nucleus chromosome gene - living...

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GeneticsGenetics

Chapter 12 Chapter 12

DO NOWDO NOW: List From Largest to : List From Largest to SmallestSmallest

DNA GeneDNA Gene

Nucleus ChromosomeNucleus Chromosome

Largest to SmallestLargest to Smallest

Nucleus

Chromosome

Gene

DNA

•• What was responsible for transferring What was responsible for transferring

genetic material?genetic material?

____________________________________________________________

•• Already knew that chromosomes were Already knew that chromosomes were

made of proteins & DNA.made of proteins & DNA.

•• Was it the protein or the DNA?Was it the protein or the DNA?

Scientist’s Questioned…..Scientist’s Questioned…..

What is Genetics?What is Genetics?

�� The study of how genes are passed from The study of how genes are passed from

generation to generation (generation to generation (HEREDITYHEREDITY).).

�� The study of how genes give an organism The study of how genes give an organism

its traits.its traits.

�� ChromosomesChromosomes

-- Contain DNA and proteins.Contain DNA and proteins.

-- have the genetic information that is have the genetic information that is passed down to family members passed down to family members

•• DNADNA

-- the instructions for each trait (a blue print).the instructions for each trait (a blue print).

•• GeneGene

-- segments or parts on a chromosomesegments or parts on a chromosome

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GeneGene

FunctionsFunctions: :

1. Controls the making of proteins called 1. Controls the making of proteins called

protein synthesisprotein synthesis..

2. Directs the 2. Directs the orderorder of amino acids.of amino acids.

3. Determines the 3. Determines the traitstraits (characteristics) & (characteristics) &

function of a cell.function of a cell.

Name Some TraitsName Some Traits

�� Hair colorHair color

�� Eye colorEye color

�� HeightHeight

�� WeightWeight

The Gene Chromosome Model

Chromosomes

Genes

The genes consist of DNA which is made up

of four chemical letters

The chromosome is made up of genes

Chromosomes- 23 pairs

A cell

3

Different genes are activated (turned on) in different cells. So

each cell has a specific protein that makes it special!

�� NucleotidesNucleotides-- subsub--units units that make up DNA that make up DNA

1 NucleotideNucleotide is made of:

1 1 55--carbon ringcarbon ring

1 phosphate1 phosphate

1 nitrogen base1 nitrogen base

5 CarbonSugar

Four Types of Nucleotide making up DNA

S

S

S

S

S

Nucleotide connects by a

bond to form a DNA strand

1 DNA Stand 1 DNA Strand

S

S

S

S

S

SS

S

S

S

S

S

Hydrogen

bond

A Double Helix

(2 Strands = 1 DNA) 2 Types of Nucleic Acids2 Types of Nucleic Acids

DNADNA: Deoxyribonucleic acid: Deoxyribonucleic acid-- in nucleusin nucleus

RNARNA: Ribonucleic acid: Ribonucleic acid-- in cytoplasmin cytoplasm

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DNA RNADNA RNA

• DOUBLE Stranded Helix

• Deoxyribose sugar

• Nitrogen bases:

A, T, C, G

• 1 type of DNA

• Connected by weak

bonds

• SINGLE Stranded

• Ribose sugar

• Nitrogen bases:

A, U, C, G

(u- uracil, no- thymine)

• 3 RNA Types

DNADNA

�� DNA acts as a DNA acts as a TEMPLATETEMPLATE..

�� Meaning it acts as a Meaning it acts as a patternpattern so it can be so it can be COPIEDCOPIED..

�� DNA is DNA is copiedcopied (replicated) before mitotic & (replicated) before mitotic &

meiotic cell division. meiotic cell division.

3 Types of RNA3 Types of RNA

� mRNA = messenger RNA (copies DNA, carries the instructions for protein assembly)

� tRNA = transfer RNA

(transfers/carries amino acid)

� rRNA = ribosomal RNA

(makes ribosomes in cytoplasm, site for protein synthesis)

? Questions ?? Questions ?

