Membranes Flashcards
Name the membrane component: diffuses quickly and faces the same plane as the membrane
Phospholipids
Name the Membrane Component: diffuses slowly, and faces the same plane as the membrane.
Lipids & Proteins (think lipid rafts)
Name the Membrane Component: requires flipases to diffuse to the opposite side of a membrane
Phospholipids
What are Lipid Rafts made of?
cholesterol & proteins
What enzyme allows phospholipids and lipids to flip to face the other side of a membrane, and thus keep them diffusing easily and quickly to even out their concentration all over the membrane?
flipases
Why do phospholipids move to areas of the membrane where they’re least concentrated?
they’re diffusing
What region of the membrane is made of: proteins, carbohydrates, and phospholipid heads?
the hydrophilic membrane region
The ___ ____ membrane creates hydrophilic planes in and outside of cells.
fluid mosaic
The membrane is ___ ____.
Selectively Permeable
Name the two main types of fatty acids in membranes.
Saturated (each carbon holds as many hydrogens as possible) and Unsaturated (double or triple bonds take the place of where some hydrogens could be bonded to carbons)
Why are unsaturated fatty acids harder to “stack” and therefore less solid at room temperature?
their double bonds create a “kink” in the hydrocarbon chain that makes it harder to stack them
Adding saturated fatty acids make a membrane ___ fluid, while adding unsaturated fatty acids make the membrane ___ fluid.
less ; more
Which type of fatty acid would have a higher melting point?
saturated fatty acids
Fatty acids play a role in energy storage by being converted to ___ molecules.
triglyceride
What are triglyceride molecules made of?
3 fatty acids attached to a sugar (glycerol) backbone
How are triglycerides changed into glycerophospholipids for insertion into membranes?
a fatty acid chain is removed so a negatively charged phosphate group can be added
Name the parts of a phospholipid (technically called a glycerophospholipid!)?
2 fatty acids ; 1 glycerol ; 1 phosphate
What membrane lipid stabilizes the membrane in extreme heat, and gives it fluidity in the cold?
cholesterol
What are the three main types of fats found in the membrane?
Sphingolipids (1) ; Cholesterol (2) ; and Waxes (3)
____ ____ can activate or deactivate transporters for facilitated diffusion and active transport.
Membrane Receptors
Name 3 primary roles of cholesterol
steroid synthesis ; stabilizing the cell membrane ; increasing cell membrane fluidity
What lipids are derived from sphingosine?
sphingolipids
Phospholipids have __ less fatty acids than triacylglycerol.
1
What type of fat increases rigidity in plant cells membranes by stabilizing the hydrophobic region of the cells’ membranes?
waxes
What are waxes composed of?
a long fatty acid chain with a long chain ester
Name the 4 types of sphingolipids found in a cell membrane?
ceramides, sphingomyelin, cerebrosides, and gangliosides
Where do sphingolipids differ from phospholipids (region)?
in their hydrophilic region (they have an ester long chain instead of a sugar and phosphate)
What is the point of sphingolipids?
to yield biologically important (necessary) lipids: ceramides, sphingomyelin, cerebrosides, and gangliosides
Name the 4 major molecular components of the cell membrane.
Proteins ; Carbohydrates ; Membrane Receptors ; Cell-Cell Junctions
___ (a major membrane component) are important for forming biofilms and cell membrane communication and messaging.
carbohydrates
Name the 3 major types of membrane proteins.
Integral Proteins (Transmembrane & Embedded, I think?) and Peripheral (Membrane Associated)
Are transmembrane and embedded proteins both integral proteins?
idk ask
What type of membrane protein is Cytochrome C? (Hint: it’s vital for making ATP)
it’s a membrane-associated (peripheral) protein
What type of membrane protein is Cytochrome C Oxidase?
Membrane-Associated (peripheral) protein
What type of membrane protein goes through both ends of a membrane, and likely carries out tasks on both sides?
Transmembrane Proteins
What type of membrane protein is an Aquaporin?
transmembrane protein
What kind of membrane protein is the Sodium-K Pump?
transmembrane protein
What kind of membrane proteins are chloride channels?
transmembrane proteins
What kind of membrane protein is found on the outer edges of the membrane and is not associated with the membrane’s interior?
Membrane-Associated (Peripheral) Proteins
What kind of membrane protein can associate with the interior or exterior of a cell membrane, but not both?
Embedded Proteins
What kind of membrane protein are prostaglandin syntheses 1 and 2? (Hint: these make the proteins that cause smooth muscle contraction in the outer bilayer.)
Embedded Proteins
Why are membrane carbohydrates generally hydrophilic?
they tend to have lots of oxygen molecules
What types of carbohydrates tend to attach to proteins on extracellular surfaces?
membrane carbohydrates
True / False: membrane carbohydrates form the cell coats found in biofilms, which compose plaques on our teeth?
True!
True / False: Blood types come from surface carbohydrates!
true!
___ (membrane component molecule) can be recognized by both the immune system and microbes.
True!
Name the 3 types of cell-cell membrane junctions.
Gap Junctions (1) ; Desmosomes (2) ; and Tight Junctions (3)
In __ diffusion, permeable (?) substances follow their concentration gradients across the membrane.
Simple Diffusion (a type of passive transport)
In ___ diffusion, energy could be supplied by concentration gradients or entropy changes, but NOT ATP.
