HOMEWORK REVIEW

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– DUE FEBRUARY 23rd

How DNA is Used by the Cell

THE FUNDAMENTAL RELATIONSHIPTHE FUNDAMENTAL RELATIONSHIP

Chromosome Gene Message Product

(DNA) (mRNA) (protein)

DNADNAThe Molecular The Molecular Basis of LifeBasis of Life

GENETIC CODEGENETIC CODE

the program for the cellthe program for the cell

DNADNA(de-oxy-ribo-nucleic acid)(de-oxy-ribo-nucleic acid)

a nucleic acid that stores a nucleic acid that stores and transmits the genetic and transmits the genetic

information from one information from one generation to the nextgeneration to the next

aka…. aka…. DNADNA is the mackdaddy is the mackdaddy without DNA we without DNA we

would have no way to would have no way to store genetic store genetic information!!!information!!!

The Quest The Quest for the Structurefor the Structure

of DNAof DNA

Big Players in DNABig Players in DNAChargaffChargaffRosalind FranklinRosalind FranklinWatson and CrickWatson and Crick

People knew that DNA People knew that DNA was made up of:was made up of:

Adenine (A)Adenine (A)Guanine (G)Guanine (G)Cytosine (C)Cytosine (C)Thymine (T)Thymine (T)

Erwin Chargaff• Discovered that in any

sample of DNA, the amount of A equals the amount of T and the amount of C equals the amount of G.

• This suggested that A binds with T and that C binds with G.

Rosalind Franklin’sX-Ray Crystallography

• Took x-ray photographs of crystallized DNA

• Discovered that the shape of DNA must be a helix, because of the x-ray pattern

• Died of cancer

(too many x-rays?)

An example of X-Ray Crystallography

Watson and Crick• Credited for

discovering the structure of DNA in 1953

• Used Chargaff and Franklin’s discoveries along with toy models to discover the structure

A 3-D Model of DNA

What Shape is this called…

Double Helix!!!

NUCLEOTIDESNUCLEOTIDESMade up of:Made up of:A phosphate group (P,O)A phosphate group (P,O)5 carbon sugar5 carbon sugarNitrogenous BaseNitrogenous Base

(either A,T,G,C)(either A,T,G,C)

The deoxyribose sugar and phosphate group are identical in all DNA nucleotides… nitrogenous bases differ

PURINESPURINESAdenine (A)Adenine (A)Guanine (G)Guanine (G)

PYRIMIDINESPYRIMIDINESCytosine (C)Cytosine (C)Thymine (T)Thymine (T)

Base Pairing Base Pairing in DNAin DNA

A-T A-T

C-GC-G

Adenine Nucleotide

Cytosine Nucleotide

Guanine Nucleotide

Here’s What a Nucleotide Looks LikeHere’s What a Nucleotide Looks Like

Write the complementary DNA strand for each of these DNA strands:

DNA• GAATTACA• CCAATTAG• ATAGACAG• CCAGTACA

DNA• CTTAATGT• GGTTAATC• TATCTGTC• GGTCATGT

Each of the 96 columns represents one DNA Each of the 96 columns represents one DNA sequence. A different colored dye attached to sequence. A different colored dye attached to

each of the four nucleotides.each of the four nucleotides.

ReplicationReplication

The act of making The act of making an exact copy of an exact copy of

DNADNA

Semi-Conservative Semi-Conservative ReplicationReplication

Each strand of the Each strand of the original molecule acts as original molecule acts as

a template for the a template for the synthesis of a new synthesis of a new

complementary DNA complementary DNA moleculemolecule

Do Not Copy!!!

With semi-conservative

replication, each new strand is ½ new and ½

old

Examples of DNA Examples of DNA ReplicationReplication

HelicaseHelicase is is an enzyme an enzyme that unzips that unzips the DNA the DNA moleculemolecule

WHAT DO WE KNOW NOWWHAT DO WE KNOW NOW We know how DNA COPIES ITSELFWe know how DNA COPIES ITSELF Why is this important?Why is this important?

