BIOL 1362- Biology 2 Exam 2 Review
BIOL 1362- Biology 2 Exam 2 Review BIOL 1362
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This 44 page Study Guide was uploaded by Alexis Clowtis on Wednesday March 9, 2016. The Study Guide belongs to BIOL 1362 at University of Houston taught by CHEEK in Spring 2016. Since its upload, it has received 97 views. For similar materials see Biology 2 in Biology at University of Houston.
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Date Created: 03/09/16
BIOL 1362 Exam 2 Review Chapters 9,10,12, and 13 Chapter 9, 10 Cell Cycle Fig. 9.7 Interphase • Interphase=90% of cell’s life • Growth • Normal function • Most body cells are in interphase • G1 (gap 1, growth)- making organelles(need phospholipid membrane) and proteins • Muscle cells stay in G1 for most of life, cells just get bigger when you work out • Normal function: • Muscle cell- contractionll- absorption and secretion • Nerve cell- conduction • Length of phase depends on type of cells • S= synthesis of DNA; copy all genetic info • cell now)es are duplicated to prepare for cell division (copy machine)= 12 feet of DNA (92 chromosomes in • G2= gap 2 • Continued growth and preparation for cell division Mitotic Phase • Mitosis- division of chromosomes • Prophase • Prometaphase • Metaphase • Anaphase • Telophase • Cytokinesis- division of cytoplasm Prophase • Nucleoli disappear (so not synthesizing rRNA anymore) • Chromosomes- coiled tightly, visible under microscope • Appear as sister chromatids • 2 centrosome forms • Spindle forms • Centrosomes begin to move away from each other Prometaphase • between prophase and metaphase: • Centrosomes at opposite poles, no nuclear envelope (breaks down) and all chromosomes all kind of flowy in between centrosomes • Nuclear envelope has to be disintegrated because centrosomes have to get in and attach to chromosomes • Each chromatid has a kinetochore: protein structure associated with centromere, connects chromosome to spindle fiber • Centrosomes are at opposite poles • Spindle microtubules invade nucleus/enter nuclear space • Some attach to kinetochores • Other interact with microtubules from other side and helps push poles apart Metaphase • really fast; once in center, move to next phase • Chromosomes are in center of cell • Kinetochore of each chromatid is attached to microtubule from opposite pole • Centrosomes at opposite poles • Counteracting forces of spindle eventually make them line up at metaphase plate Anaphase • Sister chromatids separate • Kinetochore microtubules shorten • Daughter chromosomes moved towards poles Telophase • Nuclear envelope reforms, making 2 nuclei • Chromosomes relax and become mesh of stuff again • Nucleoli reappear (ribosomal synthesis resumes) • Spindle microtubules depolymerize (pull apart 1 “brick” at a time) Cytokinesis • Cytoplasm is separated • Cleavage furrow is formed 2 daughter cells Cell Division • 3 main steps required: • Duplication of chromosomes • Separating chromosome copies to opposite ends of cell • Splitting cytoplasm into 2 daughter cells • 3 major functions • Reproduction of single-celled organisms • Development from zygote to embryo • Repair and renewal of tissues Mitosis in eukaryotes • Ploidy level at beginning and end of cell division of mitosis- diploid cell produces 2 diploid daughter cells (2n) • Outcomes of mitosis: 2 identical daughter cells • Organs in which mitosis occurs- skin, muscle, liver, etc. Body cells-NOT gametes (sex cells) Terms • Chromosome- colored body; 1 double stranded molecule of DNA wound around proteins • Ploidy- number of sets of chromosomes in a cell/in the cells of an organism • Haploid- 1n; single copy of each chromosome; “a single set of chromosomes” • Diploid- 2n; 2 copies of each chromosome; “2 sets of chromosomes” Meiosis • Crossing over- chunks of DNA are swapped between non-sister chromatids • chromosomes DNA then after switch, other enzymes glue pieces to other • If crossing over happened between sister chromatids, genetic info wouldn’t change • Products of meiosis • 4 1n (haploid) daughter cells genetically different from each other and from parent • Occurs in GAMETES only • Key steps that result in genetic diversity from parent cell and other daughter cells: • Crossing over • Independent assortment • Fertilization Meiosis I Fig 10.8 Prophase I • Homologous