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Cambridge IGCSE BiologyExtended Level

Classification

Plants, Bacteria, Viruses and Fungi

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You should be able to:

• List the main visible features of monocotyledonous and dicotyledonous flowering plants.

• List the main features of viruses, bacteria and fungi, and their adaptations to the environment

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Flowering plants are classified into two groups:Monocotyledonous plants

1 cotyledon

strap like leaves

parallel veins

flower parts divisible by 3

example: kaffir lily

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Flowering plants are classified into two groups:Dicotyledonous plants

2 cotyledons

broad leaves

branching veins

flower parts divisible by 4 or 5

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Comparing monocotyledons and dicotyledons:

Feature monocotyledon dicotyledon

Number of cotyledons 1 2

Leaf shape strap like broad

Vein pattern parallel branching

Flower parts divisible by: 3 4 or 5

Example Kaffir lily Hibiscus

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Which plant is a monocotyledon and which is a dicotyledon?

dicotyledon monocotyledon

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Types of root systems

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Which one is a monocotyledonous plant?

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Bacteria are single celled organisms

• Bacteria cells are about 1/1000th the size of animal or plant cells.

cell membrane

cytoplasm

DNA

cell wall

slime capsule

made of peptidoglycans

no nucleus, DNA is one long strand kept in the cytoplasm

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Viruses are not classified as living things as they are not made of cells• Viruses are very small, approximately 100nm

across (1nm = 1/1000 000 of a mm)

proteins of the virus coat

RNA

cross section of the human immunodeficiency virus (HIV)

10nm

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Viruses reproduce by invading other cells

1. Virus attaches to cell membrane

2. Virus RNA enters cell

3. DNA copy of the RNA is made

4. Nucleus makes copies of the virus RNA

5. Virus cores are made in the cytoplasm

6. New viruses leave the cell

White blood cell (lymphocyte)

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The main body of a fungus is the mycelium, which is made of hyphae• Fungal cells have cell walls made of substances

such as chitin

Mucor growing on moist bread

hyphae of Mucor mycelium:Secrete digestive enzymes

sporangium containing sporesmushroom

spores produced here

hyphae of mushroom mycelium

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Now you should be able to:

• List the main visible features of monocotyledonous and dicotyledonous flowering plants.

• List the main features of viruses, bacteria and fungi, and their adaptations to the environment

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Cambridge IGCSE Biology

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