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DNA, Replication, Protein Synthesis
2013
Goals for Today• Know ALL of Genetics
• Be able to name the scientists that helped build our knowledge of DNA and be able to describe their contributions
Test Corrections Assignment
• REWRITE each question completely.– Write out the correct answer (do NOT just put
the letter of the correct answer!)
– When finished place Study guides, Qods, & Notes in Folders.
Introduction to DNA
Goals for Today• Be able to name the scientists that helped
build our knowledge of DNA and be able to describe their contributions
• Be able to discuss how scientific understanding is built
• Be able to list or understand the contributions of less known scientists
• Be name the 3 basic components of DNA
Question of the Day
• What is DNA? Write your thoughts down, and what you know about it, you don’t have to be sure you are correct!
DNA is shaped like a double helix (a twisted ladder)
This shape was discovered by two scientists: James Watson & Francis Crick
Scientific Knowledge
• Scientific knowledge and discovery is always built on what we already know, past discovery & knowledge
• Were Watson & Crick the only ones responsible for discovering the structure of the DNA molecule?
Who is Rosalind Franklin?
Griffith’s Experiments
Griffith discovered that harmless bacteria could turn virulent when mixed with bacteria that cause disease.
A bacteria that is virulent is able to cause disease.
Griffith had discovered what is now called transformation, a change in genotype caused when cells take up foreign genetic material.
MOUSE LIVES!!!!
• When virulent bacteria are heat-killed and injected into a mouse……..
• The Mouse Lives!
• This told Griffith it was not the PROTEIN capsule on the bacteria that killed the mice.
Mouse Dies • When virulent bacteria are heat-killed and
COMBINED with injected into a mouse……..with live non-virulent bacteria.
• Mouse Dies• Griffith discovered that the non-virulent
bacteria had acquired genes from the virulent bacteria.
• This process is now known as transformation
Avery’s Experiments
•In 1943, a series of experiments showed that the activity of the material responsible for transformation is not affected by protein-destroying enzymes.
•The activity is stopped, however, by a DNA-destroying enzyme.
•Thus, almost 100 years after Mendel’s experiments, Oswald Avery and his co-workers demonstrated that DNA is the material responsible for transformation NOT protein.
DNA Nucleotide – a nucleotide is the three component parts together
PhosphateGroup N
Nitrogenous base(A, G, C, or T)
Sugar(deoxyribose)
Goals for Today• Be able to name the scientists that helped
build our knowledge of DNA and be able to describe their contributions
• Be able to discuss how scientific understanding is built
• Be able to list or understand the contributions of less known scientists
• Be name the 3 basic components of DNA
Question of the Day
• What are the contributions of these two scientists:
• Griffith: -
• Avery -
DNA’s Role Revealed
In 1952, Alfred Hershey and Martha Chase used the bacteriophage T2 to prove that DNA carried genetic material.
A bacteriophage, also referred to as phage, is a virus that infects bacteria.
When phages infect bacterial cells, the phages are able to produce more viruses, which are released when the bacterial cells rupture.
Life Cycle of a virus (bacteriophage)
Hershey & Chase use viruses to prove DNA is the genetic material
Who is Rosalind Franklin?
Erwin Chargaff
• Chargaff’s research determined that in DNA there were always equal parts
• Adenine = Thymine As well as equal parts • Cytosine = Guanine
Goals for Today• Be able to name the scientists that helped
build our knowledge of DNA and be able to describe their contributions
• Be name the 3 basic components of DNA
• Be able to list and describe the nitrogen bases and how they pair
Question of the DayWhat are the contributions of these scientists:
• Chargaff:
• Hershey & Chase:
Chargaff - Determined that in DNA there are always equal parts Adenine-Thymine & equal parts Cytosine-Guanine
Hershey & Chase-Used bacteria & Viruses to prove that DNA was the genetic material
Question of the Day continued
DNA…. what is good for?
• DNA has 2 major functions in our body:
1. Make more DNA
2. Make Protein
The Structure of DNA• DNA – Deoxyribonucleic Acid
• A double helix• Made of 3 basic components:
– Sugar– Phosphate Group– Nitrogen bases
The backbone of DNA• The Sugar (deoxyribose) & phosphate
group form the “backbone” of DNA or the sides of the ladder.
DNA Nucleotide – a nucleotide is the three component parts together
The Nitrogen Base is the Variable Piece of the Nucleotide
PhosphateGroup
NNitrogenous base(A, G, C, or T)
Sugar(deoxyribose)
Nitrogenous Bases
Purines• A –Adenine• G – Guanine
Pyrimidines• T – Thymine• C - Cytosine
Rosalind Franklin• It was Franklin’s photograph that
ultimately allowed Watson & Crick to get the correct base pairing, because they now new exactly how wide the helix was (The width between the sides of the double helix).
