1/18/2016 Structure and Function of the Microbes Genetic Material Learning Objectives Invisible Invaders Define genetics,genome,chromosome, gene,genetic code,genotype,phenotype Amazing Allies and genomics Describe how DNA serves as genetic information ASE Describe the process of DNA replication Chapter 8 .Describe protein synthesis.including Microbial Genetics transcription,RNA processing.and translation Genetics:the study of heredity Genome:Structure and Function 1-what genes are Genetics 2-how they carry information Genome-all the genetic information in a cell 3-how information is expressed (chromosomes+mitochondria,chloroplasts,and/or 4-how genes are replicated plasmids) Chr Organism level Cell level Chromosome:structure containing DNA that physically carries hereditary information:the chromosomes contain the genes Bacterial chromosomes are a single circular loop Eukaryotic chromosomes are multiple and linear
1/18/2016 1 Invisible Invaders Amazing Allies Chapter 8 Microbial Genetics Learning Objectives Structure and Function of the Genetic Material • Define genetics, genome, chromosome, gene, genetic code, genotype, phenotype, and genomics • Describe how DNA serves as genetic information • Describe the process of DNA replication • Describe protein synthesis, including transcription, RNA processing, and translation Genetics Genetics: the study of heredity 1 - what genes are 2 - how they carry information 3 - how information is expressed 4 - how genes are replicated Chromosome Molecular level level Organism level Cell level Genome – all the genetic information in a cell (chromosomes + mitochondria, chloroplasts, and/or Genome: Structure and Function plasmids) genome of cells – DNA genome of viruses – DNA or RNA Chromosome: structure containing DNA that physically carries hereditary information; the chromosomes contain the genes • Bacterial chromosomes are a single circular loop • Eukaryotic chromosomes are multiple and linear
1/18/2016 Genomes Vary in Size Genome:Structure and Function ·Smallest genome viral encoding 4-5 genes Escherchia coli single chromosome containing 4,288 genes 1 mm long 1,000X longer than cell Human cell DNA emerging from a 46 chromo disrupted Escherichia coli containing 31,000 genes cell as a single chromosome 6 feet long 180,000X longer than cell Genes Chromosomes are subdivided into genes.the fundamental unit of heredity responsible for a Cell given trait. DNA Gene:a segment of DNA that encodes a functional product,usually a protein Three basic categories of genes: 1.Genes that code for proteins structural genes Nucleus Chromosome 2.Genes that code for RNA 3.Genes that control gene expression regulatory genes
1/18/2016 2 Genome: Structure and Function Genomes Vary in Size • Smallest genome viral encoding 4-5 genes • Escherchia coli single chromosome containing 4,288 genes 1 mm long 1,000X longer than cell • Human cell 6 46 chromosomes containing 31,000 genes 6 feet long 180,000X longer than cell DNA emerging from a disrupted Escherichia coli cell as a single chromosome • Chromosomes are subdivided into genes, the fundamental unit of heredity responsible for a given trait. Genes g ven tra t. • Gene: a segment of DNA that encodes a functional product, usually a protein Three basic categories of genes: 1. Genes that code for proteins structural genes 2. Genes that code for RNA 3. Genes that control gene expression regulatory genes
1/18/2016 DNA DNA 'a晋 .Base pairs are specific DNA is composed of Adenine pairs with repeating units of Thymine nucleotides Cytidine pairs with DNA exists in the cell Guanine as a double helix Base of one sequence Strands are held determines sequence of together by hydrogen the other strand.The bonds two strands are thus complementary explains two 9eahus6tb6Sgal information storage DNA structure explains two 1,Linear sequence provides the features of biological biological information information storage storage 2.Maintenance of the code: Four letter alphabet complementary structure allows for precise Provides variety:1000 of duplication of DNA during these letters equals the cell division. average gene size can be arrange in 41000 different ways! .Genetic code is the set of rules that determines how a DNA sequence is converted into an amino acid sequence 3
1/18/2016 3 • DNA is composed of repeating units of DNA nucleotides • DNA exists in the cell as a double helix •Strands are held together by hydrogen bonds • Base pairs are specific Adenine pairs with Thymine DNA Cytidine pairs with Guanine • Base of one sequence determines sequence of the other strand. The two strands are thus complementary DNA structure explains two features of biological information storage 1. Linear sequence provides the biological information storage • Four letter alphabet • Provides variety: 1000 of these letters equals the average gene size can be arrange in 41000 different ways! • Genetic code is the set of rules that determines how a DNA sequence is converted into an amino acid sequence DNA structure explains two features of biological information storage 2 . M i f h d Maintenance of the code: complementary structure allows for precise duplication of DNA during cell division
1/18/2016 Genotype and Phenotype Flow of Genetic Information All types of genes constitute the genetic makeup-genotype. Horizontal gene Vertical gene The expression of the genotype creates transter transfer observable traits-phenotype. DNA Replication:Preserving the Code and Overall Steps of DNA Replication Passing it On Each daughter molecule is identical to the parent in composition,but only one strand is completely The process of the genetic code duplicated new semiconservative replication and passed on to each offspring Requires 30 different enzymes Must be completed during a single generation fime Complementary structure provides a template for DNA replication
1/18/2016 4 Genotype and Phenotype All types of genes constitute the genetic makeup – genotype. The expression of the genotype creates observable traits – phenotype. Flow of Genetic Information Vertical gene t f Horizontal gene t f rans er transfer DNA Replication: Preserving the Code and Passing it On • The process of the genetic code duplicated and passed on to each offspring • Must be completed during a single generation time • Comp m ntary structur pro s a lementary structure provides a template for DNA replication Overall Steps of DNA Replication • Each daughter molecule is identical to the parent in composition, but only one strand is completely new semiconservative replication • Requires 30 different enzymes DNA Polymerase Helicase Template strands
1/18/2016 Replication requires: Some Enzymes Involved in DNA 1 Uncoiling the parent DNA Replication and Their Functions 2.Unzipping the hydrogen bonds between base pairs exposing the nucleotide sequence of each strand to serve as a Enzyme Function template Helicase Unzipping the DNA helix 3.Synthesizing two new strands by attaching complementary Primase Synthesizing an RNA primer nucleotides to each single-strand template DNA polymerase IIl Adding bases to the new DNA chain;proofreading the chain for mistakes Ligase Final binding of nicks in DNA during synthesis and repair Gyrase Supercoiling Details of DNA Replication Details of DNA Replication Begins at an origin of replication:a short AT rich sequence DNA polymerase III adds nucleotides in a 5'to 3'direction Helicase unwinds and unzips the DNA double helix; leading strand-synthesized continuously in 5to 3 breaks hydrogen bonds direction ection is 3'to 5 G 5
1/18/2016 5 Replication requires: 1. Uncoiling the parent DNA 2. Unzipping the hydrogen bonds between base pairs exposing the nucleotide sequence of each strand to serve as a template 3. S nthesizin t ne str nds b tt chin Synthesizing two new strands by attaching c mplement r complementary nucleotides to each single-strand template DNA Polymerase Helicase Template strands 1 2 3 3 • Begins at an origin of replication: a short AT rich sequence • Helicase unwinds and unzips the DNA double helix; Details of DNA Replication p ; breaks hydrogen bonds • An RNA primer is synthesized by primase, an RNA polymerase • DNA polymerase III adds nucleotides in a 5′ to 3′ direction leading strand – synthesized continuously in 5′ to 3′ Details of DNA Replication leading strand synthesized continuously in 5 direction lagging strand – synthesized 5′ to 3′ in short segments; overall direction is 3′ to 5′