Dolly 5 July 1996 14 February 2003

RNARNA(ribo-nucleic acid)(ribo-nucleic acid)

a nucleic acid that is a a nucleic acid that is a messenger between messenger between

DNA and the DNA and the ribosomesribosomes

Differences between DNA and Differences between DNA and RNARNA

1.1. Different sugars Different sugars (DNA=deoxyribose)(DNA=deoxyribose)(RNA=ribose)(RNA=ribose)

2.2. RNA is single stranded (1 side)RNA is single stranded (1 side)DNA is double stranded (2sides)DNA is double stranded (2sides)

3.3. RNA has “U” (uracil)RNA has “U” (uracil)DNA has “T” (thymine)DNA has “T” (thymine)

Always remember…Always remember…

RNARNAlovesloves

UU

Write the RNA strand for Write the RNA strand for each of these DNA strands:each of these DNA strands:

½ Strand of DNA

• GAATTACA• CCAATTAG• ATAGACAG• CCAGTACA

RNA

• CUUAAUGU• GGUUAAUC• UAUCUGUC• GGUCAUGU

TranscriptionTranscription

The process by The process by which DNA is which DNA is

copied into mRNAcopied into mRNA

mRNAmRNAMessenger RNA, is the Messenger RNA, is the copy of the DNA that copy of the DNA that

goes from the nucleus goes from the nucleus to the ribosome…. to the ribosome….

TranslationTranslation

The decoding of a The decoding of a mRNA message mRNA message

into proteins into proteins

Transcription vs Translation

• DNA goes to mRNA (messenger RNA)

• Takes place in nucleus

• Messenger RNA is read in the cytoplasm and proteins are made

• Done in the cytoplasm not the nucleus

Explain to your parents in the form of a Explain to your parents in the form of a letter letter with pictureswith pictures how DNA replicates how DNA replicates itself, the process of transcription, and the itself, the process of transcription, and the process of translationprocess of translation

Make sure that your parents can Make sure that your parents can understand what you write and use proper understand what you write and use proper EnglishEnglish

Graded for Classwork GradeGraded for Classwork Grade Rubric: Daily Assignments Section 5 pointsRubric: Daily Assignments Section 5 points

5 = at least 5 sentences with pictures of each 5 = at least 5 sentences with pictures of each processprocess

3 = middle of the road job with not much effort3 = middle of the road job with not much effort 0 = did not do assignment0 = did not do assignment

FACTFACTProteins are Proteins are made up of made up of amino acidsamino acids

tRNAtRNATransfer RNA, Transfer RNA,

matches up with matches up with mRNA and has an mRNA and has an amino acid on its amino acid on its

toptop

CODONCODONEach combination Each combination of 3 nucleotides on of 3 nucleotides on a strand of mRNAa strand of mRNA

ANTICODONANTICODON

Each Each combination of 3 combination of 3 nucleotides on a nucleotides on a

tRNAtRNA

Why is base pairing important?Why is base pairing important?

I WAS MADONNAI WAS MADONNAI SAW MADONNAI SAW MADONNA

JUST A FLIP OF ONE JUST A FLIP OF ONE LETTER!!!!!!!LETTER!!!!!!!

Why did Mr. Gibney make you Why did Mr. Gibney make you do this?.... Is he just whack??do this?.... Is he just whack??

Where is the Mona Lisa?Where is the Mona Lisa? In the In the LouvreLouvre

In France

Mona Lisa = DNAMona Lisa = DNALouvre = Louvre = NucleusNucleusSketch of Painting = mRNASketch of Painting = mRNACopy on outside = Protein Copy on outside = Protein

AssemblyAssembly100% Hot Class

Table of Codons

1. What did Willerslev find? Why do you think this is important?

2. How do the scientists think the DNA got into the soil?

3. Do you think we can re-create species from Animal Poop?

4. Think about the last 3 weeks in class and describe to me how important DNA is.

Jurassic Park Movie StyleJurassic Park Movie Style 1. Find and collect amber. Amber is tree sap that has hardened 1. Find and collect amber. Amber is tree sap that has hardened

and fossilized also preserving insects inside of it. and fossilized also preserving insects inside of it. 2. Take out the mosquito from the amber and extract red blood 2. Take out the mosquito from the amber and extract red blood

cells from its gut (Mosquitos suck blood out of organisms... cells from its gut (Mosquitos suck blood out of organisms... such as... DINOSAURS). such as... DINOSAURS).

