Unit 2 Study Guide
Unit 2 Study Guide BIOL 121N
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This 15 page Study Guide was uploaded by Dominick Ramos on Sunday September 27, 2015. The Study Guide belongs to BIOL 121N at Old Dominion University taught by DOUGLAS J MILLS in Fall 2015. Since its upload, it has received 111 views. For similar materials see GENERAL BIOLOGY I in Biological Sciences at Old Dominion University.
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Date Created: 09/27/15
BiollZlNUnit 2 Study Guide Stem Cells What are they A stem cell is an unspecialized cell that can divide to produce 0 Other stem cells 0 Progenitor cells that can develop into specific cell types Some uses of stem cells 0 Human development research 0 Drug development 0 Cell therapy There are three types of stem cells Totipotent Pluripotent Multipotent Derivedfrom Can develop into any cell type in the body blastocysts embryos that are about a week Sources include old 0 Embryo after the 8cell stage Can develop into 0 Umbilical cord blood 0 An individual 0 Parts of the placenta 0 Every cell type there are about 200 embryonic stem cells in human embryo will remain totipotent until the embryo reaches totipotent stem cells 1 Q blastocyst contaunun plunpotenl stem col 5 o o 00 Isolated pluripoxont 5C5 from Inner cell mass 3 939 V o a harmhxxwd b S43 r null gtCs quotVSWKquot quotDI 5 75 tissuespecific SCs 7 t I I I an 0 1 cultured punpotent SCS A 93 e n a 39 quot quot quotnutter5 Hl39x1 um ltIlu quotquotquot lhuul If tuu luau nul r Also known as adult stem cells or somatic stem cells Infants children and adults have adult stem cells that enable the body to grow renew repair and defend against disease Cell Theorv What are Cells The cell is the most fundamental unit of life It is the smallest biological unit that can 0 Acquire and process energy independently 0 Repair itself independently o Reproduce independently Dominick Ramos BiollZlNUnit 2 Study Guide Manv cell types are required to form the human body The human body consists of o 220 cell types 0 Between 60200 trillion total cells These cells are used for movement repair detecting and attacking foreign invaders reproduction etc Prokaryotic Cells Eukaryotic Cells 0 Lack a nucleus probefore karyote nucleus and other organelles surrounded by a membrane 0 Typically smaller than eukaryotic cells 0 Can be spherical rodshaped spiral 0 Contain internal compartments called microcompartments 0 Have a unique set of biochemical functions along with a unique set of enzymes 0 They make an essential contribution to the cell function 0 Surrounded by a protein shell 0 Contain a nucleus 0 contain specialized organelles that are comprised of one or more membranes 0 these organelles have unique biochemical functions due to their containment of enzymes and other chemicals 0 usually bigger than prokaryotic cells Proka ryotes o Consist of one cell 0 Have a single chromosome 0 Were the first cells to appear in the fossil record Examples include archaea bacteria Eukaryotes 0 Contain one or more eukaryotic cells Examples include plants animals fungi etc Tissues A tissue is a group of cells organized into a functional unit 0 Simple tissues made of one cell type 0 Complex tissues made of multiple cell types Dominick Ramos BiollZlNUnit 2 Study Guide Epithelial Connective Muscle 0 Covers all parts of the The glue to connect other Gives the body the ability to body exposed to the types of tissues cells move outside world Forms a protective barrier to protect against foreign invaders microbes viruses Moves foreign particles in mucous membranes Has sensory abilities Absorbtion food during digestion Secretion digestive substances mucous sebum sweat Permits gas exchange 02 and C02 o Enables proper cell development 0 Suppliesstores hormones 0 Muscle attachment 0 Connects muscle tissue to epithelial tissue 0 Provides nutrient supply to epithelial tissue 0 Stretches elasticity o Cushions joints 0 Energy storage adipose tissue 0 Transport veins arteries blood 0 Physical support skeleton 0 Tissue repair fibroblasts Skeletal striated muscle tissue ability to move bones Smooth organ muscle tissue enables the adjustment of the size and shape or organs and blood vessels Cardiac heart muscle tissue provides heart with pumping ability Nervous Dermal Plants Ground Plants Coordinates the body s Covers the outer surfaces of Specialized for activities all plant organs Specialized o photosynthesis Rapid long distance communication Senses external and internal conditions Integrates forms of information and generates the proper bodily response based on info collected and processed Enables cognition creativity decision making learning memories emotions