Does a membrane separate two water compartments?
yes
What controls the cell's internal environment?
cell membrane
What provides energy for the cell?
mitochondria
What is energy stored as (high energy)?
ATP
Where is DNA located?
nucleus
What makes proteins?
rough ER
What has no ribosomes, stores and releases calcium ions and makes and breaks down fats (lipids) and steroid hormones?
smooth ER
What organelle makes ribosomes?
nucleolus
Where is the nucleolus located?
nucleus
In what kind of cells would you expect to find an abundance of smooth ER?
muscle
What are proteins transported by after they're made in the rough ER?
golgi apparatus
Vesicles from the Golgi apparatus deliver proteins for.....? or.....?
export out of the cell or to become part of the cell membrane
What are vesicles?
small spheres surrounded by a membrane. comes off golgi apparatus and transports it back inside
_____ vesicles carry proteins to the outer membrane of the cell where the proteins may leave the cell
exocytotic
_____ vesicles are part of the outer membrane of the cell that surround part of the fluid outside of the cell, then break off and carry material into the cell
endocytotic
What organelle contains enzymes that break down old organelles or bacteria?
lysosomes
What organelles contains other enzymes that digest fatty acids and toxic foreign materials?
Peroxisomes
What is the cytoskeleton made up of?
3 proteins- actin microfilaments, microtubules, and intermediate filaments
What part of the cytoskeleton gives shape to the cell?
intermediate filaments
Actin filaments and microtubules give _____ and allow _____ of the organelles
structure, movement
What are two special types of connections between cells?
Tight junctions and desmosomes
If something is polar is it hydrophilic or hydrophobic?
hydrophilic
What can membrane proteins function as?
1. transport proteins that allow polar (hydrophilic) materials to pass
2. receptor proteins for signal molecules (specific hormone or neurotransmitter)
3. structural connections to surrounding cells and tissue
4. enzymes that allow specific reactions to occur next to the cell membrane
When concentration is equally distributed, the solution is said to be in?
equilibrium
Molecules diffuse from _____ concentration to _____ concentration
high ---> low
The difference of electrical potential energy across the membrane is called?
membrane potential
Membrane potential denotes the charge _____ the cell?
inside
If you want to determine the concentration gradient acting on a molecule, then you look at the ______ of that specific molecule inside the cell versus the outside of the cell
concentration
If you want to determine the electrical gradient acting on a molecule, then you look at the _______ and the _____ of that specific molecule
membrane potential, charge
If energy is required is it active or passive transport?
active
If the molecule moves down the gradient is it active or passive transport?
passive
If the molecule moves against the gradient is it active or passive transport?
active
If the molecule moves through the membrane alone, with a cannel protein or with a protein carrier is it active or passive?
passive
What molecules move through the membrane without help?
non-polar hydrophobic molecules
Small, polar molecules use protein ____ to pass through the membrane
channels
Large, polar molecules use protein _____ to pass through the membrane....What is this called?
carrier, facilitated diffusion
What type of transport has ATP provided for it directly?
primary active transport
What are examples of primary active transport?
sodium potassium pump, calcium ATPase, Hydrogen ATPase
What does ATP give to a protein to activate the protein and change the shape of the protein?
phosphate
The suffix "-ase" on the end of a word usually denotes that particle is an.....?
enzyme
What are the steps of the sodium potassium pump?
1. pump is opened on the inside of the cell, 3 Na+ ions enter and bind to the pump
2. the phosphate (from ATP) binds to the pump and pushes the 3 Na+ to the outside of the cell
3. the protein now has 2 places on the outside that attach to K+
4. The phosphate is released so the protein goes back to original shape and 2 K+ move inside the cell and are released into the cytoplasm
What are the two types of secondary active transport?
co-transport & antiport (exchanger)
What is co-transport?
two solutes move in the same direction
-ex: sodium down its gradient and glucose against its gradient (in the intestine)
What is anti port/exchanger?
two solutes move in opposite directions
-ex: sodium down its gradient and calcium up its gradient (in the heart)
If the inside of the cell is negative, the electrical force pushes K+____ the cell
into
The concentration force pushes K+ ____ the cell
out of
If a molecule is hydrophobic can it move through the membrane without a protein?