1. What is the shape of a DNA molecule?

Double Helix

2. Name the 3 chemical groups that make up a nucleotide?

Sugar, phosphate group, 1 nitrogen base

3. Name 3 ways that the chemical make-up of RNA differs from DNA.

RNA- sugar (ribose), nitrogen base- uracil not thymine, single strand of nucleotides

Complimentary PairsComplimentary Pairs

What Does This Mean?

A Good Match or Fit!!!!

DNA (Chromosome) ReplicationDNA (Chromosome) Replication::

Complimentary StrandComplimentary Strand

A A -------------------------------------- TT

G G -------------------------------------- C C

http://www.dnai.org/lesson/go/19436

http://fig.cox.miami.edu/~cmallery/150/gene/mol_gen.htm

DNA Replication - the copying of DNA to

have a complete set of DNA molecules.

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DNA ReplicationDNA ReplicationOLD NEW

http://www.sumanasinc.com/webcontent/animations/content/meselson.html

Old Strand New Strand New Strand Old Strand

Template

Critical ThinkingCritical Thinking

�� Copy this base sequence for the DNA Copy this base sequence for the DNA

strand:strand:

TGGCAATCTGTGGCAATCTG

What would be its What would be its base sequencebase sequence for the for the

complimentary strand?complimentary strand?

ACCGTTAGAC

What is the What is the RoleRole ofofDNA Polymerase?DNA Polymerase?

�� JoinsJoins the DNA strands together the DNA strands together

during DNA replication.during DNA replication.

�� It It proofreadsproofreads the DNA strand to make the DNA strand to make

sure it is a sure it is a perfect fitperfect fit for the for the

complimentary base!complimentary base!

• Genes are found within the

_______________________.On the chromosome in the nucleus

• After DNA replication, the 2

strands are referred to as the _____ and _______ strandsOld New

• Which strand is referred to as the template? The Old strandThe Old strand

��AA codoncodon. This is every . This is every 3 bases3 bases on on mRNA.mRNA.

��Each set of Each set of 3 bases3 bases = = 1 1 amino acidamino acid..

What is a Triplet CodeTriplet Code?

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Pairing Pairing ––Up Rule for RNAUp Rule for RNA

A A (DNA)(DNA) -------------------------------- UU (mRNA) (mRNA) NO THYMINENO THYMINE

C C (DNA)(DNA) -------------------------------- GG (mRNA)(mRNA)

http://biology.unm.edu/ccouncil/Biology_124/Summaries/T&T.html

A Sequence of NucleotidesA Sequence of Nucleotides

� What is the sequence of the mRNA molecule

transcribed from this gene.

GAC-AAG-TCC-ACA-ATC

CUG-UUC-AGG-UGU-UAG

GAC-AAG-UCC-ACA-AUC 1. Substitue all “T”’s for “U”.

CUG-UUC-AGG-UGU-UAG 2. Translate all

OR

Protein SynthesisProtein Synthesis

1. 1 side of the DNA strand is 1. 1 side of the DNA strand is copiedcopied by by

mRNA in the mRNA in the nucleusnucleus..

2. mRNA travels to a ribosome in the 2. mRNA travels to a ribosome in the

cytoplasmcytoplasm (rRNA is found here)(rRNA is found here)


Process 1: TranscriptionTranscription (copy)

Process 2: TranslationTranslation1. 1. mRNA has the instructions to code for the order of mRNA has the instructions to code for the order of

specific amino acids to make a specific amino acids to make a polypeptide chainpolypeptide chain(protein).(protein).

2. tRNA carries the 2. tRNA carries the anticodonanticodon (3 nitrogen bases)(3 nitrogen bases) & 1 kind of amino acid. tRNA binds with mRNA.

3. A protein is made (a polypeptide chain).3. A protein is made (a polypeptide chain).

4. tRNA leaves to pick up another amino acid.4. tRNA leaves to pick up another amino acid.

5. A 5. A STOPSTOP codon is reached on the mRNA.codon is reached on the mRNA.

6. The ribosome releases mRNA & an amino acid chain (a 6. The ribosome releases mRNA & an amino acid chain (a protein).protein).

Summary ReviewSummary Review

�� TranscriptionTranscription: DNA is copied into mRNA.: DNA is copied into mRNA.