Simple Diffusion
Can water move along it’s own concentration gradient?
yes
What is Osmosis?
diffusion of water
When the solute concentration is equal inside and outside of a cell, what kind of state is the cell in?
Isotonic
True / False: If the environment around a cell is hypotonic, then that cell has a lower water concentration than it’s surroundings.
True!
True / False: If the environment around a cell is hypertonic, then that cell has a higher water concentration than it’s surroundings.
True!
____ ____ (pi) is the driving force behind osmosis.
Osmotic Pressure (Pi)
Is Osmotic Pressure (Pi) a colligative property?
Yes
What is the formula for Osmotic Pressure (Pi)?
Pi = iMRT i = Van't Hoff Factor (number of particles that dissociate into solution) because Osmotic Pressure is a colligative property M = Molarity R = Ideal Gas Constant T = Temperature in Kelvin
How can you quickly tell which solution of ions will have the highest or lowest ionic pressure?
the solution that dissociates into the most ions with the highest molarity will have the highest ionic pressure
___ ___ uses membrane proteins to transport molecules that are otherwise impermeable to the membrane.
Facilitated Diffusion
The ___ ___ of the cell membrane is too high for large / polar / charged molecules to pass through it freely so that a membrane protein is needed to help these across.
Energy Barrier
What type of transport could move ions across a membrane without the input of energy?
Facilitated Diffusion ; sodium ions are impermeable, so you need a protein to transport them
What is Simple Diffusion in reference to solute transport across membranes?
small, non polar molecules (like diatomic oxygen and carbon dioxide) are able to diffuse across the membrane according to their concentration gradients.
In what type of transport does water move down it’s own concentration gradient across the membrane through specialized proteins? Hint: water always moves aganst the concentration gradient of solute.
Osmosis
Water always moves (with / against) the concentration gradient of the solute.
AGAINST
For ___ ___ the solute still moves across the membrane down it’s concentration gradient (no ATP is used), but needs to travel through a protein channel or a carrier protein because it is impermeable to the membrane.
Facilitated Diffusion
Symport and Antiport are two processes associated with what kind of solute transport across membranes?
Secondary Active Transport
What is Symport?
a type of secondary active transport in which the particles being moved are moving in the same direction across the membrane
What is Antiport?
a type of secondary active transport in which the particles are moving in opposite directions across the membrane
What are the two types of active transport?
Primary Active Transport: uses ATP
Secondary Active Transport: uses one molecule flowing down it’s concentration gradient to fuel transporting another molecule going against it’s concentration gradient
EX: Na+ ions are flowing down their concentration gradient through a membrane protein, that uses this flow to move in an amino acid against it’s concentration gradient (in the opposite direction of the sodium ions). What type of transport is this?
Secondary Active Transport: the Na+ concentration gradient fuels the amino acid going against it’s own gradient.
What is the driving energy source behind secondary active transport, since ATP cannot be used to fuel it?
the entropy change of allowing a solute to go with it’s concentration gradient (same driving force as facilitated diffusion and passive transport!)
What is Primary Active Transport? What proteins does it typically use?
a type of active transport (moves solute against it’s concentration gradient) using ATP as it’s fuel ; typically done using transmembrane ATPases (the membranes that accomplish this are called this???)
What is Secondary Active Transport?
a type of active transport (moves solute against it’s concentration gradient) using the energy from the entropy change of ANOTHER molecule flowing down (with) it’s concentration gradient
What’s our quick and dirty way to see what solute has the most osmotic pressure?
look at it’s molarity and the number of ions it will dissociate into, that quantity (roughly multiplied) is directly proportional to osmotic pressure!!
Osmosis is driven by ___ ___.
Osmotic Pressure
While passive transport is driven by entropy change, what drives active transport? (in terms of energetic quantities)
enthalpy and temperature
Facilitated Diffusion transports impermeable solute across membranes using what two proteins?
Protein Channels: can be open or closed in response to diverse signals
Carrier Proteins: work like revolving doors so that a solute enters from one side, and the protein shuts behind it before opening it’s other side to let the solute exit
What is the Occluded State? Hint: it applies to Carrier Proteins.
the occluded state is when the protein is not open to either side. this state occurs in between letting the protein enter and letting it exit. Remember, revolving door.
True / False: gong down one’s concentration gradient creates more disorder (S) and is therefore favorable.
hell yasss
True / False: as temperature increases so does the rate of passive transport!
True
Delta G is negative and positive for what kinds of transport, respectively?
delta G is negative for favorable processes, no energy input, spontaneous = Passive Transport
Delta G is positive for non spontaneous processes, need energy input, non spontaneous = Active Transport
White blood cells eating pathogens is exocytosis or endocytosis? Specify.
endocytosis, specifically phagocytosis
Neurotransmitter release at the synapse is an example of exocytosis or endocytosis?
Exocytosis
There are tow main reasons that a cell would choose endo/exocytosis for transport. Name them
the particles being transported are:
- too big to be transported by a protein
- too big of a quantity to effectively transport any other way
What is Pinocytosis?
the cell is getting fluids and dissolved compounds
What is Phagocytosis?
pac man ; cells eats solids
Do phagocycotis and pinocytosis use vesicles?
yes ; vesciles are necessary for this process
