Download presentation
Published byRoss Williamson Modified over 9 years ago
1
Cell Membrane & THE WAYS MOLECULES MOVE Chapter 7-3
Cellular Membrane & Transport (Ch. 7-3) Cell Membrane & THE WAYS MOLECULES MOVE Chapter 7-3 Cellular Membrane & Transport (Ch. 7-3)
2
Cellular Membrane & Transport (Ch. 7-3)
Cell Membrane 1) POLAR ends face INSIDE & OUTSIDE cell (where water is…Hydrophilic) 2) NONPOLAR tails face each other inside bilayer (to avoid water…Hydrophobic) Cellular Membrane & Transport (Ch. 7-3) 2
3
Cellular Membrane & Transport (Ch. 7-3)
Outside of cell Inside (cytoplasm) Cell membrane Proteins Protein channel Lipid bilayer Carbohydrate chains Cellular Membrane & Transport (Ch. 7-3) Cellular Membrane & Transport (Ch. 7-3) 3 3
4
Cellular Membrane & Transport (Ch. 7-3)
4 4
5
Cellular Membrane & Transport (Ch. 7-3)
3) FUNCTION: SELECTIVE PERMEABILITY = allows only certain materials to go into & out of cell Cellular Membrane & Transport (Ch. 7-3) 5 5
6
Cellular Membrane & Transport (Ch. 7-3)
* Why doesn’t the cell membrane let everything through? HOMEOSTASIS! - Cells maintain a stable environment by controlling what enters & leaves. Cellular Membrane & Transport (Ch. 7-3) 6
7
Diffusion
8
FROM A LOT to NOT Molecules move _______“where there’s _______”
9
DIFFUSION across a space
Happens anytime there is a __________ in concentration in one place compared to another = ________________________ DIFFERENCE Concentration gradient
10
DIFFUSION across a SPACE
Molecules move automatically _______ the concentration gradient _______ an area of _______ concentration ____ an area of ________ concentration EXAMPLES DOWN from Higher to Lower Blue dye in beaker demo, Someone making popcorn/grilling out Strong perfume, Bad smell in room
11
DIFFUSION across a space
Diffusion continues until the concentration is ________________ in space = ________________________ equal everywhere Equilibrium
12
Molecules need to move across membranes in cells
13
Diffusion can happen ________ a _____________ in a cell, too
across membrane …as long as membrane will let the molecule _________________ pass through
14
CELL EXAMPLE: DIFFUSION automatically moves oxygen from HIGHER concentration (in lungs) to a LOWER concentration (in blood) CO2 automatically moves from where there is a HIGHER concentration (in blood) to where there is a lower concentration (in lungs)
15
PROBLEM for CELLS? Diffusion only moves molecules from high concentration to low concentration.
16
What if cell needs to move a molecule _________ the CONCENTRATION GRADIENT? _______________
AGAINST (LOWER HIGHER) Cell example: Want to put MORE glucose into mitochondria when there is already glucose in there
17
PROBLEM for Cells? Cell membranes are SELECTIVELY PERMEABLE
See a movie
18
What if a cell needs to move _____ or ______ molecules that can’t get through the membrane?
LARGE POLAR
19
PROBLEM for CELLS? Diffusion happens very slowly
20
What if cell needs to move molecules really _______
What if cell needs to move molecules really _______? (can’t wait for it to diffuse) FAST Cell example: Movement of Na + & K+ ions required to send nerve signals
21
Cells need a ____ to ____ molecules across cell membranes that _______ across by ___________
WAY HELP can’t go themselves
23
Kinds of ________ Transport
PASSIVE __________________________________ ___________________________________ _______________________________ Diffusion Facilitated Diffusion Carriers Channels
24
DIFFUSION across a membrane
DIFFERENCE Happens anytime there is a __________ in _____________ on one side of the membrane compared to the other concentration See diffusion animation
25
DIFFUSION PASSIVE DOWN HIGHER to LOWER OXYGEN Carbon dioxide
No energy required = _______ Moves _______ concentration gradient from ___________________ Works for any molecules that can pass through the membrane Example of molecules that move this way in cells: ________ & ____________ DOWN HIGHER to LOWER OXYGEN Carbon dioxide
26
FACILITATED DIFFUSION uses _______________ to help molecules across 2 kinds of proteins help: _________ & ____________ membrane proteins Carriers Channels
27
Facilitated Diffusion with CARRIER PROTEINS
grabs molecule, changes shape, and flips across to other side like a revolving door
28
FACILITATED DIFFUSION with CHANNELS
Membrane proteins create a tunnel through which molecules can pass ION CHANNELS charged _______________ allow________ ions to get past the ____________ center hydrophobic
29
FACILITATED DIFFUSION with CHANNELS
polar ________ proteins allow ________ _________ molecules to get past the __________ middle of cell membrane. Aquaporin WATER hydrophobic
30
FACILITATED DIFFUSION with CHANNELS
The movement of water molecules across a cell membrane is called ______________ OSMOSIS
31
ALL KINDS OF FACILITATED DIFFUSION
PASSIVE No energy required = _____________ Moves ________ concentration gradient from ________________________ ___________________ help molecules get across membrane DOWN HIGHER to LOWER Membrane proteins
32
EXAMPLES OF FACILITATED DIFFUSION IN CELLS
