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189 Cards in this Set
- Front
- Back
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what does duplication of cells require
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1)replication
2)segregation of each chromosome 3)cytoplasmic division |
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how do prokaryotic cells divide and what is the beginning site and ending site of replication called?
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binary fission (origin of replication-->terminus)
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what protein contracts the middle of a cell to divide the cell into two during binary fission?
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ring of FTsZ proteins
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define a centromere
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centromeres are the constrictions seen at the center of chromosomes
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define a kinetochore
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protein found at the centromere that attaches to the microtubule during mitosis
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define cohesin
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protein that holds two sister chromatids together
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define a nucleosome
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a histone octamer wrapped with with about 200 base pairs
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what is the name for a tightly coiled string of nucleosomes
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solenoid
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what is the level of organization of chromatin
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"30nm fiber" solenoid
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name all the phases of the cell cycle
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G1, S, G2, mitosis (prophase, prometaphase, anaphase, telophase), cytokinesis
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describe prophase
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chromosomes finish condensing
centrioles move to poles of cell nuclear envelope disappears spindle apparatus appears |
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describe prometaphase
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chromosomes attach to spindle apparatus
chromosomes begin to migrate |
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describe anaphase
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chromosomes split and move toward oppostie poles
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describe telophase
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spindle apparatus disassembles
chromosomes start uncoiling nuclear envelope reassembles |
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define what a cyclin is
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proteins that are produced and destroyed in synchronization with the cell cycle
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define what a Cdk is
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cdk's are enzymes that control the progress of cell division by phosphorylating proteins needed for division
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a signal activates a complex to initiate the splitting of the chromosomes. name it
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anaphase promoting complex
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the APC activates what protein that hydrolyzes cohesin
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separase
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what elaborate structure do homologous chromosomes line up on during meiosis 1?
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synaptonemal complex/metaphasic plate
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what was the general name of the view of genetics prior to Mendel
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blending inheritance-offspring was a mix of the parents' features
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define particulate inheritance
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idea that discrete physical units carry the traits from each parent and don't blend (now called genes)
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define a locus
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the physical location of a gene on a chromosome
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define a marker
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a known locus being used to keep track of what is going on genetically
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define an allele
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a particular form of a gene that exists
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describe the principle of independent assortment
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different genes will behave independently of one another during the production of gametes
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what genotype is always needed to perform a test cross
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a homozygous recessive
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describe incomplete dominance and give an example
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phenotype appears intermediate between the two homozygotes.
example: black cow and white cow make brown cow |
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describe codominance and give an example
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full phenotypes of both genes are visible. example: calico cats
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define pleiotropy
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a single gene product influences multiple traits
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define epistasis
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one gene obscures the action of another genes.
ex: when an animal has a homozygous recessive for one gene and the phenotype of the other gene isn;t seen at all |
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define sex-linkage
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alteration in patterns of inheritance based on the sex
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which sex will always show the recessive sex-linked traits
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the heterogametic sex (the one with different sex chromosomes)
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describe genetic recombination
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crossing over occurs on a chromosome, producing recombinant offspring
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describe the correlation between genetic map distance and recombination
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the farther apart two loci are, the more frequent recombination will be
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what is the relationship between percentage recombinant offspring and map units between two loci
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1% recombination=1 map unit
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indpendent assortment is more likely if genes are __________
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farther apart
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define an anonymous marker
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a molecular marker that does not produce any phenotypic change, but at a molecular DNA level, changes can be seen
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define a SNP
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a single nucleotide polymorphism that is used as an anonymous marker in genetic mapping
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cross breeding of a true breeding round tall strain with a true breeding wrinkled short strain will produce what ratios in the F1 and F2 generations?
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F1: all heterozygous
F2: 9 round tall, 3 round short, 3 wrinkled tall, 1 wrinkled short |
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what does semiconservative mean in terms of DNA replication
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each strand of an old "template" are copied to make a new copy with one old strand and one new strand
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name the 5 basic requirements for DNA replication
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1: Template
2: Synthesizing enzyme 3. Nucleotides 4. Something to open helix 5. Something to relieve torsional strain of unwinding |
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Name the enzyme that unwinds the helix
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helicase
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Name the type of enzyme that relieves torsional strain and the specific one that is used in humans
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topoisomerase enzyme
gyrase |
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In what direction are bases added to the existing DNA strand?
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5'-->3'
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What other protein complex is needed for DNA synthesis to start?
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RNA primer
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Describe some polymerases exonuclease activity.
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the ability of some polymerases to remove bases from the end of a DNA strand, in either 5--3 or 3--5 direction
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What enzyme creates the RNA primer?
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Primase
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What is the function of DNA Pol III?
