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LEARNING OUTCOMES

To state the necessity for cellspecialisation in multicellular organisms

as compared to unicellular organismsTo describe cell specialisation inmulticellular organisms

To describe cell organisation in theformation of tissues, organs & systemsin multicellular organisms.

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CELL ORGANISATIONOrganisms are divided into 2 : unicellular organisms & multicellular organismsUnicellular organisms :- single-cell organismssuch as A moeba sp. & Paramecium sp .

Each cell is able to carry out all the functions of life independently.M ulticellular organisms :- larger organismswith more than one cellNeed many different types of cells to carry out allthe different functions of lifeEach cell has to change in shape & form duringcell specialisation to become specific cells inorder to perform different functions

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2.2 CELL ORGANISATION

U NICELL U LARORGANISMS

Simple organisms

consisting of onlyone cell eachAble to carry out allliving processes inorder to surviveExamples : A moeb aand Parameciu m

(protozoa)

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Membrane : respiration gaseous exchange by simplediffusion. CO2 & any dissolveddiffuses out into the water

Cytoplasm : clear on theoutside (ectoplasm) &grainy on the inside(endoplasm)

Contractile vacuole :water continuallyenters by osmosis.Contractile vacuoleswells up fullexpels the water fromthe cell =osmoregulation

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Amoeba sp.Live in water, including water in the

soil.Have no fixed shape .

Movement : form a pseudopodium(false-foot) extension of cytoplasm .

Reproduction : Binary fission whenit has grown to certain size, its nucleusdivides to form two daughter nuclei

then the cytoplasm divides and twodaughter A moeba are formed. U nder adverse conditions such as during adrought, its divides by spore formation .

F eeding : phagocytosis

pseudopodium moves round a foodparticle and takes it into its cytoplasmwhere it forms a food vacuole.Enzymes are added to digest the food.

Any waste is left behind as it moves

away.

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Membrane : respiration gaseous exchange by simplediffusion. CO2 & any dissolveddiffuses out into the water

Contractile vacuole :water continuallyenters by osmosis.Contractile vacuole

swells up fullmoves to the side of the membraneexpels the water fromthe cell =osmoregulation.

Alternate.

Cilia : tiny hairsthat cover thewhole surface

Oral groove :leads food to gullet

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Paramecium sp.Lives in stagnant water containingdecaying plant material. Have fixedshape, like a slipper.

Movement : rhythmic beating of thewater by the cilia (rows of tiny hair)propels the Paramecium along. If itencounters to an obstacle, it stops,

backs up, turn 30o

then moves off.(Avoiding reaction)

F eeding : the cilia around the oralgroove brush the food down to thegullet. A food vacuole formed.

Enzymes are added to digest it andthe nutrient diffuse into the foodcytoplasm. Waste is released througha weak spot in the membrane calledthe anal pore.

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REPRODUCTION Through binary fission.Also can reproduce sexually by

conjugation.

Two individual come together andexchange parts of their nuclei. Theythen separate and each can later divides to give four new cells.

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MULTICELLULAR ORGANISM

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MULTICELLULAR ORGANISM

Organisms that have more than onecell

More complex than unicellularorganisms

Need many different types of cells

to carry out their life process. Achieved through cell specialisationand cell organisation .

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H uman

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CELL SPECIALISATION

Achieved through the process ofDIFFERENTIATIONw here the cells begin tochange in shape and form as they gro w.

The cell acquire special structures andbecome specialised cells .Each type of cell performs only one

specific function. This is kno w n as divisionof labour .Through these, different functions in thebody can be performed at the sametime and can be carried out smoothlyand efficiently .

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CELL Basic un its of l ife in a ll org a n ism s.

The st ru ct ur a l fe at ure s of ce lls a re re lated to t h ei r fun ctio n s.Ce lls un de rg o di ff e re n tiatio n to acq u ire specia l st ru ct ur es a n d b eco m e specia lised ce lls w it hspeci fic fun ctio n s.

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EXA M PLES OF ANI M AL CELL

Red blood cells

Nerve cells

Muscle cells

Sperm cells

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Exa m p les o f p la n t ce lls

Guardcell

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TISSUESA group of similar cells that work together to perform a specific functionF our main types of animal tissues :

epithelial tissues, nervous tissues, muscletissues & connective tissues .Mnemonic (EN.MyC)

The four main types of plant tissues :epidermis tissue, meristem tissue,vascular tissue & ground tissue

MNEMONIC EM..VideoGames!