yes
A _______ messenger will use a receptor protein to send its message
hydrophilic (polar)
Does a receptor protein allow the signal molecule to pass into the cell?
no
Receptors only allow____ molecules to bind
specific
A ____ is an enzyme that adds a phosphate group to a protein
kinase
What is the process of adding a phosphate to a protein (thus activating the protein)?
phosporylation
What enzyme removes a phosphate from proteins?
phospatase
What enzyme inactivates Protein Kinase A by breaking down cAMP?
phosphodiesterase
What are the steps of a G protein using adenylate cyclase?
1. signal molecule binds to receptor so receptor conformation changes
2. G protein splits off to activate enzymes
3.G protein activates an enzyme (adenylate cyclase) in the membrane
4.The activated adenylate cyclase speeds up the chemical reaction that splits ATP into the second messenger (cAMP)
5. cAMP then activates a protein kinase
6. Protein kinase activates other proteins through the process of phosphorylation
7. to turnoff the signal, cAMP is broken down by a phosphodiesterase
8. Phosphatase removes phosphate from the target proteins
What enzyme does the G protein directly activate in the pathway that leads to the release of calcium from the smooth ER?
phospholipase C
What are the two second messengers in the G protein system that uses phospholipase C?
IP3 and Ca++
What are the steps of a G protein that releases calcium?
1. signal molecule binds to the receptor
2. G protein activates an enzyme (phospholipase C)
3. Phospholipase C promotes a reaction that breaks off part of the membrane (IP3) that acts as a second messenger
4.IP3 opens a channel in the smooth ER to let out Ca++
5. Ca++ acts a second messenger to activate other enzymes or proteins, which will carry out an effect
6. To turn off the pathway, Ca++ is returned to the smooth ER by the calcium pump (an example of primary active transport)
c-AMP pathway- G protein acts on? enzyme? second messenger? purpose?
G protein acts on: adenylyl cyclase
enzyme involved: adenylyl cyclase, protein kinase A
second messenger: c-AMP
purpose: phosphorylate many proteins for cellular response
Phospholipase C-G protein acts on? enzyme? second messenger? purpose?
G protein acts on: phospholipase C
enzyme: phospholipase C
second messenger: IP3, Ca++
purpose: release calcium from smooth ER to trigger response
membrane channel pathway- G protein acts on? enzyme? second messenger? purpose?
G protein acts on: protein channels
*
no enzymes and no second messengers
*
purpose: open protein channel to allow an ion in or out of the cell ex- acetylcholine causing G protein to open K+ channel in the heart
An ion has reached its ______ _______ when its electrical force is equal to its concentration force
equilibrium potential
Which ion's channel is probably open if the membrane potential of the cell is -90m V?
K+
At what voltage will sodium stop moving into a cell, sodium's equilibrium potential?
+60mV
Is the membrane potential equal in all cells?
no
What two types of cells are excitable?
nerve cells (neurons) and muscle cells
Why does membrane potential change?
opening and closing of ion channels
What does it mean when a cell is at rest at -70 mV?
it's polarized
What is depolarization?
When a nerve impulse passes along the axon, sodium channels open that allow sodium to move in and make the membrane potential positive
What is repolarization?
Just after opening, the sodium channels close and potassium channels open so potassium moves out and returns the membrane potential to a negative charge
What is the resting membrane potential?
-70mV
What are ion channels that open and close depending on the membrane potential?
voltage-gated channels
Are all sodium channels voltage gated?
yes
How many channels does potassium have?
2
What are the two potassium channels?
1. voltage-gated channel, which opens when the inside of the membrane becomes positive
2. leak channel, which allows K+ to move out of the cell all the time and explains why the membrane potential of a resting cell is negative
Is the voltage-gated sodium channel open, closed or inactivated when the membrane is at rest?
closed
Is the voltage-gated sodium channel open, closed or inactivated during depolarization?
open
Is the voltage-gated sodium channel open, closed or inactivated during repolarization?
inactivated
All action potentials are the same _____ and last for the _____ amount of time
height, same
What moves sodium ions back out of the cell after they move in during the action potential?
sodium-potassium pump
The _________ period is the period when all Na+ channels are either open or inactivated
refractory
What are two ways that stimulate the membrane potential to raise to -55 mV so that voltage-gated sodium channels will open?