�� TranslationTranslation: mRNA matches with tRNA : mRNA matches with tRNA who carries the amino acid that codes for who carries the amino acid that codes for

mRNA.mRNA.

�� Use Use Genetic Code ChartGenetic Code Chart to find out the to find out the

amino acid that the mRNA codes for.amino acid that the mRNA codes for.

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Diagram Summary of Diagram Summary of


Process 1: Transcription DNA

unwinds (Nucleus)

Process 2: Translation Protein Synthesis (in the ribosome) of the

Cytoplasm


DNA -transcription

RNA -translation to make

a polypeptide chain(Protein)

Reading the Reading the Genetic Code ChartGenetic Code Chart

is to Determine is to Determine the the Sequence of Amino AcidsSequence of Amino Acids

for a for a SPECIFIC PROTEINSPECIFIC PROTEIN

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Genetic ProblemsGenetic Problems

�� DNA GeneDNA Gene: AAA: AAA--GTTGTT--ATGATG--CGTCGT--TGTTGT--CTTCTT

��Translate into mRNATranslate into mRNA

mRNA: mRNA: UUUUUU--CAACAA--UACUAC--GCAGCA--ACAACA--GAAGAA

Find amino acid sequenceFind amino acid sequence (chart) (chart)

�� Amino acidAmino acid: : PHEPHE--GLNGLN--TYRTYR--ALAALA--THRTHR--GLUGLU


�� DNA GeneDNA Gene: TAC: TAC--CATCAT--GTTGTT--TCTTCT--GTGGTG


mRNA: mRNA: AUGAUG--GUAGUA--CAACAA--AGAAGA--CACCAC


�� Amino acidAmino acid: : METMET--VALVAL--GLNGLN--ARGARG--HISHIS

Review QuestionsReview Questions

The Process for The Process for


• Protein synthesis takes place

.

Outside the NUCLEUS or in the ribosome

located in the cytoplasm

•What helps DNA direct the

synthesis of proteins?

RNA

�� The first & second process called?The first & second process called?

Transcription & Translation

•• What is the 1What is the 1stst step that takes place in step that takes place in

the nucleus during transcription?the nucleus during transcription?

DNA unwinds or separates

• Which type of RNA meets with a DNA

strand in the nucleus to transcribe the

codons?mRNA

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�� Where Does mRNA travel to?Where Does mRNA travel to?

Cytoplasm, specifically to a ribosome

•• Which RNA transports the anticodon Which RNA transports the anticodon

specific for the mRNA’s codon?specific for the mRNA’s codon?

tRNA

• What is located on tRNA besides the

anticodon?

A specific amino acid

�� How is the sequence of codons read?How is the sequence of codons read?

Three nitrogen bases at a time.

•• What do every three codons represent?What do every three codons represent?

A different amino acid

• What term is used to refer to the

completion of protein synthesis?

Translation

�� The end result of translation is a protein. The end result of translation is a protein.

What is the structure of a protein What is the structure of a protein

called? called? A polypeptide chain or a polymer

of amino acids

•• What holds each amino acid together?What holds each amino acid together?

A peptide bond

• What happens to tRNA after its’

anticodon connects with mRNA’s codon?

Leaves to go back to the cytoplasm & pick up

another specific amino acid


�� DNA GeneDNA Gene: AAA: AAA--GTTGTT--ATGATG--CGTCGT--TGTTGT--CTTCTT


mRNA: mRNA: UUUUUU--CAACAA--UACUAC--GCAGCA--ACAACA--GAAGAA


�� Amino acidAmino acid: : PHEPHE--GLNGLN--TYRTYR--ALAALA--THRTHR--GLUGLU

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Do NowDo Now: Fill in the Schematic : Fill in the Schematic Diagram for Protein SynthesisDiagram for Protein Synthesis

? ? ? ?

?Word Bank: rRNA mRNA Protein

tRNA Gene of DNA in Nucleus

A Schematic DiagramA Schematic Diagram

Gene of DNAin nucleus

mRNA rRNA tRNA

Protein

Sequence copied

Goes to cytoplasm

Carries over amino acid

DNA

Replication

Important!!!!!!!!!!!!Important!!!!!!!!!!!!

