Study Guide Biology Test 3
Study Guide Biology Test 3 1103.0
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This 15 page Study Guide was uploaded by Chandler Darden on Monday August 24, 2015. The Study Guide belongs to 1103.0 at University of Georgia taught by Brickman in Fall 2015. Since its upload, it has received 173 views. For similar materials see Concepts in Biology in Biological Sciences at University of Georgia.
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Date Created: 08/24/15
Biology Exam 3 Study Guide Ch 9 Genetics and Cell Division DNA contains an organism s genome Genome the complete collection of that organism s genetic information o This information exists in units called genes that lie along DNA s double helix 0 Humans pass on half of a father s genome and half of a mother s genome in reproduction to produce a whole new genome Proteins get produced through information in DNA DNA s code is the 4 substances that lie along the double helix 0 1 Adenine A o 2 Thymine T o 3 Guanine G o 4 Cytosine C The sequence of the A s T s G s and C s determine which protein is being formed 0 Separate sequences of bases are separate genes DNA Architecture 0 2 handrails made of sugar and phosphate molecules 0 The steps consisting of A T C or G s The Path of Protein Synthesis 0 1 DNA is transcribed onto mRNA 0 2 mRNA exits the cell s nucleus and goes to a ribosome o 3 mRNA is read and a string of amino acids are put together in the order speci ed by the sequence 0 4 A protein is formed Genetics the study of physical inheritance among living things o It concerns the storage duplication and transfer of information Collection of genes in a living thing its genome o The human genome is estimated to include 2000025000 genes 0 Millions of copies of genomes because cell s split and divide Cells only come from other cells 0 By division Cells need to be replaced because 0 They die 0 They become to large to function They divide when they become to large Certain parts of the cell must duplicate before it splits 0 DNA must duplicate Parent cell divides into 2 daughter cells Replication the duplication of DNA Mitosis the apportioning of it into 2 identical quantities Cytokinesis the splitting of the cellular material When mitosis occurs 0 Original DNA unwinds into 2 strands 0 Each original strand picks up their cobase A picks up a new T T picks up a new A etc Chromosome structural unit containing part or all of an organism s genome consisting of DNA amp associated proteins chromatin 0 Human cells have 46 chromosomes Chromatin a molecular complex composed of DNA amp associated proteins that makes up the chromosomes of eukaryotic organisms The collection of chromosomes makes up nearly the entire complement of a cell s DNA DNA is replicating the chromosomes that DNA helps make up are duplicating Chromatid one of the two identical strands of chromatin that make up a chromosome in its duplicated state 0 Sister chromatids combine to make a duplicated chromosome The 46 chromosomes we have come form both parents 0 23 from mom and 23 from dad Homologous Chromosomes chromosomes that are the same in function and hence size 0 Don t have to look exactly alike 0 Ex Red hair chromosome amp brown hair chromosome homologous chromosomes The one exception to the matchedpairs rule in human chromosomes is the sex chromosomes of males 0 Can either be an x or a y 0 xx female xy male Mitosis the separation of a cell s duplicated chromosomes prior to cytokinesis Cytokinesis the physical separation of one cell into 2 daughter cells Cell Cycle the repeating pattern of growth genetic duplication and division seen in most ces O O O lnterphase that portion of the cell cycle in which the cell simultaneously carries out its work and in preparation for division duplicates its chromosomes 0 Mitotic Phase that portion of the cell cycle that includes both mitosis and cytokinesis 1 lnterphase 61 S 62 Normal cell operations and cell growth Synthesis phase Synthesis of DNA resulting in the duplication of the chromosomes More cytoplasmic growth amp preparation for cell division DNA synthesis is stopped in 62 amp 61 0 There is a gap in DNA synthesis The length of the cell cycle varies from one type of cell to the other 0 Typical animal cell averages 24 hours total lnterphase takes the longest O 2 Mitotic Phase 0 Mitosis has 4 phases 0 O O O O Prophase 1 Prophase 2 Metaphase 3 Anaphase 4 Telophase Marks the end of interphase DNA begins to pack itself into wellde ned chromosomes The nuclear envelope begins to break up Microtubules stretch the cell as a whole and physically move the cell s chromosomes around Centrosome a cellular structure that acts as an organizing center for the assembly of microtubules Duplicate to make 2 The centrosomes migrate to the cellular poles while the chromosomes rst align and then separate along a cellular equator called the metaphase