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DNA, RNA & ProteinSynthesisChapters 12 & 13

The Structure of DNA

A little HistoryYearScientist(s)Discovery1928Frederick GriffithBacteria transfer genetic material from cell tocell.1944Oswald Avery,Colin Macleod &Maclyn McCartyGriffith had discovered DNA!1950Erwin ChargaffOf the four possible nucloetides: As Ts & Gs Cs.1952Alfred Hershey &Martha ChaseGenetic material in viruses is also DNA.1952Rosalind FranklinDemonstrated that DNA is a helix.1953James Watson &Francis CrickDNA is a double helix.2000Craig Venter &Francis CollinsSequenced human DNA.

DNA In prokaryotes (nonucleus), DNA iscircular. In eukaryotes, DNAis on thechromosomes in thenucleus.

Structure of DNA Double-strandedhelix Linked nucleotides

Nucleotide Parts1) Sugar - deoxyribose2) Phosphate group (haselement phosphorous)3) Nitrogenous base Sugar and phosphatemake the sides.Bases make therungs.

Nucleotide Types1)2)3)4)Adenine (A)Thymine (T)Cytosine ( C )Guanine (G) A bonds with TG bonds with C Called complementary base pairing

DNA Replication

DNA ReplicationWhen does it happen? Before cell division (mitosis ormeiosis)Where does it happen? In the nucleus

DNA Replication: Step 1 Enzyme (DNAPolymerase)unwinds DNA

DNA Replication: Step 2 Enzyme attachesfree nucleotides tothe original strandsuntil both strandsare copied.

DNA Replication: Step 3 Replication occursin many spots alongthe DNA until allparts are copied. Two identicalstrands are made. Now cell divisioncan occur! molgenetic

Replication in Different CellsIn prokaryotes:In eukaryotes:Starts at a singleBegins at manypoint andplaces andproceeds in twoproceeds in twodirections until thedirections until theentireentirechromosome ischromosome iscopied.copied.

RNA

Genes Section of DNA withthe instructions tomake 1 protein. Found in thenucleus.

ProteinsClick here for animation - XX Many amino acids linked together. Proteins are made in the cytoplasm.

Proteins are made in the cytoplasm byribosomes, but the instructions for doingthis (the DNA) can’t leave the nucleus.

How can this work?RNA A single-stranded copy of DNA.

DNA vs. RNARNADNA Chain ofnucleotides. Sugar is ribose. Single-stranded. Bases are A,U,G,C.(U uracil.) Chain ofnucleotides. Sugar isdeoxyribose. Double-stranded. Bases are A,T,G,C.

Types of RNAMessenger RNA(mRNA) Copies DNA in thenucleus.Transfer RNA(tRNA) Brings amino acid tothe ribosome forprotein assembly.Ribosomal RNA(rRNA) Inside ribosome.Helps withtranslation.

To go from DNA to a Protein,there are two steps:1) Transcription- mRNA makes copy ofDNA2) Translation- protein is made frommRNA

Transcription: mRNA copiesDNAStep 1: enzyme (RNA Polymerase)unwinds DNApromoter: regions of DNA where theenzyme bindsStep 2: mRNA bases make a copy imat/molgenetics/transcription.swf

Transcription (Part 2)Step 3: introns (bad bases) are removed,exons (good bases) are spliced togethermRNA AUACGUACnow AUCUACStep 4: cap and tail are addedStep 5: mRNA leaves the nucleus for thecytoplasm.Link - Click Here for Animation

Ribosomes & ProteinSynthesis

Codons A section of threemRNA bases in a rowthat codes for oneamino acid.

Anticodons The correspondingtRNA that carriesthe amino acid.

Translation: the mRNA istranslated into a proteinAnimation - Click Here for Animation - XX1.) Ribosome finds the start codon, AUG, on mRNA.2.) The corresponding anticodon on the tRNA binds into place.3.) The ribosome reads the next codon & its correspondinganticodon binds.4.) The ribosome bonds the two amino acids on the tRNAtogether. The tRNA lets go.5.) This continues until a stopcodon is reached. Then thelast tRNA & ribosome fall off.6.) The amino acid chain foldsinto its proper structure.

