Download cscope Cell Transport And Homeostasis Terms ppt

November 7, 2012 (You do not have to write the questions)
Cell Transport &
Homeostasis Key
Terms
Biology Unit 04 Lesson 02
Semi-permeable
• Allowing certain substances to pass
through
• Cell membrane is semi-permeable, it
allows certain substances to cross but
not others
Review of the Types of
Membranes:
1.
2.
3.
Permeable
Impermeable
Semi-permeable
1.

Permeable
Write this in your notes!
ALL types of molecules can get
through, regardless of size or charge.
Permeable
Pavement
2. Impermeable (non-permeable)
Write this in your notes!
NO molecules can get
through
3. SEMI-PERMEABLE !!!:

SOME
MOLECULES CAN
GET THROUGH
– Very small or
– Non-charged
Write this in your notes!
Homeostasis
• Regulation of an organism’s internal
environment in order to maintain
conditions suitable for survival
• Happens on the organism and cellular
level
Passive Transport
• Movement of substances across the
cell membrane that does not require
energy from the cell (high
concentration to low concentration)
Diffusion
• Movement of particles
from an area of higher
concentration to an
area of lower
concentration
• Type of passive
transport
Conceptual Diagram:
Facilitated Diffusion
• Substances cross the cell membrane with
the help of special carrier proteins
• Type of passive transport
Osmosis
• Diffusion of water from an area of
higher concentration to an area of
lower concentration
Hypotonic Solution
• A solution or environment
surrounding a cell that has less
dissolved solutes and more
water than the cell
• This type of solution will cause
water to move into the cell via
osmosis, resulting in swelling of
the cell
Hypertonic Solution
• A solution or environment
surrounding a cell that has
more dissolved solutes and
less water than the cell
• This type of solution will cause
water to move out of the cell
via osmosis, resulting in
shrinking of the cell.
Isotonic
• A solution or
environment
surrounding a cell that
has the same amount
of dissolved solutes and
the same amount of
water as the cell
Active Transport
•Movement of particles across a
membrane to an area of higher
concentration, which requires
energy
Ion or Protein Pump
• Proteins that are able to transport ions across the cell
membrane from low to high concentration by changing
their shape which requires ATP (energy) from the cell
• Example: sodium-potassium pump (important in nerve
responses)
Endocytosis
• Cell brings in a bulky substance from its
surroundings by wrapping its
membrane around the substance and
forming a vesicle
• Ex: White blood cells “eat” bacteria
using this process.
Exocytosis
• Cell releases substances by merging a
vesicle with the cell membrane and
releasing the substances into the fluid
around the cell
• Ex: cell releases waste products
Change in cell membrane
(2nd type of active transport process)

Endocytosis

Takes in (engulfs) large material

Cell membrane moves in until it encapsulates material,
becoming a vesicle.
Endocytosis: (IN)

Two types:


Phagocytosis
Pinocytosis
Phagocytosis:

“Cell Eating”


Pseudopods engulf material with
extensions of the cell membrane.
Ex. White blood cell taking in
foreign material for destruction.
Pinocytosis:

“Cell Drinking”

Membrane wraps around a big
drop of solution (solute &
solvent) and pulls it in.
Pinocytosis:
Change in cell membrane
(2nd type of active transport process)

Endocytosis

Takes in (engulfs) large material


Cell membrane moves in until it encapsulates material,
becoming a vesicle.
Exocytosis

Vesicle that gets rid of large material
Exocytosis: (OUT)

Vesicle fuses with cell membrane, releasing
contents to outside of cell.


ex. Waste
ex. Digestive enzymes
Exocytosis: (OUT)
RNA
Rough ER
Golgi apparatus
Protein in vesicle
Plasma membrane
Conceptual Diagram:
Definitions

Solute:
– what gets dissolved

Solvent:
– What does the dissolving, more plentiful that solute

Solution:
– the mixture of solutes and solvent

Example: H2O and NaCl
Solute: NaCl
Solvent: H2O
Solution: H2O and NaCl
For each scenario, answer the
following questions:
Will the H2O move?
 Will the solute move?
 Will they reach
equilibrium?
 If equilibrium is
reached, what will the
solute concentration on
each side?

For each scenario, answer the
following questions:
Will the H2O move?
 Will the solute move?
 Will they reach
equilibrium?
 If equilibrium is
reached, what will the
solute concentration on
each side?
