Cells

1
Chapter 4

• Cells

2
Formation of the Earth

• 5 bya universe formed
• Accumulation of particles of dust and hydrogen
  and helium gas
• 4.6 bya Earth and other planets were formed
• Oldest rocks 4.1 bya

http//www.aber.ac.uk/iges/cti-g/STHAZARDS/radiati
on/ajs6/the20formation20of20the20earth.htm
3
The Beginning of Life

• AI Oparin (1922)
• Stanly Miller(1950s)

4
First Cells

• Capacity to replicate
• Presence of enzymes
• Membrane to separate internal from external
  environment
• Sidney Fox- Proteinoid microspheres

http//www.geo.lsa.umich.edu/crlb/COURSES/117/Lec
13/lec13.html
5

• Oldest fossils resemble modern day bacteria
• 3.4 to 3.5 bya
• Life formed 3.8 bya
• Earth is about 4.5 bya

http//online.morainevalley.edu/WebSupported/BIO11
2/new_page_1.htm
6
http//www.geo.lsa.umich.edu/crlb/COURSES/117/Lec
13/lec13.html
7
Heterotrophs and Autotrophs

• Heterotrophs
• Autotrophs
• Photosynthetic autotrophs
• Chemosynthetic autotrophs

http//www.lsc.org/extreme_deep/ecosystems.html
8
Cell theory

• All living things are made of cells
• Chemical reactions of organisms occur with in the
  cell
• Cells arise from other cells
• Cells contain the hereditary information of the
  which they are part
• All evidence shows that there is an unbroken line
  from the first cells

9
All cell have

• Cell membrane
• Plasma membrane
• Genetic material

http//137.222.110.150/calnet/cellbio/page4.htm
10
Prokaryote vs.
Eukaryote

• pro before
• Circular DNA
• In nucleoid region
• Contain small ribosomes 70S
• No other organelles
• Cell wall
• Smaller
• Only form of life for about 2 billion years

• Eu true
• Linear DNA
• In nucleus
• Contain larger ribosomes- 80S
• Variety of organelles
• Some cell wall
• larger

11
Origin of Multicellularity

• First appearance 750 mya
• Fossil and genetic evidence suggest that first
  multicellular organisms evolved from
  single-celled eukaryotes

http//www1.fccj.org/dbyres/protista.htm
12
http//www.esb.utexas.edu/mabrybio211/chapter26/ch
apter_26.htm
13
Microscopes-

• Human eye 1/10 millimeter resolution
• Resolution ability to differentiate between two
  dots

14
Light microscope

• Resolving power of 0.2 micrometers
• Improve naked eye by 500 times
• Light range from .4 to .7 micrometers

Click on picture for more about light microscopes
http//science.howstuffworks.com/light-microscope3
.htm
15
Electron Microscope- transmission electron
microscope

• Resolution of .2 namometers
• 500,000 times that of human eye

http//www.deutsches-museum.de/ausstell/dauer/phys
ik/physik23.htm
http//www.weizmann.ac.il/home/garty/scanning_elec
tron_microscope.html
16
Electron Microscope- scanning electron microscope

• Resolving power of 10 nanometers

http//www.udel.edu/Biology/Wags/b617/tem/tem.htm
http//7starm.asu.edu/soot.html
http//www.weizmann.ac.il/home/garty/scanning_elec
tron_microscope.html
17
Preparation of Specimens

• Light microscope specimens are treated with dyes
• Must be fixed first
• Electron microscopes are treated with heavy
  metals
• Dehydrated first

http//www.microscope-microscope.org/activities/sc
hool/preparing-slides.htm