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BIOL 111 Test 3
N/a
175
Biology
Undergraduate 1
04/03/2010

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Term
how many different cell types are there in humans?
Definition
210
Term
an unseen molecular "decision" that precedes overt changes caused by differentiation
Definition
cell determination
Term
once a cell _____, it can't change to a different kind of cell
Definition
determines
Term
___ initiate determination. examples?
Definition
morphogens -- rna, mrna, proteins
Term
2 types of morphogens, categorized by their origin
Definition
cytoplasmic determinants and induction agents
Term
___ are morphogens inherited in cytoplasm from the egg
Definition
cytoplasmic determinants
Term
___ are morphogens that are received as signals from other cells
Definition
induction agents
Term
___ are localized in certain areas of the egg cell, when the cell cleaves into smaller cells, each well get these depending on what part of the egg cells they were cleaved from
Definition
cytoplasmic determinants
Term
when are cytoplasmic determinants deposited in the egg cytoplasm?
Definition
during oogenesis
Term
___ is the process through which molecules produced by embryonic cells are secreted in the to extracellular membrane, diffuse to nearby cells, and then act as morphogens in the next cell
Definition
induction
Term
___ creates a cell type gradient, which means that cells in the posterior part of the body make the highest concentration of posterior morphogens
Definition
induction
Term
___ are either transcription factors or they activate or inactivate transcription factors
Definition
morphogens
Term
___ commits a cell to a particular developmental pathway
Definition
cell determination
Term
which comes first, determination or differentiation?
Definition
determination
Term
how do you see cell determination?
Definition
experimentally through transplant process
Term
determined and differentitated cells only produce daughter cells that are similarly determined/differentiated.
Definition
Term
___ is the method by which Dolly was cloned
Definition
SCNT - somatic cell nuclear transfer
Term
process of SCNT
Definition
remove differentiated mammary cells, egg cells from another sheep are enucleated, arrest cell cycle in resting state, take the nucleus out of the egg cell and transfer the mammary cell into the egg, successful embryos are placed in surrogate
Term
___ showed that genetic changes are reversitble by using an egg cell to reprogram the DNA in a somatic cell to revert it to a stem cell
Definition
cloning
Term
what did cloning dolly prove?
Definition
determination is reversible - a differentiated cell can be reprogrammed to be totipotent
Term
problems with reproductive cloning
Definition
low success rate, cryptic (unexplainable) diseases, produces offspring with early onset age-associated diesease
Term
in _____, stem cells are cloned from a person's own tissues so the body readily accepts them
Definition
therapeutic cloning
Term
in _____, an embryo is broken apart and its embryonic stem cells are extracted and then grown in culture and then used to replace diseased or injured tissue
Definition
therapeutic cloning
Term
why is therapeutic cloning advantageous?
Definition
stem cell phenotype is dominant over every other kind of phenotype, including cancer
Term
___ are created from adult somatic cells, function similarly to embryonic stem cells, and are made wtihout the need to create and sacrifice embryos
Definition
induced pluripotent stem cells
Term
4 mechanisms of development
Definition
cleavage, determination and differentiation, pattern formation, morphogenesis
Term
___ is the establishment of embryonic axes and segments
Definition
pattern formation
Term
2 axes established through pattern formation
Definition
ant/post (head to tail), dorsal/ventral (back to front)
Term
the body plan is produced by sequential activation of what three classes of segmentation genes?
Definition
gap genes, pair-rule genes, segment polarity genes
Term
___ genes encode map out the coarsest subdivision of the body- the axes
Definition
gap genes
Term
gap genes are usually what kind of morphogen
Definition
cytoplasmic determinants
Term
___ genes divide the embryo into 7 zones
Definition
pair rule
Term
___ genes work through induction to further subdivide the 7 zones of the embryo
Definition
segment polarity
Term
___ genes give identity to segments
Definition
homeotic (hox) genes
Term
mutations in ___ genes lead to normal body parts in unusual places
Definition
hox
Term
hox genes contain a conserved, 180-base sequence called the ____
Definition
homeobox
Term
hox genes encode a 60 amino acid DNA binding domain called the _____
Definition
homeodomain
Term
plants have ___ genes that have the same function as vertebrate hox genes
Definition
MADS box
Term
____ is the process of formation of different forms and structures
Definition
morphogenesis
Term
morphogenesis is achieved through changes in what 4 things? Which of these things do not happen in plants?