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synthesize new DNA
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What is the function of DNA Pol I?
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to remove RNA primers after DNA Pol III has initiated its synthesis
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What enzyme seals gaps between DNA fragments after the primer has been removed?
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DNA Ligase
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Describe the replisome.
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The replisome is the large complex structure in which all the proteins of DNA synthesis are housed.
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study specific and nonspecific repair mechanisms for DNA
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DO IT NOW!
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DNA polymerase II function
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not involved in replication. repair only
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Describe the relationship between oncogenes and tumor suppressor genes and cancer.
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Oncogene mutation causes proliferation by a gain of function, tumor suppressor gene mutation causes proliferation by way of loss of function
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Define homeostasis
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the ability of organisms to maintain a constant internal environment despite a constantly changing external environment
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Name the 5 methods of cellular communication.
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Autocrine
Paracrine Endocrine Neuronal Direct Contact |
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Define autocrine signalling
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a cell sends out a signal that ends up triggering receptors on its own surface
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define direct contact signalling
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communication that occurs between receptors on cells that are touching each other
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define paracrine signaling
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release of communication molecules to extracellular fluid to diffuse to nearby cells
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define endocrine signalling
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release of communication into bloodstream where they travel to target cells in another part of the body
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name some endocrine organs/glands
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hypothalamus, pituitary, thyroid, thymus, adrenal glands, pituitary, gonads, pancreas
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name some organs that are involved in endocrine processes but their main function lies elsewhere
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liver, kidneys, skin
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define a tropic hormone
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a hormone made by one endocrine gland that targets another endocrine gland which, in turn, produces another hormone
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define a non-tropic hormone
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a hormone that targets an organ or group of cells that is not one of the main endocrine structures
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how are hormones differentiated molecularly
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lipophilic/hydrophilic
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what three main classes of lipophilic hormone are there
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steroid hormones
thyroid hormones retinoids |
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where do lipophilic hormones travel?
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bound to transport proteins in the blood
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what three main classes of hydrophilic hormones are there
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amino acid derivatives
peptides proteins |
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where do hydrophilic hormones travel
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can travel dissolved in the blood stream
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how do lipophilic hormones enter the target cell?
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diffuse through the membrane and attach to intracellular receptors
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LOOK AT THE HORMONE-TARGET CELL DIAGRAMS
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DO IT NOW
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how do hydrophilic hormones enter the target cell?
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they attach to an extracellular receptor and initiate a signalling sequence inside the cell
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name the two main classes of paracrine signallers
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prostaglandins
growth factors |
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LOOK UP THE HYPOTHALAMUS PITUITARY AXIS
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DO IT NOW
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LOOK UP THE DIFFERENT HORMONES RELEASED FROM THE HYPOTHALAMUS PITUITARY AXIS
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DO IT NOW
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what class of hormones controls the anterior pituitary
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neurohormones
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define a neurohormone
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neurotransmitters that originate in the hypothalamus but travel through the blood to cells in the anterior pituitary
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define a ligand
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a signalling molecule
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what are the two different types of receptors?
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nuclear/cytoplasmic
membrane |
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describe the functional domains of steroid hormone receptor
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hormone binding domain
DNA binding domain transcription-activating domain |
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LOOK UP STEROID HORMONE-TRANSCRIPTION INTERFACE
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DO IT NOW
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name the three types of membrane receptors
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channel-linked
enzymatic G-protein couple receptors |
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how do enzymatic receptors activate enzyme activity?
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activation of a protein kinase cascade via phosphorylation
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LOOK UP AUTOPHOSPHORYLATION
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DO IT NOW
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describe the action of a GPCR
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G proteins are attached to the membrane receptor and are activated by ligand-binding
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how many transmembrane domains do GPCR's have?
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7
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describe a MAP Kinase cascade
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ligand called a mitogen (growth-stimulating) activates a kinase cascade
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G proteins are active when bound to what and inactive when bound to what?
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active when bound to GTP, and inactivated by binding to GDP
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what subunits are usually part of the G-Protein
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alpha
beta gamma |
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what subunit of a G-protein dissociates when a ligand binds to the GPCR?
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alpha
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the G protein beta and gamma subunits do what after the alpha subunit has dissociated?
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activate an effector protein that either directly activates a signal transduction cascade or produces a second messenger
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how are G-proteins considered self-regulating?
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they can hydrolyze GTP back to GDP, shutting off their own activity
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name two common effector proteins activated by G-proteins
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adenylyl cyclase
phospholipase C |
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what is the action of the effector protein adenylyl cyclase?
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converts ATP to cAMP, a very useful second messenger
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what is the action of the second messenger inositol trisphosphate/the action of phospholipase C?
