Chapter 12 dna and rna
Download
1 / 52

Chapter 12: DNA and RNA - PowerPoint PPT Presentation


  • 123 Views
  • Uploaded on

Chapter 12: DNA and RNA. Wheatley-Heckman Honors Biology/Chemistry. DNA. DNA is a long molecule made up of units called nucleotides . Each nucleotide is made up of 3 basic components: 5-carbon sugar (deoxyribose) Phosphate group Nitrogenous base.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Chapter 12: DNA and RNA' - zenda


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Chapter 12 dna and rna

Chapter 12: DNA and RNA

Wheatley-Heckman

Honors Biology/Chemistry


DNA

  • DNA is a long molecule made up of units called nucleotides.

  • Each nucleotide is made up of 3 basic components:

    • 5-carbon sugar (deoxyribose)

    • Phosphate group

    • Nitrogenous base





  • Years before the double helix was discovered, a scientist named Edwin Chargaff discovered that:

    • The percentages of guanine (G) and cytosine (C) are almost equal in any sample of DNA.

    • The percentages of adenine (A) and thymine (T) are almost equal in any sample of DNA.

  • This became known as Chargaff’s Rules



  • The hydrogen bonds could form only between certain bases, and provide just enough force to hold the 2 strands of the double helix together.base-pairing rules became:

    • For every A (adenine) on one strand, there is a T (thymine) on the other strand.

    • For every C (cytosine) on one strand, there is a G (guanine) on the other strand.

The two strands are said to be “complementary”.


Practice
Practice! hydrogen bonds could form only between certain bases, and provide just enough force to hold the 2 strands of the double helix together.

  • Following the base-pairing rules, write the complementary strand of DNA for the given sequence of nucleotides:

  • AAGCCAGATAGT


Building a dna molecule
Building a DNA Molecule hydrogen bonds could form only between certain bases, and provide just enough force to hold the 2 strands of the double helix together.

  • Black pentagons: Deoxyribose sugar

  • White tubes: Phosphate groups

  • Colored tubes: Nucleotides

    • Orange: Adenine

    • Green: Thymine

    • Blue: Guanine

    • Yellow: Cytosine



  • Continue adding nucleotides until you have completed a strand following the code below:

    A C T G G A T C T

  • Once that single strand is completed, build a complementary strand.

  • Connect the two strands with hydrogen bonds (white solid pegs).

  • Twist the two strands to make a double helix.


Dna replication
DNA Replication strand following the code below:

  • During DNA replication, the DNA molecule separates into two strands, and then produces two new complementary strands following the rules of base pairing.

  • Each strand of the double helix serves as a template, or model for the new strand.


  • Step 1: strand following the code below: An enzyme called helicase “unzips” the double helix by breaking the hydrogen bonds between bases.

  • The region where the two strands are splitting is called the replication fork.


  • Step 2 strand following the code below:: A second enzyme, DNA polymerase, adds complementary nucleotides to each of the original separated strands.

  • As DNA polymerase adds new nucleotides, it also “proofreads” to avoid any errors in base-pairing.



  • Leading strand to the orientation of the 5-carbon sugar. : strand that reads 5’-3’

    • Replicated continuously.

  • Lagging strand = strand that reads 3’-5’

    • Creates fragments called “Okazaki Fragments” that are later connected by the enzyme ligase


  • Review Animation


    Rna and protein synthesis
    RNA and Protein Synthesis been replicated.

    • Genes are coded DNA instructions that control the production of proteins.

    • These genetic messages must first be copied from DNA to RNA.

    • The RNA is then used to make proteins.


    Structure of rna
    Structure of RNA been replicated.

    • There are 3 main differences between DNA and RNA:

      • The sugar in RNA is ribose instead of deoxyribose.

      • RNA is generally single-stranded.

      • RNA contains uracil in place of thymine.


    Types of rna
    Types of RNA been replicated.

    • There are three main types of RNA:

      • messenger RNA (mRNA)

      • ribosomal RNA (rRNA)

      • transfer RNA (tRNA)


    • Messenger RNA been replicated. (mRNA)carries copies of instructions for assembling amino acids into proteins.


    Ribosomes are made up of proteins and been replicated.ribosomal RNA (rRNA).



    Protein synthesis
    Protein Synthesis been replicated.

    • The process of making proteins has two steps:

      • Transcription

      • Translation

    DNA strand

    (template)

    TRANSCRIPTION

    mRNA

    TRANSLATION

    Protein


    Transcription
    Transcription been replicated.

    • Helicase separates the DNA double helix, and an enzyme called RNA polymerase uses one strand of DNA as a template to make a single strand of mRNA.

    • Regions called promoters determine which segment of DNA (which gene) the RNA polymerase will copy, or transcribe.



    Rna editing
    RNA Editing before, except that

    • Some DNA within a gene is not needed to produce a protein. These areas are called introns.

    • The DNA sequences that code for proteins are called exons.



    The genetic code
    The Genetic Code before, except that

    • Proteins are made by joining amino acids into long chains.

    • There are 20 different amino acids, and it is the unique combination of amino acids in your proteins that determine your genes.

    • Amino acids are coded for by mRNA.


    • A before, except that codon consists of three consecutive nucleotides on mRNA that specify a particular amino acid.




    Translation
    Translation translate the codons into amino acids using the wheel:

    • Translation is the decoding of an mRNA message into a polypeptide chain (protein).

    • Translation takes place on ribosomes.

    • During translation, the cell uses information from messenger RNA to produce proteins






    DNA the golgi body, where it will be packaged and shipped to its final destination.

    mRNA

    Protein


    Summary of protein synthesis
    Summary of Protein Synthesis the golgi body, where it will be packaged and shipped to its final destination.

    • Transcription

    • Process by which genetic information encoded in DNA is copied onto messenger RNA

    • Occurs in the nucleus

    • DNA  mRNA

    • Translation

    • Process by which information encoded in mRNA is used to assemble a protein at a ribosome

    • Occurs on a Ribosome

    • mRNA  protein


    Types of mutations
    Types of Mutations the golgi body, where it will be packaged and shipped to its final destination.

    • Mutations are changes in the genetic material.

    • Gene mutations: involve changes in one or a few nucleotides, known as point mutations.

      • Substitutions

      • Insertions

      • Deletions


    • Substitutions the golgi body, where it will be packaged and shipped to its final destination. usually affect no more than a single amino acid.


    • The effects of the golgi body, where it will be packaged and shipped to its final destination.insertions or deletions are more dramatic.

    • The addition or deletion of a nucleotide causes a shift in the grouping of codons.

    • Changes like these are called frameshift mutations.


    In an the golgi body, where it will be packaged and shipped to its final destination.insertion, an extra base is inserted into a base sequence.






    ad