Exam 3 Study Guide
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This 8 page Study Guide was uploaded by Ally Bradfield on Friday April 29, 2016. The Study Guide belongs to 1020 at Auburn University taught by Dr. Zanzot in Fall 2015. Since its upload, it has received 6 views. For similar materials see Principles of Biology in Biology at Auburn University.
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Date Created: 04/29/16
UNIT 3 Chapter 12: The Cell Cycle Cell division: parent cell divides into two or more daughter cells -prokaryotes go through binary fission Chromosomes replicate, a copy of the origin moves to the other end of the cell until replication is complete, the plasma membrane curves in and a cell wall is made to separate two daughter cells. -eukaryotes (somatic cells) go through mitosis & (gametes) go through meiosis Interphase: GI, S Phase (DNA synthesis/replication), G2 Prophase: Chromosomes condense, mitotic spindle begins to form, centrosomes move and the nucleolus disappears Pro-metaphase: Nuclear envelop fragments and spindle microtubules attach to kinetochores Metaphase: Mitotic spindle is complete, nuclear envelop is completely gone, and chromosomes align at metaphase plate Anaphase: Chromatids separate and resulting daughter chromosomes move to opposite poles of cell due to cohesion protein removal Telophase: Cytokinesis occurs, daughter nuclei form, and nuclear envelops form isolating each cell *** DNA replication does NOT occur in animals MAIN GOAL OF CELL DIVISION & REPRODUCTION OF CELLS: the continuity of life; repair, reproduction, development/growth Cell Cycle Regulation -Cyclins and cyclin-dependent kinases (CDKs) help control the cell cycle as regulatory proteins -Cyclin-CDK complex = Maturation Promoting Factor (MPF) enables G2 to go to M phase by phosphorylation -Cytoplasmic factor: chemical signals in cytoplasm ultimately drive cell cycle -Platelet-Derived Growth Factor (PDGF): regulates cell division through anchorage dependence (need for cell to attach to surface) and density dependence (need for cell to cover surface area through replication) Normal cell undertakes transformation to become a cancer cell -cancer cells make own growth factors and signals & continue to divide/grow -lose density and anchorage dependence -form tumors: masses of abnormal cells in normal tissue Benign tumors: remain at original site, harmless Malignant tumors: spread, harmful -Metastasis: spread of cancer through rapid proliferation and mestasizing (migrating to other parts of the body) Cancer Treatment -surgery -chemotherapy: targets cell division -radiotherapy/radiation: damages DNA Basics -DNA = sugar + phosphate + base (nucleotides) Nucleotide chain = nucleic acid Double helix with hydrogen bonds -DNA + proteins = chromatin Chromatin condenses into chromosomes Cleavage furrow: indention in cell surface where cytokinesis occurs Cell plate: basically the cleavage furrow in plant cells Chapter 13: Meiosis and Sexual Life Cycles Reproduction -Asexual: mitotic division, producing genetically identical offspring (clone) -Sexual: gametes form zygote through fertilization, producing genetically different gamete offspring (gene recombination) Ploidy -n = one pair of homologous chromosomes -haploid: (n) ex. Somatic cells -diploid: (2n) ex. Zygote ***Polyploidy: having more than two pairs of chromosomes PURPOSE OF MEIOSIS: increase genetic variation -crossing over in Prophase I of homologous chromosomes -Independent Assortment allows alleles to be inherited without influence of others -Random fertilization Meiosis -> Produces 4 genetically different daughter cells -Interphase & M phase same as mitosis Interkinesis: no DNA replication Prophase II: spindle apparatus forms Metaphase II: chromosomes align at metaphase plate Anaphase II: sister chromatids separate to opposite poles Telophase II: cytokinesis, nuclear envelopes form Random/Independent Assortment -2^n when n = number of homologous pairs -> assortments -assortments^2 = number of combinations Basics Diploid cells -> haploid gametes -> fertilization -> diploid zygote ***Fungi go through meiosis AFTER fertilization Chapter 14: Mendel and the Gene Idea Inheritance Hypothesis -Particulate: offspring are a combination of parents, variation is maintained over time, variation is maintained over time -Blending: offspring are a blend with new alleles, variation disappears over time Law of Segregation: alleles separate in meiosis randomly as parents are homozygous or heterozygous Benefits of the Pea-plant Experiment 1. Controlled mating & self fertilization of purebreds 2. Rapid reproduction producing a large number of offspring 3. Short generation time Crossing -Monohybrid cross: two individuals for one trait (heterozygous offspring) -Dihybrid cross: two individuals for two traits (heterozygous offspring for both) Genetic Linkage -Linked genes: inherited together since they’re