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cleaves PIP2 to produce IP3 and DAG
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how does the bacteria Vibrio cholera affect human cellular functoin?
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activates a specific G-protein and keeps it turned on, allowing ions to be continuously transported out of the gut, resulting in dehydration
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define cleavage
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the stage of early cell divisions in an embryo
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what is the name for the group of cells left at the end of cleavage?
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blastocyst
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what cells compose a blastocyst?
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blastomere cells
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what is the name of the central cavity of a blastocyst?
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blastocoel
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define a stem cell
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cells that can mature into a range of specialized cells and can divide indefinitely
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name the four tupes of stem cells
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totipotent
pluripotent multipotent unipotent |
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define a totipotent stem cell
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can mature into any cell type, including placenta
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define a multipotent stem cell
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can mature into any of a group of specialized cell, such as any type of blood cell
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define a pluripotent stem cell
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can mature into any type of cell of the embryo(excludes placenta)
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define a unipotent stem cell
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can mature into only one specialized cell type
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define a morphogen and its function
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a morphogen is a biomeolecule that can influence the development of cells, serve as signalling molecules during development (proteins, nucleic acids)
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what two types of morphogens are there?
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cytoplasmic determinants
induction agents |
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define a cytoplasmic determinant
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a molecule found in the cytoplasm of the embryo before fertilization, are usually unevenly distributed in the egg, highly localized
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define an induction agent
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a molecule released by a cell to the cells around it to influence the developmental fate of the cells around it
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define differentiation
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cells that have differentiated have taken on the physical characteristics of the cells they are determined to be
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define determination
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determined cells are already destined to be a certain cell type, but yet lack the physical characteristics of that cell
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describe pattern formation in embryonic development
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establishment of axes and segments in the embryo, establishment of the cell's polarity
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name the succession of pattern formation genes activated in a growing embryo
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gap genes-->pair-rule genes-->segment polarity genes
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why is segmentation of an embryo important
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cells in each segment know where they are because of the induction agents recieved by surrounding cells in that segment
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what genes determine the identity of each segment in an embryo?
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Hox genes
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define morphogenesis
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the process of creating non-identical cells, (formation of an ectoderm, endoderm, mesoderm)
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what protein is very important to cell migration in embryonic development?
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cadherin proteins that help cells stick to each other
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what protein is very important in keeping a cell where it belongs?
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integrin proteins that help cells stick to their foundation
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what proteins are responsible for bringing about apoptosis and how do they do it?
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proteases that hydrolyze, or break down, other proteins
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what two things are absolutely necessary for the nervous system?
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a way to sense stimuli, and a way to respond to those stimuli
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define neuroglia
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support cells that nourish neurons
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LOOK UP SCHWANN CELLS AND OLIGODENDROCYTES
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DO IT NOW
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where are the resting membrane charges on the neuron
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positive outside, negative inside
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name the factors essential to maintenance of the resting potential
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NA+/K+ pump that transports NA out and K in. diffusion of K+
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look up NA+/K+ resting potential characteristics
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DO IT NOW
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what two anions are important in neurons
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Cl- and negatively charged proteins
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why are Cl- and negatively charged proteins important in the neuron
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LOOK IT UP
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depolarization is making the membrane more _________
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positive
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hyperpolarization is making the membrane more _________
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negative
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define a graded potential
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a change in polarization of the membrane
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look up exact graded potential definition
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DO IT NOW
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what is the combination of graded potentials called?
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summation
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define a voltage gated channel
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a channel that opens and closes in response to changes in membrane potential
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look up stages of an action potential
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DO IT NOW
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what is the all-or-none principlcle
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the action potential can either be all the way completed, or not done at all
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what does the membrane potential travel from and to during an action potential
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goes from -70mV to 50mV
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what are the two gates of the NA+ voltage gated channel responsible for
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activation gate responsible for large influx of ions, inactivation gate slowly closes to terminate the rising phase after depolarization
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what causes repolarization
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slow opening of the K+ channel that causes K+ to flow outward
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what causes the undershoot
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the K+ gate also closes slowly
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how does action potential stay unidirectional?
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the inactivation gates of channels "behind" the potential remain closed for a short period of time
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what three ways can action potential speed be increased?
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1) raise temperature
2) increase axon diameter 3) insulate with myelin |
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what neurotransmitter stimulates muscle tissue?
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acetylcholine
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GO OVER DIFFERENT TYPES OF NEUROTRANSMITTER
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DO IT NOW
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the central region of the sarcomere occupied by myosin is which band
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the A band
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the region that action doesn't overlap myosin is what band
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the I band
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name the 4 steps of muscle contraction
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1)myosin hydrolyzes ATP
2)Myosin releases Pi, binding actin 3)myosin releases ADP, power stroke 4) ATP binds to myosin, releasing actin |
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look up muscle contraction steps
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DO IT NOW
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what does the poison curare do?