»Additionally, it was Franklin who suggested that the bases would go on the inside of the helix & not the outside as Watson & Crick originally thought
Nitrogenous Base Pairing
Nitrogen bases form the rungs of the “ladder” by forming Hydrogen bonds
What Watson & Crick had to figure out was how the bases paired up
Nitrogen Base Pairing• There were 3 scientists, other then
Rosalind Franklin, whose research & help contributed to Watson & Crick coming up with the correct pairing of the nitrogen bases
• Adenine - Thymine• Cytosine - Guanine
2 Hydrogen bonds between Adenine & Thymine
3 Hydrogen bonds between Cytosine & Guanine
DNA Nucleotide – a nucleotide is the three component parts
together
PhosphateGroup N
Nitrogenous base(A, G, C, or T)
Sugar(deoxyribose)
Goals for Today
• Be able to describe the process and enzymes involved in DNA replication.
• Be able to list and describe the nitrogen bases and how they pair
• Be name the 3 basic components of DNA
Question of the DayWhat are the contributions of these scientists:
• Rosalind Franklin:
• Watson & Crick:
Rosalind Franklin- Her research provided the basis for the first accurate model of DNA
Watson & Crick- First to accurately describe and model the chemical structure of DNA
Question of the Day continued
Base Pairing Practice!
DNA…. what is good for?
• DNA has 2 major functions in our body:
1. Make more DNA
2. Make Protein
Making More DNA…• DNA replication is the process we use to make
more copies of DNA
• When would we need to make more DNA?
Making More DNA…
• DNA is copied in the “S” phase of interphase to prepare for cell division.
• DNA replication occurs so new daughter cells will have the same information and the same number of chromosomes as the parent cell.
Enzyme Review
*What two things can enzymes do?
What has to break for the DNA strand to come apart?
DNA ReplicationDNA replication occurs in 3 basic steps:
1.The enzyme DNA helicase opens the double helix by breaking the hydrogen bonds that link the complementary nitrogen bases between the two strands.
• Complementary bases -
DNA Replication
DNA Replication2. The Enzyme DNA polymerase move along
each of the DNA strands. DNA polymerase adds nucleotides to the exposed nitrogen bases, according to the base-pairing rules.
3. Two DNA molecules form that are identical to the original DNA molecule.
*What do both of these enzymes end in?
DNA ReplicationDNA Replication is known as“Semiconservative process”
Semi = Conserve =
Lets see it in real time!
• DNA REPLICATION in Real Time
• How fast do you think this happens?
DNA REPLICATION
Anti-parallel
Goals for Today
• Be able to describe the process and enzymes involved in DNA replication.
• Be able to list and describe the nitrogen bases and how they pair
• Be name the 3 basic components of DNA
Question of the DayWhat is the difference between a Purine & Pyrimidine?
Purines =
Pyrimidines =
Write the complementary base pairs including hydrogen bonding below:
Skills Check Tomorrow• Scientists & Contributions• Labeling parts of a nucleotide – variable parts• Base Pairing – Complements• Hydrogen bonding• Purines/Pyrimidines• Enzymes & Replication• Shape of DNA• “Backbone” of DNA
Time to make your own DNA….
• AND REPLICATE IT!
What you will need for your DNA
• This is per pair, not for each individual• 2 paper towels• 2 red twizzlers• 2 chocolate twizzlers• Colored marshmallows ~40• Toothpicks ~40
Goals for Today
• Demonstrate that we are able to describe the process and enzymes involved in DNA replication.
• Demonstrate that we are to list and describe the nitrogen bases and how they pair
• Demonstrate that we are able to name the 3 basic components of DNA
• Begin learning about Protein Synthesis
Question of the Day• What process did we model in our lab
yesterday?
• What is the purpose of this process? Why do we do it?
Get out your labs please!
Skills Check TODAY• Scientists & Contributions• Labeling parts of a nucleotide – variable parts• Base Pairing – Complements• Hydrogen bonding• Purines/Pyrimidines• Enzymes & Replication• Shape of DNA• “Backbone” of DNA
Ok…….So what is DNA good for?
• DNA has 2 major functions in our body:
1. Make more DNA
2. Make Protein
The Library• Library - • Book/Original recipe -
– • Librarian• Transcribed recipe• Chef (Who takes the recipe & puts it together?)• Runner/Person who delivers ingredients to the chef• Ingredients• Final product
Assignment after QuizDue Tuesday
• Read pages 235-241
• Describe the RNA molecule• Describe the process of transcription & list the
molecules involved (2)• Describe the process of translation and list the molecules
involved• On what molecule is a codon found?• On what molecule is an anti-codon found? What else is
found on this molecule?