Definition
cell division, cell shape and size, cell death, and cell migration. Cell migration doesn't happen in plants bc of the cell wall.
Term
the orientation of the ___ determines the plane of cell division in eukaryotic cells
Definition
mitotic spindle
Term
changes in cell shape and size (morphogenesis) occurs through changes in the _____.
Definition
cytoskeleton
Term
self-destruct sequence in cells consists of what 3 parts?
Definition
activator, inhibitor, and apoptotic protease
Term
How do the activator, inhibitor, and protease work together?
Definition
the activator activates the protease, which initiates apoptosis... the inhibitor inhibits either the activator or the protease so apoptosis will not occur
Term
apoptosis is responsible for what two things?
Definition
elimination of transitory organs and tissues ::: tissue remodeling
Term
example of tissue remodeling in humans?
Definition
fingers and toes originally grow together in the fetus... apoptosis separates them into individual fingers and toes. failure of apoptosis results in webbed fingers and toes.
Term
cell-to-cell interactions in cell migration are mediated by ____ proteins
Definition
cadherin
Term
cell-to-substrate interactions in cell migration often involve complexes between ___ and ____.
Definition
integrins and the extracellular matrix
Term
sensory receptors
Definition
detect the environment around us -- ear, eye, tongue, skin
Term
motor affectors
Definition
muscles - respond to the sensory receptor input
Term
afferent/efferent neurons collect info from sensory receptors and relay it to the CNS
Definition
afferent
Term
afferent/efferent neurons get info from the CNS and relay it to muscles, glands, etc to elicit a response
Definition
efferent
Term
The CNS consists of what two organs
Definition
brain and spinal cord
Term
the ___ consists of most of the sensory and motor neurons
Definition
PNS
Term
2 parts of the PNS
Definition
somatic and autonomic NS
Term
somatic nervous system
Definition
part of PNS -- stimulates skeletal muscles at will
Term
autonomic nervous system
Definition
part of the PNS that happens without you thinking about it -- heart rate, breathing, smooth muscle, glands
Term
interneurons are entirely in which nervous system?
Definition
CNS
Term
3 common features of neurons
Definition
cell body, dendrites, axon
Term
neuroglial cells that make myelin sheath that insulates axons to keep electrical transmission in its intended axon and keep it from jumping to another cell
Definition
schwann cells and oligodendrocites
Term
Schwann cells are in the ___, Oligodendrocites are in the ___.
Definition
PNS, CNS
Term
schwann cells/oligodendrocities are big and can interact with 50 different nerve cells at once. Schwann/oligodendrocites are smaller and you need several per axon
Definition
oligo .. schwann
Term
a ___ is a nervous system cell. a ___ is a bundle of nervous system cells.
Definition
neuron. nerve.
Term
what is a schwann cell made up of and why is that importnat?
Definition
phospholipids - so that ions cannot permeate the membrane and just flow through the axon wtihout getting out
Term
electrical different in charge between two sides of a cell
Definition
membrane potential
Term
a negative charge on one side of the cell means what?
Definition
its just not as positive as the other side but is not actually negatie
Term
avg membrane potential. range of membrane potentials.
Definition
-70mV ... -40--90mv
Term
which side of the cell is always negative.. inside or out?
Definition
inside
Term
there is more Na/K on the inside of the cell and more Na/K on the outside of the cell.
Definition
Na inside, K outside
Term
why is the inside of the cell negatively charged, even though it has a lot of K?
Definition
it also has a lot of negatively charged proteins and Cl-
Term
Players in the Resting potential of a cell
Definition
Na/K pump, K+ ion leakage channel
Term
the Na/K pump lets #K in for every #Na out
Definition
2 K for 3 Na
Term
in the resting state, the K leakage channel lets K flow which way?
Definition
both - diffusion makes it go out bc of higher K conc on inside and electromotive force (electrostatics) makes K flow in bc of high conc of pos charge on outside
Term
____ are small, short lived changes in difference in electrical charge across a membrane
Definition
graded potentials
Term
player in graded potential
Definition
ligand-gated ion channels -- ligands are neurotransmitters, ion is usually Na -- typical response: neurotransmitter binds to channel and allows Na to flow into cell
Term
Depolarization v. hyperpolarization
Definition
depolarization makes membrane potential more positive - reduced difference between inside and outside
Term
____ potentials can add up (summation). implications?
Definition
graded .. allows you to integrate info at the cellular level - to reinforce or negate -- two depolarizations = reinforcement, depolarization + hyperpolarization = negation
Term
communication between cells requires what 2 things?
