A Tour of the Cell

Chapter 7

All Organisms are Made of Cells

7.1

Cell•Basic unit of life

Robert Hook•Found the first cell

•1665

Anton Van Leuwenhoek•Invented the microscope

•1673

The Cell Theory•1. All living things are made up of cells.

•2. Cells are the basic units of structure and function in living things.

•3. New cells are produced from existing cells.

Microscopes

•Use lenses to magnify the image of an object by focusing light or electrons

Monocular Compound Light Microscope

•Monocular = one eyepiece

•Compound = magnifies in 2 places

•Light = it has a light

Micrograph

•A picture taken through a microscope

Just for fun!!!

Transmission Electron Microscope

•TEM•A beam of e- thru a thin specimen

•Magnifies 200,000X•Ex) pg 22

A TEM in action

Scanning Electron Microscope

•Spray specimen with gold dust

•Specimen emits e- which are detected by the scope

•Magnifies 100,000X•Image is 3-D

An SEM in action

Surface of Steel

• http://melodymaker.posterous.com/amazing-electron-microscope-shots

Cell Size•Volume always increases faster than surface area

•Cells can’t bring in nutrients fast enough to supply entire cell!!!

•Sooooo cells are small

Shape helps determine fxn

Cell boundaries•Bacteria and plant cells – cell wall

•All other cells – plasma membrane

Cell membrane•Thin, flexible barrier that encloses a cell

•FLUID

Nucleus•Control center of cell

•Contains cells DNA•DNA contains instructions on how to build and maintain the cell

Prokaryotes•Organelles not wrapped in a

membrane•No nucleus•Lacking variety of organelles•not complex•All bacteria!!!

Eukaryotes•Organelles and nucleus wrapped in a membrane

•Wide variety of organelles•Complex•Any cell that isn’t bacteria

Cell Structure

7.2

Cytoplasm•Fluid portion of the cell outside the nucleus

•Anything between the plasma membrane and nucleus

Organelle•Part of a cell that performs a specific task

•A lot like organs

Cell Organelle Activity•Using pages 196-207•Research your assigned

organelle and begin completing the chart

•You will present to the class tomorrow

Two Processes in Organelles

• Cellular Respiration – using sugar and oxygen to make energy and heat

• Photosynthesis – using water and carbon dioxide and SUNLIGHT to make sugar and oxygen

Mitochondria

•Location for cellular respiration

•Animal and Plant cells

6O2 + C6H12O6 6CO2 + 6H2O + Energy

Chloroplasts

•Location for photosynthesis

•Plant cells only

6CO2 + 6H2O + sun 6O2 + C6H12O6

Tour of the cell

The Cell/Plasma Membrane•Controls what enters and exits cell

•Cell boundary•Fluid!!!•Also known as phospholipid bilayer

Selectively Permeable•Selectively permeable = Some things can go thru while others can’t

•H2O, O2 & CO2 can go thru•Sugar, salt & ions need help

Phospholipid•Head = hydrophilic (loves water)

•Tail = hydrophobic made of fatty acids (hates water)

Phospholipid bilayer

•How would the phospholipid

orient itself to create 2 layers?

Membrane Proteins•Can be enzymes•Allow cells to communicate

•Allows larger items to go into or out of cell

Cell Membrane Video

• http://www.youtube.com/watch?v=moPJkCbKjBs

Cell Project Resources

• 20.2 Prokaryotes– Pages 580-585

• 20.3 Diseases Caused by Bacteria (and Viruses)– Pages 586-592– Remember only bacteria are CELLS!– Viruses are not living things!