DNA and RNA
The Chain of Life
DNA
• DNA – Deoxyribonucleic Acid
• DNA … RNA…proteins… make up cells…life
• DNA is often called the blueprint of
life.
DNA
• Why important to you?
1) every new cell needs copy of DNA to make
proteins
2) pass on DNA to offspring
3)medical benefits such as cures for diseases,
4)better food crops and animals
Who discovered structure? - movie
• James Watson
• Francis Crick
A HISTORY OF DNA
•
Discovery of the DNA double helix
A. Frederick Griffith – Discovers that a factor in diseased
bacteria can transform harmless bacteria into deadly
bacteria
(1928)
B.
Rosalind Franklin - X-ray photo of DNA.
(1952)
C.
Watson and Crick - described the
DNA molecule from Franklin’s X-ray.
(1953)
DNA
• Made up of
polymers – composed of sub units called
monomers
DNA
• DNA and RNA repeating units = nucleotides – 2
together form DNA chain
DNA
• Called a DOUBLE HELIX
• Held together with hydrogen bonds : share 1
electron
DNA
• Nucleotides – 3 parts
5 carbon sugar called deoxyribose
phosphate group
nitrogen base ( 4 kinds)
DNA
• adenine
purines: 2 rings
guanine
DNA
• thymine
pyrimidines : 1 ring
cytosine
DNA
• A = T with two hydrogen bonds
C = G with three hydrogen bonds
• DNA structure movie
DNA by the numbers
•
•
•
•
•
Each cell has about 2 meters of
DNA.
The average human has 75 trillion
cells.
The average human has enough
DNA to go from the earth to the sun
more than 400 times.
DNA has a diameter of only
0.000000002 m.
It contains information equal to some
600,000 printed pages of 500 words
each!!!
(a library of about 1,000 books)
The earth is 150 billion m
or 93 million miles from
the sun.
DNA is like a fingerprint because everyone’s
is a little different!
How does the police look at DNA to
figure out who committed a crime?
The DNA gets cut up by special scissors!!!
The scissors can only cut the same color!
All of the cut up pieces of DNA are different sizes.
A special machine sorts the DNA by size.
(Little pieces are fast, so they move faster to the bottom.)
BIG
TOP
LITTLE
BOTTOM
We are ALL a little bit different!
BIG
Mrs. Nickerson’s DNA
LITTLE
Sara’s DNA
Soooo….
How do we tell people apart just by
their DNA anyways???
Our DNA has different sizes of pieces so it
makes a different pattern when it’s all cut up.
Mrs. Nickerson’s DNA
Sara’s DNA
Mrs. Nickerson’s
Sara
This is what it really looks like!!!
Mrs. Nickerson’s
?
Sara
Is the red box
around Mrs.
Nickerson’s
DNA or around
Sara’s DNA?
DNA
• Replication : Unwind and Unzip
hydrogen bonds are broken with enzyme called
helicase
free floating nitrogen bases come in and bond
copying occurs
Replication…
• Replication flash
Movie
Replication full movie
Identical
base sequences
Mutations
Wild type"Normal Gene"
THE ONE BIG FLY HAD ONE RED EYE
Missense
THQ ONE BIG FLY HAD ONE RED EYE
Nonsense
THE ONE BIG
Frameshift
THE ONE QBI GFL YHA DON ERE DEY
Deletion
THE ONE BIG HAD ONE RED EYE
Duplication
THE ONE BIG FLY FLY HAD ONE RED EYE
Insertion
THE ONE BIG WET FLY HAD ONE RED EYE
Expanding
(P) THE ONE BIG FLY HAD ONE RED EYE
Expanding
(F1) THE ONE BIG FLY FLY FLY HAD ONE
RED EYE
Expanding
(F2) THE ONE BIG FLY FLY FLY FLY FLY FLY HAD
ONE RED EYE
RNA
• – synthesize proteins – Ribonucleic Acid
RNA
• Plants – photosynthesis
Animals – protein synthesis
RNA
• 3 Differences!
1) 1 strand of nucleotides instead of 2
2) ribose not deoxyribose
3) uricil not thymine
RNA - types
• Types
- mRNA – messenger RNA – used to transmit
information from DNA
-RNA Types
• t RNA – transfer RNA – single strand of RNA able
to bend back upon itself so that the correct bases
can bond together
-RNA Types
• - rRNA – ribosomal RNA – globular, not in a
strand – main factor in ribosome organelles
Protein Synthesis – how proteins are
made
• Proteins… polymers called polypeptides…
specific sequence of amino acids… linked
together by peptide bonds
Protein Synthesis
• 20 amino acids
- genetic code = array of nitrogen base
combination
- 3 sequences on one side of chain = codon…
AUG start code
All others…= 64 possibilities
Amino Acid Decoder Chart
-RNA Transcription – how RNA is made
• RNA enzyme polymerase unzips a DNA chain
• Hydrogen bonds occur between DNA and RNA
• Copies until it reaches stop code then triggers
release
Transcription - movie
-RNA Translation
• assembling of protein molecules in mRNA
codons paired with anticodon
Translation - movie
• rRNA
Bonds chain of Amino Acids to form a
Polypeptide Protein