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DNA--The Blueprint of Life
DEOXYRIBONUCLEIC ACID
The Genetic Code
• Genetic - relates to heredity
• Heredity - The passing of traits from the
parents to their young.
• Traits - Characteristic that a living thing
can pass on to its young, (eye color)
• Characteristic - A description of a trait ,
(blue eyes)
The Genetic Code
• Genetic code - is the store information that
is passed from one generation to the next.
• Transformation - the exchange of genetic
information between 2 different (but
similar) organisms.
The Genetic Code
• Transforming Factor - A scientist named
Avery discovered through experimentation
that DNA is the molecule responsible for
transformation .
The Structure of DNA
• Nucleotide - The base unit of structure to
form the DNA molecule
• Three basic parts of a nucleotide
– 1. Deoxyribose - a sugar made of 5 carbon
atoms
– 2. Phosphate group
– 3. Nitrogenous, or nitrogen base
The Structure of DNA
• Nitrogenous Bases
– PURINES
• Adenine
• Guanine
- PYRIMIDINES
*Cytosine
* Thymine
The Structure of DNA
• Nucleotides form long chains using the
deoxyribose (sugar) and the phosphate
groups as the backbone and the
nitrogenous bases stick out from the chain.
The Structure of a Nucleotide
Nitrogenous
base
Phosphate
group
Deoxyribose
(sugar)
The Nucleotide-A more Technical View
The Structure of Organic Bases
PURINES
Guanine
Adenine
PYRIMIDINES
Thymine
Cytosine
The Structure of DNA
The Structure of DNA
• The Double Helix
– Watson and Crick discovered the twisting
(spiral shape) of the DNA molecule.
– Stole the research from Rosalind Franklin to
determine the shape
– Stole the research from Erwin Chargaff to
determine the arrangement of the purines and
pyrimidine bases
The Structure of DNA
• Watson and Crick won the Nobel Prize in
1962 for their discoveries.
• Why didn’t Rosalind Franklin earn the
Nobel Prize?
The Replication Of DNA
• Base Pairing
– Thymine will only bond to Adenine in the DNA
molecule
– Cytosine will only bond with Guanine in the DNA
molecule
The Replication Of DNA
Base Pairing (Naming of Bases)
•
•
•
•
Thymine
Cytosine
Guanine
Adenine
(T)
(C)
(G)
(A)
The Replication Of DNA
• Base Pairing
– To show a nucleotide chain it is abbreviated
A-C-T-G-T-A-T-A-T-C-G-C-C-G
– To each of the bases above they would have
the matching base below
T-G-A-C-A-T-A-T-A-G-C-G-G-C
– These are the opposite base nucleotides
The Replication Of DNA
• Base Pairing
“A” to “T” is a double bond
“C” to “G” is a triple bond
These Hydrogen bonds
make the
molecule twist
The Replication of DNA
• Replication - the process in which DNA
makes a copy of itself before the cell can
divide.
• This process ensures that the two new
daughter cells have the same DNA
Replication Process
Replication Process
Replication Process
Replication Process
Replication Process
Replication Process
Replication Process
Replication Process
Replication Process
Replication Process
Replication Process
Replication Process
Replication Process
Replication Process
It is Quiz Time
Please take out a clean sheet of
paper
Question 1
• What does the abbreviation DNA stand for?
Please spell it the best you can!
Question 2
• True or False
• An example of a trait is “hair color”
Question 3
• True or False
• If someone tells you that you have beautiful
brown eyes, they are complimenting a
characteristic.
Question 4
• True or False
• Heredity is the passing of a trait from the
parents to the offspring
Question 5
• What did “Avery” discover in his
experiments?
• A. Protein is the transforming factor
• B. DNA is the transforming factor
• C. RNA is the transforming factor
Question 6
• Fill in the blank
• The base unit of structure that makes up
the DNA molecule is the _____________.
It contains 3 basic parts
Question 7
• What are the nitrogen bases that make up
the purines?
–
–
–
–
adenine
thymine
cytosine
guanine
Question 8
• What are the nitrogen bases that make up
the pyrimidines?
–
–
–
–
adenine
thymine
cytosine
guanine
Question 9
• What 2 parts of the DNA molecule builds the
backbone?
–
–
–
–
–
Phosphate group
Deoxyribose Sugar
Nitrogen Base
Purines
Pyrimidines
Question 10
• What did Watson and Crick steal from
Rosalind Franklin?
Question 11
• What did Watson and Crick steal from Erwin
Chargaff?
Question 12
• What did Waston and Crick earn for all their
hard work?
Question 13
• Why didn’t Rosalind Franklin earn the same
prize?
Question 14
• What two nitrogen base pairs always pair
together in the DNA molecule?
