Download Cells

ETV “Junior Secondary Science” Programme
Cells
Teachers’ Notes
Target Audience
Secondary 1 - 3
Duration
20 minutes
Production Aim
This programme is a teaching resource produced especially for enriching the
classroom teaching of the Syllabus for Science (Secondary 1 – 3) prepared by the
Curriculum Development Council (1998).
The content of the programme serves to illustrate the following part of the
Syllabus：
“Unit 3 – Cells and Human Reproduction
Topic 3.1 The basic units of living things
Core content and Suggested activities of all the Key Points.”
Key Points
1.
2.
3.
4.
An introduction to the structure of a typical animal cell and a typical plant
cell.
An introduction to the cell - body relationship in living things.
An introduction to the biological importance of cell division..
A brief introduction to the importance of division of labour among cells in
the structure and functioning of the body of a living thing..
Content Outline
This programme is divisible into 7 segments as follows:
1. Hooke’s discovery
Making use of the story of Robert Hooke’s discovery and the findings of other
biologists as recorded in history of science, the audience is introduced to the
origin of the term “cell” and the conception that “the cell is the building block of
life”.
2. Animal Cells
A demonstration of the method to collect human cheek cells for microscopic
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observation*, the form and structure of the human cheek cells, and the effect of
stains on cells. This is followed by a series of images of cells (e.g. human cheek
cells, frog blood cells, human blood cells, nerve cells in human brain, epithelial
cells in human intestinal lining, human egg cell) to illustrate the diversity of
animal cell form.
【* The Education Department has warned teachers NOT to allow students to perform this
experiment in the school premises because of the potential hazard of transmission of hepatitis
B.】
The structure of a typical animal cell is illustrated by a segment of computer
animation, showing the location and functioning of cell membrane, cytoplasm
and nucleus, and elaborating on the concept of metabolism and the relationship
between chromatin and DNA.
3. Plant cells
A demonstration of the method to remove cells from the inner surface of a scale
of the onion bulb and to prepare a wet mount slide for microscopic observation.
This is followed by a series of images of cells (e.g. epidermal cells in the inner
surface of the scale of an onion bulb, moss leaf cells, cells in a young pine twig)
to illustrate the diversity of plant cell form.
The structure of a typical plant cell is illustrated by a segment of computer
animation, showing the location and functioning of cell membrane, cytoplasm,
nucleus, cell wall, chloroplast, central vacuole, and elaborating on the process of
photosynthesis .
4.Cells in the body of living things
The audience is shown a series of images of one-celled animals (e.g. paramecium,
Vorticella sp., Halteria sp. and Stylonychia sp.) and many-celled animals (e.g.
spirogyra, Scenedesmus sp., rotifer, hydra, and trochophore of pond snail) . These
serve to illustrate the fact that the body of a living thing consists of one single cell
or a number of cells
5.Cell division
The audience is shown a segment of computer animation to illustrate the fact that
division is a universal feature in the life of a cell. The animation also illustrates
how the behaviour of the divided cells affects the body structure of a living thing.
This is followed by images of living ginseng and sika deer to illustrate the
relationship between cell division and the processes of reproduction, growth and
wound healing in living things.
6. Division of labour among cells in the human body
A segment of computer animation to illustrate how the cells in the human body
differentiate into tissues which organize into organs and organ systems.
7.The human organ systems
A brief narration of the major organs constituting the ten organ systems in the
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human body, including
-
digestive system : consisting of buccal cavity, oesophagus, stomach, intestines
reproductive system: consisting of testes/ovaries, penis/vagina, sperm ducts/
oviducts, prostate gland and seminal vesicles/uterus
excretory system: consisting of kidneys, ureters, urinary bladder, urethra
endocrine system: consisting of adrenal glands, thyroid gland, testes/ovaries
respiratory system: consisting of nose, pharynx, larynx, trachea, lungs
circulatory system: consisting of heart, blood vessels
nervous system: consisting of sense organs, brain, spinal cord, nerves
skeletal system: consisting of vertebral column, limb bones, ribs
muscular system: muscles
- integumentary system: skin
The benefit derived from differentiation of cells and organization of organ systems
in the human body is emphasized.
Suggestions for Utilization
1. The S1 Science teacher is advised to show the programme in one lesson. The
large number of anatomical terms in Segment 7 may be rather threatening to S1
students. The main aim of this segment is to illustrate the principle that the human
organs are organized into organ systems for division of labour resulting in more
effective and efficient functioning of the human body. The teacher is advised to
make this principle clear to the students. Students are not expected to indulge in
the study of the names of human organs.
2. The S4 Biology/Human Biology teacher is advised to show Segments 5,6 and 7
only for illustration of the principle of human body organization.
3. The teacher may spend 5 to 10 minutes at the beginning of each lesson to lead
students to discuss with reference to the Preparation before viewing the
programme part of the Suggested Activities. The teacher may then show the
programme. After the show, the teacher may spend another 10 to 15 minutes to
discuss with students with a view to consolidating the concepts and methods
illustrated in the programme. The teacher is advised to refer to the Activities after
viewing the programme part of Suggested Activities.
Suggested Activities
(The following activities are suggested for teacher’s reference only. The teacher
may wish to use the activities according to students’ abilities, the learning
environment of the class, and the teaching time available.)
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Preparation before viewing the programme
The teacher may invite students to speculate the materials which constitute the
human body. The students may be guided to mention the names of human organs
and the concept of cells. The teacher then invites students to view the programme.
Activities after viewing the programme
The teacher may lead students to compare the structure of a typical animal cell
with that of a typical plant cell. The students should be able to mention the major
differences between animal and plant cells, such as the presence of the cell wall in
plant cells and its absence from animal cells .
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