3.8, 3.12, 4.1, 4.2
Help!
|
|
||||
|---|---|---|---|---|---|
| typical life of a protein | a few days
🗑
|
||||
| a _____ protein is more readily degraded than ______ protein | degraded ; intact
🗑
|
||||
| what causes a protein to be degraded very quickly? | chemical or physical damage
🗑
|
||||
| ubiquitin | targets protein for degradation (attachment of peptide), sends to proteasome
🗑
|
||||
| proteasome | large protein complex that breaks protein up into individual amino acids and recycles it
🗑
|
||||
| ligand | any molecule that is bound to and affects a protein by either electrical attractions or weaker attractions due to hydrophobic forces
🗑
|
||||
| binding site | the region of a protein where a ligand binds
🗑
|
||||
| what does the binding of a ligand do to a protein? | it changes the conformation of protein (either activates it or inhibits it)
🗑
|
||||
| the closer the surface of ligand and binding site... | the stronger the attraction
🗑
|
||||
| for a ligand to be able to bind to a protein.. | it has to be close to the protein
🗑
|
||||
| what is a ligand's binding ability based on? | shape
structure
chemical composition
🗑
|
||||
| chemical specificity | CAN IT BIND
allows protein to identify one particular ligand
🗑
|
||||
| what does chemical specificity depend on? | the shape of binding site
🗑
|
||||
| molecules that are less specific can.. | bind a number of related proteins
🗑
|
||||
| the less specific a mlx is... | the more types of proteins that can bind
🗑
|
||||
| what determines the side effects of drugs? | the degree of specificity
🗑
|
||||
| affinity | WILL IT BIND & STAY BOUND
the STRENGTH of the ligand-protein binding
🗑
|
||||
| what determines how likely it is that a bound ligand will leave the protein surface and return to its unbound state? | affinity
🗑
|
||||
| different proteins can have the same_______ for a ligand but have different _____ for that same ligand | chemical specificity ; affinity
🗑
|
||||
| when there is high affinity... | very little of the ligand is needed to bind to the protein
🗑
|
||||
| saturation | the fraction of total binding sites that are occupied at any given time
🗑
|
||||
| all binding sites are occupied | 100% saturation
🗑
|
||||
| half the binding sites are occupied | 50% saturation
🗑
|
||||
| % saturation depends on | 1. the concentration of unbound ligand in the solution
2. the affinity of the binding site for the ligand
🗑
|
||||
| the greater the ligand concentration... | the more likely it is a ligand enters a binding site and binds
🗑
|
||||
| even if specificity is low, what can drive binding? | a high concentration
🗑
|
||||
| competition | when more than one type of ligand can potentially bind to a certain binding site
🗑
|
||||
| allosteric modulation | when a protein has two binding sites and the binding of a ligand to one of the sites alters the shape and activity of the other site
🗑
|
||||
| functional (active) site | carries out the protein's physiological function
🗑
|
||||
| regulatory site | where the modulator mlx binds, modifies shape and activity
🗑
|
||||
| what happens to a modulator in allosteric modulation? | once it binds and activates, it leaves/falls off
🗑
|
||||
| covalent modulation | covalent bonding of charged chemical groups to a protein
🗑
|
||||
| most common type of covalent modulation | adding a phosphate group to hydroxyl
🗑
|
||||
| is covalent modulation permanent or reversible? | it is permanent unless phosphoprotein phosphatase cuts the phosphate group off
🗑
|
||||
| what does adding or removing a phosphate group require? | enzymes
🗑
|
||||
| kinase | enzyme that ADDS the phosphate group to a protein
🗑
|
||||
| phosphatase | enzyme that REMOVES the phosphate group from a protein
🗑
|
||||
| the rates of enzyme-mediated runs can be increased by.. | increasing temp
increasing substrate concentration
increasing enzyme activity
increasing enzyme concentration
🗑
|
||||
| maximal saturation | when the active binding site of every enzyme is occupied by a substrate
🗑
|
||||
| what happens when the substrate concentration is too high concerning glucose in the kidney? | when glucose is too high, it will end up in urine, because the kidneys could not reabsorb
🗑
|
||||
| if there is twice as much enzymes.. | the saturation point is twice as high
🗑
|
||||
| in order to change concentration of an enzyme... | you must change the rate of enzyme synthesis or breakdown at the DNA level
🗑
|
||||
| first characteristics of enzymes | 1. does NOT undergo a chemical change as a consequence of the reaction that it catalyzes
🗑
|
||||
| second characteristic of enzymes | binding of substrate to enzyme's active site is the same as ligand binding to a protein
🗑
|
||||
| third characteristic of enzymes | enzyme increases rate of chemical reaction but doesn't cause a reaction to occur that wouldn't occur in its absence
🗑
|
||||
| fourth characteristic of enzymes | does not change chemical equilibrium, it only increases the RATE at which equilibrium is achieved
🗑
|
||||
| co-factor | helps binding and protein shape but does not participate in reaction
🗑
|
||||
