Term
| how many different cell types are there in humans? |
|
Definition
|
|
Term
| an unseen molecular "decision" that precedes overt changes caused by differentiation |
|
Definition
|
|
Term
| once a cell _____, it can't change to a different kind of cell |
|
Definition
|
|
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
|
|
Term
| ___ are morphogens that are received as signals from other cells |
|
Definition
|
|
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
|
|
Term
| when are cytoplasmic determinants deposited in the egg cytoplasm? |
|
Definition
|
|
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
|
|
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
|
|
Term
| ___ are either transcription factors or they activate or inactivate transcription factors |
|
Definition
|
|
Term
| ___ commits a cell to a particular developmental pathway |
|
Definition
|
|
Term
| which comes first, determination or differentiation? |
|
Definition
|
|
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
|
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
|
|
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
|
|
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
|
|
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
|
|
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
|
|
Term
| gap genes are usually what kind of morphogen |
|
Definition
|
|
Term
| ___ genes divide the embryo into 7 zones |
|
Definition
|
|
Term
| ___ genes work through induction to further subdivide the 7 zones of the embryo |
|
Definition
|
|
Term
| ___ genes give identity to segments |
|
Definition
|
|
Term
| mutations in ___ genes lead to normal body parts in unusual places |
|
Definition
|
|
Term
| hox genes contain a conserved, 180-base sequence called the ____ |
|
Definition
|
|
Term
| hox genes encode a 60 amino acid DNA binding domain called the _____ |
|
Definition
|
|
Term
| plants have ___ genes that have the same function as vertebrate hox genes |
|
Definition
|
|
Term
| ____ is the process of formation of different forms and structures |
|
Definition
|
|
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
|
|
Term
| changes in cell shape and size (morphogenesis) occurs through changes in the _____. |
|
Definition
|
|
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
|
|
Term
| cell-to-substrate interactions in cell migration often involve complexes between ___ and ____. |
|
Definition
| integrins and the extracellular matrix |
|
|
Term
|
Definition
| detect the environment around us -- ear, eye, tongue, skin |
|
|
Term
|
Definition
| muscles - respond to the sensory receptor input |
|
|
Term
| afferent/efferent neurons collect info from sensory receptors and relay it to the CNS |
|
Definition
|
|
Term
| afferent/efferent neurons get info from the CNS and relay it to muscles, glands, etc to elicit a response |
|
Definition
|
|
Term
| The CNS consists of what two organs |
|
Definition
|
|
Term
| the ___ consists of most of the sensory and motor neurons |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| part of PNS -- stimulates skeletal muscles at will |
|
|
Term
|
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
|
|
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
|
|
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
|
|
Term
| a ___ is a nervous system cell. a ___ is a bundle of nervous system cells. |
|
Definition
|
|
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
|
|
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
|
|
Term
| which side of the cell is always negative.. inside or out? |
|
Definition
|
|
Term
| there is more Na/K on the inside of the cell and more Na/K on the outside of the cell. |
|
Definition
|
|
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
|
|
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
|
|
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
|
|
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
|
|
Term
| why can paracrine signaling over work over a short distance ? |
|
Definition
|
|
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
|
|
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
|
|
Term
| the sequence of events within a cell that occur in response to ligand binding |
|
Definition
|
|
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
|
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
|
|
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
|
|
Term
| what kind of membrane receptor? receptor is an enzyme that is activated by ligand binding |
|
Definition
|
|
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
|
Definition
|
|
Term
|
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
|
|
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
|
|
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
|
|
Term
|
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
|
|
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
|
|
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
|
|
Term
| ____ stem cells retain the ability to divide indefinitely but can only create a cell identical to themselves |
|
Definition
|
|
Term
| a strong pattern of depolarization that reverses membrane polarity in a characteristic manner |
|
Definition
|
|
Term
| ___ are caused when graded potentials reach a threshold level of depolarization |
|
Definition
|
|
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
|
|
Term
| all action potentials have the same amplitude (magnitude) of about ___ |
|
Definition
|
|
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
|
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
|
|
Term
| a ___ is an intercellular junction - a gap between two nerves, a nerve and a cell, etc. |
|
Definition
|
|
Term
| 2 basic types of synapses |
|
Definition
|
|
Term
| ____ synapses invovle direct cytoplasmic connections between the two cells formed by gap junctions |
|
Definition
|
|
Term
| ___ synapses are direct and thus need not convert the message |
|
Definition
|
|
Term
| ___ synapses have a synpatic cleft between the cells where a message is converted |
|
Definition
|
|
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
|
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
|
|
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
|
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
|
|
Term
| ____ is involved in the regulation of sleep and digestion |
|
Definition
|
|
Term
| ____ are short sequences of amino acids and gases |
|
Definition
|
|
Term
| ___ is a string of 9 amino acids (a neuropeptide) that is released from sensory neurons activated by painful stimuli |
|
Definition
|
|
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
|
|
Term
| ____ regulate muscle contraction |
|
Definition
|
|
Term
| the ____ is the basic unit of muscular control |
|
Definition
|
|
Term
| the ___ is the part of the sarcomere that is the length of the thin filament, and is divided by the Z line |
|
Definition
|
|
Term
| a sarcomere is contained by a ____ at each side |
|
Definition
|
|
Term
| the ___ is the overlapping region between actin and myosin |
|
Definition
|
|
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
|
|
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
|
|
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
|
|
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
|
|
Term
| The ____ is the part of the muscle that stores calcium |
|
Definition
|
|
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
|
|
