7/23/2019 Science Form 1 Chapter 2: Cell is the unit of life
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CELL AS A UNIT OF LIFE
Science form 1
7/23/2019 Science Form 1 Chapter 2: Cell is the unit of life
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2.1 What is aCell?
1. A cell is the basic nitof life.
2. Its fnction is to carr!
ot life "rocesses.
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Who #isco$er cells?
Theodor Schwann 1839
% All animal tissues are composedof cells&
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Cells
All li$in'or'anismsare ma#e
ot of cells
Animal
(mans
)lants
Smallestnit
Fnctionan#sr$i$e on
its o*n
+ro*th,
res"iration,#i$ision an#
e-cretion
Will #ie ot e$entall!.
All ne* cells are forme# b!cell #i$ision of other cells
mitosis/
0ierentsies an#sha"es
Lon',short,o$al, has
tail
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3icrosco"e
1. A microsco"e is se# to st#! the'eneral strctre of a cell.
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4o#! tbe
Nose"iece
Lo* "o*er
3e#im"o*er(i'h "o*er
Sta'e cli"s
0ia"hra'm
Li'ht sorce
E!e"iece
Arm
Sta'e
Coarsea#5stment
Finea#5stment
4ase
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No. 3icrosco"e "art Fnction
1. 4o#! tbe 6
2. Nose"iece (ol#s the lo*, me#im an# hi'h "o*er ob5ecti$elenses, can be rotate# to chan'e ma'ni7cation
8. Lo* "o*erOb5ecti$e lenses 9 ma'ni7cation ran'es from 1:-to ;:-
;. 3e#im "o*er
<. (i'h "o*er
=. Sta'e cli"s (ol# the sli#e in "lace
>. 0ia"hra'm e'lates the amont of li'ht on the s"ecimen
@. Li'ht sorce )ro5ects li'ht "*ar#s thro'h the #ia"hra'm,the s"ecimen an# the lenses
. E!e"iece Contains oclar lens
1:. Arm Use# to s""ort the microsco"e *hen carrie#11. Sta'e S""ort the sli#e bein' $ie*e#
12. Coarsea#5stment
3o$es the sta'e " an# #o*n for focsin'
18. Fine a#5stment 3o$es the sta'e sli'htl! to shar"en the ima'e
1;. 4ase S""orts the microsco"e
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7/23/2019 Science Form 1 Chapter 2: Cell is the unit of life
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Animal an# "lant cells
Cellmembran
eC!to"las
mNcles
Chloro"last
Bacole
Cell *all
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Animal cells )lant cells
Irre'lar in sha"e e'lar in sha"e
No cell *all (a$e cell *allNo chloro"lasts (a$e chloro"lasts
3ostl! no $acoles (a$e lar'e
$acoles
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The fnctions of cellstrctre
Strctre Fnction
Ncles Controls all cellacti$ities
C!to"lasm A "lace *herechemical "rocessestae "lace
Cell membrane Controls Do* of
materials in an# otof cell
Cell *all +i$es sha"e to the
cell
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First science form 1 "ro5ect
• 4il# a mo#el that sho*s thestrctre of animal an# "lant cells
E-am"le
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2.2 Unicelllar an# mlticelllar
or'anisms
1. A nicelllar or'anisms has one cellonl!.
2. A mlticelllar or'anisms has man!cells.
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)aramecim E'lena Amoeba
Unicelllar or'anisms
Chlam!#omonas
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7/23/2019 Science Form 1 Chapter 2: Cell is the unit of life
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3lticelllar or'anisms
S"iro'!ra
(!#ra
S"oran'im
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2.8 Cell or'anisation in the (man
4o#!
Cell sim"le/
Tisse
Or'an
S!stem
Or'anism
com"le-/
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1. The t!"e an# fnction of hman
cells
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7/23/2019 Science Form 1 Chapter 2: Cell is the unit of life
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7/23/2019 Science Form 1 Chapter 2: Cell is the unit of life
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2. Tisse
Tisse is a 'ro" of similar cells that*or to'ether to "erform a "articlarfnction.
E"ithelialtisse
3scletisse
Ner$etisse
Connecti$e tisse
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8. Or'an
An or'an consists of t*o or more in#sof tisses 5oine# into one strctre thathas a certain tas.
; S t
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;. S!stem
• +ro"s of or'ans form or'an s!stems
• Each s!stem carries ot a ma5or
acti$it! in the bo#!.
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<. Or'anism
All s!stem in the bo#! fnction in acoor#inate# manner to form amlticelllar or'anism.
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2.; (man bein' 9 a com"le-
or'anism
1. A hman bein' is a com"le-mlticelllar or'anism becase thecells are or'anise# into tisses,
or'ans an# s!stems.
2. Cell s"ecialisation hel"s to #i$i#ebo#! fnction amon' the #ierent
t!"es of cells.8. Cell s"ecialisation an# cell
or'anisation ensre the life
"rocesses are carrie# ot eecti$el!