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MINUTE MADNESS! How much do you already know about cells?
On your hand out write down 5 things you know about cells…
Discuss
Get ready to find out more!

Blood cell
Bone marrow cell
Lung cell
Photo by Markus Nolf
Bacteria cell
Picture by: Nicolas.Rougier
Nerve cell
Leaf cell
Sperm & Egg cells (Sex cells)

People did not know cells existed until the discovery of the microscope .
The microscope was invented by Robert Hooke in
1665 and therefore he was the first person to see cells.
When Hooke saw cork cells he compared them to the small rooms in a monastery which were called cells and coined the word “cell”

Anton van Leeuwenhoek –
(1683)was the first person to observe living organisms in pond water.
"Commons" and
"Wikipedia"

Uses a series of glass lenses to magnify images
Click to see magnifications
Click here !

A cell is the smallest functioning part of an organism.
The shape of a cell is related to function – why do you think blood cells are smooth and round but nerve cells have many long projections?
Cells vary in size and shape. Click here to have a look at an animation that illustrates the size of cells
Some Organisms are Unicellular =

•All living things are made up of cells.
•Cells are the basic units of all living things.
•All cells are produced from existing cells.
Schleiden,Sc hwann and
Virchow

smallest & simplest cells lack a nucleus lack organelles no specialized functions .
Example: Bacteria
have a nucleus have organelles
Have specialized functions .
Example: plant & animal cells

Prokaryotes
• Prokaryotes are the single-celled organisms, such as bacteria.. Unlike Eukaryotes, prokaryotes do not have a nucleus that houses its genetic material.
Rather, the genetic material of a prokaryote cell consists of a large DNA molecule in the cytoplasm

Prokaryotes
• Prokaryotes are asexual, meaning their offspring nearly always have the exact characteristics of the parent cell. The prokaryotic cell replicates itself according to its own
DNA.

Eukaryotes
Eukaryotic cells - Can be unicellular (protists such as paramecium and amoebae) or multicellular
(animals, and plants or fungi).
Wikipedia

Eukaryotes
• Eukaryotic cells are the more complex cells of plants and animals.
They have specialized organelles.
• Eukaryotic DNA is enclosed by a membrane making a well defined nucleus.
Note that this is a plant cell – animal cells are also eukaryotic

Eukaryotes
• Cell division in eukaryotes is different from prokaryotes.
There are two types of division processes involved in eukaryotic cells.
• The first is called mitosis, one cell divides to produce two genetically-identical cells.
• The second is meiosis, which is required in sexual reproduction, cells undergo recombination of each pair of parental chromosomes.

Eukaryotes
Plant
Cells
( click here for picture )
Animal
Cells
( click here for picture )
have cell walls have chloroplasts have only cell membranes have a large vacuole tend to be squared or rectangular have smaller vacuoles tend to be round

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• Back

Can you spot a few differences between plant and animal cells?

Similarities
Both Plant and Animal Cells have:
• A Nucleus with a nuclear envelope
• A Nucleolus
• Endoplasmic
Reticulum (both
Smooth and Rough )
•
•
• Ribosomes
Cell Membranes
• Golgi apparatus
• Cytoplasm
Mitochondria

Plant Cells have… Animal Cells have…
• Chloroplasts – an organelle which allows the plant to make it’s own food)
• Vacuoles (large)Some animal cells have small vacuoles but plant vacuoles hold water and take up a lot of room – they provide structure and support for the cell
• Cell Walls – a hard outer shell that also provides structure for the cell – it’s a carbohydrate that we call fiber
• Lysosomes – involved in cellular digestion – they contain enzymes which break down wastes and cellular debris
•
Centrioles –
Involved in cellular reproduction.

• Review this material using this link
• This website has an excellent review of all these topics
• Further sections of this Unit
Include:
• Cells part 2 –The Plasma Membrane
• Cells part 3 – Organelles
• Cells part 4 – Transport in Cells