So…How much do YOU know about genetics? Writing Log today: Take the pre-test in your notepacket....

GENETICS 101: DNA

CHAPTER 12

So…How much do YOU know about genetics?

Writing Log today: Take the pre-test in your

notepacket. We will learn about each of the concepts in the pre-test throughout this unit, and then we will take the post-test and see

how well you did on the pre-test.

Section 1: DNA -

What’s this stuff made

of?

What do we find inside the nucleus?

DNA Deoxyribonucleic acid

Genetic Code

Revised 10-10-2006

DNA: Deoxyribonucleic Acid

DNA James Watson and Francis CrickRosalind

Franklin

DNA: Deoxyribonucleic Acid

What do we call this shape?

Watson and Crick:Came up with the model we accept

today as a DOUBLE HELIX • Double helix: where the two

strands are wound around each other

Do you want to build with building blocks?

Did you play with blocks as a kid?

DNA DNA is made up of nucleotides

Nucleotides are the BUILDING BLOCKS of DNA

NUCLEOTIDE: building block of DNA

Three parts of a NUCLEOTIDE:1. Sugar (What the sugar

called?)2. Phosphate group3. Nitrogen Base

Backbone : Deoxyribose Sugar and Phosphate

Inner Molecule: Nitrogen Bases

4 kinds of nitrogen bases

Adenine Guanine

4 kinds of nitrogen bases

Adenine Guanine Both of

these types of

molecules are called

purines

4 kinds of nitrogen bases

Thymine Cytosine

4 kinds of nitrogen bases

Thymine

Cytosine Both of these types

of molecules are called

pyrimidines

www.youtube.com/watch?v=ID6KY1QBR5s

Bio Rad video

LETS MAKE SOME NUCLEOTIDES

Plant CellAnimal Cell

All organisms use the same four bases as a blueprint for that organism.

Plant CellAnimal Cell

All organisms use the same four bases as a blueprint for that organism.

If there are only four types of nitrogen bases, and those nitrogen bases are the blueprint for all organisms, how come we don’t all look the same? Why are there so many different types of organisms?

Before you answer:

Morse Code is a simple code of

only 2 symbols…and yet it can be

used to send complex

information

Base Pairing Edwin Chargaff:

In 1950, he analyzed the amount of each of the bases in the DNA of various species

Erwin ChargaffAustrian BiochemistThe area he was from in now in what is Ukraine

Base Pairing Chargaff’s Data (What do you

notice?)

HumansFruit flyCornBread MoldBacteriaBacteria

Base Pairing Chargaff’s Rule:

Chargaff found that the percentage of A (Adenine) equals the percentage of T (thymine); and C (cytosine)= G (guanine) % of A=% of T and % of C= % of GErwin Chargaff

Austrian Biochemist

Base Pairing Base Pairs: two nucleotides

hydrogen boding together Adenine (A) will bond or pair with Thymine (T)

Cytosine (C) will bond or pair with Guanine (G)

Hydrogen Bonding Turns out purines (Adenine (A) and

Guanine (G)) like to bond with pyrimidines (Cytosine (C) and Thymine (T))

Hydrogen Bonding A (Adenine) and T (Thymine) have

Two Hydrogen Bonds holding those nucleotides together

G (Guanine) and C (Cytosine) have three hydrogen bonds

Lets put our “nucleotides” together

Section 2: What is a

DNA Replication?

What is DNA Replication

https://www.youtube.com/watch?v=27TxKoFU2Nw

DNA Replication Before cell division, DNA is replicated Semiconservative Replication:

parental strands of DNA separate, serve as templates, and produce DNA molecules that have one strand of parental DNA and one strand of new DNA.

In other words,Old strands of DNA act as a template

DNA Replication

DNA Replication Steps of DNA Replication:

Helicase unwinds double helix (breaks hydrogen bonds)

DNA Replication

DNA Replication Steps of DNA Replication:

Helicase unwinds double helix (breaks hydrogen bonds)

RNA primase adds a primer to parental/template strands

DNA Replication

DNA Replication Steps of DNA Replication:

Helicase unwinds double helix (breaks hydrogen bonds)

RNA primase adds a primer to parental/template strands

DNA Polymerase adds new nucleotides to create the complimentary strand to parental/template strand

DNA Replicationhttps://www.youtube.com/watch?v=OnuspQG0Jd0

DNA ReplicationLets try DNA Replication:Original DNA StrandATTCGATCCGTTACCATGATAAGCTAGGCAATGGTACT

ATTCGATCCGTTACCATGA

TAAGCTAGGCAATGGTACT

New replicated DNA Strand

New replicated DNA Strand

Original DNA Strand

Section 3: What is a

gene?

Genes

First let’s compare Chromosomes to a

towel

Chromosome

Chromatin = Long strands of DNAChromosome : coiled up strand of chromatin

The “X” shape is where the chromosome has been copied.

Chromatin Chromosome

How many chromosomes do we have in our nucleus?

How many chromosomes do we have in our nucleus of each of our cells?

a. 23b. 52

c. 108d. 46

What is a Gene? Gene: functional unit that

controls inherited trait expression that is passed on from one generation to another generation.

