Class 9 Cell: The Unit of Life Mock Test (ICSE)

Topics in Cell: The Unit of Life

• Cell theory
• Prokaryotic and eukaryotic cells
• Cell organelles and their functions
• Plant and animal cells compared

Cell: The Unit of Life practice questions with answers

1. Q1Multiple choice·1 mark
   In a field of view under the microscope, a student counts 8 plant cells. Chloroplasts are seen in 6 of these cells. The percentage of cells showing chloroplasts is:

   1. (a)25%
   2. (b)60%
   3. (c)80%
   4. (d)75%
   Show answer and step marks

   1. Correct option: (d) 75%. Percentage = (6 / 8) × 100 = 75%.+1

   Answer: (d)
2. Q2Multiple choice·1 mark
   The large, membrane-bound sac filled with cell sap and found in the centre of a mature plant cell is called the

   1. (a)Vacuole
   2. (b)Plastid
   3. (c)Lysosome
   4. (d)Centrosome
   Show answer and step marks

   1. Correct option: (a) Vacuole+1

   Answer: (a)
3. Q3Assertion and reason·1 mark
   Assertion (A): Animal cells are generally round or irregular in shape. Reason (R): Animal cells do not have a rigid cell wall around the cell membrane.

   1. (a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
   2. (b)Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
   3. (c)Assertion (A) is true but Reason (R) is false.
   4. (d)Assertion (A) is false but Reason (R) is true.
   Show answer and step marks

   1. Correct option: (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).+1

   Answer: (a)
4. Q4Assertion and reason·1 mark
   Assertion (A): The cell theory states that all living organisms are composed of one or more cells. Reason (R): The nucleus of a bacterial cell is enclosed within a double-membrane nuclear envelope.

   1. (a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
   2. (b)Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
   3. (c)Assertion (A) is true but Reason (R) is false.
   4. (d)Assertion (A) is false but Reason (R) is true.
   Show answer and step marks

   1. Correct option: (c) Assertion (A) is true but Reason (R) is false.+1

   Answer: (c)
5. Q5Short answer·2 marks
   Cells of onion epidermis, seen under a microscope, are each about 0.2 mm long. Calculate the number of such cells that would lie end to end along a strip 6 mm long.
   Show answer and step marks

   1. Number of cells = $6 \div 0.2 = 30$ (both lengths in mm)+1
   2. 30 cells+1

   Answer: 30 cells
6. Q6Long answer·4 marks
   A student stained a drop of yoghurt and a thin peel of onion and observed both under a microscope at the same magnification. The yoghurt cells were about 1 µm across and the onion cells were about 40 µm across. In the onion cells the genetic material lay as a dense, round body. In the yoghurt cells the genetic material lay as a diffuse, irregular region with no boundary around it. (a) Name the type of cell seen in the yoghurt sample. [1] (b) Name the structure in the onion cell that the dense, round body represents. [1] (c) Calculate how many times wider the onion cell is than the yoghurt cell. [1] (d) Name the region of the yoghurt cell in which its genetic material lies. [1]
   Show answer and step marks

   1. (a) Correct answer: prokaryotic cell (the genetic material is not enclosed by a membrane)+1
   2. (b) Correct answer: nucleus (a membrane-bound nucleus of the eukaryotic onion cell)+1
   3. (c) Ratio = onion cell width ÷ yoghurt cell width = $40 \div 1 = 40$+1
   4. (d) Correct answer: nucleoid+1

   Answer: (a) Prokaryotic cell; (b) Nucleus; (c) 40 times; (d) Nucleoid

More Class 9 Biology mock tests