis.

wlYY9zpU_h-4a

Fig. 1

Deduce which phase of mitosis this cell is in.

How did you do?

2b
Sme Calculator2 marks
Fig. 2 below shows a sample of root tissue collected by a researcher.



yiK-E2bF_picture1

Fig. 2

The mitotic index is the proportion of cells in a tissue sample that are undergoing mitosis and can be calculated as follows:

Mitotic space index space equals space fraction numerator Number space of space cells space undergoing space mitosis over denominator Total space number space of space cells end fraction

Calculate the mitotic index of the tissue sample in Fig. 2.

How did you do?

2c
Sme Calculator2 marks

A student’s research determined that the cell cycle of the growing tissue in a similar root as part (b) was 1,560 minutes in length, and that on average, cells spent 5 hours in the visible stages of mitosis.

Calculate the percentage difference between the data gathered by the student and the mean length of the mitotic stages found by the researcher in part (b).

How did you do?

2d
Sme Calculator2 marks

Suggest two possible reasons why there may have been differences in the mitotic index the researcher determined and the student’s value.

How did you do?

Did this page help you?

3a
Sme Calculator3 marks

Fig. 1 shows a cell undergoing the prophase stage of mitosis.

59rOPy_I_2-1

Fig. 1

Identify structures A to C and describe how they behave during prophase. Use Table 1 to construct your answer.

Table 1

Label Name of structure Behaviour during prophase
A    
B    
C    

How did you do?

3b
Sme Calculator4 marks

Some cell biologists believe that use of the term 'cell division' should be discontinued and replaced with 'cell multiplication'.

Discuss the reasons in favour of this claim by using your knowledge of the cell cycle.

How did you do?

3c
Sme Calculator2 marks

A team of researchers estimated the numbers of cells in different stages of the cell cycle in healthy, growing onion plants. They took two tissue samples, A and B, from different parts of a plant.

One tissue sample came from a root tip, the other from a large leaf near the bottom of the plant's stem.

Their results are shown in Table 2.

Table 2

Stage of the cell cycle Tissue A / number of cells counted Tissue B / number of cells counted
 Interphase 779 559
 Metaphase 36 165
 Prophase 57 178
 Anaphase 44 115
 Telophase 42 88
 Total 958 1 105

In tissue sample B, a full cell cycle took 20 hours and 45 minutes.

Calculate the time, in minutes, that these cells were in telophase during one cell cycle.

Show your working.

How did you do?

3d
Sme Calculator2 marks

Identify which tissue sample, A or B, was taken from the root tip.

Explain your answer using the information in Table 2.

How did you do?

Did this page help you?

1a5 marks

Cells divide by mitosis to form new cells.Describe the changes that occur within the cell between the beginning of prophase and the end of metaphase.

How did you do?

1b2 marks

Fig. 1 shows a diagram of a chromosome in a cell undergoing mitosis.

5-2-fig-1-1Fig. 1

(i)

Identify structure P.

[1]

(ii)

Describe the role of structure P during mitosis.

[1]

How did you do?

1c2 marks

From the image in Fig. 1

(i)

Identify the stage of mitosis that the chromosome could be in.

[1]

(ii)
State a reason for your answer to part i).
[1]

How did you do?

1d1 mark

Explain why it is important for DNA replication to take place before mitosis can occur.

How did you do?

Did this page help you?

2a3 marks

Fig. 1 is a light microscope image of a section of onion (Allium cepa) root tip showing cells in various stages of mitosis.

onion-root-tip

Image courtesy of Doc. RNDr. Josef Reischig CSc. Licenced under Creative Commons Attribution-Share Alike 3.0 Unported License. Reused and distributed under conditions found at: https://creativecommons.org/licenses/by-sa/3.0/

Fig. 1

Identify the stages of mitosis taking place in cells Q, R and S.

How did you do?

2b3 marks

Assuming that the cells in Fig. 1 have a chromosome number of 6, sketch and label one of the nuclei from cell S to show the appearance of the chromosomes.

How did you do?

2c2 marks

The daughter cells that are produced during mitosis are genetically identical to each other and to the parent cell.

Explain the importance of this.

How did you do?

Did this page help you?

3a
Sme Calculator6 marks

In a dividing cell, DNA replication occurs before mitosis.

Steps in DNA replication are outlined in Fig.1

Complete Fig.1 by filling in the gaps using the most appropriate terms.

  1    Helicase enzyme allows the DNA double helix to unwind and the hydrogen bonds between the two strands to break, exposing the four bases, A, T, C and G.

       The names of these bases are:
       A = ..............................................................
       T = ...............................................................
       C = ...............................................................
       G = ...............................................................

   2   An enzyme molecule attaches to each of the two separated parental strands. The two enzyme molecules move in opposite directions, each catalysing the formation of a new strand of DNA. This enzyme is known as ...............................

   3   DNA ................................................., the monomers of DNA, are free in the nucleus for the synthesis of the new strands.

   4   The bases of the DNA monomers form hydrogen bonds with the bases on each separated parental strand of DNA, according to the rules of  ........................................ .

   5   One DNA strand is synthesised continuously and the other is synthesised in sections known as Okazaki fragments. The fragments are joined by an enzyme called ......................................... , which catalyses the formation of phosphodiester bonds.

  6   The result of replication is two DNA molecules, each one containing an original parental strand and a newly synthesised strand. This type of replication is described as ......................................... .


Fig. 1

How did you do?

3b
Sme Calculator6 marks

Fig. 2 is a photomicrograph of root tip cells at different stages in the cell cycle.

A cell in interphase is labelled.

fig6-2-qp-specimen-2022-9700-02

Fig. 2

(i)

Complete Fig. 2 by naming the stage of mitosis shown in each of cells J, K and L in Fig. 2.

[3]

(ii)

State one feature of the cell in interphase, visible in Fig. 2, that shows this cell is not in early interphase.

[1]

(iii)

Describe the stage of mitosis shown in cell J.

[2]

How did you do?

Did this page help you?