Download Cell Transport

Cell Transport
TEKS
• (4) Science concepts. The student knows that cells are the basic
structures of all living things with specialized parts that perform
specific functions and that viruses are different from cells. The
student is expected to:
• (B) investigate and explain cellular processes, including
homeostasis, energy conversions, transport of molecules, and
synthesis of new molecules
Important Vocabulary
1.
2.
3.
4.
5.
6.
7.
8.
PhosphoLipid bi-layer
Membrane
Integral proteins
Selectively permeable
Diffusion
Facilitated diffusion
Osmosis
Active transport
9. Aquaporins
10. Solute, solvent,
solution
11. Concentration
gradient
12. Slope
13. Hypertonic
14. Hypotonic
15. Isotonic
16. Equilibrium
17. Net-movement
18. Osmotic potential
19. Osmotic pressure
20. Turgor
21. Plasmolysis
22. Cytolysis
Plasma (Cell) Membrane (Phospholipid Bilayer)
• Outer boundary of cytoplasm
• Semipermiable (only certain molecules enter
& leave)
Outside
of cell
Proteins
Carbohydrate
chains
Cell
membrane
Inside
of cell
(cytoplasm)
Protein
channel
Lipid bilayer
Phospholipid bilayer
• A double layer that is an effective barrier for most molecules
• Hydrophobic = “water fearing” tails in the center, prevent most
things from entering
• Hydrophilic = “water loving” heads attract water to edges of
membrane
Outside
of cell
Proteins
Carbohydrate
chains
Cell
membrane
Inside
of cell
(cytoplasm)
Protein
channel
Lipid bilayer
Fluid Mosaic Model
• Cell membranes are mosaics that contain many
different molecules like proteins, cholesterol,
glycoproteins, etc.
Proteins embedded in membranes can be:
• Channels “gates” to interior for transporting into & out
of cytoplasm
• Receptors “windows” for gathering information about
cell surroundings
• Markers “name tags” that identify type of cell to others
Membranes are Selectively permeable
• The plasma membrane enables
only certain molecules to enter or
exit the cell.
• Why is this important?
Surface to volume ratio
• Why are larger organisms are multicellular? Why aren’t they just one
big ol’ cell?
• Because materials must be transported across cell membranes,
maximizing the amount of membrane surface area increases
transport efficiency.
Comparing surface area to volume
(Complete the calculations with your table partner and be ready to share)
• Surface area: 6 mm x 6 mm x 6
sides = ___ mm2
• Volume: ___ mm3
• S / V = ___
• Surface area: 3 mm x 3 mm x 6
sides x 8 cubes = ___ mm2
• Volume = ___ mm3
• S / V = ___
Types of passive transport
• Diffusion
• random spread of molecules from
higher to lower concentration
• Examples?
Types of transport across membranes
1. Diffusion (Simple
Diffusion) movement from an
area of high concentration to an
area of low concentration.
2. Facilitated diffusion
large molecules (ie. Glucose or
water) move through protein
channels in the cell membrane.
3. Active transport
movement of molecules against the
concentration gradient – requires
cellular energy
Passive or Active transport?
current
(Concentration gradient)
Passive vs Active transport:
which requires energy output?
Diffusion across a membrane
In which pictures do we see the greatest gradient?
In which pictures do we see equilibrium?
Osmosis across a membrane
Osmosis
• Diffusion of water across a selectively permeable membrane from
higher water purity to lower water purity
• When solutions of varying water concentrations are found across a
membrane, the solutions are given names.
• Hypertonic
• Hypotonic
• Isotonic
Types of osmotic solutions
Hypotonic
• High water purity & less solutes = water moves in &
cell expands and may burst (Cytolysis)
Isotonic
• Equal solutes & water, so equal movement of water
into and out of the cell
Hypertonic
• Low water purity because of more solutes = water
moves out & cell shrinks (Plasmolysis)
Cells in hypotonic solution
Cells in isotonic solution
Cells in hypertonic solution
Cells in various solutions
Copy this chart in your IAN
Hypotonic
LYSE
Isotonic
Hypertonic
NORMAL
animal
PLASMOLYSIS
Plant,
fungus,
algae,
bacteria
TURGID
FLACCID
Achieving equilibrium
Active transport video
Types of Active Transport
Endocytosis
• cell brings molecules
in.
Pinocytosis
• Liquids are
brought in.
Phagocytosis
• Phage means to “eat”
• large particles (food or
bacteria) are surrounded
& engulfed by cell.
• Examples = an ameba
feeding &
a white blood cell
destroying an invader.
Why are white blood cells
called MacroPhages?
“Cell eating”
Exocytosis
cell deposits
particles outside
cytoplasm
• Secretion = cell products given off
• Excretion = wastes products given off
of
The Big Idea: Cell structure is related to it’s
function
• All cells are different.
• Cell specialization → different cells have different
jobs.
• Each cell serves different needs.
• Diversity on a individual scale helps stabilize the
organism
• Diversity on a large scale helps stabilize the ecosystem