Campbell Biology Chapter 4 A Tour of the Cell

, Chapter 4-A Tour of the Cell

4.7 reveal the world of the cell
Microscopes
(LM) First
Light microscope
->
microscope
·




Can to 1K times
magnified by up
->




·
How LM works:




projectedViewer's
VISIBLE passes passes
- Specimen >Glass lenses eye
LIGHT through through



Magnification Increase in
object's image compared wits actual size
·
->
an size



Resolution The
ability to distinguish 2
nearby objects separate
· ->
as




Limitations of
microscope:
·




Usage of LM
by scientists: (studied
·




I.
microorganisms
2. animal & cells
plant
3. some structures within cells



cell all of cells
theory ->
living things composed
·
are


-> all cells come from other cells

, Electron (EM) to view the ultrastructure of cells
Microscope
· ->



-> uses a beam of e-(not light)
->
can resolve
biological structures as small as 2 nanometers (nm)
to 100K times
-> can
magnify up



EN
c X
Transmission
Scanning electron
microscope (SEM)
electron microscope
(TEM)
↓

study the detailed architecture
study the details of internal

of cell surface cell structure




↑SEM of Paramecium ↑ TEM of Toxoplasma


QUIZ

Which type of microscope would you use to study
(a) the changes in shape of a living human white blood cell;
(b) the finest details of surface texture of a human hair;
(c) the detailed structure of an organelle in a liver cell?

a. (LM)
Light microscope

b. (SEM)
Scanning electron
microscope

Transmission electron (TEM)
c.
microscope