Every Every ProteinProtein has a has a SPECIFICSPECIFIC

�� SEQUENCESEQUENCE (order) of amino acids(order) of amino acids

�� SHAPESHAPE

�� FUNCTIONFUNCTION

What Does Gene Expression What Does Gene Expression Mean?Mean?

�� Means a gene is Means a gene is ONON so its making a so its making a

protein (protein (protein synthesisprotein synthesis). ).

�� When gene is When gene is OFFOFF, gene is not being , gene is not being

expressed and no protein is made (no expressed and no protein is made (no

protein synthesis).protein synthesis).

Different genes are activated (turned on) in different cells. So

each cell has a specific protein that makes it special!

What would cause this rabbit’s What would cause this rabbit’s

color to change?color to change?

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Gene Expression Gene Expression

& the Environment& the Environment

�� Himalayan rabbitHimalayan rabbit

-- Changes in Temp. causes change in gene expression.Changes in Temp. causes change in gene expression.

-- Cold temp. (below 33 C) turns on the gene that Cold temp. (below 33 C) turns on the gene that

controls black pigment.controls black pigment.

Gene Expression Gene Expression

& the Environment& the Environment

�� Painted TurtlePainted Turtle

-- The sex of the turtle during development is The sex of the turtle during development is

determined by the incubation temperature.determined by the incubation temperature.

-- Low temp produce males. High temp Low temp produce males. High temp

produce females.produce females.

Do Different Species Have Similar Do Different Species Have Similar Genes & Proteins?Genes & Proteins?

�� Let’s take a look……………Let’s take a look……………

1.1. Human DNA (hemoglobin)Human DNA (hemoglobin)

AGCAGC--CCGCCG--GTAGTA--CAGCAG

mRNAmRNA: : UCGUCG--GGCGGC--CAUCAU--GUCGUC

a.aa.a: SER: SER--GLYGLY--HISHIS--VALVAL


2. DNA Gene (gorilla)2. DNA Gene (gorilla)

AGAAGA--CTCCTC--CGTCGT--CATCAT

mRNAmRNA: : UCUUCU--GAGGAG--GCAGCA--GUA GUA

a.aa.a: SER: SER--GLUGLU--ALAALA--VALVAL


3. DNA Gene (chimpanzee)3. DNA Gene (chimpanzee)

AGTAGT--CCTCCT--GTGGTG--TCCTCC

mRNAmRNA: : UCAUCA--GGAGGA--CACCAC--AGG AGG

a.aa.a: SER: SER--GLYGLY-- HISHIS-- ARG ARG

Which species is more closely Which species is more closely related to humans? Why?related to humans? Why?

�� The The chimpanzeechimpanzee has has 33 of the of the same amino same amino

acidsacids as humans with the exception of one as humans with the exception of one –– ARG.ARG.

�� The gorilla has 2 of the same & 2 different.The gorilla has 2 of the same & 2 different.

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Genetic MutationsGenetic Mutations

Albino Koala Albino Koala (San Diego)(San Diego)

June 5, 1998

Albino Albino alligatoralligatorLouisianaLouisianaApril 2, April 2, 20082008

Albino Albino Peacock Peacock Colombia Colombia June 15, June 15, 20052005

Snowflake

The world’s only captive Albino Gorilla, died 2003 from skin

cancer. Lived past 40 years at the Barcelona zoo in Spain.

AlbinoAlbinoNo Skin PigmentationNo Skin Pigmentation

�� Both parents carry the recessive gene for Both parents carry the recessive gene for

albinism.albinism.

�� However, the parents themselves were of However, the parents themselves were of

normal color (grey/black).normal color (grey/black).

What is aWhat is a MUTATIONMUTATION ??

�� A A permanent change in the structure or change in the structure or amount of genetic material.amount of genetic material.

