Science Form 1 - Chapter 2

CHAPTER 2

CELL AS A UNIT OF LIFE 2.1

WHAT IS CELL? Identify cell as the basic unit of living things Use a microscope Identify drawing and labeling general structure of cell Comparing between animal cells and plant cells Explain the function of each cell structure

WHAT IS CELL? A cell is the basic unit of all living things The cell structures can be observed by using a microscope Plant cells and animal cells differ in their shapes and functions Plant Cell

Animal cell Cell Membrane

Cell Membrane Cell wall

Cytoplasm

Cytoplasm Nucleus Vacuole Chloroplast

Nucleus

Similarities & Differences Plant cell

Similarities

Animal Cell

Both have :

»Cell membrane »Cytoplasm »Nucleus

Plant cell

Differences

Animal Cell

Has cell wall

Cell wall

None

Definite shape

Shape

Indefinite shape

Usually large vacuole

Vacuole

Usually has no vacuole

Has Chloroplast

Chloroplast

None

Functions of Cell structures : CELL STRUCTURES

FUNCTIONS

Cell Membrane

Controls the movement of materials in and out of the cell

Cytoplasm

Allows chemical reactions to take place

Nucleus

Controls all cellular activities. It contains genetic information

Cell Wall

Maintains the shape of the cell

Vacuole

Contains cell sap. Cell sap is a liquid with dissolved substances such as sugar and salt

CHAPTER 2

CELL AS A UNIT OF LIFE 2.2

UNICELLULAR & MULTICELLULAR ORGANISMS State the meaning of unicellular organisms and multicellular organisms Provide examples of multicellular and unicellular organisms

WHAT IS….? An unicellular organism consist of only one cell each. The only one cell does all the body functions to keep them alive. Examples of unicellular organisms are : Amoeba, Paramecium, euglena and zooplankton.

Paramecium

Amoeba

Euglena

WHAT IS….? A multicellular organism consist of many cells. Examples of multicellular organisms are : Butterfly, ant, hydra and spirogyra

A multicellular organism consist of many cells. Examples of multicellular organisms are : Butterfly, ant, hydra and spirogyra

Mucor

Spyrogira

CHAPTER 2

CELL AS A UNIT OF LIFE 2.3

Cell Organaisation In The Body

Name different types of human cells State the function of different types of human cells Arrange sequentially cell organization from simple to complex

WHAT IS….? Human being is a multicellular organism. There are many different types of cells in our human body. Different cells perform different functions. Some of the examples are given below. Shape of cell

Type of cell

Function

Red Blood cell

Transport oxygen throughout the body

Muscle cell

To allow movements of the body

Shape of cell

Type of cell

Function

White Blood cell

Kill germs that invade body

Sperm

Fertilizes the ovum in sexual reproduction

Nerve cell (neuron)

Conveys messages throughout the body

Organisation of human cells

Cell

Tissue

A group of similar cells that perform the same function

A group of different tissues that carry out a certain function

Organs

Systems

Organism

Several different organs connected to one another and perform a particular function form a system

Human Body Systems Function Associated Organs

Breaks down food materials for absorption by the body Mouth, oesophagus, stomach and small intestines

Function

Associated Organs

Digestive system

Secretes hormone to maintain activities of body

Pituitary glands, Thyroid glands, pancreas, adrenal glands, ovaries and testes Endocrine System

Human Body Systems Function

Coordinates activities of the body

Associated Organs

Brain, spinal cord and nerve fibres

Function

Associated Organs Nervous System

Provides support to the body,maintains the shape of the body, protects internal organs and allow body movements

Bones and cartilages

Skeletal System

Human Body Systems Function Associated Organs

Function Associated Organs Blood circulatory system

Transports nutrients, oxygen and excretory products Heart, veins and arteries

Moves parts of the body Muscles and tendons

Muscular System

Human Body Systems Function

Takes in oxygen and removes carbon dioxide. Oxidizes food to produce energy

Associated Organs

Nose, trachea, lungs, diaphragm

Function Associated Organs Respiratory system

Removes excretory products from the body Lungs, skin, kidneys and urinary bladder Excretory System

Human Body Systems

Reproductive system Function

Associated Organs

Give birth to babies

Man : Testes and penis Woman : Ovaries, uterus, vagina

CHAPTER 2

CELL AS A UNIT OF LIFE 2.4

The Human Being – a complex Organism

Explain why human beings are complex organisms

WHAT IS….?

Human beings are considered complex organism. Human cells are organized into tissues, organs and systems. Human cells are specialized. They perform certain specific functions only.

With the proper organization of cells, life processes can be carried out affectively.

SMK Perempuan Likas Sabah