plate Metaphase plate a plane located midway between the poles of a dividing cell 0 Not a physical structure Mitotic Spindle the microtubules active in cell division Metaphase 0 Nuclear envelope has disappeared completely 0 Microtubules that were growing toward the chromosomes now attach to them 0 Each chromatid faces the pole opposite of its sister chromatid Anaphase o The genetic material divides o The chromatids are pulled apart Becomes a chromosome Pulled by a shortening of the microtubules to which it attached Telophase o Represents a return to things as they were before mitosis started 0 Chromosomes unwind and lose their shape 0 New nuclear membranes form 0 Binary Fusion prokaryotic cell division 0 Can complete cycle in as little as 20 minutes Ch10 Meiosis Gametes reproductive cells 0 Sperm and egg cell 0 Human sperm or eggs only have 23 chromosomes in them not pairs Both unite to make a 46 chromosome zygote o The reducedchromosome cells are said to be in the haploid state Haploid single number 0 As egg and sperm unite it returns to the diploid state Diploid double number 46 chromosomes Meiosis a process in which a single diploid cell divides to produce 4 haploid reproductive cells 0 Diploid cells 2n cells haploid cells n Meiosis includes one chromosome duplication followed by 2 cellular divisions which means the process produces 4 cells 0 Mitosis only produces 2 cells 0 Steps of Meiosis o Meiosis l Homologous chromosomes are positioned close together Then they will move apart into opposite sides of the cell 0 Meiosis ll The chromatids of the nowseparated chromosomes will separate into different daughter cells Meiosis I o 1 Prophasel Homologous chromosomes pair up Tetrad when two homologous chromosomes pair up 0 Ex Maternal chromosome 5 pairs with paternal chromosome 5 Chromosomes link up crossing over 0 2 Metaphasel Microtubules move homologous chromosomes to metaphase plate the middle Maternal chromosome moves to one side and the paternal chromosome moves to the opposite side 0 3 Anaphasel Microtubules separate homologous chromosomes 0 Sister chromatids remain together 0 4 Telophasel Cytokinesis occurs 0 Cell divides into 2 completely separate daughter cells 0 2 haploid cells Meiosis ll involves a separation of sister chromatids Crossing over a process occurring during meiosis in which homologous chromosomes paternal and maternal exchange reciprocal portions of themselves 0 Independent assortment the random distribution of homologous chromosome pairs during meiosis 0 Each offspring is unique except identical twins Meiosis generates genetic diversity while mitosis does not mitosis makes genetically exact copies of cells Meiosis and sexual reproduction provide an array of models for nature to choose from each generation 0 Sex chromosomes the chromosomes that determine what sex an individual will be 0 Females xx 0 Males xy or yx o If the egg is fertilized by a sperm holding the x chromosome then it will be a female if it is the y then it will be a male Gamete formation the process by which the egg and sperm are produced 0 Oogonia the starting female cells in gamete formation 0 Spermatagonia the starting male cells These are the diploid cells that give rise to the 2 other sets of diploid cells primary oocytes amp primary spermatocytes Sperm formation 0 Spermatogonia exists in the male testes The volume of an egg is 200000x the volume of a sperm 0 Only one oocyte per month that s expelled from the ovary will complete meiosis l and enter meiosis ll Meiosis II is not completed until the oocyte is fertilized by a sperm 0 Polar bodies nonfunctional cells produced during meiosis in females 0 Life cycle the repeating series of steps that occur in the reproduction of an organism Sexual reproduction the union of 2 reproductive cells to create a new organism o Humans mammals Asexual reproduction reproduction that does not involve sex 0 All female lizard species 0 Binary ssion bacteria 0 Vegetative reproduction 0 Regeneration star sh o Offspring is genetically identical to their parents Spermatagonia are regarded as stem cells because they can produce not only a specialized variety of cell the spermocyte but also more spermatogonia The oognia are produced in females only prior to birth 0 The function of eggs as rich sources of nutrients and cellular materials results in oogenesis producing not 4 cells but 1 viable cell and several polar bodies Ch11 Mendel and His Discoveries Mendel Father of Genetics 0 Dealt with pea plants Pisum sativum Mendel s main inferences were correct 0 1 The basic units of genetics are material elements 0 2 These elements come in pairs 0 3 These elements genes can retain their character through many generations 0 4 Gene pairs separate during the formation of gametes Pea plants can selfpollinate and crosspollinate o Crosspollinate one plant can pollinate another Mendel did this with tweezers and