CARRIER PROTEINS ION CHANNELS AQUAPORINS (OSMOSIS) GLUCOSE Na+ , Cl- , Ca++ , K+ WATER
34
Kinds of ________Transport
ACTIVE ________________________________________ __________________________________ ________________________________ ___________________________________ PUMPS Sodium-Potassium Proton Vesicles Endocytosis Exocytosis
35
Na+ and K + PUMP See a movie about Na+ - K+ pump
36
SODIUM-POTASSIUM PUMP
ACTIVE ___________ transport (requires energy from ______) Can move molecules from _____ concentration to ______ Special just for Na+ and K + ions Uses _______________________ called ____________ to move molecules Example: nerve cells Na+ is pumped out of cells at same time K + is taken into cells ATP low high membrane proteins pumps
37
PROTON PUMP H+ Moves Protons across membrane = ___ ions
See a movie proton pump More on this in Chap 8 & 9
38
PROTON PUMP ACTIVE ATP low high Protein pumps ___________ transport
(requires energy from ______) Can move molecules from _____ concentration to ________ Special just for H+ ions Uses integral ________________ to move molecules Examples: Lysosomes need acidic conditions for digestion Photosynthesis/Respiration (more on this to come in Ch 8 & 9) ATP low high Protein pumps
39
ACTIVE TRANSPORT with VESICLES
___________ are small membrane sacs that pinch off of cell membranes used by cells for transporting molecules Used for transporting molecules: If entering the cell = ______________ If exiting the cell = _______________ ENDOCYTOSIS EXOCYTOSIS
40
2 KINDS of ENDOCYTOSIS for taking substances into cell
If taking in: fluid or small molecules =_________________ large particles or whole cells =______________ PINOCYTOSIS PHAGOCYTOSIS Animation from:
41
ENDOCYTOSIS Substances taken into cell
ACTIVE energy __________ transport (requires________) Uses ______________ to carry substances Can move molecules from _____ concentration to ______ Examples in cells: one celled organisms eat this way white blood cells get rid of bacteria this way VESICLES low high
42
ENDOCYTOSIS Protist eating another
43
PHAGOCYTOSIS White blood cell germs ___________ destroying _______
44
WHITE BLOOD CELL ENGULFING BACTERIA (Phagocytosis)
45
EXOCYTOSIS Substances released outside of cell
ACTIVE energy __________ transport (requires________) Uses ______________ to carry substances Can move molecules from _____ concentration to ______ Examples in cells: _________ release packaged proteins this way VESICLES low high GOLGI
46
GOLGI BODIES USE EXOCYTOSIS
See a Golgi movie
47
INSULIN being released by pancreas cells using exocytosis
48
VOCAB _____________ = substance that is dissolved in a solvent to make a solution _____________ = substance in which a solute is dissolved SOLUTE SOLVENT
49
__________________ = mass of a solute in a given volume of solution
CONCENTRATION MORE The _______ molecules there are in a given volume the ____________the concentration GREATER
50
Use new vocab to make Koolaid
Koolaid powder sugar Solutes = ______________& __________ Solvent = ____________ Koolaid drink = ______________ Water solution
51
What if there is a difference in concentration but solute molecules can’t move across a membrane?
WATER will move until concentration reaches equilibrium
52
See an animation Osmosis1
53
What will happen to an animal cell placed in different solutions?
Solute concentration Greater outside than inside Lower outside than inside Equal outside and inside HYPERTONIC HYPOTONIC ISOTONIC What will happen to an animal cell placed in different solutions?
54
Cells try to “maintain stable internal conditions =
Remember: Cells try to “maintain stable internal conditions = ____________________ HOMEOSTASIS So an animal cell in ISOTONIC conditions stays same size Water entering = water leaving Video Choose Blood Isotonic link
55
If cells can’t maintain
“stable internal conditions” . . . damage can result and cells can die.
56
OSMOSIS swell and possibly burst Video LESS THAN
See an animation Osmosis3 Video Choose Blood Hypotonic link HYPOTONIC: Concentration outside cell is ________________ inside the cell More water enters than leaves cell so cell will ___________________ LESS THAN swell and possibly burst
57
OSMOSIS shrinks GREATER THAN Video
See an animation OSMOSIS 4 HYPERTONIC: Concentration outside cell is ____________________ inside cell More water leaves cell than enters so cell ____________ GREATER THAN shrinks Choose Blood Hypertonic link Video
58
Animal cells _________ __________ = CYTOLYSIS = CRENATION
59
Plant cells _____ keeps ___________ = PLASMOLYSIS CELL WALL
plant cells from bursting = PLASMOLYSIS CELL WALL
60
VACUOLES store WATER OSMOTIC PRESSURE _____________________________ =
_____________________________ = Pressure exerted by the movement of water during osmosis
61
SO WHAT? hypotonic Bath water is ________________ compared to you
Sitting in the bathtub causes your fingers and toes to wrinkle up when water ________ your skin cells by osmosis enters
62
Grocery stores spray water on their veggies to “plump them up”
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.