• Molecules that tend to repel, not absorb, or not dissolve/mix with or by water.
Hydrophobic
• Molecules that tend to be attracted to, absorb, or dissolve/mix with or by water.
Hydrophilic
• Triglycerides. • Phospholipids. • Sterols.
What are the three main biological lipids?
• Energy storage.
What is the function of triglycerides?
• Hydrocarbon chain. • Carboxyl group at the end of the chain.
What makes up a fatty acids structure? (2)
• Cannot absorb anymore hydrogen atoms in its carbon chain; commonly found in animal fats. • No double bonds.
Saturated Fatty Acid (2)
• Can absorb additional hydrogen atoms; found in vegetable oils. • Has a double bond.
Unsaturated Fatty Acid (2)
• 3 fatty acids. • Glycerol anchor.
What makes up a triacylglycerols structure? (2)
• Charged molecule. • Phosphate. • Glycerol. • 2 fatty acids.
What makes up a phospholipids structure?
• Charged molecule. • Phosphate. • Glycerol.
What makes up a phospholipids head group?
• 2 fatty acids.
What makes up a phospholipids tails?
• False.
A phospholipids head groups repels water, true or false?
• True.
A phospholipids tails repel water, true or false?
• Tight packing between them. • Less fluidity. • Restricted movement.
What are the characteristics of saturated phospholipid fatty acid tails?
• Looser packing between them. • More fluidity. • More movement.
What are the characteristics of unsaturated phospholipid fatty acid tails?
• Regulates transport in and out of the cell.
What does the cell membrane do?
• Membrane.
Which part of a cell is commonly known for the following:
• Communication • Chemical Reactions
• Selective.
What type of permeability do membranes have?
• Allows some molecules to pass through the membrane.
Selective Permeability
• Yes.
Is it possible for lipids and proteins to coexist in a membrane?
B) Laterally.
Which way do lipids and proteins diffuse in a membrane?
A) Diagonally B) Laterally C) Horizontally D) They don't diffuse across the membrane
• Protein.
Transport involves what types of channels and carriers?
• Involves enzymes and the binding of substrates to enzymes.
Enzymatic Activity
• Involves a hormone that binds to a receptor.
Signal Transduction
• Attachment points for cytoskeleton and extracellular matrix.
Attachment/Recognition
• Junctions - Connect and join two cells together. • Enzymes - Fixing to membranes localizes metabolic pathways. • Transport - Facilitated diffusion and active transport. • Recognition - Markers for cellular identification. • Attachment - Attachment points for cytoskeleton and extracellular matrix. • Transduction - Receptors for peptide hormones.
JETRAT
(I found this online and thought it would help to remember the different types of membrane protein functions)
• Short fatty acid tails. • Unsaturated fatty acids. • Higher temperature. • Sterols.
What factors increase the fluidity of a membrane?
• They change the strength of van der Waals forces.
How do short fatty acid tails increase a membranes fluidity?
• Sterols.
What factor both increases and decreases the fluidity of a membrane?
• To prevent freezing, sterols stop phospholipids from packing too tightly together. • To prevent melting, sterols fill in gaps between phospholipids.
How do sterols regulate membrane fluidity (for both preventing freezing and melting)?
• More solutes can pass through the bilayer more quickly.
If fluid membranes are "leaky" what happens?
• Fewer solutes are able to pass through the membranes more slowly.
Why are viscous membranes better barriers?
• Small, uncharged, barely polar molecules.
What can diffuse across a lipid bilayer?
• Large, charged, polar molecules. • Ions.
What cannot diffuse across a lipid bilayer? (2)
• Maintain homeostasis. • Cells live in dynamic environments. • Allows for concentrations of molecules on the inside that are different from the outside. • Transport of molecules is regulated by cells.
Why do cells need a selective barrier? (4)
• An area of high concentration distributes evenly to an area of lower concentration.
Diffusion
• The concentration gradient (high in entropy).
Where does the energy in diffusion come from?
• Diffusion of water from a low solute to a high solute.
Osmosis
• Capability of a solution to modify the volume of cells by altering their water content.
Tonicity
• No net movement of water, causing the cell to not change in size or shape.
Isotonic Conditions
• Water diffuses out of the cell, causing shrinkage.
Hypertonic Conditions
• Water diffuses into the cell, causing swelling.
Hypotension Conditions
• Transport of a solute through diffusion.
Passive Transport: Simple Diffusion
• Moves down or with its concentration gradient. • Powered by potential energy in the concentration of the gradient. • A greater concentration gradient = greater rate of movement.
What are the characteristics of passive transport (simple diffusion)? (3)
• Involve protein carriers to help carry large/charged/polar molecules into and out of the membrane.
Passive Transport: Facilitated Diffusion
• Moves down with the concentration gradient. • Direction of transport is reversible. • Rate of transportation depends on concentration gradient. • Substrate specific.
What are the characteristics of passive transport (facilitated diffusion)? (4)
• Bind a single solute and transport it across the lipid bilayer.
Carrier Proteins
• Form hydrophilic channels in the membrane which water and ions can move across.
Channel Proteins
• They move solutes away from equilibrium (low energy state).
How do cells establish a concentration gradient?
• ATP.
In order for cells to establish a concentration gradient, what molecule is needed?
• Involves specific protein pumps that cross the membrane and moves solutes up (against) their concentration gradient.
Primary Active Transport
• ATPO.
What does the transporter pump use in primary active transport?
• Chemical gradients. • Electrochemical gradients.
What types of gradients do transporter pumps generate? (2)
• Specific protein pumps that move solutes up their concentration gradient. • Powered by the energy released as different solutes move down its concentration gradient.
Secondary Active Transport Pumps (2)
• Both solutes move in the same physical direction.
Symporters
• Solutes move in opposite physical direction.
Antiporters
• Having both hydrophobic and hydrophilic parts.
Amphiphatic
• A type of membrane protein that is permanently attached to the biological membrane.
Integral Proteins
• Interact with the surface of the lipid bilayer of cell membranes.
Peripheral Proteins