DNA, Replication, Protein Synthesis

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)



• Be able to discuss how scientific understanding is built

• Be able to list or understand the contributions of less known scientists


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




• 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.


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


Sugar(deoxyribose)

Goals for Today

• Be able to describe the process and enzymes involved in DNA replication.



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!



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?

http://www.youtube.com/watch?v=bee6PWUgPo8

DNA REPLICATION

Anti-parallel

Goals for Today

• Be able to describe the process and enzymes involved in DNA replication.



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?


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



Now its your turn! – Answer Key• Pyrimidines

• Purines



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?


PhosphateGroup N


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



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.



Question of the Day

• What process makes an mRNA molecule?

• What is needed to produce it?

• What sets mRNA apart from DNA?


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)


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)

Anatomy of a (tRNA)

http://www.google.com/url?sa=i&rct=j&q=trna&source=images&cd=&cad=rja&docid=96AN04I2YX4YOM&tbnid=MlY2VHxNym-zIM:&ved=0CAUQjRw&url=https%3A%2F%2Fwikispaces.psu.edu%2Fpages%2Fviewpage.action%3FpageId%3D112526684%26navigatingVersions%3Dtrue&ei=I94sUYOJGMmZqAG7nIHQCQ&bvm=bv.42965579,d.aWc&psig=AFQjCNFVUJiCqNiZCpwXu-9DSqKEKMr6GQ&ust=1361981251037183


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)

Translation

• Real Time Animation

https://www.youtube.com/watch?v=kbB2kMkmb0w

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.



Question of the Day

• Draw a molecule of tRNA below and label the parts of the tRNA

• What does the “t” stand for?

Anatomy of a (tRNA)

http://www.google.com/url?sa=i&rct=j&q=trna&source=images&cd=&cad=rja&docid=96AN04I2YX4YOM&tbnid=MlY2VHxNym-zIM:&ved=0CAUQjRw&url=https%3A%2F%2Fwikispaces.psu.edu%2Fpages%2Fviewpage.action%3FpageId%3D112526684%26navigatingVersions%3Dtrue&ei=I94sUYOJGMmZqAG7nIHQCQ&bvm=bv.42965579,d.aWc&psig=AFQjCNFVUJiCqNiZCpwXu-9DSqKEKMr6GQ&ust=1361981251037183

Translation

Create the mRNA, tRNA and find the Amino Acid coded for on mRNA

Translation

• Real Time Animation

https://www.youtube.com/watch?v=kbB2kMkmb0w

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?

Documents

DNA, Replication, Protein Synthesis