MRS C GREN

CELL

CellAll living things are made up of tiny units called cells. No matter what kind of living thing we look at, the cells are similar in how they are made up and how they work.

Cell theory states that:All living things are made up of cells and cells are only produced from other cells.

Unicellular

or

Multicellular

MulticellularAll plants and animals are called multicellular as they consist of many cells. Some small plants and animals consist of a few thousand cells, while larger animals and plants such as humans and trees consist of billions of cells. There are many different types of cells found in plants and animals.

UnicellularThere are microscopic organisms (micro-organisms) that consist of one cell only. These unicellular organisms include bacteria, some fungi and protist.

Plant cells are different from animal cells but they have many features in common.

Most cells can be classified as either plant or animal cells. Although they are basically similar, they are some differences between the two. This is because plants and animal do some things the same but do other things differently.

What do you think is the main difference between

the plant and animal cells?

Plant cells make their own food because they are producers but animal cells can’t make their own food.

Both plants and animals are built out of cells. Plant cells have a thick cell wall outside of their cells, but animals cells do not have a cell wall.

Animal Cell

Plant Cell

Organelle Function PlantOr Animal

Cell membrane

Both

Cell wall Plant only

Cytoplasm Both

Nucleus Both

Chloroplast Plant only

Vacuole Both, small vacuole in animal

Name two cell parts that are only found in plant cells.Chloroplasts, cell wall, large vacuole

Name the cell structures that are found in both plant and animal cells.Cytoplasm, cell membrane, nucleus

Name the substance that gives plants their green colour and where is it found?Chlorophyll found inside a chloroplast

Name the structure which controls what chemicals go in and out of the cell?Cell membrane

Why do plant cells need a cell wall and animalcells do not.Cell wall provides support as they grow vertically, towards the light(shoot) or water(roots).

Describe what would happen to their sap vacuoles when a bean plant has not been watered for a long time.Sap vacuoles get smaller, reduces the pressure on the cell – the plant wilts.

Cells can look very different because they carry out different functions (roles) within an organism.

The structure and shape of a cell allows it to carry out its function.

MULTICELLULAR ORGANISM CELLS

Cells of the same type are generally found together. A group of similar cells is called a tissue. A tissue is a group of cells organised to do a particular job in the body.

ExampleMuscle tissue that lines your stomach and gut is made from muscle cells

Nerve tissue in the brain and spinal cord is made from nerve cells.

Reproductive organs produce gamete cells(sperm or egg)During reproduction, a sperm cell fertilizes an egg to form a zygote. The zygote cell goes through cell divisions to form an embryo.

Onion Skin cells

Leaf guard cells

Muscle cells

Nerve cells

Ciliated cells

To store food

molecules

To let gases in and out

To make limbs move

To convey

messages

To sweep debris along

Metabolism

Chains of different chemical reactions occur inside cells, especially in the cytoplasm. The series of reactions are called metabolism, and are controlled by special chemicals called enzymes. In these reactions, new chemicals can be made or broken down.

For example, cells make proteins, fats and carbohydrates.

Cells are like ‘chemical factories’, so cells have been called living factories.

KINGDOM

Unicellular organisms

• Organisms that are too small to be seen with the naked eye are called micro-organisms.

• Each micro-organism carries out all of the life processes that larger organisms carry out – movement, respiration, sensitivity, cell (metabolism), growth, reproduction, excretion and nutrition.

Unicellular Organism

Some organisms consist of only one cell.

These single cells are complete organisms and can live independently from other organisms.

Friend or foe?• Many micro-organisms play important roles as

decomposers, recycling carbon and nitrogen as they break down dead organisms.

• Others are used by humans in making cheese, yogurt, wine, bread and medical drugs.

• Micro-organisms can be unhelpful when they make food go mouldy or off.

• There are also many micro-organisms that cause diseases, such as tetanus, tuberculosis (TB), food poisoning, thrush and athlete’s foot. They are called pathogens.

Feeding method: NUTRIENT

• Extracellular digestion– Have no mouthpart.– In their cells, they make enzyme which can

breakdown large molecules of food. – The enzyme help breakdown the large

molecules of food. When enzyme pass out of the body, dead organism’s body is

attacked and large molecules are broken

down to smaller ones. These molecules

are absorbed into the bacterial cell.

REPRODUCTION• Bacteria reproduce by binary fission.

The cell grows to a certain size and makes a copy of its genes. It then divides into two smaller cells, each with a copy of those genes.

• Binary fission occur every 20minutes.

Bacteria Euglena Paramecium

MOVEMENT

RESPIRATION

SENSITIVITY

CELL

GROWTH

REPRODUCTION

EXCRETION

NUTRITION

Cell Processes of Unicellular Organisms