Science Form 1 Chapter 2
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CHAPTER 2 Cell as a unit of life
2.1 WHAT IS A CELL?
A cell is the basic unit of life.
Its size is too small to be seen with the naked eye.
We need an instrument called a microscope to observe cells.
MICROSCOPE
THE FUNCTIONS OF MICROSCOPE’S PARTS Part
Function
Eyepiece
To magnify the image formed by he objective lens.
Objective lens
To magnify the image of the object.
Stage clip
To hold the microscope slide in position.
Adjustment knob
To get a sharper focus of the object.
Diaphragm
To control the amount of light entering the objective lens.
Stage
To support the microscope slide.
PLANT CELL AND ANIMAL CELL
SIMILARITIES BETWEEN PLANT AND ANIMAL CELL
Have cell membrane – controls the movement of substances in and out of the cell
Have nucleus – control all activities of a cell
Have cytoplasm – it’s a jelly like-substance fluid filled with cell sap (where chemical processes take place)
DIFFERENCES BETWEEN PLANT AND ANIMAL CELL
2.2 UNICELLULAR AND MULTICELLULAR ORGANISMS
Organism consists of living things which include microscopic of animals and plants (bacteria, viruses and fungus)
A life process is a process conducted by all living things to enable them to survive in the world
Life process conducted by multicellular organisms are more complex compare to a unicellular organisms
UNICELLULAR ORGANISMS
Organisms that consist of only one cell are called unicellular organisms.
These organisms usually live in water. Some of them such as bacteria and yeast can even live in air and human body.
UNICELLULAR ORGANISMS THAT PHOTOSYNTHESIZE
Unicellular organisms such as euglena and chlamydomonas which consists of chloroplasts can produce food by themselves through the process of photosynthesis
MULTICELLULAR ORGANISMS
Multicellular organisms are complex organisms that made up of many cells.
Multicellular organisms have many types of different cells with its special function. This caused them to have a huge size in shape
Hydra
Spirogyra
Mucor
2.3 ORGANISATION OF CELLS IN THE HUMAN BODY
Human body is the most complex multicellular organism. It has about 60,000 billion of cells The cells differ by its size, shape and structure to enables it to perform a particular function A speciallised cell is a cell that performs only one specific function in order to carry out and maintain the stability of a huge processes
HUMAN CELLS AND ITS FUNCTIONS Send nerve impulses to the whole body
Carry oxygen from lungs throughout the whole body
Form the outer layer of skin to protect the body surface Fertilises the ovum in sexual reproduction
Allows movement
Found in bones and functions in the support system of the body
TISSUES
A tissue is a group of similar cells that carry out the same function. Example, Tissues
Function
Epithelium tissue
to protect the tissues beneath it
Muscle tissue Made up of muscle cells that contracts and relaxes to enable movements of body Nervous tissue
Carry massages from one part of the body to another
Connective tissue
To connect and join several tissues together for support and protect the organs and body.
ORGANS When different tissues co-operate to carry out a certain function is called an organ For example, heart is an organ formed of muscle tissues and connective tissues that co-operate to carry out the function of blood circulation to the entire body
THERE ARE SOME EXAMPLES OF HUMAN ORGANS AS SHOWN BELOW:
SYSTEMS
A group of different organs that co-operate to perform a certain function of life process is known as the systems
The body systems as a whole enable human to carry out life process normally and more efficiently
There are 10 main systems in a human body
SYSTEM AND ITS FUNCTIONS
Digests food and absorb nutrient
Transport oxygen and digested food to the body Carries unwanted excretory materials to organs to be disposed from the body
Inhales oxygen into the body and exhales carbon dioxide out of the body
During respiration, the exchange of oxygen and carbon dioxide gases occur in the alveolus
Coordination of body activities , such as digestion and metabolism
SKELETAL SYSTEM
Preserves the body shape
Provides support and protection to internal organs such as the heart, lungs and other organs
MUSCULAR SYSTEM
Enables body movement
Muscles usually react as opposing pairs to produce movement
REPRODUCTION SYSTEM
Produces offspring to continue the generation
EXCRETORY SYSTEM
Dispose waste from the body
Lung − carbon dioxide and water vapour
Skin − Urea, mineral salt and water
Kidney − Urea, mineral salt and water
Co-ordinates and control all activities in the body
Responds to the stimuli when the sensory organs receive impulses from brain
LYMPHATIC SYSTEM
Body defense
Remove bacteria from the tissue
ORGANISMS
All systems in the body works together to perform a life process that produce an independent organism
Cell organisation allows different types of work in body to work more smoothly and efficiently
2.4 THE HUMAN BEING– A COMPLEX ORGANISMS
Human considered to be a complex organisms because they have various types of cells that form tissues, organs and systems. (cell specialisation)
2.1 WHAT IS A CELL?
A cell is the basic unit of life.
