GRADE 12 ST ANDREW’S SCHOOL TIME: 1h30

BIOLOGY (MAIN) MID-TERM II 2021 EXAMINATIONS

NAME____________________________________ INDEX NUMBER _______________________

ATTEMPT ALL QUESTIONS

CHOOSE THE CORRECT ANSWER AND ENCIRCLE THE APPROPRIATE LETTER.

1 Which row correctly shows the presence of a cell structure in typical plant cells and in typical
prokaryotic cells?

2 Which parts of a cell contain ribosomes?

1 chloroplast 2 mitochondrion 3 Golgi body 4 cytoplasm
A 1, 2, 3 and 4 B 1, 2 and 3 only C 1, 2 and 4 only D 3 and 4 only
3 Which are found in typical prokaryotic cells and in typical plant cells?
1 cell wall 2 circular DNA 3 cytoplasm
A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only
4 What is the definition of the resolution of a light microscope?
A the degree of sharpness produced by the microscope
B the greatest distance between two objects visible in the same field of view
C the minimum distance that allows two objects to be viewed as separate
D the size of the smallest object visible using the microscope
5 Which row correctly shows a feature of a cell structure?

6 Mitochondria are thought to have evolved from prokaryotic cells that were ingested by an ancestral
cell. Which feature have these prokaryotes lost during their evolution into mitochondria?
A cell wall B circular chromosome C internal membranes D ribosomes

Page 1 of 7
7 Which row describes the membranes surrounding each cell structure?

8The mean width of mitochondria in an electron micrograph is 6 mm. The magnification of the electron
micrograph is 9600. What is the actual mean width of the mitochondria?

A 6 10–3 mm B 6 10–4 mm C 6 10–2 m D 6 103 m

9 The diagram shows three circles, 1, 3 and 5, representing chloroplasts, mitochondria and typical
Prokaryotes

Which row correctly identifies the three circles and some of the structures that are shared between
them?

10 A prokaryotic cell is 5.0 m in length. A virus particle is 300 nm in length. How many times larger is
the prokaryotic cell compared to the virus particle?
A2 B 17 C 60 D 167
SECTION B
ANSWER THE FOLLOWING QUESTIONS IN THE SPACES PROVIDED.
1 A student compared an image of a plant cell with an image of an animal cell. Both images were at
the same magnification. Parts (a) to (c) are four correct comparative statements about these images.
(a) Both cells contain large numbers of an organelle, bound by a double membrane. The inner
membrane of these organelles is folded. These organelles all have a similar structure but do not
always appear to have the same shape.
(i) State the name of the organelles described.
............................................................................................................................................................. [1]
(ii) Suggest one reason why the organelles described do not always seem to have the same
shape.
Page 2 of 7
...................................................................................................................................................................
............................................................................................................................................................. [1]

(b) Both cells contain cell structures that are approximately 25 nm in diameter and are not bound by a
membrane.
(i) State the name of the cell structures described.
........................................................................................................................................................... [1]
(ii) Draw a circle around the measurement that has the same value as 25 nm.

[1]
(c) There are strands of cytoplasm passing through channels in the cell wall of the plant cell. These
are not visible in the animal cell.
(i) State the name of the cell structures described.
............................................................................................................................................................ [1]
(ii) Explain one advantage to the plant cell of having these structures.
...................................................................................................................................................................
...................................................................................................................................................................
............................................................................................................................................................ [1]
(d) (i) Fig. 1.1 is a transmission electron micrograph of part of an epithelial cell from the small intestine
of a mammal.

magnification × 65000
Fig. 1.1
Name the cell structures labelled X in Fig. 1.1 and state their function.
...................................................................................................................................................................
...................................................................................................................................................................
.............................................................................................................................................................. [2]
(ii) Calculate the actual length of one of the structures labelled Y. Show your working.

Actual length=…………………………….[2]

Page 3 of 7
 [Total: 10]
2 Fig. 2.1 is an electron micrograph of a mitochondrion.

Fig. 2.1
(a) State the function of mitochondria.
............................................................................................................................................................. [1]
(b) Name structure A.
............................................................................................................................................................ [1]
(c) Calculate the magnification of the image in Fig. 2.1. Show your working.

magnification × ........................................................... [2]

(d) Explain why the light microscope could not be used to produce the image in Fig. 2.1.
...................................................................................................................................................................
...................................................................................................................................................................
.............................................................................................................................................................. [2]
(e) Scientists think that mitochondria were once prokaryotes. The evidence for this is that mitochondria
have features in common with prokaryotes. State two features that mitochondria have in common with
prokaryotes.
1. ..............................................................................................................................................
2. .............................................................................................................................................. [2]
[Total: 8]

Page 4 of 7
3 Fig. 3.1 shows part of an animal cell viewed with an electron microscope.

Fig. 3.1
(a) Name the structures A to C.

A ..............................................................................................................................................................

B ..............................................................................................................................................................

C ...........................................................................................................................................................[3]

(b) (i) State the function of structure C.

...............................................................................................................................................................[1]

(ii) Explain why structure C cannot be seen using a light microscope.

...................................................................................................................................................................

...................................................................................................................................................................

...............................................................................................................................................................[2]

(c) Suggest one disadvantage of the electron microscope compared to the light microscope for the
study of cells.

.............................................................................................................................................................[1]

(d) Calculate the magnification of the image in Fig. 3.1.

Show your working and give your answer to the nearest whole number.

Answer = ...................................[2]

[TOTAL:9]

Page 5 of 7
4 Complete Table 4.1 to show some differences between a prokaryotic cell and a eukaryotic cell.
Table 4.1

[5]

5 Fig. 5.1 is a transmission electron micrograph of a plant parenchyma cell.

Page 6 of 7
 Fig. 5.1
The image shown in Fig. 5.1 is at a higher magnification than can be obtained using a typical light microscope.
(a) Explain what is meant by the term magnification.

...................................................................................................................................................................

.............................................................................................................................................................. [1]

(b) The actual diameter of the parenchyma cell in Fig. 6.1 along the line X—Y is 35 μm.
Calculate the magnification of the image.

magnification = × ................................................................[3]

(c) Name 2 structures that can be seen from the micrograph.

…………………………………………………………………………………………………………………..[2]

(d) What is the tonoplast? What does it contain?

………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………[2]
[TOTAL:8]
[TOTAL MARKS: 50]

Page 7 of 7