RNA AND PROTEIN SYNTHESIS - PowerPoint PPT Presentation

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RNA AND PROTEIN SYNTHESIS

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RNA AND PROTEIN SYNTHESIS RNA vs DNA RNA DNA 1. 5 Carbon sugar (ribose) 5 Carbon sugar (deoxyribose) 2. Phosphate group Phosphate group – PowerPoint PPT presentation

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Title: RNA AND PROTEIN SYNTHESIS


1
RNA AND PROTEIN SYNTHESIS
  • RNA vs DNA
  • RNA DNA
  • 1. 5 Carbon sugar (ribose) 5 Carbon sugar
    (deoxyribose)
  • 2. Phosphate group Phosphate group
  • 3. Nitrogenous base Nitrogenous base
  • 4. Single stranded Double stranded
  • 5. Uracil base Thymine base

2
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3
RNA MOLECULE
4
TYPES OF RNA
  • Messenger RNA (mRNA)
  • Carries copies of instructions for
  • the assembly of amino acids
  • into proteins from DNA to the rest
  • of the cell
  • Ribosomal RNA (rRNA)
  • Makes of the major part of a ribosome
  • Transfer RNA (tRNA)
  • Transfers amino acids to ribosomes
  • during protein synthesis


5
TRANSCRIPTION
  • Transcription
  • ? The process of producing
  • RNA molecules by copying
  • part of the nucleotide
  • sequence of DNA into a
  • complementary sequence
  • in RNA
  • ? Requires the enzyme
  • RNA polymerase
  • Binds to and separates the
  • DNA strands
  • Uses one strand of DNA as a
  • template to form RNA
  • Binds to regions of DNA known
  • as promoters which have
  • specific base sequences
  • Promoters are signals in DNA
  • that indicate to the enzyme
  • where to start and stop making

6
GENE coded DNA instructions that control the
production of proteins in the cell
7
RNA Editing
  • RNA molecules have sections called
  • Introns sections not coded for
  • making proteins
  • ? cut out or edited while still in
  • the nucleus
  • Exons sections coded for making
  • proteins
  • ? spliced back together to form
  • final mRNA

8
THE GENETIC CODE
  • The Genetic Code
  • The language of mRNA instructions
  • Consist of 20 different amino acids
  • With 64 possible codons
  • ? Codon consist of 3 consecutive
    nucleotides that specify a specific amino acid (3
    bases long)
  • ? Proteins are made by joining
  • amino acids into long chains
  • called polypeptides
  • The property of a protein is determined by the
    order in which different amino acids are joined
    together to form polypeptides

9
TRANSLATION
  • Translation
  • ? The decoding of an mRNA message into a
    polypeptide chain
  • (protein)
  • ? Takes place on ribosomes in the cytoplasm
  • Begins when mRNA in the cytoplasm attaches to a
    ribosome
  • Each codon of the mRNA moves through the ribosome
  • Proper amino acid is brought into the ribosome by
    tRNA
  • Amino acid is transferred to growing polypeptide
    chain in the ribosome
  • Each tRNA carries only one kind of amino acid
  • Each tRNA has 3 unpaired bases called anticodons
    which are
  • complementary to one mRNA codon
  • Works like an assembly line
  • Polypeptide chain continues to grow until the
    ribosome reaches a stop codon
  • Polypeptide chain is released ? Protein

10
TRANSLATION
11
PROTEIN SYNTHESIS
12
PROTEINS
  • Protein
  • ? Enzymes that catalyze and regulate
    chemical reactions
  • ? Act as microscopic tools to build or
    operate a component of a living
  • cell
  • ? Genes code for proteins that in turn
    determine genetic traits

13
MUTATIONS
MUTATIONS
  • Mutation
  • Changes in the genetic material
  • Effect on organism
  • ? Most effects are neutral
  • ? Some effects are deadly
  • ? Some lead to greater genetic variability in a
    species
  • Causes
  • ? Random mistakes during DNA replication or RNA
    transcription
  • ? Prolonged exposure to excessive radiation or
    harmful chemicals
  • Types of Mutations
  • ? Point mutation gene mutations involving
    changes in one or a few

  • nucleotides
  • Occur at a single point in the DNA sequence
  • Include substitutions, insertions and deletions
  • ? Substitution one base is changed to another
  • ? Insertions base is inserted into the DNA
    sequence
  • ? Deletion Base is deleted from the DNA
    sequence

14
  • ? Frameshift mutation mutations that
    shift the reading frame of

  • the genetic message by inserting or

  • deleting a nucleotide
  • May change every amino acid that follows the
    point of mutation
  • Protein may be altered so much that it is
    unable to perform its normal function
  • May lead to termination of organism (death)
  • ? Chromosomal mutation involves changes
    in the number or

  • structure of chromosomes
  • May change the locations of genes on
    chromosomes
  • DELETIONS involve the loss or all or part of
    a chromosome
  • DUPLICATION produce extra copies of parts of
    a chromosome
  • INVERSION reverse the direction of parts of a
    chromosome
  • TRANSLOCATION part of one chromosome breaks
    off and attaches to another
  • Significance of Mutations
  • ? Most are neutral
  • ? Some are harmful
  • Causes of genetic disorders
  • Causes of many types of cancer

15
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