3. Extract 3. Extract DNADNA from the blood cells. from the blood cells. 4. Sequence the 4. Sequence the DNADNA to create a complete strand of to create a complete strand of DNADNA.. 5. Fill in any gaps in the 5. Fill in any gaps in the DNADNA by by splicingsplicing frog frog DNADNA with the with the

dinosaur dinosaur DNADNA.. 6. Insert this 6. Insert this DNADNA into crocodile ova and create an embryo. into crocodile ova and create an embryo. 7. Put the embryo inside of special plastic eggs with large yolk 7. Put the embryo inside of special plastic eggs with large yolk

sacs and little water.sacs and little water. 8. Incubate the eggs in an environment with 100% humidity 8. Incubate the eggs in an environment with 100% humidity

and a temperature of 99 °F.and a temperature of 99 °F. 9. Allow eggs to hatch naturally and for baby dinosaurs to 9. Allow eggs to hatch naturally and for baby dinosaurs to

grow. grow.

Jurassic Park: True or Jurassic Park: True or Not?Not?

1. Dinosaur 1. Dinosaur DNADNA is difficult to obtain and to sequence. Although ancient is difficult to obtain and to sequence. Although ancient dinosaur dinosaur DNADNA has been found, the has been found, the DNA DNA is broken apart and must be sequenced. is broken apart and must be sequenced. This process is a little difficult because there is not a complete strand of This process is a little difficult because there is not a complete strand of dinosaur DNA anywhere to copy. We can't simply make it complete, we have to dinosaur DNA anywhere to copy. We can't simply make it complete, we have to make sure that every base pair is in the correct place. make sure that every base pair is in the correct place.

2. Even if we have the DNA sequenced, there will be some gaps that must be 2. Even if we have the DNA sequenced, there will be some gaps that must be filled. Unlike in the movie, these gaps can't be filled by splicing frog DNA. filled. Unlike in the movie, these gaps can't be filled by splicing frog DNA. Dinosaur DNA must be used to fill in the gaps in the DNA. However, we don't Dinosaur DNA must be used to fill in the gaps in the DNA. However, we don't have the DNA to do this either. Also, splicing in frog DNA, will not create a have the DNA to do this either. Also, splicing in frog DNA, will not create a dinosaur, it would create a mutant or a frog/dinosaur type organism. dinosaur, it would create a mutant or a frog/dinosaur type organism.

3. Once the DNA is sequenced and complete, it must be inserted into an oocyte 3. Once the DNA is sequenced and complete, it must be inserted into an oocyte so that it can be cloned. The oocyte must come from the same organism that is so that it can be cloned. The oocyte must come from the same organism that is being cloned (in our case this would be a dinosaur), and since no dinosaurs are being cloned (in our case this would be a dinosaur), and since no dinosaurs are alive today, this would be impossible. It wouldn't work to insert the DNA into alive today, this would be impossible. It wouldn't work to insert the DNA into crocodile ova because crocodile ova is specialized for crocodiles, not dinosaurs. crocodile ova because crocodile ova is specialized for crocodiles, not dinosaurs.

4. Even if crocodile ova could hold dinosaur DNA, a problem still arises with the 4. Even if crocodile ova could hold dinosaur DNA, a problem still arises with the development of the dinosaur embryo. Dinosaurs were born through eggs, so we development of the dinosaur embryo. Dinosaurs were born through eggs, so we simply can't put them inside of an organism. We must put them in eggs. In the simply can't put them inside of an organism. We must put them in eggs. In the movie, the scientist created plastic eggs. However, this would not work because movie, the scientist created plastic eggs. However, this would not work because every organism must have a specialized egg. A turtle's egg will not have the every organism must have a specialized egg. A turtle's egg will not have the nutrients necessary for a fish, nor would a fish have the nutrients necessary for nutrients necessary for a fish, nor would a fish have the nutrients necessary for a turtle. Every organism must have its own special egg to nourish its young. a turtle. Every organism must have its own special egg to nourish its young.