BIO273 Biology - Flow of Information - Central Dogma PDF

BIO273 Biology Flow of Information Central Dogma How does DNA work?  DNA stores the cells information for its activities & characteristics Genes are units of genetic information One gene carries information about a particular characteristic of the organism (trait) Of...

BIO273 Biology Flow of Information Central Dogma How does DNA work?  DNA stores the cells information for its activities & characteristics Genes are units of genetic information One gene carries information about a particular characteristic of the organism (trait) Often many genes work together to create the trait  Enzymes & other proteins carry out the cell’s activity  Information stored in DNA is used to build proteins One gene carries the information to make one protein Exception with alternative splicing  Every cell has all the same DNA Only certain genes are “expressed” SCHOOL OF BIOLOGICAL SCIENCES 2 AND APPLIED CHEMISTRY Flow of Genetic Information  Information is stored in DNA  The information is copied into RNA  The information in RNA is used for the production of Proteins SCHOOL OF BIOLOGICAL SCIENCES 3 AND APPLIED CHEMISTRY Flow of Genetic Information Transcription Translation DNA mRNA PROTEIN Transcription  Sequence of nucleotides in DNA is converted into a sequence of nucleotides in RNA  Occurs in the Nucleus Translation  Sequence of nucleotides in RNA is converted into a sequence of amino acids in protein  Occurs in the Cytoplasm by Ribosomes SCHOOL OF BIOLOGICAL SCIENCES 4 AND APPLIED CHEMISTRY Ribonucleic Acid (RNA) Similar to DNA with the following changes:  Single Stranded  Uses Ribose Sugar, in place of Deoxyribose Extra –OH group reduces RNAs stability  Used Uracil as a base (UTP), in place of Thymine (dTTP) Uracil less energetically expensive than Thymine to synthesize For DNA repair, as C can degrade to U A = U in RNA SCHOOL OF BIOLOGICAL SCIENCES 5 AND APPLIED CHEMISTRY Ribonucleic Acid (RNA) Several different types of RNA, each with it’s own function  mRNA = messenger RNA Copy of a gene from DNA  rRNA = ribosomal RNA Major part of the Ribosomal subunits  tRNA = transfer RNA Attaches to a single amino acid Transfers the amino acid to the Ribosome SCHOOL OF BIOLOGICAL SCIENCES 6 AND APPLIED CHEMISTRY Messenger RNA (mRNA)  Temporary copy of a gene from DNA  Carries the protein building sequence from DNA in the Nucleus to the Ribosomes in the Cytoplasm Nucleotide sequence are the instructions  Synthesized only as needed  Unstable with ribose sugar Degrades back to nucleotides within an hour  Approximately 5% of total RNA Codon  Set of three nucleotides  “Words” of the instructions SCHOOL OF BIOLOGICAL SCIENCES 7 AND APPLIED CHEMISTRY Ribosomal RNA (rRNA)  Non-coding RNA  Converts the nucleotide sequence on mRNA into the amino acid sequence in a Protein  Synthesized in the Nucleolus  Primary component of the Ribosomal subunits (65% RNA, 35% Protein) Large subunit ~ 3700 nucleotides Small subunit ~ 1700 nucleotides  Approximately 80% of total RNA  Subunits are combined in the Cytoplasm during Protein synthesis SCHOOL OF BIOLOGICAL SCIENCES 8 AND APPLIED CHEMISTRY Transfer RNA (tRNA)  Non-coding RNA  Delivers amino acids to the Ribosome during Protein synthesis  Distinctive 3D shape  Single Amino Acid is attached at one end  Approximately 15% of total RNA Anticodon  Set of three nucleotides  Complementary to the mRNA codon  Specific Amino Acid attached to tRNA with correct anticodon SCHOOL OF BIOLOGICAL SCIENCES 9 AND APPLIED CHEMISTRY Summary  DNA is the permeant storage for genetic information  Copies of DNA are created in the form of RNA  RNA is then used to make Proteins  mRNA is a copy of the gene coding for a Protein Contains the genetic information for a Protein as Codons  rRNA is a majority component of the Ribosome, used to synthesize Proteins  tRNA has an Anticodon that will align with the Codon on mRNA tRNA is bound to specific amino acids SCHOOL OF BIOLOGICAL SCIENCES 10 AND APPLIED CHEMISTRY