DNA--The Blueprint of Life DEOXYRIBONUCLEIC ACID “The Twisted Ladder” “The Double Helix”

DNADNA--The Blueprint of Life--The Blueprint of Life

DEOXYRIBONUCLEIC ACID

““The Twisted Ladder”

The Twisted Ladder”

““The Double Helix”

The Double Helix”

The Genetic Code

• Genetic - relates to heredity• Heredity - The passing of traits from

the parents to their young.• Traits - Characteristic that a living

thing can pass on to its young, (eye color)

• Characteristic - A description of a trait , (blue eyes)

The Genetic Code

• Genetic code - is the store information that is passed from one generation to the next.

• Transformation - the exchange of genetic information between 2 different (but similar) organisms.

The Genetic Code

• Transforming Factor - A scientist named Avery discovered through experimentation that DNA is the molecule responsible for transformation .

The Structure of DNA

• Nucleotide - The base unit of structure to form the DNA molecule

• Three basic parts of a nucleotide– 1. Deoxyribose - a sugar made of 5

carbon atoms– 2. Phosphate group– 3. Nitrogenous, or nitrogen base

The Structure of DNA

• Nitrogenous Bases– PURINES - PYRIMIDINES

• Adenine *Cytosine• Guanine * Thymine

The Structure of DNA

• Nucleotides form long chains using the deoxyribose (sugar) and the phosphate groups as the backbone and the nitrogenous bases stick out from the chain.

The Structure of a Nucleotide

Phosphategroup

Deoxyribose(sugar)

Nitrogenousbase

The Nucleotide--A more Technical View

The Structure of Organic The Structure of Organic BasesBases

Adenine

Guanine

Thymine Cytosine

PURINES

PYRIMIDINES

The Structure of DNA

The Structure of DNA• The Double Helix

– Watson and Crick discovered the twisting (spiral shape) of the DNA molecule.

– Stole the research from Rosalind Franklin to determine the shape

– Stole the research from Erwin Chargaff to determine the arrangement of the purines and pyrimidine bases

The Structure of DNA

• Watson and Crick won the Nobel Prize in 1962 for their discoveries.

• Why didn’t Rosalind Franklin earn the Nobel Prize?

The Replication Of DNA

• Base Pairing– Thymine will only bond to Adenine in

the DNA molecule

– Cytosine will only bond with Guanine in the DNA molecule

The Replication Of DNA

Base Pairing (Naming of Bases)

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

The Replication Of DNA

• Base Pairing– To show a nucleotide chain it is

abbreviated A-C-T-G-T-A-T-A-T-C-G-C-C-G– To each of the bases above they would

have the matching base belowT-G-A-C-A-T-A-T-A-G-C-G-G-C– These are the opposite base

nucleotides

The Replication Of DNA

• Base Pairing

“A” to “T” is a double bond

“C” to “G” is a triple bond

These Hydrogen bonds make the molecule twist

The Replication of DNA

• Replication - the process in which DNA makes a copy of itself before the cell can divide.

• This process ensures that the two new daughter cells have the same DNA

Replication Process

Replication Process

Replication Process

Replication Process

Replication Process

Replication Process

Replication Process

Replication Process

Replication Process

Replication Process

Replication Process

Replication Process

Replication Process

Replication Process

It is Quiz Time

Please take out a clean sheet of paper

Question 1

• What does the abbreviation DNA stand for? Please spell it the best you can!

Question 2

• True or False• An example of a trait is “hair color”

Question 3

• True or False• If someone tells you that you have

beautiful brown eyes, they are complimenting a characteristic.

Question 4

• True or False• Heredity is the passing of a trait

from the parents to the offspring

Question 5

• What did “Avery” discover in his experiments?

• A. Protein is the transforming factor

• B. DNA is the transforming factor• C. RNA is the transforming factor

Question 6

• Fill in the blank• The base unit of structure that

makes up the DNA molecule is the _____________. It contains 3 basic parts

Question 7

• What are the nitrogen bases that make up the purines?– adenine– thymine– cytosine– guanine

Question 8

• What are the nitrogen bases that make up the pyrimidines?– adenine– thymine– cytosine– guanine

Question 9

• What 2 parts of the DNA molecule builds the backbone?– Phosphate group– Deoxyribose Sugar– Nitrogen Base– Purines– Pyrimidines

Question 10

• What did Watson and Crick steal from Rosalind Franklin?

Question 11

• What did Watson and Crick steal from Erwin Chargaff?

Question 12

• What did Waston and Crick earn for all their hard work?

