B2.1_Cells

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Transcript B2.1_Cells

B2 – Biology
Cells, Cell Structure and
specialised functions of cells
Miss Gifford
B2.1 – Biology – Cells
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All living things are made up of cells. The structures of
different types of cells are related to their functions.
AIM:
to relate the structure of different types of cells to their
function in a tissue or an organ.
B2.1 – Biology
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Most human cells like most other animal cells have the
following parts:
 a nucleus which controls the activities of the cell
 cytoplasm in which most of the chemical reactions take
place
 a cell membrane which controls the passage of
substances in and out of the cell
 mitochondria, which is where most energy is released in
respiration
 ribosomes, which is where protein synthesis occurs.
B2.1 – Biology
Animal Cell!
B2.1 – Biology
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Plant cells have a cell membrane, a nucleus and
cytoplasm as do animal cells. They also have a
cell wall which strengthens the cell.
Plant cells also often have:
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chloroplasts which absorb light energy to make food
a permanent vacuole filled with cell sap.
B2.1 – Biology
Plant Cell!
B2.1 – Biology
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The chemical reactions inside cells are
controlled by enzymes
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Cells may be specialised to carry out a particular
function.
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Types of Specialised Cell:
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Sperm cell
Egg Cell
Palisade Cell
Root Hair Cell
Cilia Cell
B2.1 – Biology
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Specialised Cells:
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1) The sperm cell - designed to fertilise eggs
A sperm cell is very small and has a little tail which provides movement so it can swim and find an egg to fertilise
Its head contains enzymes (in the vacuole) which allow it to digest its way through an egg membrane so the two nuclei can
join
It contains half the number of chromosomes in the nucleus - these carry genetic information from the father, which will be
passed on to the offspring
2) The ovum (egg) cell - designed to be fertilised
An ovum is large and bulky because no active movement is needed - it just sits and waits for the sperm to find it
It contains yolk (in the cytoplasm) which provides a large food store needed for the developing young organism once it's
fertilised
It contains half the number of chromosomes, which carry genetic information from the mother - this will be passed on to
the offspring
3) The palisade cell - designed for photosynthesis
A palisade cell is tall with a large surface area
It's found on the top side of a leaf - ideal for good absorption of carbon dioxide and light - both are needed for
photosynthesis
They're packed with chloroplasts, which contain the green pigment chlorophyll, which is needed for photosynthesis
4) The cilia cell - designed to stop lung damage
Cilia cells line all the air passages in your lungs
They have tiny hairs, which filter the air as it blows through
The hairs sweep mucus (snot) with trapped dust and bacteria up to the back of the throat where it is swallowed
5) The root hair cell - designed for absorbing
The long hair cell increases the surface area of the root, which helps absorption of water and minerals
It has a really thin cell wall, which makes it easier for minerals to pass across into the root itself
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B2.1 – Biology
Cilia Cell
Palisade Cell
Root Hair Cell
B2.1 - Biology
B2.1 – Biology
B2.1 – Biology
B2 – Biology