DNA

eoxyribo

ucleic

cid

DNA DNA is found in the is found in the nucleus of a cell. It makes nucleus of a cell. It makes up our chromosomes. up our chromosomes.

(what about prokaryotes?)(what about prokaryotes?)

It is also found in these It is also found in these organelles:organelles:

_______________ &_______________ &

________________________________

ChloroplastsChloroplasts

MitochondriaMitochondria

Interesting Interesting Factoid:Factoid:

Each Each human human cellcell has about has about 1.8 meters 1.8 meters (5.5 feet) of (5.5 feet) of DNA!DNA!

DNA DNA FunctionFunction Controls all protein Controls all protein

production for the production for the body.body.

Controls all genetic Controls all genetic traits.traits.

Controls some Controls some personality traits?personality traits?

The Monomer of DNA The Monomer of DNA is…is…

A Nucleotide!

A nucleotide consists of:

- A sugar (deoxyribose)

- A Phosphate

- A Nitrogenous Base (either Adenine, Guanine, Cytosine or Thymine)

Nitty Gritty on Nitty Gritty on DNADNA DNA is like a twisted ladder, this is DNA is like a twisted ladder, this is

called a called a double helix. double helix. It twists It twists upon itself to form tight knots upon itself to form tight knots calledcalled histones histones which are found on which are found on chromosomes.chromosomes.

The “backbones” are made of The “backbones” are made of alternating sugar (deoxyribose) & alternating sugar (deoxyribose) & phosphatesphosphates

The “rungs” are made of The “rungs” are made of nitrogenous bases (A,T,C, & G)nitrogenous bases (A,T,C, & G)

Adenine ALWAYS goes with Adenine ALWAYS goes with ThymineThymine

Cytosine ALWAYS goes with Cytosine ALWAYS goes with GuanineGuanine

What happens during What happens during Interphase?Interphase?

The original strand of DNA The original strand of DNA “unzips”.“unzips”.

Each “open” nucleotide binds Each “open” nucleotide binds to a new complimentary to a new complimentary nucleotide.nucleotide.

End result is two identical End result is two identical strands of DNA, each half of strands of DNA, each half of the original and half new.the original and half new.

Yup! Chromosomes duplicate, or make an exact copy!

http://www.youtube.com/watch?v=rpwjZX_z5rg

DNA Replication YouTube Clip

Protein ProductionProtein Production

DNADNA RNARNA ProteinProtein

Protein SynthesisProtein Synthesis

The process of making The process of making enzymesenzymes, which are , which are catalysts and used in many life processes to catalysts and used in many life processes to build up and break down compounds.build up and break down compounds.

•Also, structural proteins are made, which form organs and tissues.

RNA: Ribonucleic AcidRNA: Ribonucleic Acid

A nucleic acid which has only A nucleic acid which has only oneone strand.strand.

It is made from DNA, and codes for It is made from DNA, and codes for specific specific amino acidsamino acids, the building , the building blocks of proteins.blocks of proteins.

Ribonucleic Acid: Ribonucleic Acid: RNARNAPieces of DNA are copied onto RNA. RNA carries that

information out of the nucleus and to the “job site” (which is called the _______________.)

Only one gene on the DNA molecule is copied into RNA. (Even though it carries ALL information for ALL genes)

Just like a cook book contains 100’s of recipes, but you use the information for just one recipe at a time.

ribosome

3 Types of RNA3 Types of RNA1.1. mRNA (messenger RNA):mRNA (messenger RNA): The The

single stranded RNA that copies single stranded RNA that copies the information from a portion of the information from a portion of DNA and leaves the nucleus.DNA and leaves the nucleus.

three bases = codonthree bases = codon1.1. tRNA (transfer RNA):tRNA (transfer RNA): These These

are only 3 base pairs long and are only 3 base pairs long and contain an anti-codon (the contain an anti-codon (the complements to a codon) and complements to a codon) and carry a single amino acid to the carry a single amino acid to the “production site” of the protein.“production site” of the protein.

2.2. rRNA (ribosomal RNA):rRNA (ribosomal RNA): This is This is (obviously) found in the ribosome (obviously) found in the ribosome and helps tRNA and mRNA and helps tRNA and mRNA communicate.communicate.

Basic RNA StructureBasic RNA Structure RNA is single RNA is single

strandedstranded

DNA has deoxyribose DNA has deoxyribose sugar, while RNA has sugar, while RNA has ribose.ribose.

RNA uses Uracil RNA uses Uracil instead of Thymine.instead of Thymine.

(Also, RNA can leave the (Also, RNA can leave the nucleus. nucleus. DNA CANNOT!!!!)DNA CANNOT!!!!)

Transcription: The Transcription: The process of making process of making

messenger RNA from messenger RNA from DNA.DNA.

Codons & Anti-Codons & Anti-CodonsCodonsMUY IMPORTANTE!!!MUY IMPORTANTE!!!

