Exam 2 AP study guide-1

What term means within the cell?

intracellular

What term means between cells?

extracellular

What is the term for what happens in a cell between the binding of a ligand to a receptor and the final response in the cell?

signal transduction

What is the term for a drug that can bind to a receptor and trigger signal transduction?

agonist

What receptor signaling pathway involves a cascade of phosphorylations?

receptor tyrosine kinase

What enzyme converts cAMP into AMP, thus inactivating it?

cAMP phosphodiesterase

State two type of receptors that are themselves enzymes.

1. guanylyl cyclase receptor

2. receptor tyrosine kinase

What are the substrate and products of the reaction catalyzed by guanylyl cyclase? Be sure to say which is the substate and which are the products.

substrate: GTP

products: cGMP = 2 inorganic phosphates

What is the advantage of having so many steps in the signal transduction pathway of many of the receptors?

it allows for amplification of the response

Draw a flow chart for the steps of signal transduction in the Gs protein-coupled receptor pathway. Include all the steps from lecture. Start with ligand binds to G protein-coupled receptor.

add

Protein receptors for intercellular messengers have the same four characteristics of protein binding sites (chemical specificity, saturation, affinity, and competition).

false

The number of protein receptors in the plasma membrane of a cell is very stable over time.

true

Intercellular messengers that bind to intracellular receptors are

lipophilic

The JAK protein often phosphorylates what transcription factor as discussed in lecture? (use abbreviation)

STAT

What was the general name given in lecture for drugs that can bind to a protein receptor but do not activate signal transduction.

antagonist

Most intracellular receptors are transcription factors

true

Most intercellular messengers bind to

Membrane-bound receptors

Ion channel receptors are

Ligand-gated ion channels

What effect does the alpha subunit of the Gi protein have on adenylyl cyclase?

Decrease its activity

The movement of charge is called

current

The difference in charge between two location is called the

voltage/electrical potential

What chemicals are produced when cyclooxygenase enzymes are activated?

prostaglandins

What enzyme liberates arachidonic acid from a membrane phospholipid?

phospholipase A2

What protein, discussed in lecture, does calcium bind to in order to activate a specific protein kinase?

calmodulin

What are the organs of the central nervous system?

brain, spinal cord

What two organ systems are involved in coordinating the functions of cells to maintain homeostasis? Which of these two systems acts more specifically and quickly?

nervous system- quicker and more specific

endocrine system

What are the two sources for the calcium that can enter the cytosol of cells?

smooth endoplasmic reticulum (smooth ER)

extracellular fluid

What are the three components of a synapse?

1. presynaptic axon terminal

2. synaptic cleft

3. post synaptic density

What are the three types of synapses based on the location of the synapse on the post-synaptic cell?

1. axosomatic synapses

2. axodendritic synapses

3. axoaxonic synapses

How does the concentration of first messenger at a receptor decrease over time?

• diffusion of the messanger out of local area

• enzymes degrade the messanger

• reuptake by releasing cell or uptake by after cell

• receptor mediated endocytosis

How does phosphorylation of receptors reduce the activity of the signal transduction pathway?

phosphorylation of the receptor can decrease the receptors’ affinity for the first messenger and its second messangers. Phosphorylationcan also target the receptor for endocytosis

Draw a neuron and label the parts

List the five types of glial cells

1. oligodendrocyte

2. Schwann cell

3. astrocytes

4. microglia

5. ependymal cells

oligodendrocyte

makes myelin in the central nervous system

Schwann cell

makes myelin in peripheral nervous system

astrocytes

regulate concentration of neurotransmitters nutrients, ions in the cerebrospinal fluid help form the blood brain barrier

microglia

immune function for central nervou system

ependymal cells

line ventricals and make cerebral spinal fluid

Which of the following are second messengers?

1. cAMP

2. IP3

3. Calcium

4. Protein kinase A

5. Alpha subunits of G proteins

6. DAG

7. G protein coupled receptors

8. Adenylyl cyclase

Gs and Gi protein-coupled receptors would not both be present in the same cell.

false

Neurons usually use ________ for intracellular communication, and _________ for intercellular communication.

electrical signals, chemical signals

The excess negative change in cells is

only along the membrane

What proteins are involved in anterograde transport in axons

kinesins

A solution containing 200 mM of a permeable solute and 300 mM of a non-permeable solute would be

hypersomotic

A solution containing 200 mM of a permeable solute and 300 mM of a non-permeable solute would be

isotonic

what proteins ar involved in retrograde transport in axons?

dyneins

A collection of neuronal cell bodies outside the central nervous system is called a

ganglion

A collection of neuronal axons inside the central nervous system is called a

tract

which type of neurons are most numerous?

interneurons

A single neuron can be both pre-synaptic and post-synaptic

true

A single neuron msy be post-synaptic to thousands of pre-synaptic neurons

true

What protein uses the most ATP in the brain?

sodium potassium pump

What two factors determine the driving force for ions?

