dna structure and analysis n.
Skip this Video
Loading SlideShow in 5 Seconds..
DNA Structure and Analysis PowerPoint Presentation
Download Presentation
DNA Structure and Analysis

Loading in 2 Seconds...

play fullscreen
1 / 44

DNA Structure and Analysis - PowerPoint PPT Presentation

  • Uploaded on

DNA Structure and Analysis. Central Idea of Genetics!. DNA RNA PROTEIN. Transcription. Translation. DNA Structure. There are four kinds of bases in DNA: adenine guanine cytosine thymine. DNA Structure. Nucleotides join together to form long strands

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

PowerPoint Slideshow about 'DNA Structure and Analysis' - allen-cooley

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
central idea of genetics
Central Idea of Genetics!




dna structure
DNA Structure

There are four kinds of bases in DNA:

  • adenine
  • guanine
  • cytosine
  • thymine
dna structure1
DNA Structure
  • Nucleotides join together to form long strands
  • DNA consists of two strands
  • Strands twist around each other to form a double helix
  • Nucleotides are held together by a phosphodiester bond
    • Connects the sugar of one nucleotide to the phosphate of another
  • Nucleotide sequence can vary

Phosphodiester bonds


DNA Structure

  • DNA consists of two strands joined together by hydrogen bonds between the base pair
  • Base pairs are complementary on opposite strands
    • Adenine only base pairs with thymine
    • Guanine only base pairs with cytosine
  • Two strands are considered antiparallelbecause the polarity of each strand opposite
    • Necessary for nitrogen bases to align and form hydrogen bonds
polarity of dna
Polarity of DNA
  • Each strand of nucleotides has a 5’ end and 3’ end
    • The 3’ end used to bond to another nucleotide
    • The 5’ end is attached to the phosphate group of the nucleotide
  • A strand of DNA runs from the 5’ 3’
  • Each carbon in the deoxyribose is numbered 1’-5’

DNA structure


dna animations
DNA Animations
  • http://www.pbs.org/wgbh/nova/genome/dna.html#
  • http://learn.genetics.utah.edu/content/begin/tour/
  • http://www.johnkyrk.com/DNAanatomy.html
  • http://www.sumanasinc.com/webcontent/animations/content/DNA_structure.html
chromosomes and dna replication
Chromosomes and DNA Replication

DNA makes up chromosomes!

dna and chromosomes
DNA and Chromosomes
  • In prokaryotic cells, DNA is located in the cytoplasm.
  • Most prokaryotes have a single DNA molecule containing nearly all of the cell’s genetic information.
dna and chromosomes1
DNA and Chromosomes
  • Many eukaryotes have 1000 times the amount of DNA as prokaryotes.
  • Eukaryotic DNA is located in the cell nucleus inside chromosomes.
  • The number of chromosomes varies widely from one species to the next.
dna and chromosomes2
DNA and Chromosomes
  • Chromosome Structure
    • Eukaryotic chromosomes contain DNA and protein, tightly packed together to form chromatin.
    • Chromatin consists of DNA tightly coiled around proteins called histones.
    • DNA and histone molecules form nucleosomes.
    • Nucleosomes pack together, forming a thick fiber.
dna replication
DNA Replication
  • Necessary to create new cells!
  • Each strand of DNA has all the information needed to reconstruct the other half
  • Strands are complementary and can be used to make the other strand
dna replication1
DNA Replication
  • Semiconservative Replication
    • Parent strands separate and serve as templates for new strands
    • New DNA molecule holds one parent strand and one new strand
dna replication2
DNA Replication

1. The DNA molecule separates into two strands.

2. Produces two new complementary strands following the rules of base pairing.

3. Each strand of the double helix of DNA serves as a template for the new strand.

dna replication3
DNA Replication

New Strand

Original strand

Nitrogen Bases



Replication Fork

Replication Fork

DNA Polymerase

\\loyola2\bschuller$\Biology PresentationExpress\Chapter12\Section02\Resources\ActiveArt\index.html



  • http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/dna-rna2.swf
  • http://www.youtube.com/watch?v=hfZ8o9D1tus
  • http://www.youtube.com/watch?v=4jtmOZaIvS0
dna replication4
DNA Replication

DNA Replication

1. Unwinding - Enzymes unzips DNA by breaking hydrogen bonds. Strands separate at the replication fork.

Replication Fork


DNA Replication

  • Base Pairing - New complementary nucleotides are added to the 3’ end to make a new strand – the new strands are formed in opposite directions; the enzyme DNA polymerase attaches nucleotides to produce new strands.

DNA Replication

  • 3. Joining- DNA polymerase joins the fragments together. The new DNA strand is proofread
rna and protein synthesis
RNA and Protein Synthesis

Genes are coded DNA instructions that control the production of PROTEINS.

Genetic messages can be decoded by copying part of the nucleotide sequence from DNA into RNA.

RNA contains coded information for making proteins.

central idea of genetics1
Central Idea of Genetics!





RNA – Ribonucleic Acid

  • Composed of a long strain of nucleotides
  • Contains sugar, phosphate group, and nitrogen base


  • Messenger RNA (mRNA) – messenger from DNA to the rest of the cell
  • Ribosomal RNA (rRNA) – make up ribosomes
  • Transfer RNA (tRNA) – transfer amino acids to the ribosomes
  • The process of making RNA by copying part of the DNA sequence into a complementary RNA sequence

Requires enzyme RNA polymerase

  • RNA Polymerase binds to DNA and separates strands
  • RNA Polymerase uses DNA as template and assembles complementary RNA strands
transcription animations
Transcription Animations
  • http://www-class.unl.edu/biochem/gp2/m_biology/animation/gene/gene_a2.html
  • http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/transcription.swf
rna editing
RNA Editing
  • The DNA of eukaryotic genes contains sequences of nucleotides, called introns, that are not involved in coding for proteins.
  • The DNA sequences that code for proteins are called exons.
  • When RNA molecules are formed, introns and exons are copied from DNA.
rna editing1
RNA Editing
  • The introns are cut out of RNA molecules.
  • The exons are the spliced together to form mRNA.
protein review
Protein Review
  • Proteins are made by joining
  • Each protein contains a combination of the 20 amino acids
  • The function of the protein is determined by number and sequence of amino acids
  • (A polypeptide is a protein!)

Protein 1

Protein 2

genetic code
Genetic Code
  • The genetic code is the “language” of mRNA instructions.
  • A codon consists of three consecutive nucleotides on mRNA that specify a particular amino acid.

Each codon specifies a particular amino acid that is to be placed on the polypeptide chain.


Genetic Code

RNA Sequence -


Codon Sequence –

U C G – C A C – G G U

Use the Amino Acid Guide to determine amino acid –

U C G – C A C – G G U

Amino acid sequence –

U C G – C A C – G G U

Serine – Histidine – Glycine

  • 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.

1. Messenger RNA is transcribed in the nucleus, and then enters the cytoplasm where it attaches to a ribosome.


2. The ribosome “reads” the mRNA codon and the corresponding amino acid is brought to the ribosome by the tRNA

Amino Acid

Amino Acid



3. The ribosome forms bonds between the amino acids to form the protein

Bond formed


4. Translation continues until the ribosome reaches a stop codon on the mRNA and releases the protein (polypeptide)

translation animation
Translation Animation
  • http://www-class.unl.edu/biochem/gp2/m_biology/animation/gene/gene_a3.html
  • http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/translation.swf