Download Extension worksheet – Chapter 2 - Cambridge Resources for the IB

Cambridge Biology for the IB Diploma
Extension worksheet – Chapter 2
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2
a
A typical bacterium has a cell diameter of 1 µm. Draw a bacterial cell at a magnification
of 10 000.
(1)
b
At the same scale, show a typical mitochondrion.
(1)
c
At the same scale, show a typical animal cell.
(1)
d
Approximately 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)
Copy 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
3


The following table gives descriptions of some eukaryotic organelles. Identify each one.
Description
(4)
Organelle
rod-shaped structure, 1 µm wide and approximately 7 µm long, with a
double membrane, the inner membrane is folded into cristae
disc-shaped structure, about 1 µm across and 5 µm long, which contains a
system of thylakoids
structure surrounded by a double membrane, which contains the cell’s
genetic material
round organelle, 25 nm in diameter, consisting of RNA and protein
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Cambridge Biology for the IB Diploma
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5
Human 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
a
Would all cell membranes have the same composition as red blood cells? Explain your
answer.
(2)
b
Why are red blood cells useful for chemical analysis of membranes? Why are other cells
less suitable?
(2)
c
What function might the protein component of the membrane have?
(2)
The graph below shows the quantity of DNA in a cell at various times during the cell cycle.
a
Name the phases A and B.
(2)
b
During which stage of the cell cycle does the quantity of DNA in the cell double?
(1)
c
Explain why this occurs.
(1)
d
What is taking place during the third section of phase A?
(1)
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