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Introduction to the Cell
Cell Video

Cell Video to Introduce
Day 1 Warm-Up

What were the five characteristics of
living things?
Day 2 Warm-Up




Compare / Contrast prokaryotic and
eukaryotic cells.
Schleiden said:
Schwann said:
The Cell Theory states:
1.
2.
3.
Day 3 Warm-Up
Describe the function of the following:
Nucleus
Ribosome
Lysosome
Cell wall
Before Microscopes…
Now we know – the cell is the basic unit of living things.
van Leeuwenhoek

Developed the first
light microscope
 Master lens grinder
Compound Light Microscope
Egg cell using LM
Higher Magnification:
Compound light microscope – 1500 X
 Scanning electron microscope – 1940’s
Uses a beam of electrons scan the surface to
give a 3-D image. 500,000 X
 Transmission electron microscope –
studies the inside of the cell.
 Scanning Tunneling microscope – uses flow
of electrons to study atoms on the surface of a
molecule.

Electron Micrographs
Ebola virus
Diatom
Robert Hooke

Gave us the term
“cell”
 He published
Micrographia.
The Cell Theory
Schwann – all
animals are made of
cells
 Schleiden – all
plants are made of
cells

The Cell Theory
1. All organisms are
composed of one
or more cells.
2. The cell is the
basic unit of
organization of
organisms.
3. All cells come
from preexisting
cells.
Prokaryotic vs. Eukaryotic
“Prehistoric Cells”
“Newer Cells”
•Contain no membrane-bound
organelles (has ribosomes)
•Contains membrane-bound
organelles
•Chromosomes in the cytoplasm
•Chromosomes in the
nucleus.
• Domain Archae & Bacteria
•Domain Eukarya – plants,
animals, fungi, protists
The Plasma Membrane 7.2
Maintaining HOMEOSTASIS
Plasma Membrane
Plasma membrane controls:

Cells need an inside & an outside…

separate cell from its environment
cell membrane is the boundary –
IN maintains HOMEOSTASIS!
OUT

food
- sugars
- proteins
- fats
salts
O2
H2 O
waste
- ammonia
- salts
- CO2
- H2O
products
- proteins
Plasma Membrane Structure

Membrane is made of special kind of lipid



phospholipids
“split personality”
“attracted to water”
Membrane is a double layer

phospholipid bilayer
phosphate
inside cell
lipid
outside cell
“repelled by water”
Crossing the cell membrane:

What molecules can get through the cell
membrane directly?

fats and oils can pass directly through
inside cell
waste
outside cell
lipid
salt
sugar aa
H 2O
but…
what about
other stuff?
Cell membrane channels

Need to make “doors” through membrane

protein channels allow substances in & out
specific channels allow specific material in & out
 H2O channel, salt channel, sugar channel, etc.

inside cell
waste
salt
H 2O
aa
sugar
outside cell
Fluid Mosaic Model
Fluid – membrane is flexible
 Mosaic – proteins, cholesterol, and
carbohydrates

The Cell’s Organelles
The Cell’s Protection
The Cell Membrane:
• Boundary between the cell and its environment.
• Controls the passage of materials into and out of the cell.
The Cell Wall:
• Rigid structure, much thicker than the cell membrane
• Provides support and additional protection.
• Found in plants, fungi, and most bacteria – NOT in
animals.
Cell Membrane & Cell Wall
The Nucleus



The “boss” of the cell.
Contains chromatin –
strands of genetic
material (DNA).
Has its own nuclear
envelope with pores.
Nucleolus – organelle
inside nucleus where
ribosomes are made.
Ribosomes

Can be attached to
ER or free floating in
cytoplasm.
 Protein synthesis
(assembly) occurs
here.
 Directions for protein
come from the DNA.
Cytoplasm
Clear, gelatinous fluid inside the cell.
 Many nutrients for the cell are dissolved
in the cytoplasm.
 Organelles, proteins, and other cell parts
are in the cytoplasm.

Assembly, Transport and Storage:
Endoplasmic Reticulum



Site of cellular chemical
reactions.
Highly folded
membranes in the
cytoplasm = more
surface area.
Two types:


Rough – protein
synthesis.
Smooth – production
& storage of lipids,
detoxification.
Assembly, Transport and Storage:
Golgi Apparatus

Flattened system of
tubular membranes.
 They modify and
ship proteins out of
the cell.
 “Post office - UPS”
Assembly, Transport and Storage:
Vacuoles & Lysosomes

Vacuoles – membrane bound space for
storage.



Plant cells – store water, pigments, chemicals
Animal cells – smaller, sometimes used for
movement.
Lysosome – contains digestive enzymes.


Digests excess, worn out parts, food, viruses and
bacteria
Important for development, for example, tadpole’s
tail and fingers.
Energy Transformers:
Plastids


Group of PLANT
organelles used for
storage.
Chloroplasts – plastid
that contains green
pigment chlorophyll.


Photosynthesis
occurs here!
Some store starch
(plastids), lipids, and
other pigments
(xanthophyls).
Energy Transformers:
Mitochondria

Organelle that
transforms energy for
the cell – BOTH plant
and animal cells.
 Highly folded inner
membrane increases
surface area for
chemical reactions to
take place.
 Cellular Respiration
occurs here!
Support & Locomotion



Cytoskeleton – support structure in the cell.
Composed of microtubules (thin, hollow
cylinders of protein) and microfilaments (thin,
solid fibers or protein).
Cilia – short, numerous, hair-like projections,
move in a sweeping motion.
Flagella – long, whip-like motion for locomotion.
Plants
vs.
Animal
Cells
Plant vs. Animal Cells
Trait
Plant Cell
Animal Cell
Cell Wall
Yes
No
Chloroplast
Yes
No
Vacuole
Very large
Very Small
Animal Cell vs. Plant Cell
Http://:micro.magnet.fsu.edu/cells/html