Its size is too small to be seen with the naked eye.
We need an instrument called a microscope to observe cells.
MICROSCOPE
THE FUNCTIONS OF MICROSCOPE’S PARTS Part
Function
Eyepiece
To magnify the image formed by he objective lens.
Objective lens
To magnify the image of the object.
Stage clip
To hold the microscope slide in position.
Adjustment knob
To get a sharper focus of the object.
Diaphragm
To control the amount of light entering the objective lens.
Stage
To support the microscope slide.
PLANT CELL AND ANIMAL CELL
SIMILARITIES BETWEEN PLANT AND ANIMAL CELL
Have cell membrane – controls the movement of substances in and out of the cell
Have nucleus – control all activities of a cell
Have cytoplasm – it’s a jelly like-substance fluid filled with cell sap (where chemical processes take place)
DIFFERENCES BETWEEN PLANT AND ANIMAL CELL
2.2 UNICELLULAR AND MULTICELLULAR ORGANISMS
Organism consists of living things which include microscopic of animals and plants (bacteria, viruses and fungus)
A life process is a process conducted by all living things to enable them to survive in the world
Life process conducted by multicellular organisms are more complex compare to a unicellular organisms
UNICELLULAR ORGANISMS
Organisms that consist of only one cell are called unicellular organisms.
These organisms usually live in water. Some of them such as bacteria and yeast can even live in air and human body.
UNICELLULAR ORGANISMS THAT PHOTOSYNTHESIZE
Unicellular organisms such as euglena and chlamydomonas which consists of chloroplasts can produce food by themselves through the process of photosynthesis
MULTICELLULAR ORGANISMS
Multicellular organisms are complex organisms that made up of many cells.
Multicellular organisms have many types of different cells with its special function. This caused them to have a huge size in shape
Hydra
Spirogyra
Mucor
2.3 ORGANISATION OF CELLS IN THE HUMAN BODY
Human body is the most complex multicellular organism. It has about 60,000 billion of cells The cells differ by its size, shape and structure to enables it to perform a particular function A speciallised cell is a cell that performs only one specific function in order to carry out and maintain the stability of a huge processes
HUMAN CELLS AND ITS FUNCTIONS Send nerve impulses to the whole body
Carry oxygen from lungs throughout the whole body
Form the outer layer of skin to protect the body surface Fertilises the ovum in sexual reproduction
Allows movement
Found in bones and functions in the support system of the body
TISSUES
A tissue is a group of similar cells that carry out the same function. Example, Tissues
Function
Epithelium tissue
to protect the tissues beneath it
Muscle tissue Made up of muscle cells that contracts and relaxes to enable movements of body Nervous tissue
Carry massages from one part of the body to another
Connective tissue
To connect and join several tissues together for support and protect the organs and body.
ORGANS When different tissues co-operate to carry out a certain function is called an organ For example, heart is an organ formed of muscle tissues and connective tissues that co-operate to carry out the function of blood circulation to the entire body
THERE ARE SOME EXAMPLES OF HUMAN ORGANS AS SHOWN BELOW:
SYSTEMS
A group of different organs that co-operate to perform a certain function of life process is known as the systems
The body systems as a whole enable human to carry out life process normally and more efficiently
There are 10 main systems in a human body
SYSTEM AND ITS FUNCTIONS
Digests food and absorb nutrient
Transport oxygen and digested food to the body Carries unwanted excretory materials to organs to be disposed from the body
Inhales oxygen into the body and exhales carbon dioxide out of the body
During respiration, the exchange of oxygen and carbon dioxide gases occur in the alveolus
Coordination of body activities , such as digestion and metabolism
SKELETAL SYSTEM
Preserves the body shape
Provides support and protection to internal organs such as the heart, lungs and other organs
MUSCULAR SYSTEM
Enables body movement
Muscles usually react as opposing pairs to produce movement
REPRODUCTION SYSTEM
Produces offspring to continue the generation
EXCRETORY SYSTEM
Dispose waste from the body
Lung − carbon dioxide and water vapour
Skin − Urea, mineral salt and water
Kidney − Urea, mineral salt and water
Co-ordinates and control all activities in the body
Responds to the stimuli when the sensory organs receive impulses from brain
LYMPHATIC SYSTEM
Body defense
Remove bacteria from the tissue
ORGANISMS
All systems in the body works together to perform a life process that produce an independent organism
Cell organisation allows different types of work in body to work more smoothly and efficiently
2.4 THE HUMAN BEING– A COMPLEX ORGANISMS
Human considered to be a complex organisms because they have various types of cells that form tissues, organs and systems. (cell specialisation)
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