2 Causes of MUTATIONS2 Causes of MUTATIONS

1. Natural random errors (spontaneous)- happens during DNA replication with DNA polymerase.

2. Mutagenic (mutagens) – chemicals & radiation damage DNA.

Ex: x-rays, UV light, radiation, toxic chemicals

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Inherited Sporadic

Total loss of

gene function

Total loss of

gene function

SomeSome MUTATIONSMUTATIONS Are….Are….

HELPFUL NEUTRAL HARMFUL

Genetic variations result in new traits

=

Better working proteins

A change=

Unchanged protein

Defective proteins=

Nonfunctional proteins

2 Types of 2 Types of MUTATIONSMUTATIONS

CHROMOSOMEMUTATIONS

A change in 1 or morebases within a DNA,

It affects a gene on a chromosome.

Change in the NUMBER or STRUCTURE

of chromosome.

GENE

MUTATIONS

What does a Gene do?What does a Gene do?

�� It sequences the order of amino acids for It sequences the order of amino acids for

a specific protein.a specific protein.

�� A A changechange in the in the sequencesequence of a of a basebase will will

change change how mRNA will transcribe for a how mRNA will transcribe for a

specific protein. A different protein could specific protein. A different protein could be made.be made.

Gene MUTATIONSGene MUTATIONS

TYPES

Substitution

Addition

Deletion

Inversion

Definition ATACGAGCC (Normal Gene)

1 base replaces another

ATACGAGCC

ACACGAGCC

Adds an extra base

AT ACGAGCC

ATCACGAGCC

Missing base ATACGAGCC

ATAC_AGCC

Flips bases

ATACGAGCC

ATAAGCGCC

GeneGene MUTATIONSMUTATIONS

�� Alter amino acid Alter amino acid SEQUENCESEQUENCE

�� Alter protein Alter protein SHAPESHAPE

�� Alter protein Alter protein FUNCTIONFUNCTIONEx: enzyme functionEx: enzyme function

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Chromosomal MutationsChromosomal Mutations

�� Usually involves more than one gene Usually involves more than one gene

on the chromosome.on the chromosome.

�� Effects are drasticEffects are drastic

�� Usually Usually LETHALLETHAL!!!!!!!!!!!!

CHROMOSOME MUTATIONSCHROMOSOME MUTATIONS

TYPES

Translocation

Inversion

Addition/

Duplication

Deletion

Definition ABCDEFGHIJ ( Normal Gene)

2 different

chromosomes change parts with

each other

ABCDEFGXYZ

FROM

TUVWXYZ

FLIPPED Genes

(reverses the order)

ABCDEFGHIJ

ABCFEDGHIJ

ADDED GenesABCDEFGHIJ

ABCABCDEFGHIJ

MISSING GenesABCDEFGHIJ

ABCDEFJ

TUVWHIJ

FROM

ABCDEFGHIJ

Chromosome MutationsAddition/ Duplication InversionDeletion

NonNon--disjunctiondisjunction

�� Chromosomes Chromosomes failfail

to separate equally to separate equally

duringduring MEIOSISMEIOSIS(gamete cell division).

� Sperm or egg gets

less or more

chromosomes.

47

chromosomes

InheritedInherited MUTATIONSMUTATIONS

�� When mutation is passed down to When mutation is passed down to

offspring.offspring.

�� Mutation is in the Mutation is in the sex cellsex cell (sperm, (sperm,

egg)egg)

�� Happens during Happens during MEIOSISMEIOSIS

Turner Syndrome

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Turner SyndromeTurner Syndrome

• The presence of only 1 sex chromosome in the cells (X,0)

• Physically- female has underdeveloped sex characteristics, webbed neck,

low-set ears, swollen hands & feet, shorter height, heart defects & kidney problems, &

infertile.

Klinefelter Syndrome

• Has 2 X’s, one Y.

• Male with underdeveloped sex organs,

enlarged breasts, tall stature, long legs, short trunk, infertile, learning disabilities.

Genetic EngineeringGenetic Engineering

Two Ways Humans Can Alter Two Ways Humans Can Alter Genetic MakeGenetic Make--up of Organismsup of Organisms

1. Selective Breeding (artificial selection)

~ Hybridization

~ Inbreeding

2. Bioengineering

*** Both are similar because humans use these methods to develop new traits for better crops,

food, & animals.

