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Cell Structure
Prokaryotes and Eukaryotes
There are two main types of organism ­ eukaryotes and prokaryotes. Prokaryotic organisms
are prokaryotic cells (i.e. singlecelled). Eukaryotic organisms are made up of eukaryotic

Organelles are parts of cells. Each one has a specific function. If you examine a cell through

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Organelle Diagram Description Size/distr

Thin boundary
Around all
Cell membrane between cell and
most org

A large organelle
surrounded by a
nuclear envelope
(double membrane), About 1
Nucleus which contains many diameter, u
pores. The nucleus per c
contains chromatin
and often a structure
called the nucleolus

Dark staining…

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A group of fluidfilled
flattened sacs. Found in the
Golgi Apparatus Vesicles are often close to th
seen at the edges of endoplasmic
the sacs

Either floats
attached to
A very small dense endoplasmic
Size = 2

A rigid structure that
surrounds plant cells.

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A round organelle
surrounded by a
Lysosome Float in the
membrane with no
clear internal structure

A small fluidfilled sac
surrounded by a
membrane. Some are
formed by the Golgi
Found in the
Vesicle apparatus or the
or near the
endoplasmic reticulum
while others are
formed at the cell

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Eukaryotes and Prokaryotes
Eukaryotes = `true nucleus' (Greek)
Examples include:
Animal cells
Plant cells
Fungal cells
Their main features are:
Large (80s) ribosomes
Membrane bound organelles

Prokaryotes ­ `no nucleus' (Greek)
Examples include:
Bacterial cells
Their main features are:
`naked' DNA (not contained in the nucleus)
Very few organelles…

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Small (70s)
Large (80s)
Ribosomes ribosomes always
free in the cytoplasm

Made of
Cell wall peptidoglycan (or Absent Made of cellulose

Not 9+2 microfibril
arrangement 9+2 microfibril
Flagella Absent
(different internal arrangement

Gametes (egg and Egg and pollen divide
sperm) divide by by meiosis. Growing
Cell division…

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The Cytoskeleton
The organelles in cells are surrounded by the cytoplasm. The cytoplasm is more than just a
solution of chemicals ­ it's got a network of protein threads running through it. These protein
threads are called the cytoskeleton. In eukaryotic cells the protein threads are arranged as
microfilaments (small…

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Protein production

Cells within some organisms produce hormones (chemical messenger molecules that help
coordinate the activities of the whole organism. E.g. auxins in plants and insulin in animals).
1. The instructions to make the hormone are in the DNA in the nucleus
2. The specific instruction to make the hormone…

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Micrometre (µm) 0.001 mm
Nanometre (nm) 0.000001 mm

To convert a smaller unit to a bigger unit you divide by 1000.

Resolution is how detailed the image is. More specifically, it's how well a microscope
distinguishes between two points that are close together.

Types of microscope
Light microscopes ­…




Great notes just what i needed! Thankyou :-D

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