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prevents the reception of acetylcholine at the neuromuscular junction
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describe cooperativity in relation to oxygen binding
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the second and third of the 4 oxygens that bind to hemoglobin bind more easily than the first, but the 4th binds more slowly because there is only one spot left for it to bind
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the fetal hemoglobin binding curve is different from the adult binding curve how?
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shifted left
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what animal has a left shifted curve?
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llama
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what does a left shifted curve result in?
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saturation at a lower pO2
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why do llamas and fetuses need saturation at a lower pO2?
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less O2 in the environment but still need just as much oxygen delivered to tissues
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describe the Bohr shift
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pH causes the hemoglobin binding curve to shift to the right
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what does a right shift of the curve do?
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causes less saturation at the same pO2, resulting in more O2 released into the tissues
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what two types of cells make up the xylem?
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dead tracheids, vessels
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what types of cells is phloem made of?
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living sieve tube cells that resemble tracheids
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what are the three pathways that water enters the root?
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symplast, apoplast, transmembrane
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describe symplast transport
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water and minerals move through cytoplasm and plasmodesmata
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describe apoplast transport
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passive, water diffuses through cell walls and between the spaces between cells
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what protein composes the outer cells of the root endodermis
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suberin
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what is the name for these suberin-containing cells found on the outside of the endodermis?
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Casparian strip
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what benefit does the Casparian strip have?
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forces water and minerals to pass through selective membranes, allowing control of what enters and exits the cell
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how do plants move water from root hair tips to the xylem?
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root pressure as solutes are pumped closer and closer to the xylem/move through the plasmodesmata, creating water potential gradient
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what are the 4 forces that allow water to move up the xylem
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transpiration
adhesion cohesion tension |
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what structure controls gas exchange in plants?
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stomata
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what is a stomata made of?
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two guard cells with vacuoles inside that are open when the vacuoles are full and closed when the vacuoles are empty
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LOOK UP WHY HIGH WATER CONTENT LEADS TO OPEN STOMATA
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DO IT NOW
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describe the pressure flow model
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photosynthetic areas pump sugars into the phloem, which is followed by water, increasing pressure. nonphotosynthetic areas pump sugars out, which is followed by water, reducing pressure. this pressure difference is what causes water to flow through the phloem
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the peritubular capillaries surround what tubular structures?
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proximal convoluted tubule, distal convoluted tubule
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USE KIDNEY NOTECARDS TO GO OVER RENAL SYSTEM
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DO IT NOW
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define an interferon
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a protein based cytokine used in the immune system
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what "patterns
do the innate immune system recognize |
pathogen associated molecular patterns (PAMPs)
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define a PAMP
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a molecule that isn't made at all in the human body like double stranded RNA, lipopolysaccharides
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what receptors do PAMPs bind to?
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pattern recognition receptors, PRRs
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what are the three cpmponents of the innate immune system?
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1) three types of leukocytes
2)inflammatory response 3) complement activation |
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name the three types of leukocytes involved in the innate immune system
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macrophages, neutrophils, NK cells
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define chemotaxis
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attraction of other white blood cells to an area of pathogenic activity via a chemical signal (usually cytokines)
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define an opsonin
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a special marker protein used by complement to mark a pathogen for destruction by another WBC
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what type of molecule are fragments of foreign pathogens displayed on on the outside of a dendritic cell
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MHC II molecules
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what two types of cells does clonal expansion create?
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some cells capable of fighting a specific pathogen, others that specialize in remembering and can respond very quickly next time that pathogen enters the system
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what two types of T cells are there and what protein receptors do they each express
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Helper T cells-CD4
Cytotoxic T cells-CD8 |
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what is the main difference in the way the T and B cells recognize foreign antigens
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T cells bind to a short peptide that is bound to MHC II, but B cells recognize a protein, lipid, or carb on the cell surface of a pathogen
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what different things can immunoglobulins due to shut down a pathogen
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they can bind to the cell, inhibiting its function; they can act as an opsonin, or they can aggultinate pathogens
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define somatic recombination
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production of new Ig's or TCR's with the encounter of a new pathogen
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what are the 4 different segments of the genes that code for TCRs
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Variable (50)
Diversity (30) Joining (5) Constant (2) |
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describe the process of somatic recombination
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one each of the VDJ segments are selected and joined during B cell or T cell maturation. The C segment selection occurs as an mRna transcriptional modification during splicing
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define the order of segment selection in somatic rearrangement
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first a D and J are randomly chosen and joined, then a V segment is joined to the DJ, the both C regions are transcribed into the receptor, but one is deleted during intron removal
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