Scientists Manipulate Scientists Manipulate (change)(change)

DNADNA

�� Humans mate Humans mate specificspecific plants or animals to plants or animals to

produce better traits, new varieties (type).produce better traits, new varieties (type).

� Goal: To produce : To produce desirabledesirable traits.traits.

1.1. Selective Breeding

1. Plants1. Plants Make better & more crops &

flowers.

Ex: disease resistant corn crops to produce a lot of corn.

2. Animals Make better herds (livestock)

Ex: make Pure breed dogs, cats, race

horses

Ex: Produce more beef, more pork.

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Applied GeneticsApplied GeneticsPolyploidyPolyploidy-- cells have multiple, complete sets of cells have multiple, complete sets of chromosomes to obtain desirable traits in plants.chromosomes to obtain desirable traits in plants.

Chinese hibiscus (East Asia) Bt Corn &

European Corn Borer

Drought Resistant Corn

The dog in your backyard could be a result The dog in your backyard could be a result

of selective breeding.of selective breeding.

Labrador retrieverLabrador retrieverPoodlePoodle

Labradoodles?Labradoodles?

Goldendoodle?Goldendoodle?2 Types of Selective Breeding2 Types of Selective Breeding

1. Hybridization

-- 2 organisms of diff. breeds, but 2 organisms of diff. breeds, but within same species. Ex: dogswithin same species. Ex: dogs

oror

-- crossing 2 organisms of different crossing 2 organisms of different (dissimilar) species. Ex: Mule (horse (dissimilar) species. Ex: Mule (horse & donkey)& donkey)

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Goal of HybridizationGoal of Hybridization

�� 1. Increase genetic diversity1. Increase genetic diversity

�� 2. Make a new breed2. Make a new breed

�� 3. Develop new traits (stronger, size, 3. Develop new traits (stronger, size,

color)color)

�� 4. Breed out unwanted traits4. Breed out unwanted traits

�� 5. Agriculture (healthier, longer surviving 5. Agriculture (healthier, longer surviving plants)plants)

Hybrid AnimalsHybrid AnimalsWolf Dog

Zorse

Pheasant

Wolf + Dog

Horse +Zebra

2 similar pheasants

Mule

Male donkey + female horse

2. Inbreeding2. Inbreeding

-- Mating of closely related individuals Mating of closely related individuals

to maintain to maintain desirable desirable traits.traits.

Ex: cats, farm animals (horses, sheep, Ex: cats, farm animals (horses, sheep,

cattlecattle))

Goal of InbreedingGoal of Inbreeding

�� 1. Increases desirable traits (milk yield, 1. Increases desirable traits (milk yield,

rate of growth)rate of growth)

�� 2. Decreases variation in a population (lab 2. Decreases variation in a population (lab

animals: mice, rats, rabbits). animals: mice, rats, rabbits).

�� 3. Increases risk for abnormal genes (Ex: 3. Increases risk for abnormal genes (Ex:

seizures)seizures)

How can decreasing variation be How can decreasing variation be good?good?

�� Can reduce variables in an experiment.Can reduce variables in an experiment.

�� Investigate certain traits you want to study Investigate certain traits you want to study (aggression).(aggression).

�� Good for studying disease (resistance, Good for studying disease (resistance,

cancer).cancer).

Natural Occurrance of Inbreeding

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Why do the Cheetah, the Giant Panda, & the Why do the Cheetah, the Giant Panda, & the

Wolf inbreed?Wolf inbreed?

�� Factors (health weaknesses, Factors (health weaknesses,

environmental changes, & certain innate environmental changes, & certain innate behaviors) have lead to geographic behaviors) have lead to geographic

isolation resulting in inbreeding.isolation resulting in inbreeding.

�� Result in less favorable genes that will put Result in less favorable genes that will put them at risk for extinction.them at risk for extinction.

Questions?Questions?

�� Name Name 2 methods2 methods that humans use to that humans use to

develop new traits for better crops, animals, develop new traits for better crops, animals, & food.& food.