a paintbrush Allowed him to control certain attributes characters Each character can have 2 traits 0 Dominant and recessive trait 0 Ex Character Seed color Dominant trait yellow Recessive trait green Phenotype a physiological feature bodily characteristic or behavior of an organism 0 With a pea plant it s the visible characteristics Genotype genetic makeup Parental Generation P the generation that begins an experimental cross between organisms First Filial Generation F1 the offspring of the parental generation in an experimental genetic cross 0 Fxex F2 is for any succeeding generation Allele an alternative form of a gene 0 Ex Green and yellow seeds 0 They reside on separate homologous chromosomes Dominant types uppercase letters Recessive types lowercase letters Law of Segregation differing characters in organisms result from 2 genetic elements alleles that separate in gamete formation such that each gamete gets only one of the two alleles 0 Also known as Mendel s First Law Homozygous an organism that has 2 identical alleles of a gene for a given character 0 quotYYquot or quotyyquot 0 Homozygous recessive yy 0 Homozygous dominant YY Heterozygous an organism that has differing alleles for a character 0 quotYyquot Dominant a term used to designate an allele that is expressed in the heterozygous condition Recessive a term used to designate an allele that is not expressed in the heterozygous condition Monohybrid cross an experimental cross in which organisms are tested for differences in one character Dihybrid cross an experimental cross in which the plants used differ in 2 of their characters 0 9331 ratio Law of Independent Assortment during gamete formation gene pairs assort independently of one another 0 Mendel s Second Law o Incomplete Dominance a genetic condition in which the heterozygote phenotype is intermediate between either of the homozygous phenotypes 0 Ex red and white snapdragons that can make pink snapdragons Codominance a condition in which two alleles of a given gene have different phenotypic effects with both effects manifesting in organisms that are heterozygous for the gene Dominance does not eliminate a recessive allele it just is the one that gets represented in a given generation 0 Alleles don t disappear ex blonde hair they just aren t shown and will come back eventually in reproduction o It is only in a population of humans that the full range of ABO alleles can be found 0 In a population alleles can come not just in two but in many variants Multiple alleles when 3 or more alleles of the same gene exist in a population Polygenic Inheritance the inheritance of a genetic character that is determined by the interaction of multiple genes with each gene having a small additive effect on the character 0 Ex Height or skin color Not just 24 different heights Not everyone is the same shade of color 0 Bell curve a distribution of values that is symmetrical around the average o It is hard to separate genetic factors amp environmental factors 0 Environmental factor any external in uence that is favorable or unfavorable for the development of a trait in an organism Ex smoking Ch12 Chromosomes amp inheritance Hemophiliacs lack a protein which causes blood clots o 80 lack factor VIII 0 a faulty gene cause the fault factor VIII protein Recessive disorder a genetic disorder that will not exist in the presence of a functional allele 0 a single good allele will do 0 ex redgreen color blindness Autosomes chromosomes other than X or Y o Autosomal recessive disorder a recessive dysfunction related to an autosome Ex sicklecell anemia o A child must get 2 alleles for it one from mom and one from dad Carrier a person who does not suffer from a recessive genetic debilitation but who carries an allele for it that can be passed along to offspring Dominant disorders genetic conditions in which a single faulty allele can cause damage 0 Even when a second functional allele exists 0 Autosomal Dominant Disorder a dominant genetic disorder caused by a faulty allele that lies on an autosomal chromosome 0 Ex Huntington disease 0 Pedigree a familial history intended to track genetic conditions 0 Polyploidy a condition in which one or more entire sets of chromosomes has been added t the genome of a diploid organism Aneuploidy an organism has either more or fewer chromosomes than normally exist in its species full set 0 Usually gained or lost a single chromosome 0 Most common outcome miscarriage in pregnancy 0 Down syndrome is another outcome if embryo survives Nondisjunction a failure of homologous chromosomes or sister chromatids to separate during cell division 0 Brings aneuploidy All aneuploidies result in miscarriage exceptfor an additional chromosome 131821 Down syndrome a condition in 95 of cases in which a person has 3 copies of chromosome 21 rather than the standard two 0 Most aneuploidy cells resulting from mitosis will