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DNA Deoxyribonucleic Acid

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The information that determines an organisms traits. DNA produces proteins which gives it 'The power' ... How does the zipper get unzipped in DNA replication? ... – PowerPoint PPT presentation

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Title: DNA Deoxyribonucleic Acid


1
DNADeoxyribonucleic Acid
2
DNA Structure
3
What is DNA?
  • The information that determines an organisms
    traits.
  • DNA produces proteins which gives it The power
  • Many things contain and are made of proteins.
  • Skin, hair, bones, etc are made of proteins.

4
What is DNA? Contd
  • Enzymes are special proteins.
  • Enzymes control chemical reactions needed for
    life.
  • DNA contains all the information for making all
    and any proteins for human life.

5
DNA Structure
  • DNA is made of repeating subunits called
    nucleotides.
  • Nucleotides have three parts
  • Simple sugar
  • Phosphate group
  • Nitrogen base

6
1 Nucleotide
Phosphate Group
Nitrogen Base
Sugar (Deoxyribose)
7
DNA Structure
  • The simple sugar is called deoxyribose.
  • The phosphate group is made of phosphate and
    oxygen.

8
DNA Structure
  • Four possible Nitrogen Bases
  • Thymine (T)
  • Adenine (A)
  • Cytosine (C)
  • Guanine (G)

9
DNA
Backbone
  • Nucleotides join together to form long chains.
  • The phosphate group of one nucleotide joins
    together with the deoxyribose sugar of an
    adjacent nucleotide.

Teeth
10
DNA
  • Nitrogen bases pair up
  • Adenine Thymine (A-T)
  • Cytosine Guanine
  • (C-G)
  • Complementary bases

11
Watson Crick, 1953
  • Proposed DNA is put together like a twisted
    zipper
  • DNA 2 chains of nucleotides joined by nitrogen
    bases

12
Watson Crick, 1953Double Helix
  • Double DNA has two strands
  • Helix twisted like a spring, spiral

13
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14
Importance of Sequencing
  • The sequence of the four different nucleotides
    determines what organism is created.
  • For instance T-A-A-G-C-A is different than
    A-G-C-A-A-G
  • Another example E-A-R-T-H is different than
  • H-E-A-R-T

vs.
15
Importance of Sequencing
  • The more similar the order of nucleotides are,
    the closer the relationship between 2 organisms

16
DNA Replication
17
DNA Replication
  • Replication to copy
  • Process of copying DNA in the chromosomes
  • Without DNA replication, a new cell would only
    have half of its information.

18
DNA Replication
  • DNA Replication Video

19
DNA Replication 2
  • Replication VIDEO

20
DNA Replication
  • Because of the pairing- if you have one strand,
    it is easy to predict the replicated strand.
  • T-A-G-C-C-G-T
  • Remember A goes with T, C goes with G
  • A-T-C-G-G-C-A

21
DNA Replication
  • Remember The nitrogen bases are held together by
    hydrogen bonds
  • An enzyme goes to those hydrogen bonds and breaks
    them Double Helix Unzips

22
DNA Replication
Step 1 Separate the two DNA strands
23
DNA Replication
Step 2 Original DNA strands act as templates
complementary nucleotides fill in.
24
DNA Replication
Step 3 Nucleotides connected and a new
sugar-phosphate backbone is formed.
25
DNA Replication
Each new DNA molecule consists of one original
strand and one new strand
26
So now what??
27
DNA to Protein
  • DNA encodes the instructions for making proteins.
  • Remember proteins make up your bones, skin, etc.
  • Enzymes are special proteins
  • Enzymes control all chemical reactions in an
    organism

28
DNA to Protein
  • Proteins are made up of many amino acids
  • The order of nucleotides in each gene has
    information on how to make the string of amino
    acids which is a protein.
  • ESTIMATE Each cell contains about 800,000 genes