Definition
ligand (signaling molecule), receptor protein
Term
4 basic mechanisms of cellular communication
Definition
direct contact, paracrine signaling, endocrine signaling, synaptic signaling
Term
what kind of cellular communication?molecules on the surface of one cell are recognized by receptors on adjacent cells. the ligand is membrane-bound.
Definition
direct contact
Term
What kind of cellular communication? signal is released from a cell and has an effect on a nearby cell. ligands travel through extracellular fluid.
Definition
paracrine signaling
Term
why can paracrine signaling over work over a short distance ?
Definition
it relies on diffusion
Term
What kind of cellular communication? uses active transport. releases hormones from a cell and then affects other cells throughout the body. ligands travel through the blood.
Definition
endocrine signaling
Term
why can endocrine signaling travel longer distances than paracrine?
Definition
it travels through the blood and is therefore being pumped
Term
What kind of cellular communication? specialized paracrine signaling that involves nerve cells releasing a signal which binds to receptors on nearby cells. ligand is a neurotransmitter.
Definition
synaptic signaling
Term
the sequence of events within a cell that occur in response to ligand binding
Definition
signal transduction
Term
3 common cellular responses to ligand binding
Definition
making new proteins by activating transcription factors and controlling gene expression :: activating or inactivation proteins by modifying them :: control cell activities (growth, metabolism, gene expression, etc)
Term
what does a tyrosine kinase do?
Definition
adds a phosphate to a tyrosine -- is an example of a cellular response
Term
2 receptor types
Definition
intracellular (cytoplasmic) is located within the cell so the ligand has to get into the cell :: membrane/cell surface has extracellular and intracellular domains
Term
how do cells maintain control over what signals they recieve?
Definition
receptors - they can only bind ligands for which they have receptors
Term
how do intracellular receptors work?
Definition
direct response - ligand (usually a steroid hormone) binds to the receptor in the cytoplasm and then moves to the nucleus and activates gene expression directly
Term
3 steroid receptor functional domains.. intracellular receptors
Definition
hormone binding :: DNA binding :: domain that interacts with coactivators to affect gene expression
Term
most intracellular receptors act as
Definition
transcription factors
Term
why are steroid hormones usually intracellular ligands? how do they work?
Definition
they are fairly small and have non-polar, lipid-soluble membranes so they can cross the membrane :: they usually affect regulation of gene expression directly, requiring no intermediates
Term
3 types of membrane receptors
Definition
channel linked, enzymatic, and G protein coupled receptors
Term
what kind of membrane receptor? ion channels that open in response to ligand binding
Definition
channel linked receptors
Term
what kind of membrane receptor? receptor is an enzyme that is activated by ligand binding
Definition
enzymatic receptors
Term
what kind of membrane receptor? 7 transmembrane domain structure with a specialized protein that assists in transmitting the signal
Definition
g protein coupled receptors
Term
Channel linked receptors are AKA ____. How do they work?
Definition
ligand-gated ion channels -- action is direct: ligand binds to receptor, channel opens/closes and changes voltage
Term
how do enzyme receptors work?
Definition
indirectly - the external portion binds the ligand. the internal portion is the enzyme that changes the ligand as it moves through
Term
membrane receptors that act as kinases are ____.
Definition
receptor tyrosine kinases (RTKs)
Term
steps in how a receptor tyrosine kinase works
Definition
receives the ligand :: activates the enzyme by dimerization and autophosphorylation :: activates another enzyme :: adds a phosphate to tyrosine on a response protein, which causes the change in the cell
Term
what is a mitogen?
Definition
cell growth factor
Term
kinase cascade
Definition
one kinase activates another, which activates another, and so on ::: Kinase -->> Kinase kinase --> Kinase kinase kinase
Term
intracellular kinases often activate ___, and so are called _____
Definition
mitogens .. mitogen kinases (MKs)
Term
what is the purpose of the kinase cascade?
Definition
to amplify a signal and therefore a cell response because each kinase will activate multiple molecules
Term
structure of a G protein coupled receptor
Definition
extracellular domain binds signaling molecule ... 7 transmembrane alpha helices ... intracellular domain binds G protein ... G protein is made up of 3 subunits (alpha, beta, gamma) >>> G protein forms link between GPCR and effector protein
Term
is the GPCR pathway direct or indirect?
