Chapter 5 review Flashcards
What is the role of the plasma membrane?
separate intracellular fluid and extracellular fluid
regulate movement in and out of the cell
What factors affect membrane fluidity?
unsaturated fatty acids - love water
cholesterol - fewer fluids
inc temperature - inc fluidity
What two types of proteins are associated with membranes?
integral and peripheral proteins
What are the names of lipids and proteins when they have a carbohydrate attached to them?
Glycolipids & Glycoproteins
What are the components of a solution? How would you calculate the concentration of
a solution? What is osmolarity?
Solution: made up of solvents and solutes
Calculate: ___/mol
Osmolarity: concentration of all solute particles in solution
Does passive membrane transport require ATP? What are the three types of passive membrane transport?
No ATP
examples: simple diffusion, facilitated diffusion, osmosis
What is the definition of diffusion?
when molecules/ions go from an area of a high concentration to a low concentration
What are the characteristics of solutes that determine whether or not they can pass across a phospholipid bilayer? Would you expect an amino acid to pass across?
Lipid solubility - must be non-polar
size of molecule
yes an amino acid can cross due to small size
What are the two types of facilitated diffusion? What types of solutes, and what two types of proteins are involved? Is any input of energy needed?
Channel mediated diffusion and Carrier mediated diffusion
Carrier mediated: carrier alters shape for transport ex. sugars and amino acids
Channel mediated: substances diffuse through channels
leak channel open, gated channel: controlled by chemical or electrical signals ex. water, ions like salt
NO ENERGY IS NEEDED FOR EITHER
Describe simple diffusion
Diffusion of molecules directly though the bilayer
- nonpolar ex gasses, steroid hormones, fatty acids
What is the definition of osmosis? When does it occur? What direction does water move in? What is meant by osmotic pressure?
Diffusion of a solvent through a selectively permeable membrane
when: concentration of water differs on two sides of the membrane
Water moves from a more dilute to less dilute solution
Why is osmosis important for homeostasis?
distribution of water and fluid ex. healthy indv ECF=ICF
At equilibrium can both sides have the same osmolarity but different volumes?
yes
Isotonic solutions
Same concentration of non-penetrating solutes inside the cell
hypertonic solutions
higher concentration outside than inside of the cell makes cells shrink
ex. salt water
Hypotonic solutions
higher concentration inside the cell inside than outside
cells will swell
ex. pure water
How does active transport differ from facilitated diffusion?
movement of substances against the concentration gradient or movement of large substances
- ATP required
What does active transport require:
membrane protein and energy
Two types of active transport?
primary active transport
secondary active transport
Primary active transport?
substance binds to a transmembrane protein
hydrolysis of ATP
Phosphorylation of transmembrane protein
protein changes shape
substance goes to other side
Describe the sodium-potassium pump
3 sodium 2 potassium in
Atp binds with 3 na
Na binding causes ATP hydrolysis and pump changes shape
Na is released
K+ (potassium binds) and phosphate is released
Potassium in
Describe secondary active transport
coupling - one subtance goes against and one goes down
energy through substance going down
Symport transport
one direction
Antiport transport
both directions
What are the two types of vesicular transport?
ways to transport large particles
Endocytosis: substances move inside call
Exocytosis: substances moved outside cell
By what 3 mechanisms are materials endocytosed?
Phagocytosis: cells engulf the large particle at once
Pinocytosis: cell gulps tiny fluid
receptor-mediated endocytosis: receptor proteins tell which substances to enter
How are proteins exported from the cell, and what is this process called?
Exocytosis - transport to the ECF
What are the two types of local signaling and the one type of long distance signaling called?
Local signaling:
paracrine: molecules released by cell acts on nearby cells
synaptic: nerve cell releasing neurotransmitters to a synapse
Long distance:
endocrine: endocrine cells releasing hormones into body fluids
Ligands?
signaling molecules that bind to receptors
Receptor? what are the 2 types:
Proteins in plasma membrane
- G protein coupled receptors (GPCRs)
- ligand-gated ion channels
How do GCPRs work?
Ligand binds to GPCR
Gpcr activated changes shape
G protein binds to GPCR
GTP binds to G protein
G protein leaves GCPR and diffuses alng membrane
G protein binds enzyme and changes enzyme shape
cellular response occurs
