Cells: Part OneStructures and Function

All images in this presentation are public domain unless otherwise indicated. Photo credit is given where required.

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

Blood cell

Lung cell

Nerve cell

Leaf cell

Bone marrow cell

Bacteria cell

Sperm & Egg cells (Sex cells)Picture by: Nicolas.Rougier

Photo by Markus Nolf

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"

Compound Light Microscope

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 = composed of ONE cell

Some organisms are Multicellular = composed of MANY cells

Schleiden,Schwann and Virchow

Cell Theory•All living things are made up of cells.

•Cells are the basic units of all living things.

•All cells are produced from existing cells.

Prokaryotes smallest & simplest cells

lack a nucleus

lack organelles

no specialized functions.

Example: BacteriaExample: Bacteria

Eukaryotes have a nucleus

have organelles

Have specialized functions.

Example:Example:

plant & animal cellsplant & 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) have cell walls

have chloroplasts

have a large vacuole

tend to be squared or rectangular

Animal Cells(click here for picture)

have only cell membranes

have smaller vacuoles

tend to be round

After you have looked at plants and animals individually click here to compare

Go Back

• Back

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

• A Nucleus with a nuclear envelope

• A Nucleolus

• Endoplasmic Reticulum (both Smooth and Rough )

• Ribosomes

• Cell Membranes

•Golgi apparatus•Cytoplasm

•Mitochondria

SimilaritiesBoth Plant and Animal Cells have:

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.

Further Study

• 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