Download Passive transport Movement w/o input of energy. Active transport

Robert Hooke
 1665
 English
monk
 Looked at a thin slice of cork
and looked at it with a
homemade microscope
 Had no organelles
 Named the cell
Robert Hooke
Cork
Anton Van Leeuwenhoek
 1675
 Dutch
Lens maker
 Used a simple microscope
and looked at pond water
 Named these “animacules”
 1st to see living cells
Anton Van Leeuwenhoek
“animicules”
Matthias Schleiden
1838
 German botanist
 All plants are made up of cells

Matthias Schleiden
Theodor Schwann
1839
 German zoologist
 All animals are made up of cells

Theodor Schwann
Rudolf Virchow
1855
 German physician
 Studied how disease affects living things
 Learned that cells come only from other
cells

Rudolf Virchow
Cell Theory
 All
living things are composed of
one or more cells.
 Cells are the basic units of
structure and function in an
organism.
 Cells come only from the
reproduction of existing cells.
Prokaryotes vs. Eukaryotes
 No
 No
nucleus
 Nucleus
 Many
membrane
organelles
bound
 All cells other
organelles
than bacteria
 Only bacteria
Prokaryotes vs Eukaryotes
Plasma Membrane
 Limited
to surface area to volume
ratio
 Selectively Permeable
 Made up of lipid
 phospholipids
○ hydrophilic “head”
○ hydrophobic “tail”
○ Makes up bilayer
 cholesterol
 Carbohydrates
Plasma Membrane cont
 Protein
 Peripheral
○ attached to the outside of plasma
membrane
○ A.k.a. Marker Proteins and Receptor
Proteins
 Integral
○ at least some portion of their
structure within the lipid bilayer
○ A.k.a. Channel Proteins
Fluid Mosaic Model
Membrane Functions
Physical barrier
 Contains receptors
 Regulates materials in and out of the cell

 Passive transport - kinetic energy
 Active transport - requires ATP
Intracellular Environment

Cytoplasm
 Gel-like substance found between the cell
membrane and nuclear membrane
 Contains organelles
Endoplasmic Reticulum - Pathways
 Golgi apparatus - Prepares and packages cellular
products for exocytosis
 Mitochondria - Cellular respiration (ATP)
 Lysosomes - Enzymes that break down material

What is the difference between
smooth and rough ER??
Smooth- No Ribosomes
attached. Functions
include lipid and
carbohydrate synthesis
Rough- Ribosomes are
attached. Functions include
manufacturing of membranes
and proteins that will be
exported from the cell
ER/Golgi Body Comparison
Mitochondria
– Protein synthesis
 Peroxisomes – Detoxification
 Vacuoles – Stores food and
waste
 Cytoskeleton – Protein strands
that provide support
 Ribosomes
 Microfilaments and Microtubules
Ribosomes
Peroxisomes
Cytoskeleton
Cilia and Flagella
Hairlike organelles found on the surface
of the cell
 Assist in movement
 Flagella – whip
 Cilia – small hairs

Flagella
Cilia
Nucleus
Nuclear membrane
 Nucleoli - Site of RNA synthesis
 Chromatin

Nucleus
Chromatin
Plant cells
 All
the same organelles as
animals
 Cell wall – Supports and protects
cells
 Vacuoles – Stores enzymes and
waste. Very large in plant cells
 Plastids – Makes food (includes
chloroplast)
Vacuole (#2)
Plastid
Passive Transport

Passive transport
 Movement w/o input of energy.

Active transport
 Requires input of energy.
Types
Diffusion
 Osmosis
 Facilitated Diffusion
 Ion Pumps

Passive Transport

Diffusion
 Movement from greater to lesser concentration
 Movement will continue until there is an equilibrium
 Equilibrium= even throughout.
Diffusion
Osmosis

diffusion of water across a membrane.
 isotonic,
 hypotonic,
 and hypertonic solutions
Isotonic
The concentration is the same inside
and outside the cell
 Water flows both directions

Hypotonic Solution
 Concentration
of solute is
greater in the cell
 Water moves into the cell
 Pressure in plant cell is called
turgor pressure
 Can cause cytolysis
 Bursting of cells
Cytolysis
Hypertonic
 Concentration
of solute is
greater out of the cell
 Water moves out of the cell
 Cells shrink in size
 Causes plasmolysis
 Loss of turgor pressure (wilting)
Plasmolysis and Turgor Pressure
○ In hypertonic
environment, water leaves
cell and cell membrane
shrinks away from cell wall
○ Turgor pressure is lost –
plasmolysis
○ Plants wilt if not watered
due to plasmolysis
Cytolysis vs. Plasmolysis
Isotonic
 Isotonic:
concentration
s are equal
on both sides
of membrane.
Diffusion in
and out at
the same
rate.
Passive Transport
 Facilitated Diffusion
○ integral proteins helping larger proteins
○ often referred to as carrier proteins
How it works
 Na+,
K+, Ca++, Cl- ions not
soluble in lipids
 Can’t diffuse across lipid
bilayer w/o assistance
 Ion channels
 Small passageways
 Specific to a particular ion
 Some always open; some open
and close
Facilitated Diffusion
Active Transport

Materials move up a concentration
gradient, rather than against.
 Low concentration to high concentration.

Requires energy.
Active Transport
Endocytosis- Brings large particles into
the cell.
 (2 types)

 Phagocytosis- large particles like dead cells.
 Pinocytosis- liquid
Endocytosis
Phagocytosis
Many unicellular organisms feed this
way.
 Lymphocytes: white blood cells that
inject intruders such as viruses and
bacteria.

Phagocytosis
“Cellular Eating”
Pinocytosis
“Cellular drinking”
Exocytosis
Exocytosis
Sodium-Potassium Pumps
Transport Na+ and K+ ions
 Under physiological conditions - 3 Na+
outward and 2 K+ inward for each
molecule of ATP

Sodium-Potassium Pumps
Binding sites for Na+ and ATP on its
intracellular surface
 Binding sites for K+ on its extracellular
surface

Active Transport
For normal intracellular Na+
concentration, the pump rate is limited
by the availability of internal Na+
 Increased intracellular Na+ concentration
increases pump transport activities

Sodium-Potassium Pumps
More terms to know
Concentration gradient
 Equilibrium
 Contractile vacuoles
 Vesicles

Cilia

Small hairs that assist in the movement
of the cell
Cilia of the lungs
Flagella

Whip like structure that assists the cell in
movement
– Protein strands
that provide support
 Cytoskeleton
 Microfilaments and Microtubules
Prokaryotes

Bacteria are all prokaryotes
All plant and animal cells are eukaryotes
(they have a nucleus and membrane
bound organelles)
Semi Permeable Membrane

The cell membrane is semi permeableIt allows certain materials to pass into
the cell and keeps others out
REMINDER!!!
Active Transport Cont.

Exocytosis - Releasing large particle
Secretions of
hormones
, or digestive
enzymes
 Vesicles fuse with cell membrane.