1. When the positive ions from the depolarizing area move along the inside of the axon over to the resting area; these positive ions make the inside less negative, thus opening the fast gate of the sodium channel
2.When positive ions flow from the dendrites
Action potentials move fastest in axons that are ______ and have a ______ diameter
myelinated, large
In myelinated axons, action potentials only occur at?
nodes of ranvier
Where would you find a receptor for a hydrophobic messenger molecule?
inside the cell- not in the membrane
In which organelle is the sodium potassium pump made?
Rough ER
Na+ is found in highest concentration inside/outside of the cell?
outside
Is Cl- usually highest inside or outside of the cell?
outside
If a specific cell you examine has a membrane potential of +60 then what ion channels are open?
sodium
Which organelle has channels that open when signaled by IP3?
smooth ER
Where is the place where the message leaves one cell and goes to the other?
synapse
The _______ membrane is where the ______ is released
pre-synaptic, neurotransmitter
The______ membrane is where the___________ is ________ by a receptor
post-synaptic, neurotransmitter, received
When the action potential reaches the end of the axon, _______ voltage-gated channels open on the presynaptic membrane and ________ moves into the synaptic terminal because the concentration and electrical gradients both favor movement of ______ into the
calcium, calcium, calcium
When___ enters, synaptic _______ filled with neurotransmitters move to the membrane
calcium, vesicles
After the vesicles dock to the membrane, the _____ is released into the synaptic cleft by______
neurotransmitter, exocytosis
_________ gated channels open when the _____ binds to the protein.
Ligand, neurotransmitter
Can a single EPSP depolarize the membrane enough to reach the threshold?
no
An EPSP makes the post-synaptic cell _____ negative and ____ likely to fire an action potential
less, more
An IPSP makes the post-synaptic cell_______ negative and _____ likely to fire an action potential
more, less
An IPSP can either signal ligand-gated channels to let ____in or ___ out. Either movement makes the inside more _____; the membrane is said to be____
Cl-, K+, negative, hyperpolarized
EPSP's and IPSP's get _____ as they travel from the dendrites to the axon
weaker
What are six things that make EPSPs and IPSPs different from action potentials
1. can be depolarizing (EPSP) or hyper polarizing (IPSP)
2. Vary in size depending on the strength of the stimulus
3. Use ligand gated channels
4. decrease in strength as they travel
5. Can add together at the initial segment of the axon (aka summation)
6. occur at the dendrites
What are the two most common excitatory neurotransmitters?
glutamate and asparate
Inhibitory neurotransmitters open____ channels to produce an _____
Cl-, IPSP
What are the two most common inhibitory neurotransmitters?
GABA and glycine
The equilibrium potential of K+ is -90mV. If the membrane potential of a cell is 90mV, you know that
the concentration force pushing K+ out is equal to the electrical force keeping it in
Which organelle makes a molecule that is later made into the second messenger cAMP by adenylyl cyclase?
mitochondria
What are the functions/things it affects of acetylcholine? What is a possible problem?
Functions:
-memories
-control of movement
possible problems:
-alzheimer's- if deficit
What are the functions/things it affects of serotonin? What is a possible problem?
functions:
-sleep
-mood
-emotions
possible problems:
-depression if deficient
What are the functions/things it affects of norepininephrine? What is a possible problem?
function:
-attention
-alertness
-mood
-memory
no possible problem
What are the functions/things it affects of dopamine? What is a possible problem?
functions:
-pleasure
-thinking
-personality
-voluntary movement
possible problems:
- Parkinson's- if deficient
-Addiction- if over stimulated
To treat depression, a healthcare provider would want to inhibit ____ reuptake to make its effect____
serotonin, stronger
Blocking any of the reuptake pathways will produce a _____ response in the postsynaptic cell
stronger
Cocaine is a drug that blocks the reuptake of _____
dopamine
What are four ways to inactivate the neurotransmitter?