The central dogmaof molecularbiology DNA- RNA- proteingene expression:process by which agene produces itsproduct, which carriesout its function

Mutations

What are mutations? Changes in the DNA sequence thatchanges the protein it codes for. Two Types:1.) Chromosomal Mutations2.) Gene Mutations

Chromosomal Mutations Result from changes in a wholechromosome.1.) gene deletions2.) gene duplications3.) gene inversions4.) translocations

Gene Deletion Parts of a chromosome break andrejoin, with a gene missing.Ex: Cris-du-chat Syndrome

Gene Duplication Most duplications have no phenotypicconsequences.

Inversion Part of a chromosome becomesoriented in the reverse of its usualdirection. Usually no phenotypic consequences.

Translocation Part of a chromosome breaks off andattaches to a nonhomologouschromosome. Can lead to nonviable zygotes.

Point Mutations Occur at a single point in the DNA. Usually one nucleotide is substituted for another,changing an amino acid.Ex: Sickle Cell Anemia

Frameshift Mutations Type of point mutation where an extranucleotide is inserted or deleted, shiftingthe reading of codons, resulting inchanges to ALL of the amino acids.Ex: Huntingdon’s Disease

Mutagen An agent that causes a change in DNA.Ex: smoke, high energy radiation (X rays,UV light, nuclear radiation), chemicals(dioxins, asbestos, benzene, cyanide,formaldehyde), and high temperatures.Note: In some cases, a gene mutationmay have positive effects leading toevolution.

Gene Regulation &Expression

How do cells regulate geneexpression? Proteins bind to sections of DNA thatcontrol transcription. More complex in eukaryotes becausecells are specialized.

Differentiation When new cells become specialized instructure & function during embryonicdevelopment.– In humans cells, this occurs 4 days afterfertilization.Hox genes: a group of genes, located side byside on the same chromosome, that tell thecells how to differentiate as the body grows.– Hox genes exist in the DNA of manyanimals- evidence of common ancestors.

1952 Alfred Hershey & Martha Chase Geneticmaterial in viruses is also DNA. 1952 RosalindFranklin Demonstratedthat DNA is a helix. 1953 James Watson & Francis Crick DNA is a double helix. 2000 Craig Venter & Francis Collins Sequencedhuman

Related Documents:

DNA AND RNA Table 4.1: Some important types of RNA. Name Abbreviation Function Messenger RNA mRNA Carries the message from the DNA to the protein factory Ribosomal RNA rRNA Comprises part of the protein factory Transfer RNA tRNA Transfers the correct building block to the nascent protein Interference RNA

RNA and Protein Synthesis Genes- coded DNA instructions that control the production of proteins within the cell. – In order to decode genes, the nucleotide sequence must be copied from DNA to RNA, as RNA contains the instructions for making proteins. 3 main differences between RNA and DNA: – The sugar in RNA is ribose instead of .

(Structure of RNA from Life Sciences for all, Grade 12, Figure 4.14, Page 193) Types of RNA RNA is manufactured by DNA. There are three types of RNA. The three types of RNA: 1. Messenger RNA (mRNA). It carries information about the amino acid sequence of a particular protein from the DNA in the nucleus to th

DeepDISOBind and other related tools produce putative propensities for the disordered DNA, RNA and protein binding interactions for each residue in the input protein sequences. These real-valued propensities are accom-panied by binary predictions, i.e., residues are classified as either DNA/RNA/protein-interacting or non-DNA/RNA/protein .

biological significance of protein complexation with RNA has been well recognized, the specific mecha-nism of protein–RNA interaction is not fully understood [10]. Measurement of sequence–specific DNA– protein and RNA–protein interactions is a key experimental procedure in molecular biology of gene regulation.

3 DNA is a template in RNA synthesis In DNA replication, both DNA strands of ds DNA act as templates to specify the complementary base sequence on the new chains, by base-pairing. In transcription of DNA into RNA, only one DNA strand (the negative strand) acts as template. The sequence of the transcribed RNA corresponds to that of the coding

of DNA- and RNA-binding residues on the COMB_T dataset. 46 Figure 4.2. Comparison between the DNA and RNA machine learning (ML) consensus that targets combined prediction of DNA- and RNA-binding residues and the considered predictors of DNA- or RNA-binding residues on the COMB_T test

13.1 RNA RNA Synthesis In transcription, RNA polymerase separates the two DNA strands. RNA then uses one strand as a template to make a complementary strand of RNA. RNA contains the nucleotide uracil instead of the nucleotide thymine. Follow the direction