Quote / DNA “ “The secret of living in

peace with all people lies in the art of understanding each one by his own individuality.”

“Cherish forever what makes you unique, 'cuz you're really a yawn if it goes.”

What do the quotes mean?

What do you know about DNA? Tell me as much as you can.

DNA

3/10/14 Myriad Genetics Patent

What are the two main points of view regarding this controversy?

What is your position on this issue and why?

3/10/14 Bellringer: Myriad Genetics Patent

Agenda: St. Baldrick’s DNA Pre-knowledge DNA Notes Go over Genetics Exam

NO HOMEWORK!

DNA Pre-knowledge What do you definitely know about DNA?

What do you think you know about DNA?

DNA DNA (Deoxyribonucleic Acid) is a long, thin

molecule that stores genetic information Two DNA strands are bound together and then

are twisted into the Double Helix. 1952: X-rays were passed through DNA

crystals, giving an idea of their shape. (Maurice Wilkins and Rosalind Franklin)

1953: James Watson and Francis Crick used models to discover DNA’s structure

Nucleotides DNA is made of Nucleotides joined together

in long chains.

1 Nucleotide is made of

1. 1 phosphate

2. 1 sugar molecule (deoxyribose)

3. 1 nitrogen base

One nucleotide:

Phosphate

Deoxyribose Sugar (5 –carbons)

Nitrogen Base

3/11 DNA

1) Define DNA

2) What is a nucleotide made of?

3) (9th period only)

What are the four nitrogenous bases? What two sub groups do we put them in?

3/11/14 Bellringer: DNA Objective: To discuss DNA replication Agenda:

Notes on DNA replication DNA replication Demo Begin DNA homework

Homework: DNA WS due tomorrow

Nitrogen Bases

There are four nitrogen bases: Adenine (A) Thymine (T) Guanine (G) Cytosine (C) Nitrogen Bases are either purines or

pyrimidines Purines (A, G) have 2 rings of carbon and

nitrogen Pyrimidines (T, C) have only 1 ring

DNA Structure To make one DNA strand,

nucleotides bond together (dehydration synthesis)

The phosphate group of one nucleotide attaches to the sugar of another creating a phosphate-sugar “backbone”

DNA Structure Hydrogen Bonds

between the nitrogen bases hold DNA strands together

Adenine bonds to Thymine (Apple Tree)

Guanine bonds to Cytosine (Good Catch)

What is similar/different of these DNA strands?

No matter what kind of thing it is, if it is a living thing, it has DNA The only thing that makes living things different is the order that the nitrogen

bases/nucleotides are in You and a rose bush have the same kind of DNA, but your nucleotides are

in a different order

Complimentary Base Pairing Because A bonds to T, and G bonds to C, you

can deduce the second strand of DNA if you know the sequence of the first strand.

These pairs are called Complimentary Base Pairs

DNA is often abbreviated like this:-A T--G C--T A--G C--C G--C G-

Complementary DNA strands run in opposite directions (antiparalell)

DNA Replication Before a cell can divide in two to make

daughter cells, first the cell’s DNA must copy itself

This process is called replication DNA replication is semiconservative

Each of the daughter molecules has one old strand and one new strand

Steps of Replication

1. DNA Helicases are enzymes that unwind the DNA and break the hydrogen bonds between strands.

Now the DNA has a “Y” shape (replication fork) These replication forks appear at many places

along the length of the DNA molecule. This speeds up replication.

2. At the replication fork, enzymes called DNA polymerases add new nucleotides to the single strands of DNA

Replication ForkReplication Fork

DNA Replication

DNA Polymerase

Steps of Replication, cont’d

3. Sometimes a wrong nucleotide is added, so DNA polymerases also PROOFREAD the DNA molecule and remove incorrect nucleotides.

Usually this keeps errors down to about 1 per 1 billion nucleotides

Skip….Bellringer What are the characteristics of a good

purpose? What are the characteristics of a good

hypothesis? What formatting applies?

Skip…Agenda Objective: To finish the lab Agenda:

Bellringer/Discussion Go over rubric for lab Finish lab

Homework: Lit review due Friday Lab due Tuesday

3/12/14 Transcription

Tell me what this says: Beggieggoleggogy eggis thegge beggest

seggubjeggect eggaveggaeggileggablegge eggat Legginceggoln Peggark Heggigh Scheggoeggol!!!

Define gene Do you know what it means to transcribe

something?

3/12/14 Objective: To learn transcription Agenda:

Bellringer: Transcription Notes Grade DNA WS Start RNA WS

Homework: RNA WS and Model due tomorrow

Genes Genes: Sequences of DNA that code for a specific

protein The human genome contains ~30,000 genes

Some sequences on a strand of DNA do not actually code for anything

Introns: are the intervening sequences, and are “blank” Exons: are the sequences that code for proteins, and

are “expressed” Enzymes cut out the introns when proteins are made

Different genes are activated in different cells, creating the proteins that give a particular cell type its characteristics.

Central Dogma Central Dogma: The

process of using DNA to make RNA, and RNA to make proteins!

