2 The cell II
WS 04
Suggested
Answers
Textbook exercise
M.C.
4
|
5
|
6
|
7
|
8
|
C
|
C
|
C
|
D
|
B
|
(5 marks)
Q. 9 (2 marks)
(a) Cell membrane (1) and cytoplasm (1)
Con: Nucleus is not correct because many living
cells such as differentiated sieve cells in plants and red blood cells in human
do not have nucleus.
Q. 11
(a) Mitochondria (1)
(Rough)
endoplasmic reticulum (1)
(b) EM can give out an image with higher magnification and resolution (1)
The
EM technology enables the scientists to discover the structures of organelles inside cells, so that they can
investigate the functions of
organelles (1). (4 marks)
Q.13
(a) A large vacuole / chloroplasts / cell wall (any 2) (2)
(b) (i)
Description of function
|
Cell part
|
|
Controls the passage of
nutrients into the cell
|
B
|
1
|
Increase in volume when the
cell is placed in water
|
E
|
1
|
Contains genetic material
|
F
|
1
|
Prevents the cell bursting
|
A
|
1
|
Produces glucose during
photosynthesis
|
D
|
1
|
(ii) The magnification = 6.4 cm / 0.1 mm 1
=
6.4 cm / 0.01 cm
= 640 1
Con: Many students don’t know how to calculate the
magnification. Also some of them
even cannot
convert the unit “mm” into “cm”.
Q.14
a i The
magnification = 2.8 cm / 2 mm 1
= 0.028 m / 2 X 10-6
m OR 28000 mm / 2 mm 1
= 14000 1
Con: Many students don’t know how to calculate the
magnification. Also some of them
even cannot
convert the unit “cm” into “m” or “mm”.
ii Mitochondrion 1
iii Mitochondria release
energy by respiration. 1
Muscle cells require
much energy 1
for contraction. 1
Rel: Many
students just copy irrelevant information of mitochondria from teaching notes (e.g.
liver cells have many mitochondria) but cannot give an answer corresponding to
the question.
Exp: Some students explain well why muscle cells need much energy.
b Muscle cells have a
nucleus / nuclear membrane while bacterial cells do not. 1
Muscle cells have membrane-bounded
organelles while bacterial cells do not. 1
Muscle cells have no
cell wall while some bacterial cells have a cell wall. 1
Rel: Again, many
students cannot give an answer corresponding to the question. They just give a comparison of eukaryotic
cells with prokaryotic cells without the mention of muscle cells and bacterial
cells.
Q.15
Similarities:
Both prokaryotic cells and eukaryotic
cells are bounded by a cell membrane. 1
Both have DNA as genetic
material. 1
Differences:
Prokaryotic cells have no
true nucleus while eukaryotic cells have a true nucleus.
/ DNA of prokaryotic cells is lying free in the cytoplasm while DNA of
eukaryotic cells is enclosed in the nucleus.
/ Prokaryotic cells are usually smaller than eukaryotic cells.
/ The cell wall of prokaryotic cells does not contain cellulose while the
cell wall of eukaryotic cells contains cellulose.
/ Prokaryotic cells do not have organelles bounded by a double membrane
while eukaryotic cells have organelles bounded by a double membrane.
/ Prokaryotic cells do not have endoplasmic reticulum while eukaryotic
cells have endoplasmic reticulum.
/ In prokaryotic cells, ribosomes are lying free in the cytoplasm while in
eukaryotic cells, some ribosomes are attached to endoplasmic reticulum and some
are lying free in the cytoplasm.
(any 5) 1 x 5
Communication 3
Con: Many
students give up to answer question. Actually, it is easy for them to write something by converting the
table of comparison in the teaching notes into paragraphs.
Rel: Some
students only state the differences between prokaryotic cells and eukaryotic
cells without comparing their similarities.
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