chromosomes held together by synaptonemal complex- proteins • Crossing over during prophase I produces recombinant chromosomes: chromosomes that contain genes from both parents • You mix what your parents gave you TO PASS ON TO OFFSPRING because this is in making gametes • Nuclear envelope breaks down • Spindle forms and microtubules attach to kinetochores Metaphase I • Kinetochores of homologs (1/2 of homologous pair; one of each homologous pair) are attached to microtubules from opposite poles Anaphase I • Homologs separate (but chromatids still together) • Homologs move along spindle to opposite poles Telophase I & Cytokinesis • 2 haploid nuclei (separate at end of cytokinesis to 2 haploid cells) • 2 sister chromatids per chromosome • Complete haploid set of chromosomes at each pole • Cytoplasm divides • Result: 2 haploid (1n) daughter cells Meiosis II Prophase II • New spindle forms • Microtubules attach to kinetochores Metaphase II • Chromosomes aligned in center • Kinetochores of each sister chromatid attached to microtubule from opposite pole Anaphase II • Chromatids separate and move along spindle to opposite poles Telophase II & Cytokinesis • Nuclear envelope reforms • Chromosomes relax • Each nucleus contains 1 copy of each chromosome • Cytoplasm is divided Compare/Contrast Mitosis Meiosis I Meiosis II Ploidy level before 2n 2n 1n division 1 stage Prophase Prophase I Prophase II nd 2 stage Prometaphase Metaphase I Metaphase II 3 stage Metaphase Anaphase I Anaphase II 4 stage Anaphase Telophase I & Telophase II & Cytokinesis Cytokinesis 5 stage Telophase & Cytokinesis Product 2 identical 2n cells 2 different 1n 4 different 1n daughter cells daughter cells Chapter 12 Heredity Mendel • Law of segregation • Physical basis in chromosome movement during Anaphase I: Separation of homologs • the two alleles for a heritable character segregate during gamete formation and end up in different gametes • Law of independent assortment • Physical basis in chromosome movement during Metaphase I: Alternative arrangement along metaphase plate • Two or more genes assort independently- each pair of alleles segregates independently of each other pair during gamete formation Chapter 13 DNA Replication Experiments • Griffith- mouse experiment • Avery- purified Griffith’s experiment • Hershey and Chase- T2 Phage and E. coli in centrifuge • Meselson and Stahl- heavy/light DNA proving Watson and Crick’s semi-conservative model of DNA • Everyone thought protein was genetic material before experiments started proving otherwise Griffith’s Mice Experiment • R strain of bacteria= mice lived • S strain of bacteria= mice died • Dead S + Live R= mice died so something inside the R turned the S to living • Griffith concluded that some heritable trait changed S into living • Avery determined transforming substance is DNA • Experiment involved inactivating molecules via enzymes to figure out how RS • When inactivated DNA is given to mice they live while with deactivated everything else (protein, RNA) they still died so proves DNA is reason for change Hershey and Chase- Virus experiment • Label DNA vs Protein with a tag • DNA tag is radioactive phosphorus (because P is in DNA, S isn’t) • Protein tag is radioactive sulfur (S is in protein, not DNA) • Grew some virus in Sulfur-35, some in Phosphorous-32 • Put in centrifuge • Radioactive sulfur was in supernatant (top) • Radioactive phosphorus was found in pellet(heavy at bottom) with E. coli (heavy components are bacterial cells) • Means viral DNA is in bacteria Meselson and Stahl- heavy/light DNA • Hypotheses: • Conservative model • Semi-conservative model (Watson and Crick) • Dispersive model • Bacteria cultured in medium with heavy nitrogen light nitrogen Sample centrifuged after 1 and 2 replication • First replication matched semi-conservative and dispersive, but second replication matched only semiconservative so the second hypothesis by Watson and Crick was correct Chargoff’s rule • Given 1 %, find other 3 • Chargoff: investigated nitrogenous base composition of different organisms (already knew that DNA is polymer of nucleotides) -% adenine, guanine, cytosine, thymine in at least 40 species from various kingdoms • All 4 percentages add up to 100% • %A=%T • %C=%G DNA • Predict outcome if particular molecule is limited/inhibited during DNA replication • Synthesis