Definition
indirect
Term
what happens when the G protein is activated?
Definition
the subunits dissociate from each other and the alpha subunit activates the effector protein .. the effector protein then activates a second messenger which activates either another messenger or the response protein
Term
what 2 effector proteins can G proteins activate and what second messengers are associate with them?
Definition
adenylyl cyclase -- cAMP :: inositol phosphate -- calcium ions
Term
GPCR and kinases are what kind of cell signaling? direct, paracrine, or endocrine?
Definition
paracrine
Term
how do cell's identify each other?
Definition
direct contact through glycoproteins (the "face" of the cell)
Term
____ proteins are used to distinguish native from foreign cells by direct interaction with T cell receptors
Definition
MHC
Term
agonist v. antagonist
Definition
agonist - drug attaches to receptor and initiates cellular response :: antagonist - blocks the receptor
Term
cleavage (rapid cell division) is stimulated by ________
Definition
cyclins and cyclin-dependent kinases
Term
the end of cleavage is characterized by what structure?
Definition
blastocyst -- 100 blastomeres (cells)
Term
what do the diff parts of the blastocyst develop into?
Definition
inner cell mass becomes embryo, blastocoel is filled with fluid, outside of blastocyst becomes placenta
Term
where do stem cells come from in embryos?
Definition
blastomeres
Term
___ stem cells can become any cell type
Definition
totipotent -- blastomeres are this
Term
___ stem cells can become any cell type except for the placenta
Definition
pleuripotent
Term
___ stem cells are those found in adults and can become any cell of the kind they are. ex: hematopoetic stem cells can become any kind of blood cell
Definition
multipotent
Term
____ stem cells retain the ability to divide indefinitely but can only create a cell identical to themselves
Definition
unipotent
Term
a strong pattern of depolarization that reverses membrane polarity in a characteristic manner
Definition
action potential
Term
___ are caused when graded potentials reach a threshold level of depolarization
Definition
action potentials
Term
what does it mean when we say an action potential reverses membrane polarity
Definition
makes the inside of the cell more positive than the outside
Term
3 phases of action potentials
Definition
rising (depolarizing), falling (repolarizing), undershoot (refractory)
Term
___ potentials can add up or negate each other, ___ potentials are always separate
Definition
graded, action
Term
all action potentials have the same amplitude (magnitude) of about ___
Definition
40 mV
Term
how do action potentials code intensity of a stimulus?
Definition
frequency of the APs ... more frequent = stronger response
Term
Action Potentials are caused by what two kinds of channels?
Definition
voltage gated Na channels and voltage gated K channels
Term
difference bewteen voltage-gated Na channels and voltage-gated K channels
Definition
Na have two gates - activation gate response to threshold rapidly, inactivation gate responds slowly ::: K channels have a single gate that responds slowly
Term
how do the ions flow during an AP?
Definition
Na activation gate opens quickly and rapid but temporary influx of Na into the cell causes the membrane to depolarize :: Na inactivation gate closes and stops the influx of Na :: K channels open about the same time Na gate closes and the membrane repolarizes by letting K out of the cell
Term
what does the refractory period mean in terms of ion flow and what is its purpose?
Definition
it's when the inactivation gate remains closed but some K is still leaking out so the membrane is temporarily hyperpolarized ... its purpose is to keep the AP from going backward
Term
two ways to increase velocity of conduction
Definition
increase axon diameter and myelinate the axon
Term
nodes of ranvier
Definition
where the APs are produced (gap between two schwann cells
Term
____ is seen in action potentials as the impulse jumps from node to node, skipping the schwann cells as Na diffuses to the next Node of Ranvier
Definition
saltatory conduction
Term
a ___ is an intercellular junction - a gap between two nerves, a nerve and a cell, etc.
Definition
synapse
Term
2 basic types of synapses
Definition
electrical and chemical
Term
____ synapses invovle direct cytoplasmic connections between the two cells formed by gap junctions
Definition
electrical
Term
___ synapses are direct and thus need not convert the message
Definition
electrical
Term
___ synapses have a synpatic cleft between the cells where a message is converted
Definition
chemical
Term
process of chemical synapsis
Definition
AP triggers influx of calcium ions at the terminus of the axon, which causes the synaptic vesicles to fuse with the cell membrane ... the neurotransmitters in the vesicles are released by exocytosis and diffuse across the cleft to bind to ligand-gated ion channels on the post-synaptic cell and thus creates a graded potential by either exciting or inhibiting the post synaptic cell
Term
what does ACh do?