– Please write the entire base name out
• spell the best you can
Question 15
• What is the abbreviation for the following
nitrogen bases
–
–
–
–
1. Adenine
2. Thymine
3. Guanine
4. Cytosine
Question 16
• Why must a cell replicate it’s DNA before it
divides?
Question 17
• Copy the DNA strand on your paper
• Write the complementary nitrogen base to
the DNA strand
• A-T-C-C-G-T-C-A-T
Question 18
• What is needed to break the hydrogen
bonds between the nitrogen bases when
the strand starts to replicate?
RNA; Lecture II
Ribonucleic Acid
RNA
• RNA is the messenger between DNA and the
ribosomes.
• The message from the DNA will tell the
ribosomes what protein to synthesize.
RNA Structure
• RNA has the same structure as DNA with the
Sugar- phosphate group backbone.
• 3 difference between RNA and DNA
• 1. The sugar group in RNA is called “ribose”
where DNA is “deoxyribose”
• 2. RNA is a single strand of nucleotides
where DNA is a double strand of
nucleotides
RNA Structure
• 3. RNA has “Uracil” instead of “thymine” in
which DNA contains.
• RNA does follow the same base pairing
rules that DNA follows. DIFFERENCE, “Uracil”
pairs with “Adenine” just like “thymine did
in DNA.
• Uracil is abbreviated “U”
The Reason for RNA
• Because the DNA molecule is to large to
exit the nuclear membrane so it makes a
copy of itself in single strand (RNA), a
smaller molecule, to relay the commands
for protein synthesis to the ribosomes.
• This type of RNA that delivers the
commands from the DNA is called,
“messenger RNA” abbreviated mRNA
Transcription
• Synthesizes RNA from a DNA strand.
• The RNA is “transcribed” by copying a
portion of DNA to make a complementary
strand of RNA.
• Transferring DNA to RNA
Transcription
The Process of Transcription.
1. RNA polymerase (an enzyme) attaches itself
to a section the DNA molecule that needs
transcribed.
2. RNA polymerase causes the DNA molecule
two strands to separate
3. The RNA polymerase pulls in floating
nucleotide to form the mRNA from the DNA
template.
Transcription
G
A
T
C
A
T
C
T
A
G
Transcription
G
A
T
C
A
T
C
T
A
G
Transcription
G
A
T
C
A
T
C
T
A
G
Transcription
G
A
T
C
A
T
C
T
A
G
T
Transcription
A
C
A
G
T
C
T
A
G
A
T
Transcription
A
C
A
G
A
T
C
T
G
A
T
Transcription
A
C
G
A
T
C
T
A
U
G
A
T
Transcription
A
C
G
A
G
A
U
T
C
T
G
A
T
Transcription
A
C
G
G
A
U
T
C
T
A
G
A
T
Transcription
A
C
A
G
A
G
U
T
C
T
G
A
T
Transcription
A
C
A
G
A
U
G
C
T
G
T
A
T
Transcription
A
C
C
A
G
A
U
G
T
C
T
G
A
T
Transcription
A
C
A
G
U
A
G
C
T
C
T
G
A
U
T
Transcription
A
C
A
G
A
C
G
T
C
T
G
A
U
T
Transcription
A
C
A
G
GA
C
T
C
T
G
A
G
T
Transcription
A
C
U
A
G
A
C
T
C
T
G
A
T
Transcription
A
C
A
G
U
C
A
T
C
T
G
A
T
Transcription
A
C
A
G
C
A
U
T
C
T
G
A
T
Transcription
A
C
A
G
UA
T
C
T
G
A
T
Transcription
A
C
A
G
A
T
C
T
G
A
T
Transcription
A
C
A
G
A
T
C
T
G
A
Transcription
T
C
A
A
C
A
G
T
T
A
G
Transcription
C
A
C
A
T
A
T
G
T
A
G
Transcription
C
A
C
A
T
A
T
G
T
A
G
Transcription
• NOTE
• The mRNA made a copy of one side of the
DNA molecule
• The mRNA now leaves the nucleus and
travels to ribosome out in the cytoplasm
tell the ribosome what protein to make.
Protein Synthesis
• A “Protein” is a string of “Amino Acids”
when put together form a molecule called a
“polypeptide”
• There are 20 different types of Amino Acids
• The arrangement of the nucleotides codes
for which Amino Acid is needed to form a
certain polypeptide.
Protein Synthesis
• Review
• DNA contains the following nucleotide
bases ( A, T, C, G )
• RNA contains the following nucleotide
bases ( A , U, C, G )
Protein Synthesis
• It takes “3” nucleotides to code for one
Amino Acid.
• Each combination of “3” nucleotides on
mRNA is called a “Codon”
• There can be more than one codon for each
amino acid.