1. Reuptake into the presynaptic terminal
2. uptake by an astrocyte
3. breakdown by an enzyme
4. diffusion away
What does the CNS include?
spinal cord and brain
What cells make the myelin sheath in the peripheral nervous system?
schwann cell
What make the myelin sheath in the central nervous system?
oligodendrocytes
What do astrocytes do?
they create blood-brain barrier, store glycogen and take up K+ that leaks
What are microglia?
are immune system cells in the CNS
What responds to stimuli?
sensory receptor
What carries the information to the CNS?
sensory nerve
Sensory neurons are _____ neurons (carry message to CNS) as opposed to motor neurons that are _____ neurons (carry the message away from the CNS)
afferent, efferent
What is white matter made of?
axons
What is gray matter made of?
nerve cell bodies, dendrites and synapses
What makes the white matter white?
myelinated axons
How many types of stimulus does a sensory receptor detect?
one
What type of receptor is in eyes and respond to light?
photoreceptor
often perceived as pain
nociceptor
measure carbon dioxide in the medulla
chemoreceptor
responsible for taste and smell
chemoreceptor
sense stretch of the stomach
mechanoreceptor
has two types of nerve endings to monitor temp of the skin
thermoreceptor
measure oxygen levels in the blood in the arteries
chemoreceptor
in the hypothalamus to measure glucose levels in the blood
chemoreceptor
sense stretch of muscle
mechanoreceptor
carotid and aortic baroreceptors that sense stretch of the artery wall
mechanoreceptor
respond to damage (from excessive pressure, heat or chemicals that is damaging)
nociceptor
in the hypothalamus to monitor blood temperature
thermoreceptor
in the ear for hearing
mechanoreceptor
All action potentials have the same____ and _____
height, width
What differs in action potentials?
bursts differ in frequency and duration
Receptor potential is the_____ of the membrane at the nerve ending
depolarization
The receptor potential travels to the trigger zone at the beginning of the axon, where there are_____ Na+ channels
voltage-gated
What does depolarizing the voltage-gated sodium channels on the axon to threshold generate?
an action potential
The stronger the stimulus, the _____ the receptor potential and the higher the _____ of the action potential
larger, frequency
The duration of the series of action potentials is_____ the duration of the stimulus in most sensory nerves
equal to
When a receptor____, the action potential frequency decreases even when there is no change in the stimulus strength
adapts
What does the strength of a stimulus change?
frequency of an action potential
A _____ adapting receptor is good because it signals change
rapidly
Are pressure and touch receptors rapidly or slowly adapting?
rapidly
Are joint position and nociceptors rapidly or slowly adapting?
slowly
The _____ _____ of a sensory unit is the area covered by the unit's sensory receptors
receptive field
A ____ receptive field means a less precise location
large
A_____ receptive field means a more precise location
small
All A waves are...?
myelinated
A-alpha waves are the ____ of the A waves. What's an example?
largest, proprioceptive
A-delta are the _____ of the A waves. Are they myelinated?
smallest, yes
C-fibers are _____ The example from class of a C-fiber would be a____
unmyelinated, nociceptor
What kind of sensory information is carried through path A (shorter)?
fine touch, proprioception, vibration
What kind of sensory information is carried through Path B?
nociception, temp, coarse touch
Each part of the somatasensory cortex (gray matter) receives sensory input from only ___ area of the body
one
the amount of space dedicated to an area in the somatosensory cortex is indicative of how _____ that area is
sensitive
Nociceptors have _____ endings that sense harmful stimuli
free nerve
nociceptors detect an ____ of mechanical, thermal or chemical stimuli
excess
Where does a reflex response occur?
spinal cord
Prostaglandins make nerve endings____ sensitive to paracrine substances that stimulate nociceptors
more
What will carry sharp and intense pain?
myelinated A-delta fibers
What will carry dull and burning pain?
unmyelinated C-fibers
What does aspirin block the production of?
prostaglandins
What does procaine block?
voltage-gated Na+ channels on the axon
General anesthesia reduces __ conscious sensation
all
Referred pain means there is pain with an internal organ but it is felt on the body _____
surface