Definition
stimulates muscle contraction
Term
___ degrades acetylcholine and thus causes muscle relaxation
Definition
acetylcholinesterase (AChE)
Term
___ is the major excitatory neurotransmitter in the vertebrate CNS because it increases the probability of the next cell having an AP.
Definition
glutamate
Term
___ and ___ are inhibitory neurotransmitters in the CNS, decreasing the probability of the next cell having an AP by creating a hyperpolarizing event
Definition
glycine and GABA (gamma-aminobutryric acid)
Term
biogenic amines
Definition
modified amino acids - epinephrine, dopamine, serotonin
Term
___ and ___ are responsible for the flight or fight response
Definition
epinephrine/norepineprhine
Term
___ is used in some areas of the brain that control body movements
Definition
dopamine
Term
____ is involved in the regulation of sleep and digestion
Definition
serotonin
Term
____ are short sequences of amino acids and gases
Definition
neuropeptides
Term
___ is a string of 9 amino acids (a neuropeptide) that is released from sensory neurons activated by painful stimuli
Definition
substance P
Term
characteristics of skeletal muscle
Definition
striated, multiple nuclei, elongated
Term
muscles are comprised of ____, which are comprised of _____, which are made of _____, which are made of _____
Definition
fasicles, cells (fibers), myofibrils, filaments (actin and myosin)
Term
myosin filaments are ____ proteins
Definition
motor
Term
____ regulate muscle contraction
Definition
troponin and tropomyosin
Term
the ____ is the basic unit of muscular control
Definition
sarcomere
Term
the ___ is the part of the sarcomere that is the length of the thin filament, and is divided by the Z line
Definition
I band
Term
a sarcomere is contained by a ____ at each side
Definition
Z line
Term
the ___ is the overlapping region between actin and myosin
Definition
A band
Term
the ___ is the part of the sarcomere that is the zone in the middle of the A band - where the myosin fibers are in a state of non-overlap
Definition
H band
Term
what actually changes during a muscle contraction?
Definition
H and I bands - shorten and disappear during contraction
Term
what is the cross bridge?
Definition
when actin is bound to myosin and the power stroke can occur
Term
a muscle contracts and shortens because ___ contract and shorten
Definition
myofibrils
Term
5 steps of the cross bridge cycle
Definition
hydrolyze ATP to ADP to get energy, which is stored in the myosin head ::: energy pulls back myosin head to upright position ::: myosin binds to actin ::: powerstroke ::: actin is released and myosin binds to another ATP
Term
___ and ___ regulate muscle contraction by allowing actin and myosin to interact or not
Definition
troponin and tropomyosin
Term
how do troponin and tropomyosin regulate muscle contraction?
Definition
actin has a single binding site and myosin and tropomyosin compete for it. if tropomyosin is bound, myosin can't interact and the crossbridge can't occur.... if troponin moves tropomyosin away by Calcium binding to troponin and changing its shape to pull tropomyosin away and myosin can bind to actin
Term
___ are specialized structures that conduct Calcium ions across the entire muscle to make sure that the entire muscle depolarizes at the same time so the muscle contracts at the same time.
Definition
transverse tubule
Term
The ____ is the part of the muscle that stores calcium
Definition
sarcoplasmic reticulum
Term
ion flow during muscle contraction
Definition
release of ACh, opening of Na channels, Na travels through transverse tubules, membrane depolarized by Na, opens voltage gated Ca channels, Ca flows into the cell and interacts with troponin
Term
Upon signaling ligand binding, activation of a cytoplasmic receptor is most often brought about by:
Definition
release of an inhibitor molecule that was bound to the cytoplasmic receptor so that the signaling molecule can bind.
Term
What membrane receptor is characterized as having a direct effect on the cell response?
Definition
ligand gated ion channels
Term
What channels/pumps are responsible for the graded potential?
Definition
ligand-gated ion channels
Term
What would happen if the Na/K pumps stopped working?
Definition
the resting potential would gradually disappear
Term
what are interneurons responsible for?
Definition
learning and memory
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