close to one each other on the same chromosomes -Genes on the same chromosome are usually inherited together until crossing over breaks linkage -Distance between linked genes =recombination frequency -Genetic Map: orders gene loci on chromosome -Linkage Map: genetic map based on recombination frequencies Chapter 15: Chromosomal Basis Inheritance Dominance -Complete dominance: when phenotypes of heterozygous and homozygous are the same, the dominance allele covers up the recessive one completely -Incomplete dominance: new phenotype of F1 generation is between phenotypes -Codominance: phenotype shows both of parent phenotypes separately but included -Multiple alleles: when there are more than two alleles for a trait but only two are carried per person (ex. Blood type ABO) -Pleiotropy: one allele impacts multiple traits (ex. Albinism) -Epistasis: one gene influences phenotype of another (ex. Lab color) -Polygenic traits: traits that occur by gene interaction, leads to population variation -Norm of reaction: phenotype range of genotype influenced by environment Pedigrees Autosomal Dominant: equal X-linked Dominant: more in likelihood for sexes, passed on, females, doesn’t skip generations, doesn’t skip generations, all kids daughters get it if one parent has it have it when both parents do and and sons get it if both parents have half do if only one parent has it it, heterozygous mom dist. evenly Autosomal Recessive: equal X-linked Recessive: more in males, likelihood for sexes, skips never passed from father to son, generations, ¼ of offspring are daughters of affected fathers are affected if both parents are carriers heterozygous for it, happens w/ consanquinity Disorders -Autosomal dominant: Huntington’s, Achondropasia (dwarfism), Marfan syndrome (tissue formation) & polydactyly -Autosomal recessive: Ex. Albinism, cystic fibrosis, sickle-cell anemia -Sex linked: hemophilia, red/green color-blindness Multifactorial disorders: include environmental factors Ex. Heart disease, alcoholism, diabetes, etc. Nondisjunction: wrong number of chromosomes/chromatids separate Polyploidy: extra complete set of chromosomes (fatal) Aneuploidy: missing or extra copy of chromosome (trisomy vs. monosomy) Sex-linked Disorders -Down Syndrome: Trisomy 21 -Turner Syndrome: Sterile females (XO) -Trisomy X: females (XXX) -Kleinfelter syndrome: sterile males (XXY) -Jacob syndrome: low male IQ (XYY) Chapter 16: Molecular Basis of Inheritance Mendel: Law of Genetics- segregation & independent assortment Morgan: genetic material = genes & proteins Griffin: DNA genetically transforms bacteria Hershey-Chase: viruses inject DNA into bacteria DNA (deoxyribonucleicacid) 3 -> 5 -nucleotides: nitrogen base (ATCG), phosphate group, sugar -Chargraff’s rule: AT and CG pair -double helix (Watson Crick model) -two DNA & sugar phosphate backbone -antiparallel structure: A & T have 2 hydrogen bonds, C & G have 3 hydrogen bonds -A & G are purines and T & C are pyrimidines DNA Replication 1. Separate strands at origin site (replication bubble) 2. Helicase separates two strands 3. Single-strand binding proteins hold it open 4. Topoisomerases break and rejoin strands 5. Primase starts new strand with RNA primer 6. DNA polymerase replicates 5 -> 3 7. DNA polymerase replaces primer with DNA 8. Strands replicated 9. DNA ligase joins fragments on lagging strand 10. DNA polymerase proofreads nucleotides ***Telomerase lengthens telomeres (ends of chromosomes) in germ & cancer cells Replication fork -leading strand: continuous -lagging strand: fragmented (Okazaki fragments) DNA Packaging -DNA, nucleosome, packaged nucleosomes, looped domains, condensed chromatid, condensed chromosome -dNTPs are ATP but with deoxyribose instead of ribose -Prokaryotes elongate faster than eukaryotes Chapter 17: Gene Expression (transcription & translation) DNA is transcribed -> mRNA -> polypeptide Beadle & Tatum: genes encode polypeptides GENETIC CODE -mRNA encode amino acids -triplet code: 1 amino acid has 3 nucleotides (codon) -stop codons: UAA, UAG, UGA -start codon: AUG -prokaryotes have simultaneous gene expression -eukaryotes separate gene expression by nuclear envelope Transcription: Synthesis of RNA Translation: Polypeptide Synthesis (in ribosomes) splicesomes: proteins see splice sites and sometimes splice ribozymes: RNA molecules splice tRNA: transfer amino acids to grow polypeptide aminoacytl-tRNA synthase: enzyme matches tRNA and amino acid Transcription & Translation Initiation -> Elongation -> Termination -prokaryotes terminate by terminator sequence -eukaryotes terminate by polyadenylation signal that caprs G at 5 and splices Mutations (caused by mutagens) -point mutation: affect one or few nucleotides, 1 base pair change Silent: no effect Missense: wrong codon Nonsense: nonfunctional, codon stops -frameshift mutation: insertion or deletion of nucleotides
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