Plasma Membrane Flashcards
8 Functions of the Plasma Membrane
2.) Cell compartmentalization
3.) Decides which cells can pass through and not pass through, which can attach and which can’t attach
4.)Anchour
5.)Produces energy such as ATP
6.)Attacking an organ after a transplant because it can tell it’s not yours
7.)Cell division
8.) Cells stick together
2 types of metabolic pathways
Anabolic (form small to big)
Catabolic (from big to small)
Parts of a membrane
lipid bilayer
proteins
cholesterol
glycolipids
Amphipathic
A molecule has both hydrophobic and hydrophilic parts
What types of groups are always hydrophilic
Hydroxyl
What do unsaturated fatty acids look like and example
chains that are double-bonded together and kinked
Ex: canola oil that always stays liquid
What is the fluidity of the lipid bilayer influenced by
temperature and composition of lipid molecules
What happens when temp drops in a molecule
molecules pack tightly together and from a thick membrane gel
Functions of a membrane protein
transport things in and out of the cell
send a message to other cells warn them of an attack
Types of membrane proteins
integral and peripheral
Integral proteins
inside the membrane
Peripheral membrane
on the surface
held together with non-covalent bonds
made of polar and non-polar amino acids
mostly in the cytoplasmic side of the membrane
Passive transport
no energy
against the concentration gradient
low -> high concentration
Active transport
energy required
against concentration gradient
low -> high concentration
4 types of passive transport
-simple diffusion
-facilitated diffusion
-osmosis
-turgor pressure
simple diffusion
-few things go through the membrane
-aquaporin helps water get across
-wants to be at equilibrium
osmosis
-movement across a selectively permeable membrane
-only with water
-water flows to higher concentration on balance out
facilitated diffusion
-channel (open on both sides)
-Gate (open one end at a time)
-Follows the concentration gradient
-uses proteins
Turgor pressure and types
-in plant cells
Hypertonic (shrinks, water goes out)
Isotonic (equal, water goes in and out at an equal rate)
Hypotonic (fat, water goes in)
5 Types of active transport
uniport
symport
antiport
exocytosis
endocytosis
uniport
1 molecule goes across a membrane
symport
2 different kinds of molecules go across a membrane in the same direction and time
antiport
one type of molecule coming out while another type of molecule comes in
How many kinds of junction are there for animal and plant cells
4 animal
2 plant
2 Basic techniques of breaking open a cell and example
mechanical/physical (liquid nitrogen, blender)
chemical (osmosis)
What is centrifugation
spinning a sample so fast that the molecules separate into layers
4 Animal cell junctions
desmosomes
adherens
gap
tight
adherens junctions (3)
-made of actin and cadherin
-hold cell membranes together but not close enough that they fuse together
-like paces when tiling a floor
desmosomes (5)
-like buttons on a sofa
-connections that hold cells together and attach inside the cell
-placed randomly
-space big enough between that water and ions can flow
-Found in skin and intestines
Tight junctions (4)
-found in trachea
-seal adjacent cells together tightly
-creates a waterproof seal
-like quilting stiches
Gap junctions (4)
-open and close like an iris diaphragm
-how cells communicate
-connect cells with a protein channel that allows them to communicate and transfer small molecules and ions
-2-4nm space between membranes
2 types of plant cell junctions
middle lamella
plasmodesmata
middle lamella
a glue made of a polysaccharide called pectin that glues two cells together
plasmodesmata
cytoplasm that runs between to plant cells though a hole in the cell wall
the fluid mosaic model of membrane shows that
membrane components can move within the lipid bilayer
passive transport of molecules across a membrane is
an energy independent process
What can’t pass through the membrane by diffusion
ions
transmembrane proteins may be single peptides or complexes
true
chromosomes are composed of
chromatin
In prophase, chromosomes condense. How many total chromatids are there in humans at this point
92
