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Why do we classify organisms ?
There are millions of species on our planet. Although species can be very different from each other, many have similar features that allow us to put them into groups. This is called classification.
The first big division of living things in the classification system is to put them into one of five kingdoms. These are based on what an organism's cells are like.
The five kingdoms are:
1. Animals (all multicellular animals)
2. Plants (all green plants)
3. Fungi (moulds, mushrooms, yeast)
4. Protists (Amoeba, Chlorella and Plasmodium)
5. Prokaryote—bacteria (E.coli, slamonella)
Organelle specialised structure within a cell (eg, mito-
chondrion, nucleus, ribosome)
Nucleus the control centre of the cell, where the DNA
is stored
Mitochondria the site of aerobic respiration
Cell membrane controls what goes into and out of the cell
Cytoplasm the liquid gel in which most chemical reac-
tions take place
Cell wall made of cellulose and gives plant strength
Vacuole filled with cell sap. Keeps the cell rigid
Chloroplasts (green plant cells only - not roots) - site of
photosynthesis. Harvests light energy as they
contain chlorophyll
Prokaryote A single celled organism with no nucleus or
membrane bound organelles
Eukaryotes
Plant and animal cells
are both Eukaryotes.
Which means that the
cells contain a nucleus
and membrane bound
organelles
Plant cells
Plant cell s need to per-
form two functions not
performed by animal
cells:
1. produce their own
food.
2. Support their own
weight
Preparing and onion
cell slide
Cut open an onion.
Use forceps to peel a
thin layer
of epidermis from
the inside.
Lay the layer of epidermis on a microscope slide.
Add a drop of iodine solution to the layer.
Carefully place a cover slip over the layer.
The iodine solution stains starch in the cells blue-black,
making the cell features easier to see.
Magnification = eyepiece lens x objective lens
Palisade cells
Stomata and Guard cells
Specialised Plant cells
Tissues and Organs
Root Hair cell Plant Organs
Plant tissues
Xylem transports water and minerals
from the roots to the rest of the plant.
Phloem transports sugars made by
photosynthesis in the leaves to the rest
of the plant.