Cambridge IGCSE Biology Extended Level

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Cambridge IGCSE BiologyExtended Level
ClickBiology

• 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 plants1 cotyledon strap like
  leavesparallel veinsflower parts divisible by
  3example kaffir lily

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Flowering plants are classified into two groups

• Dicotyledonous plants2 cotyledonsbroad
  leavesbranching veinsflower 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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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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Bacteria are single celled organisms

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

cell membrane
cytoplasm
DNA
no nucleus, DNA is one long strand kept in the
cytoplasm
cell wall
made of peptidoglycans
slime capsule
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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)

10nm
RNA
proteins of the virus coat
cross section of the human immunodeficiency virus
(HIV)
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Viruses reproduce by invading other cells
White blood cell (lymphocyte)
1. Virus attaches to cell membrane
2. Virus RNA enters cell
6. New viruses leave the cell
3. DNA copy of the RNA is made
5. Virus cores are made in the cytoplasm
4. Nucleus makes copies of the virus RNA
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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

sporangium containing spores
mushroom
spores produced here
Mucor growing on moist bread
hyphae of mushroom mycelium
hyphae of Mucor mycelium Secrete digestive
enzymes
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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
www.clickbiology.com