SimilaritiesNucleus, mitochondria, plasma membrane,ribosomes,golgi apparatus, Endoplasmic reticulum

DifferencesAnimal cell Feature Plant cell

Generally smaller than plant cell Size Generally larger than animal cell

Does not have fixed shape Shape Fixed, regular shape

Cell wall absent Cell wall Cell wall present

Usually not present, or present as small and temporary

Vacuole Large vacuole present

Tonoplast absent Tonoplast Tonoplast present

Chloroplast absent Chloroplast Chloroplast present

Centriole present Centriole Centriole absent

Carbohydrate stored as glycogen Carbohydrate storage Carbohydrate stored as starch

Common Lysosome Uncommon

Density of organelles

• Density : total number of an organelle within a cell

•E.g : To produce enzymes, cell must have more E.R

To produce proteins, cell must have more ribosomes

To produce more energy cell must have more mitochondria.

Density of organelles

High density of mitochondria

• Cells that are very active

a) Sperm cells : need to swim, beating their tails without stopping until they reach ovum

b) Flight muscle cells: Birds & insects. Vigorous contraction during flight

c) Meristemic cells: root & shoot tips. Repeatedly undergo mitosis to produce similar cells.

d) Liver cells: carry out processes like converting sugar to glycogen, detoxification.

e) Kidney cells.

Density of organellesHigh density of chloroplast

• Palisade mesophyll cells of leaves : MAIN photosynthetic tissue

• Function: to trap sunlight during photosynthesis

Density of organelles

High density of RER

• Pancreatic cells

•Function: to synthesize and secrete enzymes & hormones (proteins)

Unicellular organisms: Protozoans

•Animal- Like

•BUT unicellular (only one cell)

Unicellular organisms: Protozoans

Amoeba sp. Paramecium sp.General features

• Irregular shape•Nucleus, food vacuole and contractile vacuole•Cell membrane= outer ectoplasm & inner endoplasm

• Slipper-like shape•Fine hairs on surface : cilia•Large macronucleus, small micronucleus,food vacuole, 2 contractile vacuole.

Diagram

Unicellular organisms: Protozoans

Amoeba sp. Paramecium sp.*Locomotion • Forms pseudopodium (false

foot)•Movement: Amoeboid movementhttp://www.youtube.com/watch?v=aZkWIz7n6VQ

• Cilia beats against water to “swim”• Movement: rotation on its axis

*Feeding • Omnivore • Engulfs food with

pseudopodia, forming food vacuole: Phagocytosis

1) 2 pseudopodia extends2) Pesudopodia encircles

food3) Food is trapped within a

vacuole

• Eats bacteria • Beating of cilia sweeps food into cytostome.• Food vacuole forms • Food is digested by hydrolytic enzymes• Nutrients are used to generate energy

Amoeba approaches food particle

Pseudopod forming

Food particle engulfed

Food vacuole formed

Unicellular organisms: Protozoans

Amoeba sp. Paramecium sp.

*Reproduction • Asexual:a) Binary fission- under favorable

conditions (I.e- sufficient food)

- Single parent- Mitotic division

b) Spores- dry / insufficient food

• Sexual & asexuala) Binary fission- favorable environmentb) Conjugation-sexual-2 parents exchange genetic

material-each parent forms 4 daughter cells-hence 2 parents =8 daughter cells

Amoeba sp. Paramecium sp.

Binary fission

Binary fission

conjugation

Amoeba sp. Paramecium sp.Osmoregulation• Freshwater habitat is hypotonic to Paramecium sp. & Amoeba sp.• Water continuously moves into Amoeba sp. & Paramecium sp. by osmosis.•To prevent bursting, contractile vacuole collects excess water.•Vacuole expels water outside cell

Gaseous Exchange (respiration)

• Simple diffusion