die but few can survive o Survivors turn into the cancer cell 0 A chromosomal deletion occurs when a chromosome fragment breaks off and then does not rejoin any chromosome Inversion a chromosomal abnormality that comes about when a chromosomal fragment that rejoins a chromosome does so with an inverted orientation 0 Translocation a chromosomal abnormality that occurs when two chromosomes that are not homologous exchange pieces leaving both with improper gene sequences which can have phenotypic effects Ch13 DNA Structure and Replication 0 Molecular Bonding the investigation of life at the level of its individual molecules James Watson and Francis Crick presented the structures of DNA l the double helix Components of DNA 0 1 Phosphate group 0 2 Sugar 0 3 Base A T G C Think of DNA as a spiral staircase o quotHandrails quot sugar and phosphate form a chain 0 quotStepsquot DNA s bases Linked by a hydrogen bond A amp T always G amp C always Bases can be laid out along the quothandrailsquot in an extremely varied manner Nucleotide the essential building block of DNA Process of DNA replication 0 1 Double helix unwinds o 2 Nucleotides of single strands are paired with free oating nucleotides that line up in new complementary strands o 3 2 strands are made Each goes in one of the daughter cells Each newly replicated helix is when joined by an appropriate protein one of the sister chromatids 2 groups of enzymes assists with DNA replication 0 1 Helicases unwind the double helix 0 2 DNA Polymerases moves along each strand of the double helix joining together nucleotides as they are added to form the new complementary strands of DNA The human genome is 32 billion base pairs long DNA Polymerases 0 Remove a mismatched nucleotide and replace it with a proper one Mutation a permanent alteration of a DNA base sequence Point Mutation a mutation of a single base pair in the genome A cancerous growth is a line of cells that has undergone a special kind of mutation one that causes the affected cells to proliferate wildly Huntington disease is caused by a repeating group of three nucleotides so it is referred to as a quottrinucleotide repeatquot disease Most mutations come about in the body s somatic cells cells that do not become eggs or sperm 0 Melanoma Some mutations arise in germline cells cells that become eggs or sperm 0 Huntington mutation o This is heritable It can be passed on from one generation to the next Mutagens substances that can mutate DNA 0 Ex Chemicals in cigarette smoke Ch14 How Proteins Are Made Polypeptide a series of amino acids linked in linear fashion 0 Polypeptide chains fold up to become proteins Each protein is put together from a starting set of 20 amino acids 0 The order of amino acids determines which protein is synthesized Ribosome site of protein synthesis Protein Synthesis Steps 0 1 Transcription the process by which the genetic information encoded in DNA is copied onto messenger RNA 0 2 Translation the process by which information encoded in mRNA is used to assemble a protein at a ribosome RNA is structured very similar to DNA 0 RNA is usually single stranded and DNA is double stranded 0 RNA uses the base uracil U instead of thymine T A links to U on RNA RNA Polymerase enzyme that unwinds the DNA sequence and then strings together a series of RNA nucleotides that is complementary to it thus producing an initial RNA chain 0 This RNA is called a primary transcript Messenger RNA mRNA a type of RNA that encodes and carries to ribosomes information for the synthesis of proteins 3 DNA bases code for an amino acid Codon each coding triplet of mRNA bases Genetic Code the inventory of linkages between nucleotide triplets and the amino acids they code for Amino acids are brought to ribosomes by transfer RNA tRNA Transfer RNA tRNA a form of RNA that in protein synthesis binds with amino acids transfers them to ribosomes and then binds with mRNA 0 tRNA binds with an mRNA codon by means of 3 bases it possesses called an anticodon Ribosomes are composed of 2 subunits 0 One larger one small 0 Both made of a mixture of proteins and ribosomal RNA Ribosomal RNA a type of RNA that along with proteins forms ribosomes 0 When subunits are joined there are three binding sites 1 E site 2 quotPquot site 3 A site A transfer RNA molecule attaches to an amino acid on one end and a colon on the other Human genome the full complement of DNA found in the nucleus of each human cell Development of vertebrae s in embryo s o 2 stretches of DNA the promoter and enhancer that do not code for protein but do serve a regulatory function They facilitate transcription by RNA polymerase Proteins bind to these DNA sequences Mutations to regulatory sequences allow an organism to ne tune its use of a protein whereas mutations to protein coding sequence are likely to result in the elimination of a protein DNA always codes for RNA but RNA does not always