for 0 Absorption 0 Gas exchange 0 Physical barrier to invaders o Secretion 0 Structural support 0 waterproofing structural support storage Dominick Ramos BiollZlNUnit 2 Study Guide Vascular Tissue Connects all parts of the plant tissue and is specialized for o systematic transport 0 structural support 0 storage RP H i 7 61 PhaseGo Phase NIE 5 Phase The cell commits to divide DNA is replicated The cell makes the nucleotide G1 building blocks of DNA The Cell duplicates organelles G2 Phase The cell prepares to divide M Phase The cell divides to produce two identical cells daughter cells The Cell Cycle Control System Is based on the accurate completion of a precise sequence of biochemical events 0 During the cell cycle a cell will advance to the next step only after the biochemical reactions of the previous step have been completed accurately The Function of Cell Cycle Checkpoints These critical points will regulate the cell cycle by producing continue and stop signals The cell cycle will pause at each checkpoint to enable checkpoint sensors to search for specific biochemical errors and coordinate their repair 0 If certain biochemical events have been completed correctly a continue signal will tell the cell cycle to continue 0 If an error occurs a stop signal will prevent the cell from advancing to the next step Dominick Ramos Biol121NUnit 2 Study Guide The Mitotic Phase or Sindle Checkoint Makes sure both daughter cells recieve two sets of chromosomes and promotes proper chromosome delivery to opposite ends during M phase The GLCheckoint Restriction recognizes an adult stem cells39 go signal to pass the restriction point and enter S phase There are 50 gosignals some are hormones ex estrogen testosterone some are growth factorszproteins that stimuate cell division The G2 Checkoint Ensures accurate completion of all necessary biochemical events during S and G2 by DNA damage sensors and DNA repair enzymes there are 200 that are active throughout cell cytcle v Some Biochemical errors cannot be repaired When an error is detected by a cell cycle checkpoint and cannot be repaired a specific signal ligand is released to induce apoptosis cell death Cancer Cells Ignore One or More Cell Cycle Checkpoints Cancer cells divide uncontrollany because some Cannot repair their damaged mutated DNA Have a continuously activated gosignal receptor that does not require a gosignal for stimulation Produce their own gosignals that stimulate gosignal receptors cannot enter apoptosis Dominick Ramos BiollZlNUnit 2 Study Guide Some Adult Stem Cells Use These Methods to Recognize Specific GoSignals and Other Signals G ProteinCoupled Receptors Tyrosine Kinase Receptors LigandGated Ion Channel Receptors o the target of many pharmaceuticals 0 some cancers relate to abnormally activated G proteins o scaffolding proteins 0 localize and arrange all of the molecules necessary for signal 0 transduction to occur used to recognize specific ligands signals neurons nerve cells and muscle cells use ligandgated ion channel receptors to recognize neurotransmitters Hvdrophilic GoSignals Hydrophilic molecules cannot directly diffuse across the cell membrane Defining a Gene Hydrophobic GoSignals Hydrophobic molecules can directly diffuse across the cell membrane A gene is a specific nucleotide sequence in a DNA molecule that codes for the 0 Amino acid sequence of a specific polypeptide 0 Nucleotide sequence of a specific RNA molecule The RNA Genomes of retroviruses and other RNA viruses also contain genes How Genetic Instructions are Stored in a Gene The specific nucleotide sequence of a gene determines the amino acid sequence of the polypeptide it encodes The linear sequence of nucleotides in a gene corresponds to the linear sequence of amino acids in the polypeptide it encodes Dominick Ramos Biol121NUnit 2 Study Guide 7 The Specific Parts of a Eukarvotic Gene Each gene contains the information to ensure that the cell will 0 Activate the gene only when the product is required 0 Read the instructions of the gene correctly The nucleotide sequence of the exons determines the amino acid sequence of the polypeptide that the gene encodes The nucleotide sequence of the introns do not determine the amino acid sequence of the polypeptide that the gene encodes DNA Replication in the Nucleus o Occurs during the S phase of the cell cycle 0 Replicates the 31 billion nucleotide pairs in 68 hours 0 Must occur before the adult stem cell divides to ensure that each daughter cell has a complete set of genetic instructions genome DNA Replication Occurs in other organelles DNA replication will also occur in o The mitochondria of animal cells 0 Mitochondria and chloroplasts of plant amp algal cells DNA