1. concentration gradient

2. electrical potential (voltage)

What is the name of the equation that can be used to determine the equilibrium potential for an ion?

Nerst equation

What equation was given in lecture for the flux of an ion?

J=g(Vm-Veq)

A trivalent cation has an intracellular concentration of 0.1 mM and an extracellular

concentration of 10 mM. What is the equilibrium potential of this cation?

(1/3)62log(10/.1)=41.33 mV

If you decrease the extracellular concentration of the above cation, what will happen to its equilibrium potential?

less positive

What happens to potassium’s equilibrium potential if you increase the amount of potassium in the cell?

It becomes more negative

What happens to sodium’s equilibrium potential if you increase the amount of sodium outside the cell?

It becomes more positive

If an anion has a higher concentration outside the cell than inside the cell, the anion’s equilibrium potential will be

negative

At the resting membrane potential, which ion has the greater driving force?

sodium

Assuming the only permeable ions across the plasma membrane are sodium and potassium, at the resting membrane potential

The inward flux of sodium equals the outward flux of potassium

If more potassium leaves the cell than sodium comes in, assuming those two are the only permeable ions, then the membrane potential will

Become more negative

If the membrane potential becomes more negative, what happens to the driving force for sodium?

Increase

If the membrane potential becomes more negative, what happens to the driving force for potassium?

decrease

Assuming the membrane is only permeable to sodium and potassium, at the resting membrane potential, the flux of sodium into the cell equals the flux of potassium out of the cell.

false

If you have two chambers separated by a semi-permeable membrane that is only permeable to potassium, and you put 10 mM of potassium chloride in one chamber, and 1 mM of potassium chloride and 9 mM of sodium chloride in the other chamber, potassium will flux across the membrane until the concentration of potassium is the same on both sides.

false

What protein uses the most ATP in the brain?

sodium potassium pump

If the concentration of a monovalent anion is 3mM inside the cell and 30mM outside the cell, what is the equilibrium potential of the anion in mV?

-62

The excess negative charge in a cell is

only next to the membrane

Potassium’s equilibrium potential is

negative

sodium’s equilibrium potential is

positive

only an extremely small percentage of the K+ in the cell has to leak out to cause a 80 mV change in potential

true

which ion is more permeable at rest?

potassium

__________ have equilibrium potentials

ions

A solution that contains 400 mM of a non-permeable solute and 200 mM of a permeable solute would be

hypertonic

A solution that contains 400 mM of a non-permeable solute and 200 mM of permeable solute would be

hyperosomotic

If a cell does not regulate chloride concentrations, then the equilibrium potential for chloride equals the resting membrane potential in that cell.

true

The concentration of potassium is the same in the cerebrospinal fluid and the blood.

false (blood brain barrier)

If you increase the potassium permeability, what will happen to the membrane

potential?

Hyperpolarize

If you increase the intracellular concentration of sodium chloride, what will happen to the membrane potential?

Hyperpolarize

If you increase the intracellular concentration of potassium chloride, what will happen to the membrane potential?

Hyperpolarize

Changing the extracellular concentration of __________________ has a bigger impact

on the resting membrane potential.

potassium

Given the following:

extracellular sodium concentration = 100 mM

intracellular sodium concentration =10 mM

extracellular potassium concentration = 10 mM

intracellular potassium concentration = 100 mM

the only permeable ions across the plasma membrane are sodium and potassium

sodium and potassium have the same permeability across the membrane

What is the membrane potential? (Remember, a number without units is meaningless.)

0 mV

If there are no active transport mechanisms for chloride in a cell, the concentration of chloride will be

the same inside and outside the cell

If you increase the sodium permeability, what will happen to the membrane potential?

depolarize

If you increase the extracellular concentration of sodium chloride, what will happen to the membrane potential?

depolarize

If you increase the extracellular concentration of potassium chloride, what will happen to the membrane potential?

depolarize

Depolarization ______________ the driving force for potassium to leave the cell.

increases

increasing the extracellular concentration of sodium chloride will cause the cell to

depolarize

Increasing the extracellular concentration of potassium chloride would cause the cell to

depolarize

decresing the extracellular concentration of potassium chloride wouls cause the cell to

hyperpolarize

decreasing the intracellular concentration of the sodium chloride would cause the cell to

depolarize

decreasing a cell’s permeability to sodium will cause the cell to

hyperpolarize

decreasing a cell’s permeability to potassium will cause the cell to

depolarize

A solution that contains 100 mM of non-permeable solute and 200 mM of permeable solute is

iso-osmtic

a solution that contains 100 mM of non-permeable solute and 200 mM of permeable solute is

hypotonic

The movement of charge in neurons is faster than the diffusion of ions.

true

When a sodium channel opens in a graded potential, this causes the flux of potassium out of the cell to increase.

true

At the resting membrane potential, (select all that apply)

• The voltage-gated potassium channel is closed

• The voltage-gated sodium channel is closed