Now its your turn!• Pyrimidines
• Purines
• Pairing Rules & Bonds
Write in the complimentary bases and connect them with the appropriate number of hydrogen bonds
Now its your turn! • Pyrimidines
• Purines
• Pairing Rules & Bonds
Write in the complimentary bases and connect them with the appropriate number of hydrogen bonds
Now its your turn! – Answer Key• Pyrimidines
• Purines
• Pairing Rules & Bonds
Write in the complimentary bases and connect them with the appropriate number of hydrogen bonds
Question of the Day
• What are the 3 major components of a nucleotide?
• Draw one if you can, and label the parts.
• Which piece is variable (changes from nucleotide to nucleotide?
DNA Nucleotide – a nucleotide is the three component parts together
PhosphateGroup N
Nitrogenous base(A, G, C, or T)
Sugar(deoxyribose)
Question of the Day• Write down the
following base pair sequence, and its complementary strand (the strand that pairs with it)
• How many base pairs are there?
• How many nucleotides?
Goals for Today• Be able to describe how DNA & RNA molecules
differ from each other.
• Be able to name and describe the two major steps of protein synthesis (how proteins are made)
• Be able to list the molecules & structures involved in Transcription & Translation.
Question of the Day• What do we know about the structure of DNA?
Protein Synthesis
• The first step in protein synthesis involves DNA & a very similar molecule, RNA that is also made of nucleotides.
• Before we talk about the individual steps in making proteins, lets compare DNA & RNA
DNA vs. RNADNA & RNA differ from each other in several important ways. See if you can fill in this chart for the DNA side of things: DNA RNA
Full Name
Sugar in NucleotideNitrogen
Bases
# of Strands
Compliments
RNA Nucleotide – a nucleotide is the three component parts together
PhosphateGroup N
Nitrogenous base(A, G, C, or )
Sugar( )
RNA – Ribonucleic Acid
RNA is like DNA except…
- it is single stranded
- it has uracil instead of thymine
- it has ribose instead of deoxyribose
Nitrogen Bases
Sugars&
Phosphates
RNA DNA
DNA or RNA?
DNA or RNA?• It is DNA because there are “T”s in it for
Thymine
DNA…. what is good for?
• DNA has 2 major functions in our body:
1. Make more DNA
2. Make Protein
DNA holds the directions for protein synthesis
Protein synthesis -making proteins
Gene section of DNA that carries the code for making one protein
Protein Synthesis• Gene section of DNA that carries the code
for making 1 protein
• There are thousands of genes on each chromosome.
• Everything in your body is made of AND by proteins! Ex. Enzymes are proteins!
Steps of Protein SynthesisThe first step of Protein Synthesis is known as Transcription
1.DNA is transcribed into messenger RNA (mRNA) by an enzyme known as:
RNA polymerase, which builds an RNA strand that is complimentary to the DNA strand.
Transcription RNA polymerase, which builds an RNA
strand that is complimentary to the DNA strand.
Steps of Protein Synthesis
• If DNA is what is being transcribed, then what part of the EUKARYOTIC cell would this occur in?
• Transcription occurs in the _____________
Transcription – Practice! RNA polymerase, which builds an RNA strand
that is complimentary to the DNA strand.
Messenger RNA - mRNAThe message of mRNA is carried in
“codons”
A codon is a three base sequence that will code for an Amino Acid (the building block of a proteins.
Together the codons in the mRNA strand code for 1 protein, typically hundreds or thousands of Amino Acids
Transcription• Try to pick out the molecules: RNA Polymerase, mRNA, Nucleotides, & DNA
Goals for Today• Be able to describe how DNA & RNA
molecules differ from each other.
• Be able to name and describe the two major steps of protein synthesis (how proteins are made)
• Be able to list the molecules & structures involved in Transcription & Translation.
Question of the Day
• What process makes an mRNA molecule?
• What is needed to produce it?
• What sets mRNA apart from DNA?
Steps of Protein Synthesis
1. DNA is transcribed into messenger RNA (mRNA) by an enzyme known as:
RNA polymerase, which builds an RNA strand that is complimentary to the DNA strand.
Transcription Assignment
Steps of Protein Synthesis• The next major process in protein synthesis
is known as “translation” in this process mRNA is translated into protein.
