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BIOLOGY

• Biology is the study of living things.• Examples of living things are humans and

trees.• Living things are found everywhere in the

world – on land, in the air, in the sea and even underground!• Another term we can use to call living

things is organism.

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Characteristics of Living Things

• Living things are called organisms. The three large groups of organism are green plants, non-green plants and animals.• There are 8 characteristics that are

exhibited by all living things.

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1.MovementThis is more apparent in animals than in plants since animals are able to move from place to place by using their limbs or appendages. For plants, parts move in response to stimuli.

2.ExcretionThis is the process by which metabolic waste substances are removed from the organism.

3.RespirationThis refers to the oxidation of food substances for the release of energy in living things. The energy is used for movement, growth, reproduction, etc.

4.IrritabilityAnimals and plants are sensitive to any changes in the environment (i.e. light, sound, touch, temperature, etc.)

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5.GrowthThis can also be defined as development; or an increase in size and mass of an organism.

6.ReproductionThis is the ability to produce new generation of offspring.

7.AdaptabilityThis is the ability to adjust and adapt to changes in the environment in order to increase the chances for survival.

8.Nutrition This is the process by which living things take in or make their own food in order to release energy used to carry daily activities.

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CELL STRUCTURE AND CELL STRUCTURE AND ORGANISATIONORGANISATION

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Lesson 1Learning Objectives1.Understand that cells are the building block of life.2.Identify the cell membrane, nucleus and cytoplasm in an animal cell.3.Identify the cell wall, cell membrane, sap vacuole, cytoplasm, nucleus and

chloroplasts in a plant.4.Construct a table of similarities and differences between plant and animal cells.5.Describe the functions of different parts of an animal and plant cell.6.State the function of the cell membrane in controlling the passage of substances

into and out of the cell.

Outline Cell

–Animal and plant cells Structures and functions

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Cells

• All living things are made of cells. Cells are the building blocks for all living things.

• A cell is a basic unit of life.• Most living things are made up of many cells and

they called multi-cellular.• For example, an adult human has 10 - 100 trillions

of cells in the body.• However, some living things have only one cell and

these are called uni-cellular.• For example, an amoeba is a one-celled organism.

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• Although cells come in different shapes and sizes, they have several common features.

• These common features include the protoplasm, which is made up of nucleus, cytoplasm and cell membrane.

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Animal Cell

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Plant Cell

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Structures & Functions

Structure Function

Nucleus Contains genetic material and controls all chemical reactions.

Cell membrane

Controls what passes into and out of the cell. It is partially permeable.

Cytoplasm A place where chemical processes take place.

Cell wall Fully permeable. It also provides support and gives shape to the cell.

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Structure FunctionChloroplast Contains a green pigment called,

chlorophyll which absorbs sunlight for photosynthesis.

Vacuole Storage bins. It may store food, or waste products. In plants, vacuole may also be used to store water, hence, maintaining the shape and structure of the cell.

Mitochondrion Also known as the “power house”. It releases energy in a process called respiration.

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Past Year Question

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Summary

Draw a table to show the structural similarities and differences between a typical animal cell

and a typical plant cell.

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Lesson 2

Learning Objective1.State, in simple terms, the relationship between cell function

and cell structure for the following:

• absorption – root hair cells; • conduction and support – xylem vessels; • transport of oxygen – red blood cells.

Outline Cell Specialisation

– Root hair cell– Xylem vessels– Red blood cell

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• Although it is useful to think about the general features of plant and animal cells, all cells in living organisms display specialised features that make them suited to carrying out their very specific jobs.

• For example, root cells, stem cells and leaf cells within a plant. A complex organism can be compared to a factory production line with different people performing different tasks.

• Cells within an organism display a similar division of labour to make the whole organism work properly and at a high level of efficiency.

Cell Specialisation

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The following illustration shows a variety of animal and plant cells, with different shapes and structures. Each has a very specific job, which helps the organism as a whole to work efficiently.

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Root hair cell

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Root hair cellFunction: To absorb water and mineral salts from the soil.

Adaptations: The root hair cell is long and narrow to increase

the surface area of the cell for faster absorption of water and mineral salts.

The root hair cell has a large vacuole which contains high concentration of salts and sugars to draw in water by a process called osmosis.

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Xylem vessel

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Xylem VesselFunctions: To transport water and minerals salts upward from the roots to

the leaves. To provide mechanical support to the plant.

Adaptations: Absence of protoplasm and cross wall to allow water to move

through the lumen easily. Wall has lignin (hard substance) to prevent the xylem vessel

from collapsing– When xylem vessels are bundled together, it prevents

the plant from collapsing

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Red blood cell

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Red blood cellFunction: To transport oxygen from the lungs to the rest of the

body.

Adaptations: Flattened, biconcave shape to increase surface area for

fast movement of oxygen into and out of the red blood cell (diffusion).

No nucleus to give space for haemoglobin. Contain haemoglobin to transport oxygen.

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Past Year Question

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Cell Specialisation

1.Draw and label a root hair cell and a red blood cell. (5)

2.What is the function of root hair cell? (1)3.What are the adaptations of root hair cell that

allows it to carry out its function? Explain.(4).

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Lesson 3

Learning Objective1.Differentiate cell, tissue, organ and organ system and

state the examples in both animal and plants.

Outline Cell Tissue Organ Organ system

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Cell Organisation In unicellular (single cell) organisms, the single cell

performs all life functions. It functions independently. However, multicellular (many cells) organisms have

various levels of organisation within them. Individuals cell may perform specific functions and

also work together for the good of the entire organism. The cells become dependent on one another.

Multicellular organisms have 5 levels of organisation ranging from the simplest to the most complex.

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Cells

A cell is a basic unit of all organisms consisting of cytoplasm bounded by a membrane and is

usually with a nucleus.

eg. human cheek cell, epidermal cell, muscle cell

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Tissues

A tissue is a group of cells with similar origin, structure, and function.

There are 4 basic types of tissues: Connective tissue Muscle tissue Nervous tissue Epithelial tissue

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Organs

An organ is made of different tissues working together to produce a particular function.

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Organ system

An organ system is a collection of different

organs working together to perform a

particular function.

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There are 11 organ systems in humans• Circulatory• Digestive• Muscular• Skeletal• Nervous • Reproductive• Respiratory• Endocrine• Immune• Integumentary• Excretory

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Organism

An organism is a collection of organ systems working harmoniously together.

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Past Year Question

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Cell Organisation_______ are the building blocks of life.

When we have a group of similar cells working together this is called a __________, for example muscle tissue is made up of lots of _________ cells. All the cells in a tissue look the same and perform the same job.

A group of different tissue working together to do a specific job is known as an __________. Examples of organ are ________ and _________.

Different organs working together form an ____________, heart and blood vessels work together as part of our __________ system.

All of our organ systems put together make up a living _________ that is you!