Question 13

• Why didn’t Rosalind Franklin earn the same prize?

Question 14

• What two nitrogen base pairs always pair together in the DNA molecule?– Please write the entire base name out

• spell the best you can

Question 15

• What is the abbreviation for the following nitrogen bases– 1. Adenine– 2. Thymine– 3. Guanine– 4. Cytosine

Question 16

• Why must a cell replicate it’s DNA before it divides?

Question 17

• Copy the DNA strand on your paper

• Write the complementary nitrogen base to the DNA strand

• A-T-C-C-G-T-C-A-T

Question 18

• What is needed to break the hydrogen bonds between the nitrogen bases when the strand starts to replicate?

RNA; Lecture II

Ribonucleic Acid

RNA

• RNA is the messenger between DNA and the ribosomes.

• The message from the DNA will tell the ribosomes what protein to synthesize.

RNA Structure

• RNA has the same structure as DNA with the Sugar- phosphate group backbone.

• 3 difference between RNA and DNA• 1. The sugar group in RNA is called

“ribose” where DNA is “deoxyribose”• 2. RNA is a single strand of nucleotides

where DNA is a double strand of nucleotides

RNA Structure

• 3. RNA has “Uracil” instead of “thymine” in which DNA contains.

• RNA does follow the same base pairing rules that DNA follows. DIFFERENCE, “Uracil” pairs with “Adenine” just like “thymine did in DNA.

• Uracil is abbreviated “U”

The Reason for RNA

• Because the DNA molecule is to large to exit the nuclear membrane so it makes a copy of itself in single strand (RNA), a smaller molecule, to relay the commands for protein synthesis to the ribosomes.

• This type of RNA that delivers the commands from the DNA is called, “messenger RNA” abbreviated mRNA

Transcription

• Synthesizes RNA from a DNA strand.

• The RNA is “transcribed” by copying a portion of DNA to make a complementary strand of RNA.

• Transferring DNA to RNA

Transcription

The Process of Transcription.1. RNA polymerase (an enzyme)

attaches itself to a section the DNA molecule that needs transcribed.

2. RNA polymerase causes the DNA molecule two strands to separate

3. The RNA polymerase pulls in floating nucleotide to form the mRNA from the DNA template.

Transcription

C

A

T

G

G

C

T

A

A

T

Transcription

C

A

T

G

G

C

T

A

A

T

Transcription

C

A

T

G

G

C

T

A

A

T

Transcription

C

A

T

G

G

C

T

A

A

T

Transcription

C

A

T

G

G

C

T

A

A

T

A

Transcription

C

A

T

G

G

C

T

A

A

T

A

Transcription

C

A

T

G

G

C

T

A

A

T

A U

Transcription

C

A

T

G

G

C

T

A

A

T

A U

G

Transcription

C

A

T

G

G

C

T

A

A

T

A U

G

Transcription

C

A

T

G

G

C

T

A

A

T

A U G

Transcription

C

A

T

G

G

C

T

A

A

T

A U G

Transcription

C

A

T

G

G

C

T

A

A

T

A U G

C

Transcription

C

A

T

G

G

C

T

A

A

T

AU GC

Transcription

C

A

T

G

G

C

T

A

A

T

AU G C

Transcription

C

A

T

G

G

C

T

A

A

T

AG C

U

Transcription

C

A

T

G

G

C

T

A

A

T

AG C

U

Transcription

C

A

T

G

G

C

T

A

A

T

AG CU

Transcription

C

A

T

G

G

C

T

A

A

T

AC U

Transcription

C

A

T

G

G

C

T

A

A

T

AU

Transcription

C

A

T

G

G

C

T

A

A

T

A

Transcription

C

A

T

G

G

C

T

A

A

T

A

Transcription

C

A

T

G

G

C

T

A

A

T

A

Transcription

CA

TG

G

C

T

A

A

T

A

Transcription

CA

TG

G

C

T

A

A

T

A

Transcription

• NOTE• The mRNA made a copy of one

side of the DNA molecule• The mRNA now leaves the nucleus

and travels to ribosome out in the cytoplasm tell the ribosome what protein to make.

Protein Synthesis

• A “Protein” is a string of “Amino Acids” when put together form a molecule called a “polypeptide”

• There are 20 different types of Amino Acids

• The arrangement of the nucleotides codes for which Amino Acid is needed to form a certain polypeptide.

Protein Synthesis

• Review• DNA contains the following

nucleotide bases ( A, T, C, G )• RNA contains the following

nucleotide bases ( A , U, C, G )

Protein Synthesis

• It takes “3” nucleotides to code for one Amino Acid.

