Transcript Cell

Biology
Ch. 6
Cell Structure
and Function
I. The Cell Theory:
- A theory that developed
over several hundred
years involving many
scientists.
I. The Cell Theory (3 parts):
* All living things are made of
cells.
* All cells come from preexisting
cells.
* Cells are the basic units of
structure and function.
Robert Hooke (1665)
- Coined term ‘Cell’
Von Leeuwenhoek (1675)
- first to see live cells
*Two Basic Cell Types:
1.Prokaryotes (ex. bacteria):
- no nucleus, very small
- no organelles
2.Eukaryotes (ex. plants, animals):
- have a nucleus & organelles
- complex internal structure
Prokaryote
Bacteria Cell
Eukaryote
Plant Cell
Eukaryote
Animal Cell
II.Cell Structure
Three main parts of cells:
* Cell membrane
* Nucleus
* Cytoplasm
A. Cell membrane:
-thin, porous layer that protects
the cell and regulates movement
in and out of the cell.
- made of:
lipid
bilayer
&
proteins
*Cell Wall:
- layered, rigid
structure that
supports and
protects plant
cells
- made of cellulose
B.Nucleus:
- control center of the cell
- contains chromosomes (DNA)
Nucleus
B.Nucleus:
- Nuclear Membrane:
surrounds the
nucleus
- Nucleolus:
makes
ribosomes
C.Cytoplasm:
- liquid material located within
the cell membrane and outside
the nucleus
- contains water with many
dissolved substances
(oxygen, sugar,
proteins)
Cytoplasm
D.Cytoplasmic Organelles
- tiny, cell structures that
carry out specialized jobs
Organelles
Eukaryote
Cell
1.Mitochondrion:
- "power house" of cells
1.Mitochondrion:
- site of cellular respiration
Glucose + Oxygen
C6H12O6 + O2
Energy + CO2 + H2O
2.Chloroplasts:
- site of
photosynthesis
in plant cells
2. Chloroplasts:
Sunlight + H2O + CO2
C6H12O6 + O2
3. Ribosomes:
- site protein production
- found in both prokaryotes and
eukaryotes
4.Endoplasmic Reticulum:
- produces and
transports
molecules
5.Golgi Body:
- collects, modifies, packages,
and distributes
molecules
6.Lysosome:
- digest food molecules
or worn-out
cells
7.Vacuole:
- stores food, waste, or water
Vacuole
Stored food
or waste
III.Movement of Materials
through the Cell Membrane
A. Diffusion
Diffusion
A. Diffusion
- movement of molecules
from high concentration
to low conc.
- until equilibrium reached
- requires no cell energy
Passive Transport:
- movement in or out of a cell
that requires no cellular energy
(ex. O2 into and out of cells)
B. Osmosis:
- diffusion of water through a
selectively permeable membrane
1.Turgor pressure:
- pressure inside plant cells
1. Turgor pressure:
Leaves
and
Onion
Epidermis
1. Turgor pressure:
Plant
Movements
from
Osmosis
2. Plasmolysis:
- loss of cell liquid
(shrinking of the cell)
2. Plasmolysis:
- loss of cell liquid
(shrinking of the cell)
3. Cytolysis:
- bursting of cells due to
internal osmotic pressure
3 Types of Solutions page 282
1. Isotonic – “iso” means
equal
The concentrations of solutes
outside the cell equals the
concentration inside the cell.
Cell is in equilibrium
2. Hypertonic solution
“hyper” means over.
The concentration of solutes
outside the cell is greater
than inside.
Causes plasmolysis ( cell
shrinks)
3. Hypotonic solution
“hypo” means under.
The concentration of solutes
outside the cell is less than
the concentration inside the
cell.
Causes cytolysis.( cell swells)
C. Facilitated Diffusion
p 294
- the diffusion of large
molecules (glucose) into
cells aided by carrier
proteins
- high conc. to low conc.
C. Facilitated Diffusion:
D. Active Transport:
- movement in or out of cells
requiring energy from cell
1. Endocytosis:
- movement of large amounts
of material into a cell
1. Endocytosis:
1. Endocytosis:
Ameba
moving
and
engulfing
food.
2. Exocytosis:
- movement of large amounts
of material out of the cell
2. Exocytosis:
2. Exocytosis:
Paramecium
pumping
water out
of cells.
IV. Cell Specialization
- cells can become adapted
for a particular function
- occurs in multicellular
organisms
IV. Cell Specialization
Can you identify these cells?
-
Muscle
Skin
Bone
Nerve
Blood
V. Levels of Organization
D. Organ
System
E.Organism
C.Organ
B.Tissue
A. Cells
The
End
IV. Cell Specialization