Transcription: The info from the DNA sequence is rewritten as messenger RNA.

Translation: The mRNA code is used to build a protein from amino acids at a ribosome.

Why do we need RNA/Transcription?

Proteins are built by ribosomes in the cytoplasm.

DNA must remain in the nucleus.

Messenger RNA is necessary to bring the DNA’s information out of the nucleus

RNA/DNA Difference RNA is a single strand RNA has a ribose sugar, not a deoxyribose RNA has Uracil instead of Thymine

Steps of Transcription

1. Initiation: RNA polymerase recognizes a starting area on the DNA (the promotor sequence), then they unwind and unzip the DNA

2. Elongation: RNA polymerase adds RNA nucleotides in a complementary fashion to the DNA strand

3. Termination: The mRNA detaches at the terminator sequence and moves out of the nucleus to the cytoplasm through a nuclear pore

3/13/14 Translation

What do these phrases mean?

1) “Sup dawg? Im finna cut Bio today, cause YOLO. #swag, #lphsproblems. ”

2) “-- .-. .--- .. … .-. .- -..”

3) How are the processes o reading these two different

4) Define translation

Agenda Objective: To introduce and discuss

translation Agenda:

Bellringer: Translation Translation Notes Grade RNA WS

Homework: Translation WS Quiz Tomorrow (Everything since Monday)

Translation Translation: The process

of using mRNA to assemble a sequence of amino acids into a protein

Occurs in the ribosome

The P and A sites are where tRNA molecules bind and bring amino acids to the ribosome.

mRNA slides through here

Translation mRNA is read by the

ribosome 3 nucleotides at a time

Codon: 3 mRNA nucleotides that code for a specific amino acid

The Genetic Code Genetic Code: The genetic code is all the

amino acids that are coded for by the various codons

The genetic code is universal Example: GUC codes for Valine (Val) in humans,

eagles, dogs, and in bacteria This is important because if we all have the

same genetic code, then it is possible that we all have the same ancestor

Translation uses tRNA tRNA is a clover shaped strand of RNA When mRNA runs through the ribosome, the tRNA is

what brings the codon-matching amino acid to the ribosome

tRNA has a anti-codon that compliments the codon it links to

Fig. 17.13

tRNA

Steps of Translation

1. mRNA binds to a ribosome2. A ‘start’ codon (AUG) on mRNA signals the

start of protein synthesis3. Free-floating amino acids are picked up by

tRNA and taken to the ribosome4. The anticodon of tRNA lines up with the

complementary codon of mRNA5. As new tRNA molecules arrive, the ribosome

holds them in place

Cont’d

6. Peptide bonds form between the amino acids on top of adjacent tRNA molecules

A polypeptide chain is formed, linked by peptide bonds

7. This is repeated until a ‘stop codon’ is reached, and the protein is released into the cell

Bellringer Define Replication Define Transcription Define Translation

Agenda Objective: To go over the steps of translation Agenda:

Bellringer/Discussion Notes Quiz

Homework: Translation WS due tomorrow

Bellringer Look at the lab on your desk.

Hypothesize what the salt is for? Hypothesize what the soap for?

Bellringer How would you define the

word “mutant”? What causes mutations in

DNA? If I were to mutate two

nucleotides in your DNA, what would that actually do?

Would it be possible to get “powers” from mutations?

Agenda Objective: To discuss mutation Agenda:

Bellringer/Discussion Notes Grade Translation WS Go over tomorrow’s lab

Homework: N/A

Mutations Any change in the nucleotide sequence of DNA Errors can occur during DNA replication, DNA

repair, DNA recombination or by mutagen This leads to a misreading of the mRNA, which

may cause a non-functioning protein to be produced, or even cell death Can involve large regions of a chromosome or a

single base pair Can cause many genetic diseases, such as sickle-

cell disease

Single Base-Pair DNA Mutations

Substitutions: Replaces one base with another Most are harmful, some are neutral, and a few

lead to advantages through natural selection

Insertion: An excess base is inserted

Deletion: A base is accidentally deleted Insertion and deletion mainly result in a non-

functioning protein

Mutation Types

Mutations may lead to change in amino acid sequence

Missense mutation: Amino acid is still produced, but is the wrong one

Nonsense mutation: Alteration in DNA changes a codon to a stop codon

Frameshift mutation: Caused by insertion or deletion that improperly groups codons

LE 10-16bLE 10-16bNormal gene

Base substitution

Protein

mRNA

Base deletion Missing

Met

Met

Met Lys

Lys

Lys Phe Gly Ala

AlaPhe

Ala

Ser

Leu His

A

A A A A

A A A

A

AAAAA U U U U

UUUU

U U U U G G GGG

G G G G

C C

C C

G G G G G CC

U

Mutagens

Are chemical or physical agents that interact with DNA to cause mutations

Physical agents include high-energy radiation like X-rays and ultraviolet light

Chemical agents include carcinogens (cancer causing)

Bellringer Define Gene Define Genotype Define Phenotype How are those terms related?

Bellringer: NO NOTES Describe the steps of DNA replication Describe the steps of RNA transcription Describe the steps of Protein Translation