Protein Synthesis
A U
G U C C
CODON CODON
A U
C G
CODON
G C
CODON
U G A
CODON
Look at Your Handout
First Letter of Sequence
mRNA
Second Letter of Sequence
mRNA
Third Letter of Sequence
mRNA
Protein Synthesis
• Note
• AUG is a “initiator” that always codes for
Methionine (amino acid) which is a start
code for protein synthesis.
• However, there are 3 codons, UAA, UAG, and
UGA, that do not code for an amino acid and
ends the protein synthesis. They are “stop”
codons. Just like a period.
Protein Synthesis
• Look at the handout
• What amino acid do the following codons
call for?
• AGC
• GGG
• CUC
• UGA
Protein Synthesis
• Look at the handout
• What amino acid do the following codons
call for?
• AGC serine
• GGG glycine
• CUC leucine
• UGA “stop” codon
Translation
• The process of translating the message
from the mRNA into a polypeptide chain.
• The amino acids are carried to the mRNA on
a specialized molecule called transfer RNA
(tRNA).
Translation
A U
Amino Acid
G
Anticodon
Translation
• The role of ribosomes in translation
• Ribosomes pass along the mRNA and calls
out the tRNA to bring in the anticodon
match to mRNA codon
• Remember the amino acid needed for the
polypeptide is attached to tRNA
Translation
A U
mRNA
G
C
G
U
A G C A C U
A
G
Translation
A U
mRNA
G
C
G
U
A G C A C U
A
G
Translation
A U
mRNA
G
C
G
U
A G C A C U
A
G
Translation
UAC
AU G
mRNA
CG U
A G C A C U
A
G
Translation
UAC
AU G
mRNA
CG U
A G C A C U
A
G
Translation
UAC
AU G
mRNA
CG U
A G C A C U
A
G
Translation
UAC
AU G
mRNA
CG U
A G C A C U
A
G
Translation
GCA
AU G
mRNA
CG U
A G C A C U
A
G
Translation
AU G
mRNA
G CA
CG U
A G C A C U
A
G
Translation
GCA
AU G
mRNA
CG U
A G C A C U
A
G
Translation
UCG
AU G
mRNA
CG U
A G C
C U
A
Translation
UCG
AU G
mRNA
CG U
A G C
U G
A
Translation
AU G
mRNA
CG U
UCG
A G C
U G
A
Translation
UCG
AU G
mRNA
CG U
A G C
U G
A
Translation
UCG
AU G
A G C
mRNA
CG U
U G
A
Translation
UCG
AU G
A G C
mRNA
CG U
U G
A
Stop Codon
Translation
AU G
mRNA
CG U
A G C
U G
A
Stop Codon
Let’s review
• If DNA copies itself it is called……..
• When DNA makes a copy of mRNA it is
called ……...
• When mRNA calls for an amino acid it is
called ……..
Let’s review
• If DNA copies itself it is called……..
• replication
• When DNA makes a copy of mRNA it is
called ………
• transcription
• When mRNA calls for an amino acid it is
called ……..
• translation
Let’s review
•
•
•
•
•
•
DNA strand
TACCCGATCACT
mRNA strand (CODON)
AUGGGCUAGUGA
tRNA strand (ANTICODON)
UACCCGAUCACU
Let’s review
• Very Important
• Remember the mRNA codon codes for the
amino acid
• Always look at the mRNA when looking to
see what amino acid is needed
Let’s review
• What amino acid do each of the DNA
strands code for?
• ATT
• GGC
• AGA
• TTG
Let’s review
• What amino acid do each of the DNA
strands code for?
• DNA
mRNA
Amino Acid
• ATT
UAA
stop
• GGC
CCG
Proline
• AGA
UCU
Serine
• TTG
AAC
Asparagine
Let’s review
• What would the tRNA anticodon for each of
the amino acids?
• Amino Acid
• stop
• Proline
• Serine
• Asparagine
Let’s review
• What would the tRNA anticodon for each of
the amino acids?
• Amino Acid
tRNA
• stop
AUU
• Proline
GGC
• Serine
AGA
• Asparagine
UUG
The End
Time for your DNA/RNA 3 dimensional
project
3-D project
• You will choose one of the three processes
we discussed in lecture to build a 3-D
model demonstrating the process.
• 1. Replication
• 2. Transcription
• 3. Translation
The model must contain ………..
•
•
•
•
1. A 3-D display of the process chosen
2. A “key” for reference
3. An explanation of the process chosen
NO food materials are to be used
Deadline
•
•
•
•
•
•
Tuesday/Wednesday (2/20, 2/21)
It is due Tuesday/Wednesday
Tuesday/Wednesday
If you are ill, have someone bring it to me.
NO EXCUSES for late assignments
will not take them after 3:30
Tuesday/Wednesday