CELL IS A UNIT OF LIFE PRESENTED BY: PN. SHAMSIDAR BT. RAMLI

INTRODUCTION What is cell? 1. Cell is the basic unit of living things 2. All living things are made up of one or more cells. 3. The term ‘cell’ was first used by Robert Hooke, a botanist. He observed that cells in a sliced piece of cork and the cells of a honeycomb alike. 4. You need a microscope to observe cells.

ANIMAL CELLS Funtions as control centre of the cell Nucleus Cell membrane Control the movement of materials in and out of the cell Cytoplasm Chemical reaction takes place here in which new substances are formed by giving out or taking in energy

PLANTS CELL Cytoplasm Nucleus Starch grains chromosomes Cell membrane Cell wall Chloroplasts Cell sap Vacuole

PLANTS CELLS FUNCTIONS 1. Nucleus Functions as control centre of the cell 2. Cytoplasm Chemical reaction takes place here in 3. Cell membrane Control the movement of materials in and out of the cell 4. Cell wall Gives it regular shape, supports and holds the cell

PLANTS CELLS FUNCTIONS 5. Chloroplasts Contains chlorophyll, a substance needed in photosynthesis 6. Starch grains Store food

Differences between an animal cell and plant cell Has an irregular and variable shape Has a regular and fixed shape Has no cellulose cell wall Has a cellulose cell wall Has no chloroplasts Has chloroplasts Has many small vacuoles Has a large vacuoles Has no stored food Has stored food in the form of starch grains

MICROSCOPE

PARTS OF MICROSCOPE Parts of microscope Function Eye piece For looking at specimens Objectives lens Enables greater magnification of a specimen by moving body tube up and down Coarse adjustment For getting a rough focus of specimen Fine adjustment For setting a sharp focus of a specimen Stage A platform to put slides of a specimen Diaphragm For controlling the amount of light to view a specimen Mirror For reflecting light up through the slide on the stage to the eye

Questions 1. An animal cell has a variable shape because A. It has a very small vacuoles B. Its cell membrane is flexibles C. It does not have chloroplasts D. Its nucleus is small and dence Answer : B

QUESTIONS 2. The vacuole in a plant cell is filled with A. chlorophyll B. water C. cell sap D. chromosomoes Answer : C

QUESTIONS 3. The diagram below shows a typical animal cell. Name the parts of the diagram labelled P, Q, R, S and T. Answer : P - nucleus R - cytoplasm T – cell membrane Q - chromosomes S - vacuole

QUESTIONS 4. Name the part of a plant cell that a) stores food starch grains b) Gives it regular shape, supports and holds the cell cell wall c) controls all the activities in the cell. nucleus

QUESTIONS 5. Give four differences between an animal cell an a plant cell a) Has no cell wall b) Has no chloroplasts c) Has no starch grains d) Has no vacuole THE END