Download Cell Membrane Cell Membrane Lecture

CELL MEMBRANES &
TRANSPORT OF MOLECULES
THROUGH IT
KL BIOLOGY
FUNCTIONS OF CELL MEMBRANES
1. PROTECT CELL
2. CONTROL INCOMING AND OUTGOING
SUBSTANCES
3. MAINTAIN ION CONCENTRATIONS OF VARIOUS
SUBSTANCES (CALCIUM, SODIUM, ETC.)
4. SELECTIVELY PERMEABLE- ALLOWS SOME
MOLECULES IN, OTHERS ARE KEPT OUT
PHOSPHOLIPID BILAYER
Hydrophobic tail (lipid)
Hydrophilic head
(phosphate)
Prefixes/Suffixes
Hydro- water
Philic- being attracted
Phobic- fear of
FUNCTIONS OF THE MEMBRANE
SOLUTIONS
• SOLUTIONS ARE MADE OF A SOLUTE AND A
SOLVENT
• SOLUTE- SUBSTANCE THAT’S DISSOLVED
(EX. SALT OR SUGAR)
• SOLVENT- LIQUID THE SOLUTE IS
DISSOLVED IN (EX. WATER)
SOLUTIONS
VOCABULARY
• HYPERTONIC SOLUTION- HIGHER CONCENTRATION
OF SOLUTE (MORE MOLECULES)
• ISOTONIC SOLUTION- SOLUTIONS HAVE SAME
CONCENTRATION OF SOLUTE
• HYPOTONIC SOLUTION- LOWER CONCENTRATION
OF SOLUTE (LESS MOLECULES)
ISOTONIC SOLUTION
ISOTONIC=SAME AMOUNT OF SOLUTE
INSIDE THE CELL AS IS IN THE SOLUTION ITS
IN
• HAVING EQUAL OSMOTIC PRESSURE AS
THE COMPARISON SOLUTION.
• SAME AMOUNT OF WATER FLOWS INTO
AS FLOWS OUT OF THE CELL
HYPOTONIC SOLUTION
• HYPOTONIC= GREATER
CONCENTRATION OF SOLUTE INSIDE
THE CELL, THAN OUTSIDE THE CELL
• CELL HAS A HIGHER OSMOTIC
PRESSURE (INTERNALLY) THAN A
COMPARISON SOLUTION
• TURGOR PRESSURE- FORCE EXERTED
ON THE MEMBRANE/WALL
• HIGH TURGOR PRESSURE CAN CAUSE
CYTOLYSIS-WHICH IS THE BURSTING
OF CELL MEMBRANES
HYPERTONIC SOLUTION
• HYPERTONIC= A GREATER CONCENTRATION OF
SOLUTE OUTSIDE THE CELL, THAN INSIDE THE CELL.
• CELL HAS A LOWER OSMOTIC PRESSURE
(INTERNALLY) THAN A COMPARISON SOLUTION
• LOW TURGOR PRESSURE CAUSES PLASMOLYSIS,
WHICH IS “CELL SHRINKING”.
• CAUSES PLANTS TO WILT
MEMBRANE TRANSPORT
(GETTING MOLECULES ACROSS A CELL MEMBRANE)
1. DIFFUSION
2. OSMOSIS
3. FACILITATED DIFFUSION
4. ACTIVE TRANSPORT
DIFFUSION
• MOVEMENT OF ANY TYPE OF
MOLECULE FROM HIGH TO LOW
CONCENTRATION
PASSIVE TRANSPORT- NO
ENERGY NEEDED
• SO DIFFUSION IS A FROM OF
PASSIVE TRANSPORT
DIFFUSION
MEMBRANE TRANSPORT
(GETTING MOLECULES ACROSS A CELL MEMBRANE)
1. DIFFUSION
2. OSMOSIS
3. FACILITATED DIFFUSION
4. ACTIVE TRANSPORT
OSMOSIS- WATER MOVING THROUGH A
CELL MEMBRANE
MEMBRANE TRANSPORT
(GETTING MOLECULES ACROSS A CELL
MEMBRANE)
1. DIFFUSION
2. OSMOSIS
3. FACILITATED DIFFUSION
4. ACTIVE TRANSPORT
FACILITATED DIFFUSION
• USE PROTEINS TO CARRY MOLECULES
ACROSS THE MEMBRANE
• LIKE A PIGGY-BACK RIDE
MEMBRANE TRANSPORT
(GETTING MOLECULES ACROSS A CELL
MEMBRANE)
1. DIFFUSION
2. OSMOSIS
3. FACILITATED DIFFUSION
4. ACTIVE TRANSPORT
ACTIVE TRANSPORT
• REQUIRES ENERGY(ATP) TO TRANSPORT MOLECULES
THROUGH THE MEMBRANE
• MOVING MOLECULES AGAINST A CONCENTRATION
GRADIENT
• REQUIRES THE USE OF “CARRIER PROTEINS”
PIGGY-BACK RIDE + ENERGY (ATP)
TYPES OF TRANSPORT
REMEMBER…
• OSMOSIS- MOVEMENT OF WATER
• DIFFUSION, FACILITATED DIFFUSION
AND ACTIVE TRANSPORTMOVEMENT OF MOLECULES
OSMOSIS LABS
• VEGETABLE OSMOREGULATION LAB
• OSMOREGULATION IN ELODEA
Title:
Vegetable Osmoregulation Investigation
Problem:
How are vegetable samples affected by hypertonic solutions? How are vegetable
samples affected by hypotonic solutions?
Hypothesis (Prediction): If IV then DV because…
Experimental Design
Independent Variable (IV):
Dependent Variable (DV):
Controlled Variables (2+):
Levels of IV:
How will the DV be measured and/or
observed?
EXPERIMENTAL CONTROL GROUP:
• HOW WILL YOU SET UP THE
BEAKER WITH ONLY
EXPERIMENTAL CONTROLS?
WHICH LABEL WILL IT HAVE?
•
•
EXPERIMENTAL GROUP:
• HOW WILL YOU SET UP THE
BEAKER THAT WILL ANSWER THE
INVESTIGATIVE QUESTION?