| what type of mlx are co-factors? | METALS
🗑
|
||||
| example of co-factor | iron
helps O2 bind
allows hemoglobin to go from oxygenated state to deoxygenated state
🗑
|
||||
| co-enzyme | plays MAJOR role and participates DIRECTLY in reaction
🗑
|
||||
| what type of mlx are co-enzymes? | ORGANIC MLX (have carbons as part of their structure)
🗑
|
||||
| example of co-enzyme | B vitamins
NAD+, binds to alcohol mlx and helps them break down
🗑
|
||||
| fat-soluble vitamins | A,D,E,K
the only vitamins that will cause overdose
🗑
|
||||
| simple diffusion | movement of mlx from one location to another bc of random thermal motion
requires no energy or heat
🗑
|
||||
| does simple diffusion require ATP? | no
🗑
|
||||
| example of simple diffusion | oxygen, nutrients, and other mlx entering capillaries
🗑
|
||||
| which way do mlx move in simple diffusion | down their concentration gradient
🗑
|
||||
| diffusion will speed up as... | increase temperature
increase magnitude of difference in solute concentration from one side to another
🗑
|
||||
| flux | the amount of material crossing a surface in a unit of time
🗑
|
||||
| diffusion equilibrium | fluxes are equal in magnitude but opposite in direction
net flux = 0
🗑
|
||||
| magnitude of flux depends on | -temp
-mass of mlx
-surface area
-medium the mlx are traveling through
🗑
|
||||
| what is the major limiting factor of membranes | its chemical composition
🗑
|
||||
| polar molecules | diffuse into cells slowly or not at all
🗑
|
||||
| examples of polar molecules | H2O, Na+, K+, proteins
🗑
|
||||
| non-polar mlx | will diffuse easily because they have large permeability coefficients
can dissolve in non polar regions of membrane occupied by the fatty acid chains of phospholipids
🗑
|
||||
| example of non-polar mlx | O2, CO2, fatty acids, steroid hormones
🗑
|
||||
| ion channel | allows ions to diffuse across the membrane
🗑
|
||||
| ion channels have selectivity based on... | - channel diameter
- charged surface of subunits
- # of water mlx associated with ions
🗑
|
||||
| channel gating | process of opening/ closing ion channels
can occur many times each second
🗑
|
||||
| ligand-gated ion channel | binding of a ligand results in opening of the channel
🗑
|
||||
| mechanically-gated ion channels | open in response to physical deformation (like pressure) of receptor
🗑
|
||||
| voltage-gated ion channels | opened by change in voltage (electrochemical potential) conduct ions accounting to electrochemical gradient
🗑
|
||||
| one function of membrane transport proteins | maintaining membrane potential and electrochemical gradient
🗑
|
||||
| what is the charge inside of the cell? | slight negative charge
🗑
|
||||
| is the cell chemically balanced? | no
🗑
|
||||
| where do the opposite charges align? | on the surface of plasma membrane
🗑
|
||||
| transporters | integral membrane proteins
mediate the passage of large/polar molecules
🗑
|
||||
| mediated transport | movement of substances through the membrane
🗑
|
||||
| factors that determine the magnitude of solute flux in mediated-transport system | solute concentration
affinity of transporters for solute
# of transporters in membrane
rate of conformational change
🗑
|
||||
| two types of mediated transport | facilitated diffusion and active transport
🗑
|
||||
| facilitated diffusion | net flux of a molecule across a membrane always proceeds from HIGH to LOW concentration
*uses a transporter to move solute
contributes significantly to metabolic homeostasis
🗑
|
||||
| active transport | used to move substances 'uphill' against the concentration gradient
referred to as pumps
DIRECT USE OF ATP
🗑
|
||||
| two types of active transport | primary and secondary active transport
🗑
|
||||
| primary active transport | hydrolysis of ATP by a transport, directly relies on ATP
🗑
|
||||
| example of primary active transport | Na+ / K+ ATPase pump
🗑
|
||||
| concentration of Na+/K+ IN cell | Na+ 15 mM
K+ 150 mM
🗑
|
||||
| concentration of Na/K+ OUTSIDE cell | Na+ 145 mM
K+ 5 mM
🗑
|
||||
| secondary active transport | movement of an ion down its electrochemical gradient
is coupled to the transport of another mlx
INDIRECTLY uses ATP
🗑
|
||||
| two binding sites of transporters in secondary active | one for ion (normally Na+)
another for second substrate (ex: amino acid, vitamin)
🗑
|
||||
| the movement of Na+ is always in what direction? | high to low
🗑
|
||||
| how does secondary active transport use ATP? | indirectly
uses stored energy in the ion to get the substrate into cell because it is moving against its concentration gradient
🗑
|
||||
| cotransport | movement of actively transported solute into cell (same direction as Na+)
🗑
|
||||
| countertransport | movement of actively transported solute OUT of cell (opposite of Na+)
🗑
|
Review the information in the table. When you are ready to quiz yourself you can hide individual columns or the entire table. Then you can click on the empty cells to reveal the answer. Try to recall what will be displayed before clicking the empty cell.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Created by:
thomask9
Popular Physiology sets