CELLS for junior high school grade 8 good luck

science for junior high school grade 8

1. Cells

2. 24.1 What are Cells?
•Living organisms are made up of small building
units of life called cells.
•Cells come in different shapes and sizes.
•Unicellular organismsare made up of one cell.
•Multicellular organisms, such as human
beings, are made of many cells.
Amoeba is an unicellular
animal.
Onion is a multicellular
organism.

3. 24.2 What’s Inside a Cell?
•A cell is made up of a tiny mass of
living matter called protoplasm.
•Protoplasm is made up of a nucleus,
cytoplasm and cell membrane.

4. An animal cell
Nucleus
•Usually the largest
structure in the cell
•Spherical in shape
•Responsible for cell
reproduction
•Controls cell activities
including repair of
worn-out parts
•Needed for cell to
stay alive
•Contains
chromosomes which
are genetic material
Chromosome
•Long thread-like
structures found in
the nucleus
•Made up of proteins
and deoxyribonucleic
acid (DNA)
•Presence of genes
which contain
hereditary materials
•Passed down from
parents to their
offspring
Cytoplasm
•Jelly-like substance
•Contains chemicals and other tiny structures that
carry out special functions
•Many chemical reactions take place herez
Vacuoles
•Fluid-filled spaces
within the cytoplasm,
surrounded by
membranes
•Store water and other
nutrients needed for
the living organism to
survive
•The animal cell
contains many tiny
vacuoles
•Usually small,
numerous and
temporary in animal
cells
Cell membrane
•A thin membrane
surrounding the cell
•Partially permeable –
allows only certain
substances to pass
through
•Serves as a boundary
between the cell and
the external
environment
•Controls substances
entering or leaving
the cell

5. A plant cell
Cell wall
•A thick layer
surrounding the cell
membrane
•Made up of cellulose
•Supports the cell and
gives it a regular
shape
Chromosome
•Similar to that of
animal cells
Nucleus
•Spherical in shape
•Responsible for cell
reproduction
•Controls most cell
activities including
repair of worn-out
parts
•Needed for cell to
stay alive
•Contains
chromosomes which
are genetic material
Cell membrane
•A thin membrane
surrounding the cell
•Partially permeable –
allows only certain
substances to pass
through
•Serves as a boundary
between the cell and
the external
environment
•Controls substances
entering or leaving
the cell
Cytoplasm
•Jelly-like substance
•Contains chemicals
and other tiny
structures that carry
out special functions
•Many chemical
reactions take place
here
Chloroplast
•Contains the green
pigment chlorophyll,
which is needed for
the plant to absorb
energy from the Sun
to make food through
photosynthesis
Vacuole
•Usually a single large
space surrounded by a
membrane
•Contains a liquid
called cell sap. Cell
sap is made up of
water and dissolved
materials such as
sugars and mineral
salts.

6. 24.3 Division of Labour
(pembagian kerja)
•Division of labouris the breakdown
of workload into smaller and more
specific tasks for maximum efficiency.

7. Division of labour in cells
•Within each cell, there are many special
structures or organelles.
•Each organelle is specially designed to
carry out a specific job.
nucleus
In a green plant cell,
the nucleus is
responsible for
controlling normal cell
activities.
chloroplast
Chloroplasts in green
plant cells allow the
cells to carry out
photosynthesis to
make food for growth
and survival.

8. Division of labour in multicellular
organisms
•Multicellular organisms are made up of
different types of cells performing different
functions.
•The cells have different shapes, sizes and
structures, designed to perform specific
tasks.
•This allows the organism to function
efficiently as a whole.

9. Division of labour in multicellular
organisms
red blood cell
•In the human body:
The red blood cellsin
blood contain the red
pigment called
haemoglobin.
Haemoglobin combines
with oxygen, which is
transported around the
body.

10. Division of labour in multicellular
organisms
nerve fibre
nucleus
nerve
cell
Nerve cellshave
specialised extensions
called nerve fibresthat
help to transmit nerve
signals to and from the
central nervous system.

11. Division of labour in multicellular
organisms
•In plants:
root hair cell
Root hair cellsare found on
the surface of roots. They are
long, which increases their
surface area. This helps the
plant to better absorb water
and mineral salts from the soil.

12. Division of labour in multicellular
organisms
•In plants:
guard cells
Guard cellson leaf surfaces
control gaseous exchange
between the leaf and the
atmosphere.stoma

13. HOW TO FORM ORGANISMS
CELLS >>>>>> ORGANISM
CELLS>>>TISSUES>>>ORGANS>>>
ORGAN SYSTEMS>>>> ORGANISM

14. CELL ORGANITATION
CELLS >>>> TISSUES >>>> ORGANS
>>>> ORGAN SYSTEMS >>> ORGANISM

15. 24.4 Forming a Multicellular
Organism
•A human body is made up of different organs
such as the heart, liver and stomach.
•Each organ has several sets of tissues working
together to allow it to function.
•These organs work together and make the five
main organ systems in your body –the
digestive system, the circulatory system, the
respiratory system, the skeletal systemand
the muscular system.

