Extension Worksheet Chapter 2

Cambridge Biology for the IB Diploma

Extension worksheet – Chapter 2

1aA typical bacterium has a cell diameter of 1µm. Draw a bacterial cell at a magnification of 10000. (1)

bAt the same scale, show a typical mitochondrion.(1)

cAt the same scale, show a typical animal cell.(1)

dApproximately what magnification would be required to show the thickness of a cell membrane so that it appears the same size as the diameter of your bacterium drawing in part a? (1)

2Copy and complete the table below, which compares the contents of prokaryotic and eukaryotic cells. Indicate with a tick () if a structure is present or a cross () if it is not. (8)

Structure / Prokaryotic cell / Eukaryotic cell
Golgi apparatus
ribosomes
mitochondria
cell membrane / 
endoplasmic reticulum / 

3The following table gives descriptions of some eukaryotic organelles. Identify each one.(4)

Description / Organelle
rod-shaped structure, 1µm wide and approximately 7µm long, with a double membrane, the inner membrane is folded into cristae
disc-shaped structure, about 1µm across and 5µm long, which contains a system of thylakoids
structure surrounded by a double membrane, which contains the cell’s genetic material
round organelle, 25nm in diameter, consisting of RNA and protein

4Human red blood cells can be broken up and the content of their cell membranes analysed. The results are as follows.

Molecule / Approx % of membrane
carbohydrate / 10
lipid / 40
protein / 50

aWould all cell membranes have the same composition as red blood cells? Explain your answer. (2)

bWhy are red blood cells useful for chemical analysis of membranes? Why are other cells less suitable? (2)

cWhat function might the protein component of the membrane have?(2)

5The graph below shows the quantity of DNA in a cell at various times during the cell cycle.

aName the phases A and B.(2)

bDuring which stage of the cell cycle does the quantity of DNA in the cell double?(1)

cExplain why this occurs.(1)

dWhat is taking place during the third section of phase A? (1)