Replication Complex Replisome or DNA Replication Bodv All of the enzymes proteins and nucleotides required to make DNA are located together in the nucleus to form a quotDNA Replication Factory 0 There are multiple replisomes in the nucleus to increase the rate of DNA replication The Logic of DNA Replication 0 Each DNA strand of the double helix is a template for the synthesis of a new complementary strand 0 DNA polymerase 0 reads the sequence of each separated DNA strand to guide the synthesis of each new DNA strand 0 It also follows the rules of complementary base pairing when synthesizing a new strand of DNA Dominick Ramos BiollZlNUnit 2 Study Guide DNA Replication Requires Specific Nucleotide Sequences Replication begins at origins of replication 0 There are many origins of replication sequences in each of our DNA molecules to increase the rate of DNA replication 0 quotDNA Initiator proteins bind to the origin of replication sequences to begin organizing DNA replication The enzymes and proteins required for DNA replication 0 HelicaseBreaks the Hbonds between complementary base pairs to unwind the double helix There are 24 human helicases that participate in other processes that change the shape of DNA and RNA 0 Topoisomeraserelieves coiling tension in the DNA double helix due to its unwinding by heHcase o Singlestrand binding proteinskeep the two strands separated and reduce strand degradation Singlestrand binding Primase proteins Helicase The Function of Primase Primase makes a short complementary RNA strand quot11 nucleotides called a primer on each separated DNA strand 0 DNA polymerase enzymes that make new DNA strands require the 3 OH 3 prime hydroxyl end of the RNA primer to begin adding DNA nucleotides to make a new complementary DNA strand Primase DIIA template 339 llllllllll39lllllll39lllllll39lll39llllllll39llll39lS s39uuuy RN A primer Dominick Ramos BiollZlNUnit 2 Study Guide The Function of DNA polymerase DNA polymerase is the enzyme that adds nucleotides to the 3 OH end of the RNA primer to make the new complementary DNA strand o It follows the rules of complementary base pairing 0 11 human DNA polymerases have been identified DNA p1l39111r l d 20 Ill l 3 N39m39v A All nc n39n I N I M4 rawnm A Jaw I4 0 Human DNA polymerase adds 50 nucleotides per second 0 Bacteria DNA polymerase adds 500 nucleotides per second 0 Another DNA polymerase removes the RNA primer and replaces it with a new DNA strand The Function of DNA Ligase DNA ligase links the 3 OH end to the 5 PO4 end to complete the synthesis of the new DNA strand 0 In a sense it seals the nicks in DNA molecules 3 5 DNA POLYMERASE I 3 5 THE RNA PRIMER 5 3 ls REMOVED DNA POLYMERASE I 5 3 3 5 THE RNA PRIMER IS 5 3 REPLACED WITH DNA THESE TWO DNA MOLECULES MUST BE JOINED TOGETHER Dominick Ramos BiollZlNUnit 2 Study Guide 10 DNA Replication Requires a Source of Energy The breaking of the energetic phosphate bonds in the four nucleoside triphosphates provides the energy for DNA polymerase to synthesize DNA New strand Template strand 5 end 3 end 5 end 3 end ENERGY HIGH BONDS Pyrophosphate 339 end Nucleoside 2 i 39 quot A fl3939 sP39 5399quot 5399quot DNA Replication is an Extremely Precise Process The error rate during DNA replication is low due to DNA polymerase s proofreading ability 0 This is essential to maintain the integrity of the genetic instructions stored in our genes 0 DNA polymerase detects and removes the mismatched nucleotide that has added 0 DNA polymerase error rate is quot 10398 per base pair 0 DNA repair enzymes further reduce the error rate to quot 1039 LO o The result is 1 mutation for every 10 billion base pairs replicated The Ends of Our Linear DNA molecules require protection The exposed ends of our linear DNA molecules can be 0 Degraded by enzymes called DNA nucleases 0 Joined together to cause lethal mutations Telomeres Protect the Ends of Our DNA Molecules Telomeres are 0 The protective caps on the ends of our linear DNA molecules 0 Disposable ends of our linear DNA molecules 0 Structures required to maintain DNA length and chromosome stability in adult stem cells Dominick Ramos BiollZlNUnit 2 Study Guide 11 0 Structures at the end of DNA molecules that consist of proteins and the DNA sequence TTAGGG repeated 1001000 times The enzyme Telomerase makes Telomeres Adult stem cells produce the enzyme telomerase to replenish the telomeres after each round of DNA replication 0 Some telomere DNA is lost during replication because DNA polymerase cannot synthesize DNA at the ends of our linear DNA molecules 0 Telomerase replaces the telomere DNA that was lost 0 This preserves the genes located near the end of the linear DNA molecules in the nucleus of our adult stem