16. 24.4 Forming a Multicellular
Organism
•A human body:
oDifferent types of cells have specialised
functions
Heart muscle cells:
A single heart muscle cell
contracts rhythmically.

17. 24.4 Forming a Multicellular
Organism
•A human body:
oCells of the same kind that perform the same
job are grouped together to form a tissue.
Some tissues have more than one type of
cell. These are called complex tissues.
Heart muscle tissue:
Formed by heart muscle cells,
this tissue contracts and relaxes
rhythmically at a steady rate.

18. The body
contains three
types of muscle
tissue: (a)
skeletal muscle,
(b) smooth
muscle, and (c)
cardiac muscle

19. heart
walls
ofblood
vessels
tendons

20. 24.4 Forming a Multicellular
Organism
•A human body:
oAn organis formed by several tissues
working together to perform a specialised
function.
Heart: An organ formed by
muscle tissue, blood vessels,
nerve tissue and connective
tissue. It pumps oxygen-rich
blood to all the cells in the body.

21. 24.4 Forming a Multicellular
Organism
•A human body:
oOrgans with related roles coordinate to
function efficiently. They work together for a
specialised purpose to form an organ
system.
Cardiovascular system:
The heart, arteries and veins
work together to transport
blood to all parts of the body.

22. •Amazing science 23 (6 organ systems)
•IPA Terpadu185 (10 organ systems)
MENTION Organs that made up Organ
System (10 Organ systems) and its
functions.

23. DISGESTIVE SYSTEM

24. CIRCULATORY SYSTEM

25. EXCRETION SYSTEM

26. SKELETAL SYSTEM

27. NERVOUS SYSTEM

28. RESPIRATORY SYSTEM

29. REPRODUCTION SYSTEM

30. MUSCULAR SYSTEM

31. INTEGUMENTARY SYSTEM

32. ENDOCRINE SYSTME
pituitary gland,thyroid
gland,parathyroid glands,adrenal
glands,pancreas,ovaries (in
females)andtesticles (in males),
produce hormones that regulate metabolism,
growth and development, tissue function, sexual
function, reproduction, sleep, and mood, among
other things.

33. 24.4 Forming a Multicellular
Organism
•A human body:
oThe different organ systems work
together to make up the entire
bodyof an organism.
Body: All the systems work
together to enable the body to
function properly.

34. DISEASES OF ORGAN
SYSTEMS

35. Symptoms
•Tiredness
•Weakness
•Shortness of breath
•Pale skin
•Lightheadedness, dizziness
•Headache
•Feeling cold
•Rapid heart
ANEMIA
CIRCULATORY
SYSTEM

36. Symptoms
•Sudden weakness or numbness of the
face, arm, and leg on one side of the body
•Sudden loss of vision or dimmed vision,
particularly in one eye
•Loss of speech, or trouble talking or
understanding speech
STROKE
NERVE SYSTEM

37. Symptoms
•Indigestion (dyspepsia)
•Heartburn
•Abdominal pain
•Hiccups
•Loss of appetite
•Nausea
•Vomiting
GASTRITIS
DISGESTIVE
SYSTEM

38. Symptoms
•Cough that produces yellow or green
mucus
•Burning sensation in the chest
•Wheezing
•Sore throat
•Fever
•Fatigue
BRONCHITIS
RESPIRATORY
SYSTEM

39. A Journey Inside Your Body
https://www.youtube.com/watch?v=3pjkQcQBTtc

40. 24.4 Forming a Multicellular
Organism
•Like the human body, plants have organ systems
too.
•The main organ systems in a plant are the shoot
systemand the root system.
•The shoot system consists of the part of the plant
above the ground.
•The organs which make up the shoot system are the
leaves, stems, buds and flowers (of flowering
plants).
•The root system consists of the parts of the plant
below the ground such as the main roots and
branched roots.

41. 24.4 Forming a Multicellular
Organism
•A plant
oGuard cells:The guard cells allow gaseous
exchange to take place.

42. 24.4 Forming a Multicellular
Organism
•A plant
oEpidermal tissue (Epidermis):The
epidermal tissue is made up of many closely
packed cells including the guard cells. This
tissue helps to reduce water loss. It also
enables gaseous exchange and the
absorption of water and nutrients.

43. 24.4 Forming a Multicellular
Organism
•A plant
oLeaf:The leaf is an organ where food
substances are formed. Epidermal tissue
forms the outermost layer of the leaf.

44. 24.4 Forming a Multicellular
Organism
•A plant
oShoot system:The shoot system includes
the organs –leaves, stems, buds and flowers
(of flowering plants).

45. 24.4 Forming a Multicellular
Organism
•A plant
oPlant:The shoot and root systems work
together to help the plant grow and function.
shoot system
root system

46. Miscellaneous
•http://www.cellsalive.com/
•http://www.forgefx.com/casestudies/prenticehall/
ph/cells/cells.htm
•http://www.northern.edu/ramsayj/etechWeb/cells
.htm
•http://web.jjay.cuny.edu/~acarpi/NSC/14-
anatomy.htm
•http://www.nelsonthornes.com/secondary/scienc
e/scinet/scinet/plants/cells/types.htm