Transcript Cell Biology - Cloudfront.net

•Cellular
Organelles
•Cellular
Transport
History
•1665 – Robert Hooke –
observation of cork
cells
•1833 – Robert Brown –
nucleus discovery
Robert Hooke’s work
•
Cell Theory
• Schleidan, Schwann, Virchow
–All organisms made up of one or
more cells
–Cells are the basic unit of
anatomy and physiology
–New cells come from existing
cells by reproduction
2 basic types of cells
•
prokaryotic
• eukaryotic
Prokaryotic Cells
• prokaryotic
– Pro = before/ kary = nucleus
– Oldest known form of life
– Very primitive
– Small (about 1 micrometer)
– No membrane bound organelles
– Ex. bacteria
Eukaryotic Cells
• Eu = true
• Have membrane bound
organelles and a nucleus
• Large (20 – 50) micrometers
• Specialized organelles carry out
cell functions
Two main types of eukaryotic cells
• Plant Cells
• Animal Cells
Plant cell
Animal Cell
•
Anatomy and Physiology
• Cellular organelles found
within eukaryotic cells
The Nucleus
• Contains DNA
• Surrounded
by nuclear
membrane
• Brain of the
cell
Interior of Nucleus
• Inside are
long thin
strands of
chromatin
and nucleic
acid
Anatomy of nucleus
• Nucleolus –
makes and
stores RNA
and ribosomes
• Nuclear
membrane –
selectively
permeable
Electron Micrograph of Nucleus
•
Ribosomes
• Site of
protein
synthesis
– free floating
or attached
to rough ER
Mitochondria
• “Power
house” of
the cell
• Enzymes
release
energy
Two membranes
• Inner membrane
– “cristae” –
folded like shelves
to increase
surface area
• Outer – separates
organelle from
cytoplasm
Electron Micrograph
of
Mitochondria
•
Endoplasmic
Reticulum
• Transport of protein and
lipids
Two types
• Rough ER
• Smooth ER
Rough Endoplasmic Reticulum
• Site of protein synthesis
• Transport to smooth ER
Smooth ER
• No ribosomes
• Forms vesicle
and transports
to Golgi
apparatus
Golgi Apparatus
• Discovered
by Camillio
Golgi
Function
• Proteins vesicles
enter
• Carbohydrates
are added or
material is
concentrated
(H2O removal)
• New membrane
formed and
secreted
Lysosomes
• Recycling centers
• Breaks down worn and
damaged cell structures
• Unaffected by digestive enzyme
inside
Lysosomes
•Common
in
animals
Vacuoles
Usually fluid filled structures
Storage
1. Animals – cytoplasm, temporary storage
site, small
2. Plants – very large, hold water
3. Unicellular – digestion, storage, contractile
vacuoles remove water and waste
Cytoskeleton
• Miniature
internal support
system in
cytoplasm
• Composed of
microtubules
• Give cells shape
Centrioles
• Mostly in animals
• Near nucleus
• Composed of microtubules
• Cellular reproduction
Plastids
• Plant cells only
• Three types
–Chloroplast
–Leucoplast
–Chromoplast
Chloroplast
• Most common
• Green
pigment –
chlorophyll
• Glucose is
made
1. Chloroplast
2. Leucoplast – storage or
proteins, lipids, starches
3. Chromoplast – yellow, red,
and orange pigments
• http://biology.about.com/library/weekly
/aa033000a.htm
• www.virtualcell.com
Plasma Membrane
•Protective Barrier
•Selectively Permeable
Structure of membrane
• Double layer of phospholipid
molecules and proteins
• Constant motion
Function
• Prevents large particles from
entering
• Permits molecules like O2,
CO2, and H2O
Cell Wall
• Composed of cellulose
• Gives shape and rigidity
3 parts
• Primary cell wall – soft and
flexible
• Secondary cell wall – develops
when cell reaches full size,
gives strength
• Middle Lamella – jellylike
polysachharide material called
pectin
Part II
Cellular Transport
Cellular Transport
• Regulated by the cell
membrane
• Dependent on the type of
solution and concentration
gradient
3 Types of Solutions
• Hypotonic – lower concentration of
solutes than solvent
• Hypertonic – higher concentration
of solutes than solvent
• Isotonic – solution same on both
sides of membrane
Examples
• Hypotonic – distilled water +
red blood cells
• Hypertonic – salt water +
red blood cells
• Isotonic – animal red blood
cells in 80% water
If the cell is in….
• Distilled water….the cell will
burst
• Salt water…the cell will
shrink
2 Types of Cellular Transport
• Passive Transport – NO
energy required to get
materials across
concentration gradient
• Active Transport – energy
required
3 types of Passive transport
• Movement from high
concentration to low
concentration
–Diffusion
–Facilitated diffusion
–Osmosis
Diffusion
• Movement of molecules in
gases and liquids from high
concentration to low
• Ex. Food coloring in water,
perfume in air
Facilitated diffusion
• Carrier molecules carry other
molecules across concentration
gradient
–Very few molecules can do this
–Proteins carry glucose molecules
into red blood cells
Osmosis
• Movement of molecules in
liquids by going across a
membrane
•
Homeostasis
• For a cell to survive, it must
be able to maintain the
process of homeostasis,
maintenance of constant
internal environment, despite
external change
Active Transport
• Energy is required to move
materials against the
concentration gradient, from
low concentration to high
• 2 types
–Endocytosis
–Exocytosis
Endocytosis
• Movement “inside” cell
–Pinocytosis – cell drinking
–Phagocytosis – food particles
•Ex. Amoeba engulfing food
particles encased in vacuoles
Exocytosis
• “outside” of cell
–Release of large molecules
and waste products,
membrane breaks open and
vacuole is released
•
•
•