Unit 2: Cells- Guided notes

History of the Cell

Antonie Van Leeuwenhoek invented and used the first simple microscope (only 1 lens)

The Discovery of the compound light microscope has several lenses and can magnify objects up to 1000 times

Robert Hooke used a compound light microscope to study cork

He called what he saw Cells because they looked like the rooms the monks stayed in

Matthias Schleiden extended Hooke’s work, studied plants, and concluded they were made of cells.

Theodore Schwann studied animals and concluded that they were made of cells

Rudolf Virchow Determined all cells come from pre-existing cells.

All of the scientists’ work helped to develop the Cell Theory

Parts of the Cell theory:

All living things are made of cells

The Cell is the basic unit of life

If you are made of one cell you are unicellular, if you are made of more than one cell, you are multicellular

All cells come from preexisting cells

Microscopes:

We now have electron microscopes to study cells

They use a beam of electrons for much greater magnification

Scanning Electron Microscope (or SEM) can scan the surfaces of cells and see their 3-dimensional shape. can magnify 60000 times

Transmission Electron Microscope (or TEM) can study structures inside the cell. Can magnify up to 100000 times

Prokaryotic cells:

Have no nucleus (pro=before)

They have DNA but it is only a Single Ring (strand) of DNA and is in the Nucleoid Region

Most of the cell is liquid and organelles called: Cytoplasm

No internal organelles surrounded by membranes

The only organelle they do have is Ribosome

Smaller and have different proteins compared to Eukaryotic Ribosomes

Have a cell membrane, surrounded by a cell wall

It is made of a protein and carbohydrate called peptidoglycan

The cell wall is usually surrounded by a capsule or slime layer

This is why bacteria can stick to surfaces and resist being destroyed easily

Many also have pili (hair-like structures that help them stick to objects)

All cells have DNA, Cytoplasm, ribosomes, and a Cell Membrane

Viruses are NOT cells, therefore not life