Page 18 - Biology_F5

Cytology
Activity 1.2: Observation of an animal
cell under a light microscope
Materials
A plastic spoon, a light microscope,
slides, cover slips, a needle, and
FOR ONLINE READING ONLY
methylene blue
Procedure
(a) Gently scrub the inside of your cheek
with a plastic spoon to obtain a cell
sample. Plastic spoons are used to
avoid damaging the cheek cells.
(b) Place the cheek cells sample on a
clean slide.
(c) Add a drop of methylene blue and
mix using a pointed needle.
(d) Cover the specimen with a cover
slip. Make sure that there are no air
bubbles under the cover slip.
(e) Observe the specimen under the light
microscope at low, medium, and high
power objectives. You will see that,
at the low power objective, the cells
appear very small; in contrast, at the
high power objective they appear to
be relatively larger.
Question
Draw what you have observed in (e) and
compare your drawing with that of
Figure 1.5.
Safety precautions
1. Be careful when working with sharp
objects such as needle, knife and
surgical blade.
2. Do not share instruments used to
obtain cell sample.
Form Five Student’s Book
Exercise 1.2
1. Describe the composition of cell
cytoplasm.
2. Explain how the discovery of the
electron microscope improved
knowledge on cell structure.
3. Describe the contribution of each
of the following scientists in cell
biology:
(a) Robert Hooke (1665)
(b) Theodor Schwann and Mathias
Schleiden
Structure and functions of the cell
Task 1.3
Search for information from the
library and internet sources about
the structural functions of the cell
membrane and cell organelles in plant
and animal cells. Write down short
notes on the structure and function of
each organelle.
In general, a cell consists of cell
membrane, the nucleus and the cytoplasm.
Every cell in the body is enclosed by a
cell membrane. The cell membrane is
the protective barrier that surrounds the
cell, which separates the material outside
the cell (extracellular), from the material
inside the cell (intracellular). It is the
barrier that maintains the integrity of a cell
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