GETTING TO KNOW DNA

WHAT DO YOU ALREADY KNOW?

PART 1: KNOWING YOUR NUCLEOTIDES

DNA is the code that makes you who you are.

The code has ONLY 4 LETTERS!!!

A = Adenine T = Thymine C = Cytosine G = Guanine

PART 1: KNOWING YOUR NUCLEOTIDES

A, T, C, & G are nucleotides.

Nucleotides: The building blocks of DNA that match up to form the double helix shape

A + T bond C + G bond

PART 1: KNOWING YOUR NUCLEOTIDES Nucleotides all have the

same general structure.

1. Phosphate Group is the backbone

2. Sugar is the link

3. Nitrogen Base is the code: A, T, C, G

The green base can change, but yellow and pink stay the same

PART 1: KNOWING YOUR NUCLEOTIDES DNA is the code to

make RNA. RNA is the code to

make proteins! RNA replaces the

deoxyribose sugar link of DNA with just a ribose sugar link

RNA also replaces the T nucleotide for a U

U = Uracil A + U bonds

DNA HISTORY: ERWIN CHARGAFF (1950)

Erwin did the experiments to prove that A matches with T and that C matches with G in a 1 to 1 ratio.

DNA HISTORY: ROSALIND FRANKLIN (1951)

Rosalind took the first clear photo of DNA

DNA HISTORY: MARTHA CHASE & ALFRED HERSHEY (1952)

First to absolutely prove that DNA is the molecule that is the code for all genes

CURRENT APPLICATION: (JUST FOR FUN)

DNA HISTORY: FRANCIS CRICK & JAMES WATSON (1953)

Determined the “double-helix” shape of DNA from Rosalind’s photo.

Some say Rosalind got it first!

CHECK FOR UNDERSTANDING

1. What is a NUCLEOTIDE?2. What are the 3 parts of a nucleotide?3. Which nucleotide bonds with “A”?4. Which nucleotide bonds with “C”?5. Which nucleotide is replaced with

“U” for RNA?6. Which nucleotide bonds with “U”?

PART 2: DNA REPLICATION

We need to pass on our genes to new cells (by Mitosis) and to our offspring (by Meiosis).

DNA Replication is the process by which perfect copies of our DNA are made!

PART 2: DNA REPLICATION

Think of DNA as a zipper, two sides that are held together by matching base pairs.

The enzyme helicase unwinds the helix and forces the zipper to open!

The Chainsaw!!!

PART 2: DNA REPLICATION

Opening the DNA causes “bubbles” to form

Replication can only happen when these single strands of DNA are exposed!

PART 2: DNA REPLICATION

Replication is “semi-conservative” because the original (parent) strands stay the same, while new matching (daughter) strands are added on.

PART 2: DNA REPLICATION The nucleus is

filled with a pool of extra nucleotides, waiting to make new DNA.

DNA Polymerase is like a train that rides along the rail of DNA and attaches matching base pairs.

CHECK FOR UNDERSTANDING

1. Why do the DNA strands need to be “unzipped” before they can be copied?

2. What is “semi-conservative” DNA replication?

3. In replication, parents strands are matched with new nucleotides to make a _________ strand.

CHECK FOR UNDERSTANDING

FIND THE MATCH!

C

G

A

T

PART 3: PROTEIN SYNTHESIS

Transcription: A process where a section of DNA code is copied into its matching RNA code.

Makes “messenger” mRNA

PART 3: PROTEIN SYNTHESIS

mRNA leaves the nucleus to find a ribosome in the cytoplasm.

PART 3: PROTEIN SYNTHESIS Translation: The

process of decoding the mRNA code

Every 3 letter code of mRNA (codon) = amino acid

Transfer RNA bring amino acids to match the codes of mRNA

Amino acids build the protein

PART 3: PROTEIN SYNTHESIS mRNA codes

for 20 different amino acids that have almost infinite combinations for making needed proteins.

AAA F CAA V GAA L UAA I

AAC L CAC V GAC L UAC M

AAG F CAG V GAG L UAG I

AAU L CAU V GAU L UAU I

ACA C CCA G GCA R UCA S

ACC W CCC G GCC R UCC R

ACG C CCG G GCG R UCG S

ACU - CCU G GCU R UCU R

AGA S CGA A GGA P UGA T

AGC S CGC A GGC P UGC T

AGG S CGG A GGG P UGG T

AGU S CGU A GGU P UGU T

AUA Y CUA D GUA H UUA N

AUC - CUC E GUC Q UUC K

AUG Y CUG D GUG H UUG N

AUU - CUU E GUU Q UUU K

COMPARING TO BUILDING A BUILDING

Architect's Office = Nucleus

The Master Plan by the architect = DNA

The location of the land to build the building = cytoplasm

The Blue Prints that communicate the Master Plan = mRNA

COMPARING TO BUILDING A BUILDING

The Supervisor at the site of construction = Ribosome

The concrete and lumber to build the building = amino acids

The trucks to bring the lumber = tRNA

The finished building = Complete Protein

CHECK FOR UNDERSTANDING

Now let’s compare building a protein to making a song.

The completed song = the completed protein

1. What is the recording studio?

2. What is the tape player?

3. What are the musical notes?