of the leading strand is initiated by an RNA primer, which must be removed and replaced with DNA, a task that could not be performed if the cell's DNA pol I were nonfunctional • If DNA ligase isn’t there then you would be left with a template strand and a bunch of chunks of complementary DNA • Without primer, DNA polymerase couldn’t start adding complimentary bases DNA Sequences • Always run antiparallel so if given 5’-3’ answer should be 3’-5’ • A pairs with T and vise versa • C pairs with G and vise versa • When complementary bases are RNA, replace T with U • Given DNA sequence ATG would have complimentary RNA sequence UAC Watson and Crick • Observed Rosalind Franklin’s X-ray of DNA to determine double helix • Had semi-conservative (correct) hypothesis for DNA strand model • 2 DNA strands separate and each strand is copied by complimentary base pairing Mechanics of DNA Replication • Helicase to unwind double helix • Primer • Primase builds primer • DNA polymerase adds nucleotides • Leading strand starts at origin of replication at 3’ of template strand (which polymerase continually brings complimentary basesuilt and then DNA • polymerase can only add from 3’-5’ of template DNA so primer is builtnd DNA further down template strand and Okazaki fragments are formed backwards and then DNA ligase goes back in and glues pieces together • Fig. 13.16 in textbook- pg. 256 Vocabulary • Interphase- cell growth • Traits- variant of character • Mitosis- cell division • Gene- unique sequence of DNA nucleotides that codes for a protein • Cytokinesis- cytoplasm division • Locus- location of gene, used interchangeablywith gene • Centrosome- center point for microtubules; “center body” out in cytoplasm • Chromosome- double stranded molecule of DNA wound around • Centromere- part of chromosome made of DNA where sister protein chromatids are closely attached (doesn’t code for protein) • Homologous chromosome- have same length and contain genes • Chromatid- chromosome named this when stuck to its identical for same character copy • Karyotype- picture of stained chromosomes; picture of all eukaryote’s chromosomes arranged in matched pairs from • Prophase longest to shortest • Spindle- array of microtubules • Autosome- carry genes for all body functions • Prometaphase- between prophase and metaphase • Sex chromosome- carry genes that determine individual’s sex • Kinetochore- protein structure associated with centromere that • Haploid- (gametes) contain one set of chromosomes (1n) connects chromosome to spindle fiber; “linker unit” • Diploid- total number of chromosomes in each body cell of • Metaphase sexually reproducing animal (2n) • Anaphase • Mitosis • Telophase • Meiosis I • Cleavage furrow- forms in animal cells for cytoplasm to divide • Meiosis II • Allele- version of a gene; codes for specific version of character • Wild type- phenotype for a character most observed in natural population • Law of segregation- the two alleles for a heritable character People segregate during gamete formation and end up in different gametes • Law of independent assortment-Two or more genes assort • Rosalind Franklin- X-ray crystallographer that independently- each pair of alleles segregates independently of ephotograph that allowed Watson and Crick to the other pair during gamete formation deduce the double-helical structure of DNA • Sex-linked gene- gene located on either sex chromosome • Carrier- do not express gene/mutation but may pass it • diffraction image of DNA by Franklin andy onto offspring confirmed DNA was helical; began building models of double helix that would match X-ray • Pyrimidine- single ring nitrogenous base measurements; two sugar-phosphate backbones • Purine- double ring nitrogenous base are antiparallel; mainly by trial and error • 3’ end of nucleotide- OH end determined key points of structure in DNA • 5’ end of nucleotide- free end • Anti-parallel- oriented in opposite directions as each other • Replication fork- y-shaped region where the parental strands of DNA are being unwound • Dnucleotide to the 3’ carbon of the preceding deoxyribose nucleotide; catalyzes formation of phosphodiester linkages between dNTP’s • Helicase- enzyme that unwinds double helix • Primer- short piece of complimentary RNA matched to parental DNA to start replication
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