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Welcome to Cell Biology! it's alive!

Welcome to Cell Biology!

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Welcome to Cell Biology!. it's alive!. Cell Theory. 2.1: Outline the Cell Theory 2.1.2: Discuss the Evidence for Cell Theory. Cell Theory. Living organisms are composed of cells Cells are the smallest unit of life - PowerPoint PPT Presentation

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Page 1: Welcome to Cell Biology!

Welcome to Cell Biology!

• it's alive!

Page 2: Welcome to Cell Biology!

Cell Theory

• 2.1: Outline the Cell Theory• 2.1.2: Discuss the Evidence for Cell Theory

Page 3: Welcome to Cell Biology!

Cell Theory

1. Living organisms are composed of cells2. Cells are the smallest unit of life3. Cells come from pre-existing cells, by division

(so that new cells cannot be constructed from non living substance)

Page 4: Welcome to Cell Biology!

The History of Cell Theory

Let’s meet who discovered cells…Meet the Scientists...

Page 5: Welcome to Cell Biology!

1. All living things are made of cells…

Digestive Tissue Goblet Cells http://www.olympusmicro.com/galleries/abramowitz/index.html 6.11.12

Page 6: Welcome to Cell Biology!

How do we know that all living things are made of cells?

Because we can SEE them through microscopes….

Page 7: Welcome to Cell Biology!

When we we first start talking about ‘Cells’?

Robert Hooke coined the term ‘cells’ since he felt that the space-filled chambers of dead cork resembled a monk’s empty cell…

Page 8: Welcome to Cell Biology!

Cell Theory: Robert HookeMicrographia, 1665:

. . . I could exceedingly plainly perceive it to be all perforated

and porous, much like a Honey-comb, but that the pores of it

were not regular. . . . these pores, or cells, . . . were indeed the first microscopical pores I ever saw,

and perhaps, that were ever seen, for I had not met with any Writer

or Person, that had made any mention of them before this. . .

Page 9: Welcome to Cell Biology!

The Father of Microscopy: Van Leeuwenhoek

The first man to visualise single-celled animals (he called protists animacules): 1674Microscopy bytes

Page 10: Welcome to Cell Biology!

Nothing smaller can survive independently

If a cell is broken down into its individual components, its

subunits cannot survive independently

Page 11: Welcome to Cell Biology!

3.All cells come from pre-existing cells: ‘Omnis Cellula e cellula ‘

• Disproving spontaneous generation

• Pasteur

Page 12: Welcome to Cell Biology!

Limitations to cell theory

Page 14: Welcome to Cell Biology!

Limitations to cell theory: multinucleated cells (syncytiae)

• Skeletal and cardiac muscle

Page 15: Welcome to Cell Biology!

Limitations to cell theory: multinucleated cells (syncytiae)

Fungal hyphae (phase contrast microscopy)

Page 16: Welcome to Cell Biology!

How large are cells?

Let's put things into perspective....

Page 17: Welcome to Cell Biology!

What units do we use to measure cells and cell components?

Page 18: Welcome to Cell Biology!

Size is relative….

Organism Size

Prokaryotic cell 1 – 10 μm

Animal Cell 10 – 30 μm

Plant Cell 10 – 100 μm

Virus < 100 ηm

DNA molecule 2 ηm

Phospholipid membrane 10 ηm

Page 19: Welcome to Cell Biology!

How do microscopes work?

• Anatomy of vision

Page 20: Welcome to Cell Biology!

Magnification and scale bars

• You will often need to calculate the actual size of a specimen/ component of a cell from a microscope image, or a photograph/micrograph

• The first step is to ensure that all parts of your calculation have the same units!!

Magnification = size of imageactual size of

specimen