Mutations and Cell Divisions
Mutations and Cell Divisions BIOL 1001-001
U of M
Popular in Evolution and Ecology
verified elite notetaker
Popular in Biology
verified elite notetaker
This 4 page Class Notes was uploaded by Mickayla Notetaker on Sunday September 20, 2015. The Class Notes belongs to BIOL 1001-001 at University of Minnesota taught by Annika Moe and Craig Packer in Summer 2015. Since its upload, it has received 190 views. For similar materials see Evolution and Ecology in Biology at University of Minnesota.
Reviews for Mutations and Cell Divisions
-Kao KIa Yang
Report this Material
What is Karma?
Karma is the currency of StudySoup.
Date Created: 09/20/15
Lecture 3 Molecular Genetics DNA deoxyribonucleic acid is a double stranded molecule that make up our genes Made up of a series of nucleotides Nucleotides are composed up of a sugar phosphate and a nitrogen base From one nucleotide to another the sugar and phosphate are the same but the bases are different Nitrogen bases There are four nitrogenous bases that make up a nucleotide Adenine Guanine Cytosine and Thymine Otherwise known as AGCT Base pairing rules Within DNA A Adenine can only pair with T Thymine and G Guanine only pairs with C Cytosine A single strand of DNA is formed by the bonding of the phosphate with the sugar and the nucleotides connect together reacting chemically and give off a molecule of water quotPhosphatesugar backbone helps to keep the DNA strand together structurally No variation within it Nitrogenous bases can appear in any order along the same strand The DNA strands are linked together by weak bonds between the nitrogenous bases DNA is a selfreplicating molecule that uses many other molecules Enzymes in the body to achieve this process 1 Replication The formation of two identical doublestranded DNA molecule from one pre existing copy a Enzymes go along the DNA strand and quotunzipquot the molecule temporarily b DNA Polymerase lines up the complimentary bases to the ones that are in the DNA strand Creates a complimentary copy of the original DNA strand Ex AGCCTAGGATC is now TCGGATCCTAG i Each side creates a template of a perfect match to the original strand 0 Mismatch repair The enzyme proofreads the DNA and fixes mistakes Removes incorrect nucleotide and finds the correct one o Excision RepairRemoves and replaces damaged segments of DNA Flow of Genetic Information DNA gtRNARibonucleic Acid gtProteins Transcription Translation 2 Transcription DNA and RNA are so similar that the Information from DNA can be directly copied to RNA RNA has a slightly different sugar than DNA They also have similar bases but no thymine uses uracil instead RNAGUAC A portion of the gene is transcribed to messenger RNA a The promoter region indicates to start copying the DNA b The DNA is temporarily separated and one strand is used as the template c The free ribonucleotides come in sequence to match the template strand d The enzyme continues to copy until it reaches the stop site e The RNA strand disconnects from the DNA strand f The enzyme disconnects from the DNA strand g The two DNA strands connect together again After Transcription but before Translation parts of the premessenger RNA are going to be excluded The strand is made up of introns and exons The introns are removed after Transcription 3 TranslationUsing the genetic codepairing rule from codon to amino acid to quottranslatequot RNA to Proteins RNA and proteins are so different that RNA has to be translated to protein Three nucleotides that code for an amino acid is called a triplet or a codon Ex UUGLeucine i tRNAtransfer RNAs the translator it moves the amino acids into place for assembly into the protein ii rRNAribosomal RNAt holds everything together as the protein forms and controls what comes into the area i The rRNA latches onto the RNA The tRNA brings the correct amino acid that pairs with the triplet of the RNA rRNA holds the amino acid in place as the tRNA leaves the rRNA This process happens over and over until the STOP codon is reached After two or more amino acids are connected they form a peptide bond ii iii iv v between each other Genomics the study of the complete sequence of an organism39s DNA 195039s It was discovered by James Watson and Francis Crick that DNA was helical and that it could selfreplicate 1976viral genome decoded 1997bacteria decoded 2006human strand decoded Proteomics The study of all proteins in an organism Lecture 4 Mutation and Cell Division Fundamental Attributes of DNA 0 It stores information o It is stable enough to replicate 0 Mistakes do happen Mutations Point Mutations BasePair substitution o SilentNo effect 0 MissenseChange in Amino acid sequence 0 NonsenseCodes for a stop Consequences o MissenseSickle cell anemiacaused when 1 basepair is substituted 0 This mutation changes the shape of the red blood cells The sickle shaped cells can39t maneuver as effectively through the veins and cause blockages which can cause ulcers 0 NonsenseCystic Fibrosis caused when the codon for a stop is received after 1282 amino acids are read instead of the normal 1480 This shortened protein causes cystic fibrosis Frame Shift Mutation o DeletionThe mutation deletes one base pair so the whole code is off by one base pair It could code a different protein from the existing code 0 InsertionA new base pair is added to the code and it is off by one base pair Consequences People with these mutations can develop heart arrhythmia or tumors later in life SpliceSite Mutations An Exon is deleted after the Transcription process leading to the wrong code being translated into a protein Consequences betathalassemia caused by the underproduction of functioning hemoglobin because of spliced exons Point mutations are relatively low but they still happen In humans there are three mutations for every billion base pair coded Human Genome 32 billion base pairs in Haploid genome 25000 are proteincoding genes 15 codes for proteins The rest is other types of RNA reglatory sequences introns and junk DNA that gets thrown away after Transcription Cell Division 1 Exact copies of original cell a Binary fissionunicellular organism i In bacteria the original cell duplicates the DNA then it splits into two identical cells from the one original b MitosisDNA is distributed into two daughter cells i The chromosomes start to condenseThese were previously copied so there are two identical chromosomes called sister chromatids the spindles form and the nucleus disappears ii The spindles which are on opposite sides have captured all of the chromosomes and lined them up across the cell iii The sister chromatids come apart and the spindles draw them away from each other to opposite sides of the cell The cell starts to elongate iv The cell elongates further and two nuclei form around the chromosomes which decondense 2 Meiosis Haploid daughters of diploid original Before meiosis the chromosomes are replicated creating sister chromatids a Chromosomes condense a pair of identical homologous chromosomes line up together to form a tetrad Crossing over may occur b Tetrads align at the center of the cell c Chromosomes are pulled apart to separate sides of the cell and sister chromatids stay together d The cell elongates and forms two haploid meaning a complete set of chromosomes daughter cells e In the two daughter cells the chromosomes line up across the cell and are pulled away from each other to opposite sides f Distinct nuclei form at the opposite poles and the cell elongates until it creates two more cells a At the end of Meiosis there are four daughter cells that have one half of the chromosomes of the original parent cell Alleles alternative forms of the same gene that both code for the same trait but differ in nucleotide sequence Ex An allele from mom codes for brown eyes and an allele from dad codes for green eyes