29
We need to figure out how to get from DNA to
Proteins!
30
RNA
  • What is it?
  • What does it do?

31
RNA vs. DNA
  • RNA
  • Single Stranded- only half of a zipper
  • Contains the sugar Ribose
  • Contains the nitrogen bases
  • Adenine
  • Uracil
  • Guanine
  • Cytosine
  • DNA
  • Double Stranded- double helix
  • Contains the sugar Deoxyribose
  • Contains the nitrogen bases
  • Adenine
  • Thymine
  • Guanine
  • Cytosine

32
RNA
  • Its job Copying DNA
  • Its goal To create proteins
  • There are 3 types, each with a different job
  • mRNA Messenger RNA copies DNA to take it out in
    the cytoplasm
  • rRNA Ribosomal RNA works on matching mRNA - to
    create the amino acids in the correct order
  • tRNA Transfer RNA gives amino acids to rRNA to
    produce the protein.

33
mRNA
  • Brings information (in the form of an RNA strand)
    from the DNA in the nucleus to the cytoplasm

34
rRNA
  • Ribosomes are made of rRNA
  • Where are ribosomes found?
  • Cytoplasm
  • rRNA attaches to the mRNA and uses its
    information to set up the amino acids in the
    correct order

Ribosome
mRNA
35
tRNA
Amino Acid
  • The supplier
  • Brings amino acids to the ribosome so that it can
    assemble the protein

36
Review Questions
  • How does information from the DNA get to the
    cytoplasm?
  • How does the zipper get unzipped in DNA
    replication?
  • Who does the work in getting the amino acids to
    the worker?
  • What is the formal name of the worker

37
Transcription
38
Transcription
  • Transcriptions purpose is to create a single
    stranded RNA molecule rather than a double
    stranded DNA molecule.
  • This is needed to allow the single stranded RNA
    to be taken out of the nucleus by the mRNA to the
    cytoplasm.

39
Transcription
  • Transcription Tutorial / SHOW
  • Transcription mRNA VIDEO

40
Genetic Code with mRNA
  • In order to take the DNA and create a mRNA, there
    are special codes used.
  • In mRNA, three nitrogen bases together form a
    code this is called a codon.
  • Looking ahead
  • this code is matched with an amino acid.
  • A string of amino acids form a protein.

41
Genetic Code with mRNA
  • Some codons code for information other than amino
    acids
  • UAG is an example of a stop codon.
  • AUG is an example of a start codon.
  • NOTE For every one codon, there is only ONE
    amino acid that can join.

42
Transcription Pictures
43
Transcription Pics
44
How does this work in the cell?
mRNA COPIES DNA INTO CYTOPLASM
NUCLEUS
DNA
rRNA USES PLAN FROM mRNA TO PUT AMINO ACIDS IN
ORDER TO MAKE PROTEINS
AMINO ACIDS TRANSPORTED BY tRNA
RIBOSOME
45
Translation
46
Translation From mRNA to Protein
  • The process of changing the information from an
    order of nitrogen bases in mRNA into the order of
    amino acids
  • Occurs at the ribosomes in the cytoplasm

47
Translation
  • When mRNA enters the cytoplasm, ribosomes attach
  • 20 different amino acids must be brought to the
    ribosomes for proteins to be made
  • tRNA brings the amino acids to the mRNA strand

48
Translation
Amino Acid
  • On the opposite side of the tRNA amino acid side
    is a set of three nucleotides that are the
    complement of the nucleotides codon
  • This is called an Anticodon

49
Translation
  • When a match is made between codons and
    anticodons- a temporary bond is formed.
  • This places the amino acid in the correct
    position to enable it to bond with the next amino
    acid

50
Translation
  • The next tRNA bonds to its codon and then the
    two amino acids bond together.
  • The first amino acid then releases itself from
    the mRNA

51
Translation
  • This continues until a stop codon is reached.
  • Amino acid chains then become proteins when they
    are freed from the ribosome and twist and curl
    into complex three-dimensional shapes.

52
Translation
53
Translation
  • Translation VIDEO

54
(No Transcript)
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