6. Guidelines for using Light
Microscopes
Carry the microscope with one hand holding
the arm and the other hand supporting the
base.
Never slide the microscope across the lab
table.
Clean lenses with lens paper only.
Always begin AND end with the lowest power
objective in place and the stage at its lowest
level.
Use the coarse adjustment knob on low power
objectives.
Use ONLY the fine adjustment knob on high
power objectives.
7. The Discovery of the Cell
Robert
Hooke
• Looked at cells in cork and named them cells
Anton
van Leeuwenhoek
• Observed pond water
Schleiden
and Schwann
• All plants and animals are made of cells
Oken
and Virchow
• Cells are produced from division of existing
cells
8. Three Parts of the Cell Theory:
1.
2.
3.
All living things are made up of cells.
The cell is the most basic unit of life.
New cells are produced from existing
cells.
9. Why are cells so small?
Small cells function more efficiently than
large cells.
• All substances that enter and leave the cell
•
must cross the cell surface.
Cells need a high surface area to volume
ratio in order to exchange substances more
readily.
11.
Common Features of Cells
•
•
•
•
Cell membrane – thin flexible barrier that
encloses and separates the cell from it’s
external environment.
Cytoplasm – the cell’s interior
Ribosomes – where proteins are made
Genetic Material – instructions for making
proteins, regulate cellular activities, and
enable reproduction
12. Eukaryotes
Cells that contain a nucleus and internal
compartments called organelles.
Eukaryotic organisms can be one-celled
(unicellular) or contain many cells
(multicellular).
14. The Cytoskeleton
supports and shapes cell
helps position and transport organelles
provides strength
assists in cell division
aids in cell movement
Three types of cytoskeleton fibers:
•
•
•
Microfilaments – made up of protein and actin
Microtubules – made up of protein and tubulin
Intermediate fibers – thick ropes of protein
15. The Nucleus
Controls most functions of
the cell.
Most of the cell’s DNA
is contained in the
nucleus.
Surrounded by the
nuclear envelope,
which separates the
nucleus from the
cytoplasm.
•
The nuclear envelope
contains small channels
called nuclear pores
which allow substances
to move in and out of the
nucleus.
18. 2 types of endoplasmic reticulum (ER):
• Rough ER – has attached ribosomes and
thus has a rough appearance.
– Helps transport proteins from ribosomes in
vesicles.
• Smooth ER – performs various functions
such as making lipids and breaking down
toxic substances.
Rough ER
Smooth ER
22. Cell Membrane
Made
of a double layer of
phospholipids
• lipid bilayer
Protects
and supports the
cell
Regulates what enters and
leaves the cell
• Selectively permeable
23. Unique features of plant cells
Cell wall
•
Chloroplast
•
thick layer of protein and cellulose
surrounding the cell membrane.
use light energy to make carbohydrates from
carbon dioxide and water.
Central vacuole
•
•
takes up much of the plant cell’s volume
Stores water and nutrients.