go to make a protein 0 Some ends up helping make tRNA or ribosomes Almost all microRNA s reduce the production of proteins 0 They interfere with mRNA s by destructing them or locking them away before they can be moved to a ribosome to be translated 0 Gene silencing is very important Human genome probably contains about 2000025000 genes RNA that is transcribed from DNA the primary transcript needs to be edited before it becomes mRNA 0 An enzyme gets the unwanted parts out o lntrons sequences that are cut out They are inteNening o Exons sequences that are retained Most are expressed as proteins 0 lntrons account for more than 90 of the length of the average human gene Alternative Splicing a process in which a single primary transcript can be edited in different ways to yield multiple messenger RNA s o Allows our 2000025000 genes to produce Humans have more than 98 of DNA that is not coding for protein 0 Highest in any organism 0 Genes help bring about proteins some of these proteins feed back on other genes and control their production of other proteins RNA sequences get spliced in different ways yielding different proteins and so forth 0 A central feature of genetic regulation is that proteins called transcription factors bind to noncoding DNA this regulating the transcription of genes Ch15 Biotechnoloqv Biotechnology the use of technology to control biological processes as a means of meeting societal needs 0 4 of the many aspects of biotechnology o 1 Transgenic biotechnology The splicing of DNA from one species into another 0 2 Reproductive cloning The production of mammals through cloning o 3 Cell reprogramming The production of needed cell types through the reprogramming of genomes o 4 Forensic biotechnology The use of biotechnology to establish identities of criminals crime victims etc o Transgenic Biotechnology 0 Transgenic organism an organism whose genome has stably incorporated one or more genes from another species Ex When HGH was taken from a human and spliced into a bacterium Bacterium became a transgenic organism 0 Restriction enzyme a type of enzyme occurring naturally in bacteria that recognizes a speci c sequence of DNA bases and cuts DNA strands at a speci c location within that sequence Produce quotsticky endsquot of DNA which have potential to stick to other complementary DNA sequences 0 Plasmids a ring of DNA that lies outside the chromosome in bacteria Can move into bacterial cells Transformation a cell s incorporation of genetic material from outside its boundary 0 Segments of human and plasmid DNA through sticky ended base pairing t together like puzzle pieces 0 Recombinant DNA two or more segments or DNA that have been combined by humans into a sequence that does not exist in nature o Cloning vectors selfreplicating agents that serve to transfer and replicate genetic material Ex Plasmids Ex A bacteriophage A type of virus that infects bacteria Reproductive Cloning 0 Clone to make an exact genetic copy of O Ex Cutting a plant putting in soil and having a new one grow Reproductive Cloning cloning intended to produce adult mammals of a de ned genotype Ex Dolly the sheep Somatic Cell Nuclear Transfer SCNT a means of cloning mammals through fusion of one somatic nonsex cell with an egg cell whose nucleus has been removed Cell Reprogramming 0 By the time we are adults almost all cells have undergone commitment Muscle cells can only be muscle cells ESC s and iPS cells represent 2 forms of cell reprogramming ESC s are being reprogrammed to yield desired cell types Ordinary adult cells are being reprogrammed to yield iPS cells that go on to yield desired cell types Stem Cell any cell that can give rise to more cells of its kind along with at least one variety of specialized cell Blastocyst a hollowedout uid lled ball of 100150 cells One section becomes the placenta Once section becomes the inner cell mass 0 Holds embryo Embryonic Stem Cells ESC39s cells from the blastocyst stage of a human embryo that are capable of giving rise to all types of cells in an adult body Induced Pluripotent Stem Cells iPS Cells cells that have been induced into state of pluripotency through the introduction of genes from outside their genome A pluripotent cell is one that s capable of giving rise to all types of cells in the body Come from people themselves whereas ESC s come from embryo s Forensic Biotechnology o Polymerase Chain Reaction PCR a technique for quickly producing many copies of a speci c segment of DNA 4 kinds of material are mixed together 0 1 DNA itself 0 2 DNA nucleotides amp DNA polymerase 3 2 DNA primer sequences 0 Counts as 2 so it equals 4 o The DNA of every individual contains groups of tandem repeats whose number can be used to establish the identity of that individual Ex TCAT can be repeated 350 times Unlikely for people to have the same amount
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