Chp 5-7 Test Flashcards
what factors might affect membrane permeability
of unsaturated and saturated fatty acid tails
temperature: high temp may denature proteins making it more permeable or cool temp will cause the membrane to solidify (if the temperature changes slightly it will stay fluid because it has unsaturated fatty acid tails that do not let them pack too tight)
amount of proteins found in the membrane: larger amount then more molecules can move in and out
pH: may denature some of the proteins
examples of passive transport
NO ENERGY: diffusion, osmosis, facilitated diffusion
diffusion
tendency for molecules to spread out evenly in a defined space; random thermal movement (high to low concentration) EX: dropping food color into water NO ENERGY NEEDED
osmosis
diffusion of water across a membrane structure EX: water entering a cell (high to low concentration) NO ENERGY NEEDED
facilitated diffusion
need a transport channel protein with a pathway because the molecules are either small and polar or too large to fit through the membrane without the transport channel protein (high to low concentration) EX: aquaporins NO ENERGY NEEDED
examples of active transport
NEED ENERGY (ATP): sodium/potassium pump, endocytosis, exocytosis
sodium/potassium pump
pump sodium against the gradient and out of the cell and bring potassium into the cell. ATP phosphorylates the transport protein causing it to change its shape
endocytosis
movement of molecules or liquids into the cell creating a vesicle using energy EX: a macrophage digesting a viral infected cell (two types, pino- and phagocytosis)
exocytosis
taking a vessel that the golgi apparatus has made and the vessel merges with the cell’s plasma membrane to empties its contents outside the cell EX: signal molecules that the cell molecules that is releasing a hormone into the blood stream
hypertonic
a solution that has higher solutes but lower water compared to whatever is in the solution. The cell will shrink and shrivel up.
hypotonic
a solution that has lower solutes but higher water compared to whatever is in the solution. The cell will expand-do not worry if a plant cell, worry if animal bc no cell wall and might burst.
isotonic
solute concentration in solution is equal to solute concentration in the cell. water concentration in solution is equal to the water concentration in the cell
what happens when signal molecules bind to G-coupled protein
G-couples protein receptors are sitting in the membrane. A signal molecule has to bind to the protein receptor-specific for it, has the same shape. Causing the G-protein/GDP to be activated by receiving a phosphate and forming GTP. Then the G-protein travels along the inside of the membrane using microtubules and ATP. It then binds to an enzyme (Adenyl cylcase) that is also in the membrane and activate it by changing its shape. When the signal molecule detaches the enzyme deactivates and goes back to its original shape and the G-protein loses a phosphate and is inactive.
what types of signal molecules pass easily through membranes
small molecules (O, CO2) or non polar molecules (steroids, estrogen). their receptors are in the cytoplasm
yeast mating factors and how they work
Yeast a creates a signal molecule called alpha and the alpha yeast will create a signal molecule called a. They release them through exocytosis. The signal molecules of alpha will bond to the alpha yeast, the signal molecules of a will bond to the alpha a. When they bind they signal each other to come together. Their nuclei together.
first messenger molecule
the original signal molecule. function: starts a signal transduction pathway
second messenger molecule
nonprotein water soluble molecule that comes in later in the pathway to help push the signal along farther into the pathway. EX: cAMP
cAMP
its a second messenger molecule and it pushes the signal farther into the pathway (cyclic AMP)
purpose of phosphorylation cascades
the transduction part of the cascade using kinases to phosphorylate other molecules which continue the signal. possible cell responses: turning on/off a gene, stop/starting to make a protein, and tells cell to divide
ATP-where is the energy stored in the molecule
in the bonds-the potential energy in the bonds of the phosphate
enzymes
usually a protein, has an active site that was coded during the folding process (active site fits the substrate). creates an environment for the substrate reaction
substrates
the molecule or molecules that fit into the enzymes active site. creating an induced fit and producing the product
allosteric regulators
a molecule that binds to the enzyme at a different place than the active site resulting in its ability to regulate the availability of the inactive site-can inhibit or enhance
exergonic reaction
spontaneous reaction, releases energy EX: ATP
endergonic reaction
non spontaneous reaction, absorbs energy EX: photosynthesis
anabolic reaction
consumes energy to synthesize complex molecules from simpler ones EX: condensation reactions
catabolic reaction
releases energy by breaking down complex molecules into simpler ones EX: hydrolysis
ways to regulate enzyme catalysis
by the amount of substrate, amount of enzyme available, inhibitors, enhancers, temp/pH if a protein
understand feedback inhibition in terms of enzymes and products
use product to start a reaction from happening. Product becomes an allosteric regulator. will block different steps of a reaction
explain the effect of pH/temperature on enzyme function
temperatrue: enzyme will unravel and denature due to the high kinetic energy of the molecules (too hot). the enzyme will denature due to the low kinetic energy of the molecules (too cold)-negative impact
pH: protons=positively charged. mess with ionic bonds in the protein-negative impact
competitive inhibitor
a molecule that competes for the active site, it will fit in the active site so the substrate cannot and inhibits the reaction
noncompetitive inhibitor
a molecule that binds to the enzyme that causes the closing off or shape change of the active site causing the substrate to not be able to bond to the active site
movement of H+ ions down the gradient is what type of transport
active transport to pump the ions, using energy, to pump from the mitochondria matrix to the inter membrane space. when the protons come through the ATP synthase by facilitated diffusion
what has to be present in the membrane for NADH and FADH2 to drop off their energy and create ATP
proteins in the membrane
ATP synthase
how is ATP produced in cell respiration-what process
cheimiosmosis process of oxidative phosphorylation
what happens when signal molecules bind to tyrosine-kinase receptors
need two signal molecules to bind to the receptors that causes the tyrosine-kinase receptors to come together and form a dimer. The receptors have sites where phosphates and ATP can phosphorylate the dimer and changes the shape slightly. Then the relay proteins can attach to the activated tyrosine area to activate the relay protein and changes their shape. To inactivate take off signal molecule.
how can the rate of reaction of an enzyme be measured
amount of product it is producing, measure of appearance of product, measure of disappearance of substrate
effect of temp on cell respiration
plant: do better in warmer temperature
animals: warm blooded have to regulate body temperature and burn more in colder temperatures to stay warm. cold blooded do not have to burn more in colder temperature