2. Before translation can happen mRNA must move out of the nucleus ( in ______ organisms) and into the cytoplasm.
Practice Transcription
Messenger RNA - mRNADNA’s “recipes” are transcribed by the
enzyme ____ ____________ to make a molecule of mRNA.
mRNA is like a different language then DNAmRNA is the language that the ribosome -
(protein building machine) can read.
Steps of Protein Synthesis• The next step of Protein Synthesis is
TRANSLATION
3. Once the mRNA strand leaves the nucleus and enters the cytoplasm the mRNA Attaches to a ribosome (our cell’s protein making machine)
Steps of Protein Synthesis
3. Once the mRNA strand leaves the nucleus and enters the cytoplasm the mRNA Attaches to a ribosome (our cell’s protein making machine)
4. Next a molecule of Transfer RNA (tRNA) attaches to the mRNA strand
Anatomy of a Transfer “t” RNA (tRNA)
Steps of Protein Synthesis
4. Next a molecule of Transfer RNA (tRNA) attaches to the mRNA strand
Steps of Protein Synthesis4. Next a molecule of Transfer RNA (tRNA)
attaches to the mRNA strand
5. Amino acids are linked together by the ribosome to form the final protein (which is really just a long chain of amino acids)
Protein Synthesis
Lets put it all together!
Create the mRNA, tRNA and find the Amino Acid coded for on mRNA
Goals for Today• Be able to describe how DNA & RNA
molecules differ from each other.
• Be able to name and describe the two major steps of protein synthesis (how proteins are made)
• Be able to list the molecules & structures involved in Transcription & Translation.
Question of the Day
• Draw a molecule of tRNA below and label the parts of the tRNA
• What does the “t” stand for?
Translation
Create the mRNA, tRNA and find the Amino Acid coded for on mRNA
Goals for Today• Demonstrate that we are able to describe
how DNA & RNA molecules differ from each other.
• Demonstrate that we are able to name and describe the two major steps of protein synthesis (how proteins are made)
• Demonstrate that we are able to list the molecules & structures involved in Transcription & Translation.
Question of the Day
• Which molecule has the “Codon” and which has the “anticodon”
• Codon =
• Anticodon =
• What do you look at in the decoder to find the amino acid? (the codon or anticodon?)
DNA or RNA?
DNA or RNA?• It is DNA because is Double Stranded
DNA or RNA?
DNA or RNA?• It is RNA because there are “U”s in it for
Uracil
Skills Check Friday• Scientists & Contributions• Differences between RNA & DNA (table)• Nucleotide parts/labeling• Steps/Stages in Protein Synthesis• DNA mRNA tRNA Amino Acid
Protein Synthesis Practice
Goals for Today• Demonstrate that we are able to describe
how DNA & RNA molecules differ from each other.
• Demonstrate that we are able to name and describe the two major steps of protein synthesis (how proteins are made)
• Demonstrate that we are able to list the molecules & structures involved in Transcription & Translation.
Question of the Day
• What is an Amino Acid?
• Which molecule brings the Amino Acid to the Ribosome?
Skills Check Today• Scientists & Contributions• Differences between RNA & DNA (table)• Nucleotide parts/labeling• Steps/Stages in Protein Synthesis• DNA mRNA tRNA Amino Acid
Goals for Today• Know all of the stages of Protein Synthesis
– Be able to describe how DNA & RNA molecules differ from each other.
– Be able to describe name and describe the two major steps of protein synthesis (how proteins are made)
– Be able to describe list the molecules & structures involved in Transcription & Translation.
Question of the Day
• What are you still struggling with in Protein Synthesis?
Skills Check corrections
• Re-write entire question and then have the correct answer.
Skills Check Today• Scientists & Contributions• Differences between RNA & DNA (table)• Nucleotide parts/labeling• Steps/Stages in Protein Synthesis• DNA mRNA tRNA Amino Acid
Goals for Today• Be prepared for our test TOMORROW
Question of the Day
• What is a gene?
• What molecule is it found on?
Goals for Today• Demonstrate What we know about:
–DNA & RNA–DNA replication–Protein Synthesis
Question of the Day
• What are the two functions of DNA?
After the test answer the following:A. What do I Know/have heard aboutB. What do I want to know what questions do I have
1. DNA Fingerprinting2. Cloning3. Genetically modified organisms (GMOs)4. Mutations5. Mutagens (things that cause mutation)6. Glance through pages 266-280 and write
down questions or things that peak your interest
Goals for Today
• Learn all of DNA & Protein Synthesis–Complete test corrections
• Have some fun!
Question of the Day
• What does the discovery to the structure of DNA tell us about the PROCESS of science?