Busy. Please wait.
or

show password
Forgot Password?

Don't have an account?  Sign up 
or

Username is available taken
show password

why


Make sure to remember your password. If you forget it there is no way for StudyStack to send you a reset link. You would need to create a new account.
We do not share your email address with others. It is only used to allow you to reset your password. For details read our Privacy Policy and Terms of Service.


Already a StudyStack user? Log In

Reset Password
Enter the associated with your account, and we'll email you a link to reset your password.
Don't know
Know
remaining cards
Save
0:01
To flip the current card, click it or press the Spacebar key.  To move the current card to one of the three colored boxes, click on the box.  You may also press the UP ARROW key to move the card to the "Know" box, the DOWN ARROW key to move the card to the "Don't know" box, or the RIGHT ARROW key to move the card to the Remaining box.  You may also click on the card displayed in any of the three boxes to bring that card back to the center.

Pass complete!

"Know" box contains:
Time elapsed:
Retries:
restart all cards
share
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

Phys Exam 1: Ch 4

Membrane Transport & Basics of Signal Transduction

QuestionAnswer
Describe 3 methods for membrane transport by simple diffusion. Give an example of an ion or solute that is transported by each mechanism. 1.Diffusion of lipid-soluble molecules; O2, CO2, Ethanol. 2.Diffusion thru pores (non-gated channels); Aquaporins - H2O. 3.Diffusion thru ion channels (voltage- and ligand-gated); Na+, K+
Name 5 factors that affect the rate of diffusion of an ion or solute through a pore or channel. 1.Concentration gradient, 2.# of pores in the membrane/# of OPEN ion channels, 3.Selectivity filter of the pore or channel, 4.Electrical Potential difference, 5.Pressure (capillary hydrostatic pressure)
If a drug is chemically modified to be more hydrophobic, would the rate of diffusion across a lipid bilayer increase, decrease, or stay the same? Increase
If aquaporins are removed from the lipid bilayer, would the rate of diffusion of water across a lipid bilayer increase, decrease, or stay the same? Decrease
After the opening of voltage-gated K+ channels, would the rate of diffusion of Na+ across a lipid bilayer increase, decrease, or stay the same? Increase
Compare & contrast primary (1*) vs. secondary (2*) active transport. The activity of which pump is the primary driving force for secondary active transport for most cells? 1*:energy needed to transport ion or molecule AGAINST favorable gradient via exergonic chemical rxn (ATP hydrolysis), use pumps; 2*:Downhill transport of 1 ion/molecule coupled w/uphill transport of another ion/molecule; exchangers or cotransporters
True or False: The Na+/K+ pump transports 3K+ to the extracellular fluid and 2Na+ into the intracellular fluid. FALSE: 3Na+ --> extracellular, 2K+ --> intracellular
True or False: The Na+/K+ pump is electroneutral. FALSE: electrogenic (moving an unequal amount of charge); 1.Creates negative charge inside cell to maintain negative resting membrane potential; 2.Establishes electrochemical gradients for movement of Na+ & K+; 3.Helps maintain cell volume
True or False: The Na+/K+ pump uses the energy liberated from the ATP hydrolysis to drive the transport of ions across a lipid bilayer. TRUE: the liberated energy drives conformational changes in the pump.
True or False: The Na+/K+ pump acts as an ATPase enzyme. TRUE: the pump cleaves a high-energy phosphate bond of 1 ATP molecule
True or False: The Na+/K+ pump helps to maintain cell volume by pumping more ions out of the cell than in. TRUE: By pumping more ions out of the cell (3 Na+) than in (2 K+), the pump helps balance osmolarity and movement of H20. Ex: If cell volume increases, pump activity increases
True or False: Ca2+ concentration in the cytoplasm is higher than the extracellular fluid for most cells. FALSE: Cytoplasmic [Ca2+] is kept EXTREMELY LOW