Genes In other words, Genes are pieces of our

DNA that code for our traits.

Proteins from Genes

• Gene: Part of chromosome that codes for a protein

How many genes do we have?

The Human Genome

• How many paired nucleotides do we have? (i.e. how many base pairs do we have?)

3 billion base pairs

In 1964, Friedrich Vogel estimated that the total number of genes in the human genome

to be ~ 6.7 million

What is a Trait?

Trait = Any characteristic

Trait

Inherited Trait

Inherited trait = a characteristic that you get from your biological parents and….

• a trait you are born with. • It’s in your DNA!• What are some examples?

EX: (Write down one of your inherited traits)

Acquired Trait

Acquired trait = a characteristic that you develop in your lifetime

• a trait you learn or pickup after you are born (not inherited from your parents)

• What are some examples?

EX: (Write down one of your acquired traits)

Section 4: transcriptio

n and translation

What are grandmas good for?

What is DNA good for?

PROTEIN SYNTHESIS:

How proteins are made…

which are coded from DNA

AKA: Transcription and Translation

Protein Synthesis

DNA RNA

Transcription

Protein Synthesis

DNA RNA Protein

Transcription Translation

DNA vs. RNA

DNA

-Double strand

-Sugar called

deoxyribose

-Bases are

C G A T

RNA

-Single strand

-Sugar called ribose

-Bases are

C G A U

DNA vs. RNA

DNA

Double strand

Sugar called

deoxyribose

Bases are

C G A T

RNA

Single strand

Sugar called ribose

Bases are

C G A U

U = Uracil

Transcription• Using DNA to make RNA• Happens inside the nucleus

Translation• Using RNA to make protein• Happens outside the nucleus

Protein:

A chain of amino acids

• Each amino acid is coded for by three nucleotides called…..

Codon:

Three bases that code for a specific amino acid

(Anticodon)

Anticodon:

The three opposite bases

A T G AA T A G C T G G A G G G A T T A A

T A C T T A T C G A C C T C C C T A A T T

Transcription (inside the nucleus)

A T G AA T A G C T G G A G G G A T T A A

A UG A A U A G CU G G A G G GA U U A A

T A C T T A T C G A C C T C C C T A A T T

A UG A A U A G C U G G A G G GA U U AA

A UG A A U A G C U G G A G G GA U U AA

ASPA

MET ASP SER TRY ARG

So WHY DNA, the real purpose?

To make PROTEIN!!

Section 5: Mutations

Mutations

Evr made a mitsake

in yourr spelng?

MUTATIONS!A mess up in the DNA

sequence

Where do mutations occur?

IN THE DNA!!

(not the RNA)

When do mutations occur?

During replication

MUTATIONS!Gene Mutations (2 types)Changes in a single base

Chromosomal Mutations (4 types)Changes in whole chromosomes

Gene MutationsPoint Mutations

Frameshift Mutations

Point Mutation

A T G AA T A G C T G G A G G G A T T T T

T A C T T A T C G T C C T C C C T A A A A

A T G AA T A G C T G G A G G G A T T T T

A UG A A U A G C A G G A G G GA U U UU

T A C T T A T C G T C C T C C C T A A A A

Point Mutation

These happen at only ONE POINT or base

Usually one base is replaced by a different base

End result:

ONE amino acid in the protein chain is wrong

A UG A A U A G C A G G A G G GA U U UU

Point Mutation

MET ASP SER ARG ARG ASPA

PHE

These happen at only ONE POINT or base

Usually one base is replaced by a different base

End result:

ONE amino acid in the protein chain is wrong

A UG A A U A G C A G G A G G GA U U UU

Point Mutation

MET ASP SER ARG ARG ASPA

PHE

A T G AA T A G C T G G A G G G A T T T T

T A C T T A T C G T C C T C C C T A A A A

Frameshift

A T G AA T A G C T G G A G G G A T T T T

A UG A A U A G C A G G A G G GA U U UU

T A C T T A T C G T C C T C C C T A A A A

Frameshift

A UG A A U A G GU G G U G G GA U U UU

Frameshift

A UG A A U A G G G G U G G G A U U UU

Frameshift

A UG A A U A G C U G G A G G GA U U UU

MET ASP SER TRY ARG ASPA

PHE

Frameshift

Frameshift

This causes a SHIFT in the rest of the sequence following the mutationEnd result:Every amino acid after the mutation is wrong!

A UG A A U A G C G G A G G GA U U UU

MET ASP SER GLY GLY ISO

MUTATIONS!

Chromosomal Mutations (4)

Changes in whole chromosomes

Chromosomal Mutations1. Deletion:

part of the chromosome is lost

Chromosomal Mutations1. Deletion:

part of the chromosome is lost

2. Duplication:

part of the chromosome is repeated

Chromosomal Mutations1. Deletion:

part of the chromosome is lost

2. Duplication:

part of the chromosome is repeated

3. Inversion:

part of the chromosome gets reversed

Chromosomal Mutations1. Deletion:

part of the chromosome is lost

2. Duplication:

part of the chromosome is repeated

3. Inversion:

part of the chromosome gets reversed

4. Translocation:

two chromosomes that are NOT pairs switch information