cells WW WI l rlomomse l1 in to 339 flanking end of telomere illJ I5 01riplqrtnurndvv 1 Icrlltyncmw RNA Bases are added usl39lg RNA as tumuldlc complements 39 l w thelaggng strand Dominick Ramos BiollZlNUnit 2 Study Guide 12 In 61 DNA is condensed into chromatin in the nucleus of the cell Chromatin is consisted of 0 DNA 0 Histoneproteins CHROMATIN MOLECULES coupness INTO CHROMOSOMES cnROMArm unms PROPHASE or MITOSIS p arm Centromere Chromosome USA National Library of Medicme Homologous Chromosomes Homologs TWO IDENT iG I MQITERTIIAL SISTER THE Homomaous mm on cHRurIIATIns cHRoMDSOMlE 1 7 w DUlRIlHG 5 PHASE W E Two IDENTIan FATERNAL SlISTER cII omes GHROMOEOME 1 lFROMI mu SISTER CHROMATIDE IIIRE LINKED TOGETHER AT THE GENITIEDMERE SEQUEIHGE AlF39lI39ER nilIA RIEPLIlGATIDIN AFTER DNA REIPILIcATIOIII TIHERE ARE FDILIR GDFIES 0F BHRDIMGSOME 1 We inherit one complete set of chromosomes from our mother and father 0 The copies of chromosome 1 that we inherit from each of our parents mom and dad are an example of homologous chromosomes 0 Females have two copies of every gene one from mom and one from dad o Males have two copies of every gene on the autosomes chromosomes 122 and one copy of each gene on the X amp Y chromosomes Mitotic Cell Division Is an Essential Process It provides all these functions in multi cell species 0 Growth 0 Repah o Renewal Dominick Ramos BiollZlNUnit 2 Study Guide 13 0 Defense 0 Reproduction The Adult Stem Cell Divides bv Mitotic Cell Division Mitotic cell division Occurs during the mitotic M phase of the cell cycle 0 Consists of mitosis and cytokinesis 0 Results in the production of two identical daughter cells with 46 chromosomes and a complete set of organelles Mitotic Cell Division Consists of Mitosis and Cvtokinesis Mitosis Two complete sets of chromosomes 46 are delivered to the opposite ends of the adult stem cell 0 When complete the adult stem cell briefly contains two nuclei 0 Each nucleus contains 46 chromatin molecules chromosomes 0 Mitosis ensures each daughter cell will receive a complete set of genetic instructions genome when the cell separates by cytokinesis Cytokinesis After mitosis is complete the adult stem cell separates into two identical daughter cells 0 Cytokinesis is the process of cell separation l l 100 um quot4 quot1 J J Contractile ring of Daughter cells microfilaments a Cleavage of an animal cell SEM Co 39 t 39i CuDubliernga PE SFSO minus cyngnl 2005 Pearson Edutal on In 1 Bengannn Cum Dominick Ramos Biol121NUnit 2 Study Guide Mitosis Prophase o Chromatin is condensed into chromosomes with the assistance of condensin protein complexes 0 Spindle Formation begins 14 Prometaphase Metaphase I A kinetochore forms on each sister chromatid The nuclear envelope dismantles to form membrane vesicles The spindle microtubules attach to kinetochores Metaphase Metaphase II o the spindle properly positions each pair of sister chromatids at the center of the cell to start the delivery of each sister chromatid to the opposite ends of the cell I Anaphase The enzyme separase degrades the cohesin proteins that hold the sister chromatids together The spindle delivers each sister chromatid to opposite ends of the cell Telophase and Cytokinesis 0 After the sister chromatids completely separate the condensin protein complexes detach and the sister chromatids unwind to reform chromatin o The nuclear envelope reforms around the chromatin molecules through membrane vesicle fusion or endoplasmic reticulum envelopment The Function and Structure of the Spindle The spindle delivers two complete sets of chromosomes 46 to opposite ends of the adult stem cell during mitosis o The spindle is a dynamic structure consisting of many long protein filaments called microtubules Dominick Ramos Biol121NUnit 2 Study Guide 15 0 Each microtubule is formed by the polymerization of the protein tubulin Astan W Microtubules Chromosomes Metaphase l plate l l Centrosome Overlappan V nonkinetochore Kinetochore mlcrotubules microtubules gt i 05 pm The Spindle Microtubules Attach to the Kinetochore on Each Sister Chromatid The kinetochore on each sister chromatid is formed from the interaction between specific proteins and the centromere DNA sequence 0 A motor protein in the kinetochore enables each sister chromatid to move along the spindle microtubule towards one ends of the cell fcdrumwarm Chromosome movement Kinetochore o 0e o Tubulin Microtubule M t r subunits protein Chromosome Mitotic Phase Checkpoint Failure M phase checkpoint failure can result in the nondisjunction of sister chromatids to cause aneuploidy o Aneuploidy the abnormal number of chromosomes in the nucleus Dominick Ramos
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