True or False: There are no 1* active transport mechanisms for Ca2+. FALSE: Primary active transport for Ca2+ into internal stores (sarco/ER, vesicles) and out of the cell.
True or False: The 2* active transport of Ca2+ is driven primarily by the activity of the Na+/K+ pump. TRUE: The transport of Na+ out of the cell by the Na/K pump encourages 2* transport of Na into the cell and Ca out of the cell via the Na/Ca exchanger
True or False: Epithelial membrane transport can only occur by simple diffusion across tight junctions. FALSE: simple diffusion, facilitated diffusion, Primary Active Transport, Secondary Active Transport
True or False: In epithelial membrane transport, the apical and basolateral membranes express identical carrier proteins. FALSE
True or False: For membrane transport across epithelia, secondary active transport is driven primarily by the activity of the Na+/K+ pump. TRUE: Na/K pump on the basolateral side sets up the [gradient] for Na to come in thru the apical side, which draws in glucose with it
Compare & contrast endocrine vs. paracrine vs. autocrine cell signal Endocrine: signal travels thru bloodstream Paracrine: b/n 2 adjacent cells (ex: neuronal synapse) Autocrine: cell makes & secretes signaling molecule (ex: immune system activation)
Name 5 common signal transduction pathways. Receptor Tyrosine Kinases, Ligand-gated Ion Channels, Steroid Hormone Receptors, Antigen Binding Receptors, G-protein Coupled Receptors
For Receptor Tyrosine Kinases, identify an example of a specific receptor, the signaling molecule the receptor binds, and the general outcome of the signal. Receptor = ?; signaling molecule = growth factors; Outcome = cell growth, differentiation
For Ligand-gated Ion Channels, identify an example of a specific receptor, the signaling molecule the receptor binds, and the general outcome of the signal. Receptor = Nicotinic ACh receptors; signaling molecule = neurotransmitters; Outcome = neurotransmission
For Steroid Hormone Receptors, identify an example of a specific receptor, the signaling molecule the receptor binds, and the general outcome of the signal. Receptor = ?; signaling molecule = steroid hormones; Outcome = multiple (sex hormones, etc)
For Antigen Binding Receptors, identify an example of a specific receptor, the signaling molecule the receptor binds, and the general outcome of the signal. Receptor = ?; signaling molecule = pathogens; Outcome = immune response
For G-protein Coupled Receptors, identify an example of a specific receptor, the signaling molecule the receptor binds, and the general outcome of the signal. Receptor = ?; signaling molecule = multiple; Outcome = multiple
Describe the general mechanism for activation of a G-protein. 1.extracellular signalling molecule binds to G-protein complex; 2.alpha-subunit releases and binds to receptor protein; 3.(a)DAG releases and binds to enzyme, (b)IP3 releases, causes Ca2+ release from ER
Describe the general mechanism for activation of a Receptor Tyrosine Kinase. Why are these molecules, or molecules in these signaling pathways frequently mutated in human cancers? 1.extracellular signalling molecule binds; 2.ATP is hydrolyzed 3.tyrosine is phosphorylated (phosphorylated dimer) and is activated; 4.Activated protein system causes the cellular resoponse
Why are the molecules, or molecules, in Receptor Tyrosine Kinase signaling pathways frequently mutated in human cancers? Because they play key roles in cell growth, proliferation, and differentiation
Discuss the clinical correlation of Multi-Drug Resistant Transporter 1 (MDR1) for Primary Active Transport 1.ATP-binding cassette (ABC) protein; 2.Use the energy of ATP hydrolysis to expel cationic metabolites and hydrophobic drugs across the cell membrane; 3.Defense mechanism in cancer cells turn on MDR1 and renders them resistant to chemotherapeutics
Which ions are higher on the outside of the cell? Na+, Ca2+,Cl-, HCO3-, Glucose
Which ions are higher on the inside of the cell? K+, Mg2+, Phosphates
Created by: hclark86