CH 4 Notes

Vocabulary ( Skip )

Gene

  • Section of DNA on a chromosome that carried code for protein

Nitrogenous Base

  • Makes DNA and RNA with its nitrogen ring(s) and forms hydrogen bonds between strands of double helix

Base Pair

  • Two nitrogenous bases connected with a hydrogen bond

Phosphodiester Bond

  • Bond that links sugars and phosphates of adjacent nucleotides

Hydrogen Bond

  • weak bond that holds the DNA together

Purine

  • Nitrogenous base with 2 rings

Pyrimidine

  • Nitrogenous base with 1 ring

Medium

  • something you can grow stuff on

Lysis

  • The rupture of cells that causes the release of DNA

R plasmid

  • Plasmid that contains gene for antibiotic resistance

Vector

  • Carrier of genes to a cell

RNA polymerase

  • enzyme that builds RNA strands from DNA strands

Enhancer

  • Increases expression of a gene (transcription factor)

Silencer

  • decreases expression of a gene (transcription factor)

Intron

  • mRNA gene region that is transcribed but Not expressed

Exon

  • Gene region that codes for a protein and is expressed u

Gene therapy:

  • Repairing genes to solve a genetic problem

Site Specific Mutagenesis

  • Changing genetic code in certain (site specific) areas.

4.1

Genes get transcribed into mRNA and then mRNA ( at the ribosome ) gets translated into chains of amino acids and those amino acids fold to form polypeptide chains

4 Nitrogenous Base Pairs

* Note the SHAPES of each of these. Guanine and Adenine have double rings

  • These shapes ensure the width is always the same

* Uracil is only used in RNA

Pairs thru hydrogen bonds , A-T , G-C

DNA REPLICATION

Why is it called antiparallel?

  • They are anti-parallel because one side is flipped upside down. They are anti-parallel because one side is flipped upside down.
  • TLDR DNA unzips and each side is copied to conserve one strand of parent DNA.

4.2

Prokaryotes do not contain membrane-bound organelles

  • In prokaryotes. DNA attaches to a spot in the cell membrane (so its not so floaty)
    • Plasmids contain only a few genes that offer proteins for extreme situations characteristics
  • One has a several thousand genes
    • entire thing codes for RNA and proteins
    • no unused proteins

Gene Regulation - Operons

  • Operons can STOP dna from being transcribed (negative feedback turns gene on or off)
  • Promoter region is where it attaches to (produces product)

Chromosomes

  • We have 23 chromosomes PAIRS and 46 total chromosomes

Genetic Engineering steps

Identify

  • Find the molecule

Separate

  • Isolate DNA sequence/ gene that codes for the molecule

Manipulate

  • Alter DNA by placing it somewhere else or altering it inside the original cell

Harvest

  • Collect molecule/product and market it.

* Note: If something has r before the name ex: “rDNA” it means RECOMBINANT

Common Gel Stains

  • Ethidium Bromide (EtBr)
    • Glows orange under UV
  • Methylene blue

Test Specific Studying

  • Need to know ALL terms and definitions
  • Isolating and Manipulating DNA Order and Step Definitions
  • Lots about Gel Electrophoresis
    • Agarose vs Polyacrymelide
      • What kind of molecules do they separate
      • If given proteins or DNA, what system would u use and why
    • Concentrations effect on molecules
    • Different Stains and how they function
  • In bacteria how many bands will u see given a certain amount of cuts
    • Ex: one cut gives __ # of bands
  • How are genes turned off and on?
    • Need to know introns extrons etc
    • Heavy on 4.2
  • How is DNA different and the same between all organisms
  • How SPECIFICALLY do you manipulate DNA

Test Studying Specific Answers:

Vocabulary at top of page

Isolation and Manipulation of DNA

Identify

  • Find the molecule

Separate

  • Isolate DNA sequence/ gene that codes for the molecule

Manipulate

  • Alter DNA by placing it somewhere else or altering it inside the original cell

Harvest

  • Collect molecule/product and market it.

Gel Electrophoresis

  • Polyacrylamide VS Agarose
    • Polyacrylamide gels (PAGE) seperate SMALLER molecules like proteins or TINY DNA/RNA
    • Agarose gel separates medium-large DNA 500-25,000 bp
  • RNA is smaller than DNA
  • Smears appear when theres a small concentration of thousands of different sizes of molecules
  • Concentration makes DNA move slower through gel

Types of Stains

  • Methylene Blue
    • attaches to DNA and proteins
  • Ethidium Bromide
    • DNA stain that glows under UV

Restriction enzymes cuts

  • # cuts = # of bands

DNA between organisms

  • All DNA has a double helix, runs antiparallel, has hydrogen bonds, etc.
  • NOT all DNA has the same number of strands
    • This means that their base pairs vary in length
  • Some DNA has LINEAR chromosomes or CIRCULAR

Manipulating DNA

  • Gene Therapy or Site Specific Mutagenesis