Every THREE base pairs on Every THREE base pairs on an RNA molecule is called a an RNA molecule is called a CODONCODON..

Every CODON codes for a Every CODON codes for a specific amino acid.specific amino acid.

An An ANTI-CODONANTI-CODON (on tRNA) (on tRNA) has the complementary base has the complementary base pairs and physically carries an pairs and physically carries an individual amino acid to the individual amino acid to the ribosome.ribosome.

HINT: Transcription and Translation occur in alphabetical order!!

Copying a portion of DNA into a strand of RNA

Converting the information on the RNA strand into a protein molecule

TranslationTranslationmaking proteins from RNAmaking proteins from RNA

Ribosome

mRNA

READ THE CODE:

1. The mRNA is “read” by the ribosome.2. The tRNA brings the correct amino

acid to the ribosome.

ASSEMBLE:

3. The amino acids are linked together in the order dictated by the mRNA strand.

4. The sequence of amino acids determines the type and structure of a protein molecule.

Transcription & Translation Transcription & Translation ReviewReview

?

?

? ?

http://Funny Transcription Video

Accurate Translation Clip

Good Clip!

Translation: Translation: Amino Acid Codon ChartAmino Acid Codon Chart

Ala Thr Glu Leu Arg Ser STOP!

MutationsMutations A mutation is a spontaneous A mutation is a spontaneous

and random change in the and random change in the base pair sequence of DNA.base pair sequence of DNA.

Mutations can be caused by Mutations can be caused by environmental factors such environmental factors such as UV light (sunshine), as UV light (sunshine), Nuclear Radiation and other Nuclear Radiation and other chemicals (“carcinogens”)chemicals (“carcinogens”)

Mutations can also occur Mutations can also occur due to an error while DNA due to an error while DNA replicates itself.replicates itself.

MutationsMutations Mutations passed on to Mutations passed on to

offspring if in offspring if in

Mutations Mutations NOT NOT passed on passed on if occur in if occur in

gametes

Somatic cells (body cells)

Types of Types of Mutations:Mutations:1. Point Mutation: This is a random change of one base

pair. In this case the A was substituted with a C. This caused Sickle Cell Anemia.

Different Different MutationsMutations

Chromosome Chromosome Mutations:Mutations:

Nondisjunction Mutation: Occurs due to an error in meiosis. Homologous chromosomes do not separate properly.

Affect many genes, visible in the phenotype

Down’s Syndrome: trisomy 21

4n

Edward’s Syndrome

Patau’s Syndrome

trisomy 13

Klinefelter’s Syndrome XXY

Turner’s Syndrome XO

Sex chromosome disorders: (Pair #23)

Detecting Mutations: Screening

Blood samples

Urine samples

Gene ExpressionGene Expression

On everyone’s chromosomes, there are On everyone’s chromosomes, there are many genes that are never expressed.many genes that are never expressed.

Some genes can be “turned on”(or turned Some genes can be “turned on”(or turned off) in response to stimuli (changes in the off) in response to stimuli (changes in the environment).environment).

Example: Example: If a person has a gene for If a person has a gene for acquiring a type of cancer, and they smoke, acquiring a type of cancer, and they smoke, the gene may be expressed. Without the gene may be expressed. Without smoking, the gene may never be expressed.smoking, the gene may never be expressed.

Environment affects gene expression

Chlorophyll production in the sunHimalayan

rabbit fur turns black with cold

Identical twins(Minnesota Twins Studies)

Changes in gene expression with Changes in gene expression with environment…environment…

Buttercup leaves Buttercup leaves underwaterunderwater

Above water leaves…Above water leaves…

DNA Electrophoresis QuizDNA Electrophoresis Quiz

1. cut the DNA into various size fragments.

2. The DNA pieces are loaded into a which acts like a maze.

3. An runs through

the gel carrying the charged DNA

through the gel. The shorter the piece, the

it travels.

Restriction enzymes

gel

electriccurrent

negatively

farther

A Classic Example of A Classic Example of Genetic EngineeringGenetic Engineering

Gene of interest for producing insulin is cut with restriction enzymes from a human chromosome.

1.

2. The circular plasmid DNA of a bacteria is cut and the human insulin gene is inserted.

3.

4.

The bacteria cells produce human insulin which is collected and bottled for diabetics.

In the past, insulin from sheep and cows was used, but using bacteria produces a safer form of the hormone!

Wacky Tobaccy!Wacky Tobaccy!

This tobacco This tobacco plant had genes plant had genes from a firefly from a firefly spliced into its spliced into its chromosomes – chromosomes – It glows!It glows!

CloningCloning

Cloning is taking the genetic material from an organism and creating an entirely new, exact copy.

Part of the challenge is to get a cell where none of the DNA is “turned off”.

video

Human Heredity experiments are not done because:

1.Small sample size

2.Long gestation

3.Immoral

4.Few offspring