• Each combination of “3” nucleotides on mRNA is called a “Codon”

• There can be more than one codon for each amino acid.

Protein Synthesis

A U G U C C A U C G G C U G A

CODON CODON CODON CODON CODON

Look at Your Handout

First Letter of Sequence

mRNA

Second Letter of Sequence

mRNA

Third Letter of Sequence

mRNA

Protein Synthesis

• Note• AUG is a “initiator” that always codes

for Methionine (amino acid) which is a start code for protein synthesis.

• However, there are 3 codons, UAA, UAG, and UGA, that do not code for an amino acid and ends the protein synthesis. They are “stop” codons. Just like a period.

Protein Synthesis

• Look at the handout• What amino acid do the following

codons call for?• AGC• GGG• CUC• UGA

Protein Synthesis

• Look at the handout• What amino acid do the following

codons call for?• AGC serine• GGG glycine• CUC leucine• UGA “stop” codon

Translation

• The process of translating the message from the mRNA into a polypeptide chain.

• The amino acids are carried to the mRNA on a specialized molecule called transfer RNA (tRNA).

Translation

A U G

Amino Acid

Anticodon

Translation

• The role of ribosomes in translation• Ribosomes pass along the mRNA

and calls out the tRNA to bring in the anticodon match to mRNA codon

• Remember the amino acid needed for the polypeptide is attached to tRNA

Translation

mRNA

A U G C G U A G C A C U A G

Translation

mRNA

A U G C G U A G C A C U A G

Translation

mRNA

A U G C G U A G C A C U A G

Translation

mRNA

A U G C G U A G C A C U A G

U A C

Translation

mRNA

A U G C G U A G C A C U A G

U A C

Translation

mRNA

A U G C G U A G C A C U A G

U A C

Translation

mRNA

A U G C G U A G C A C U A G

U A C

Translation

mRNA

A U G C G U A G C A C U A G

G C A

Translation

mRNA

A U G C G U A G C A C U A G

G C A

Translation

mRNA

A U G C G U A G C A C U A G

G C A

Translation

mRNA

A U G C G U A G C C U A

U C G

Translation

mRNA

A U G C G U A G C U G A

U C G

Translation

mRNA

A U G C G U A G C U G A

U C G

Translation

mRNA

A U G C G U A G C U G A

U C G

Translation

mRNA

A U G C G U A G C U G A

U C G

Translation

mRNA

A U G C G U A G C U G A

U C G

Stop Codon

Translation

mRNA

A U G C G U A G C U G A

Stop Codon

Let’s review

• If DNA copies itself it is called……..• When DNA makes a copy of mRNA

it is called ……...• When mRNA calls for an amino

acid it is called ……..

Let’s review

• If DNA copies itself it is called……..• replication• When DNA makes a copy of mRNA it

is called ………• transcription• When mRNA calls for an amino acid it

is called ……..• translation

Let’s review

• DNA strand• T A C C C G A T C A C T• mRNA strand (CODON)• A U G G G C U A G U G A• tRNA strand (ANTICODON)• U A C C C G A U C A C U

Let’s review

• Very Important• Remember the mRNA codon codes

for the amino acid• Always look at the mRNA when

looking to see what amino acid is needed

Let’s review

• What amino acid do each of the DNA strands code for?

• ATT • GGC• AGA• TTG

Let’s review

• What amino acid do each of the DNA strands code for?

• DNA mRNA Amino Acid• ATT UAA stop• GGC CCG Proline• AGA UCU Serine• TTG AAC Asparagine

Let’s review

• What would the tRNA anticodon for each of the amino acids?

• Amino Acid• stop• Proline• Serine• Asparagine

Let’s review

• What would the tRNA anticodon for each of the amino acids?

• Amino Acid tRNA• stop AUU• Proline GGC• Serine AGA• Asparagine UUG

The End

Time for your DNA/RNA 3 dimensional project

3-D project

• You will choose one of the three processes we discussed in lecture to build a 3-D model demonstrating the process.

• 1. Replication• 2. Transcription• 3. Translation

The model must contain ………..• 1. A 3-D display of the process

chosen• 2. A “key” for reference• 3. An explanation of the process

chosen• NO food materials are to be used

Deadline

• Tuesday/Wednesday (2/20, 2/21)• It is due Tuesday/Wednesday• Tuesday/Wednesday• If you are ill, have someone bring it to

me.• NO EXCUSES for late assignments• will not take them after 3:30

Tuesday/Wednesday