Biology Exam 3 Review: Genetics and DNA Structure - Prof. George M. Simmons, Study notes of Biology

Download Biology Exam 3 Review: Genetics and DNA Structure - Prof. George M. Simmons and more Study notes Biology in PDF only on Docsity! Biology Exam 3 Review - Trisomy: extra chromosome which may not be X or Y o Down Syndrome (Trisomy 21): extra chromosome 21 - Hemophilia: recessive; can’t form blood clots Chapter 9: DNA- The Molecule of Heredity  Chromosomes : paired structures of DNA and protein o Gametes: sex cells (egg and sperm) o Somatic: bodily cells  Gene : amount of DNA necessary to code for enzyme; 1 gene=1 protein o If gene not functional-can’t produce enzyme-changes a.a. sequence (protein)  DNA : hereditary genetic material  Alleles : different forms of a trait  Griffith’s Experiment: transformation  Hershey-Chase Experiment: DNA is genetic material not protein  Wilkins and Franklin: used x-ray diffraction to find that DNA is long and thin; helix; consists of repeating subunits  Watson and Crick : DNA is 2 separate strands, sugar-phosphate backbone, double helix, 2 strands in opposite directions: antiparallel Scientific inquiry: discovery of the double helix - Linus Pawling: protein research but little on DNA; active in peace movement - Watson and Crick : tried to construct molecular model of DNA without experiments o Got info from Wilkins o Won race to determine structure  Chargoff’s Rule : equal amount of base pairing o A-T (U in RNA) o C-G DNA Structure: sugar, nitrogenous base, phosphate Backbone: sugar and phosphate - Hydrogen bond holds bases o Figure 9.3, p 154 - Antiparallel (5’-3’, 3’-5’) - Semiconservative : 1 parent strand, 1 newly synthesized strand Enzymes: - Helicase : unzips - Polymerase : adds new bases o Synthesized in cytoplasm - Ligase : seals back together Mutations: - Not all harmful! o Nucleotide substitution : nucleotide pair changed (from A-T to T-A, etc) o Insertion : one or more nucleotides inserted o Deletion o Inversion : section flipped/inverted o Translocation : section moved from one area to another DNARNAtRNA Read 3’-5’ but synthesized 5’-3’ Chapter 10: Gene Expression and Regulation Beetle and Tatum (p168) Prokaryote Eukaryote DNA in nucleus DNA in cytosol Once mRNA availabletranslation and transcription occur (simultaneously) Transcription and translation occur separately Translation in cytoplasm Genes compact; every nucleotide codes for a.a. Alternative splicing (introns vs exons) 5’= cap 3’ end= Poly A Tail Transport mRNA from nucleus to cytosol - Replication origin/bubble : where replication occurs - Replication fork : where new strand made; 1 side replicates smoothly, other side backwards o 3-5: leading o 5-3: lagging, not as fast, replication done in segments DNA: doublestranded contains genes; sequences of bases determines a.a. sequence of protein RNA: singlestranded; intermediary, molecule that carries info from DNA in nucleus to ribosomes in cytoplasm Messenger RNA: carries code for protein-coding gene from DNA to ribosomes Ribosomal RNA: combines with proteins to form ribosomes (structures that link a.a. to form protein) Transfer RNA: carries a.a. to ribosomes Genetic Info transcribed into RNA and then translated into protein Transcription: RNA synthesis Eukaryotes DNA copied to mRNA in nucleus 1. Initiation: TATA box (sequence of DNA with As and Ts) - RNA polymerase first synthesizes - Promoter - transcription factors bind to transcription binding sites