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Types of animal cell Characteristics F unctions

Epithelial tissues Consist of epithelialcells arranged in acontinuous layer

Cover the bodysurface or line thecavities within the body

Protect the underlyingcells from mechanical

injuriesAbsorb food and water

by diffusionF orm secretory gland

Nervous tissues Consist of nerve cellscalled neuronF ound in brain and

spinal cord

Send & receiveimpulses to coordinatethe activities of thebody

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Muscle tissues Consisting of musclecells which cancontract to performwork

3 types : smoothmuscle, skeletalmuscle & cardiac

muscle

Cause bodymovement by meansof contraction

Connective tissues Consist of elastic &non-elastic fibre

Blood, adiposetissues, cartilage &bone.

Join together bodystructures, as well asprotect, hold and

support the cell in thebody

Can store & transportmaterial

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Types of planttissues

Characteristic F unctions

Epidermistissue Consisting of onelayer of cellsExamples :

epidermis of leaves, stems &roots

Covers the entire surface of theplantProtect underlying tissues from

physical damage & infectionReduces water loss

Epidermal cells of leaf differentiate to become guardcells while those at the root,become root hair cells.

Meristem tissue Consists if

undifferentiatedcells which areable to divide

Occurs at the tipof roots & shoots& in the cambiumof stems & roots

Produces new cells by cell

division

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Vascular tissue Consists of xylemtissues & phloemtissues

Transport water & mineral saltsfrom roots to the stems & leavesby xylem tissues

Transport dissolved nutrientssuch as glucose from the leavesto the roots & stems by phloemtissues

Xylems tissues provide supportto the plants

Ground tissue Consists of parenchymamesophyll tissues,collenchyma &sclerenchymatissues

Produces food by photosynthesis& stores food produced

Provides support & strengthens

the plant

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ORGANS

A group of different tissues that work together to perform a specific functionExamples of organs in animal: heart,kidneys, lungs, skin & stomach.Examples of organs in plant : leaves,stems, roots & flowers.Certain organ perform more than onefunction.

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SYSTE M SSeveral organs which work together tocarry out a specific function

The human body has twelve differentsystemsAll the system work together to form anorganismF lowering plant has two main systems :root system, shoot system

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MAJOR SYSTEMS IN H UMANS

IntegumentaryCirculatoryEndocrineLymphaticNervousDigestive

Muscular ExcretorySkeletalRespiratory

Reproductive

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THE INTERNAL ENVIRONM ENT OFMU LTICELL U LAR ORGANISM

EXTERNAL ENVIRONMENT : externalconditions imposed on the organism suchas the physical and chemical factors in its surroundings.

INTERNAL ENVIRONMENT : the conditions

created inside the organism by its ownmetabolism, its reactions to externalchanges and other activities

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EXTRACELL U LAR FL U ID : the fluid thatbathing the cells, provides the medium in

which they have to live

HOM EOSTASIS : the process to regulate thephysical & chemical factors in the internalenvironment so that it is always constant &at its optimal condition for the cells to

function efficiently ( the maintenance of theinternal environment of a living organismat a constant normal level or betweennarrow limits ).

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INTERNAL ENVIRONMENT of

MULTICELLULAR ORGANISMA multicellular organism consists of all thedifferent organ systems, each specialised tocarry out certain functions.

They work together as an integrated &coordinated unit.

To stay alive, the cells in a multicellular organismmust remain bathed in a FLUID that offersnutrients & carries away metabolic wastes.

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The combined contributions ofindividual cells, organs & organsystems help maintain the STABLEINTERNAL ENVIRONMENT required for individual cell survival .

Any increase in the value of a physicalor chemical factor w ill trigger the

homeostatic mechanism to bring itback to normal (negative feedback mechanism)

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F ACTORS A FF ECTING THEINTERNAL ENVIRONMENT

PHYSICAL F ACTORS temperature, bloodpressure & osmotic pressure

CHEMICAL F ACTORS sa lt & su gar content & p H va lue.

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NEGATIVE FEEDBACK M ECHANISM S

Body temperatureMNEMONICS C u, M au I kut N enek E nggak?

Blood glucose levelMNEMONIC D ahi E ngkau C antik! Blood pH

MNEMONIC R oti C anai E nak

Concentration of oxygen & carbon dioxide in thebloodMNEMONIC R a C uN

Osmotic pressure of bloodMNEMONIC ENCE k

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BODY TEMPERATURETo regulates & maintains human bodytemperature at 37 oC.

Body temperature rises Thermoreceptors (NS)detect contol centre in hypothalamusactivates effectors (blood vessel & sweat gland)blood vessel dilate near the surface of the

body increase the heat loss sweat glandproduce more sweat to low the body temperaturethrough evaporation BT restored to normal

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Ooosleeping in Biologyclass ek?

So stubborn la.Let me teach U first beforeMr. F AZLI become angry!!!

Waa.mama!Help me. I dontwant to fall asleep

in the classanymore!!!I SWEAR!!!