Selective breeding & Bioengineering

Hybridization

Inbreeding

Figure 17.5 A tobacco plant expressing a firefly geneFigure 17.5 A tobacco plant expressing a firefly gene

BioengineeringBioengineering�� Also called: Also called: recombinant DNArecombinant DNA or or gene splicinggene splicing..

�� DNA (genes) from 1 species is inserted into DNA (genes) from 1 species is inserted into another species DNA to produce rare another species DNA to produce rare substances that are wanted.substances that are wanted.

�� GoalGoal: To correct genetic disorders by : To correct genetic disorders by transferring normal genes to cells that do not transferring normal genes to cells that do not have the gene.have the gene.

http://www.sumanasinc.com/webcontent/animationhttp://www.sumanasinc.com/webcontent/animations/content/plasmidcloning.htmls/content/plasmidcloning.html

Transgenic bacteriaTransgenic bacteria

�� Bacteria with foreign genes in it.Bacteria with foreign genes in it.

�� ExampleExample::

-- A A bacteriabacteria is injected with the human is injected with the human gene for a rare protein (interferon, insulin, gene for a rare protein (interferon, insulin, or clotting substances) to be made.or clotting substances) to be made.

-- ResultsResults in more of the desired in more of the desired substances (proteins) to be made.substances (proteins) to be made.

Interferon- is an antiviral chemical that

helps humans fight off viruses.

What is a What is a PlasmidPlasmid??

�� A roundA round--shaped DNA molecule found shaped DNA molecule found

inside a bacteria that have genes on it.inside a bacteria that have genes on it.

What ToolTool Do Scientists Use to Insert

Genes On a Plasmid?

Restriction Enzymes Restriction Enzymes

(cuts the DNA within a specific (cuts the DNA within a specific

sequence)sequence)

19

Recognition sequences

Section 13-2

Restriction Enzymes

Recognition sequences are the places on the DNA where an

enzyme will cut it

Recognition sequences

Sticky end

Section 13-2

Restriction Enzymes

Human Cell

Gene for human growth hormone

RecombinantDNA

Gene for human growth

hormone

Sticky ends

DNA recombination DNA

insertion

Bacterial Cell

Plasmid

Bacterial chromosome

Bacterial cell for containing gene

for human growth hormone

Section 13-3

Figure 13-9 Making Recombinant DNA Steps Steps For Gene SplicingFor Gene Splicing

1.1. Cut the desired DNA into pieces using Cut the desired DNA into pieces using

restriction enzymes restriction enzymes (a protein).(a protein).

2. Next, 2. Next, plasmids are removed from bacterial are removed from bacterial

cells. cells.

3. Plasmids are placed in a solution containing3. Plasmids are placed in a solution containing

foreign DNA (test tube).foreign DNA (test tube).

4. Restriction enzyme is added to break 4. Restriction enzyme is added to break open the plasmid.open the plasmid.

5. Foreign DNA attaches to the opening of 5. Foreign DNA attaches to the opening of the plasmid to become 1.the plasmid to become 1.

6. Plasmid ring closes.6. Plasmid ring closes.

7. Insert the DNA pieces into a host cell (ex: 7. Insert the DNA pieces into a host cell (ex: virus, bacteria).virus, bacteria).

8. Bacteria replicates.8. Bacteria replicates.

Draw diagram.

http://www.sumanasinc.com/webcontent/animations/content/plasmidcloning.html

Questions?Questions?

�� A Type of Bioengineering would beA Type of Bioengineering would be

______________ or ________________________________ or __________________Gene splicing Recombinant DNA

20

CLONINGCLONING

�� An organism with An organism with EXACTLYEXACTLY the the SAMESAME

number of genes.number of genes.

� Benefits::

~ Produce better ~ Produce better livestocklivestock (cows, pigs, sheep)(cows, pigs, sheep)

~ Produce better ~ Produce better cropscrops (wheat, corn, rice)(wheat, corn, rice)

� Examples::

Identical twinsIdentical twins

Asexual reproduction Asexual reproduction (ameba, bacteria, some plants)(ameba, bacteria, some plants)Dolly the sheep (1996-2003). Courtesy of Roslin Institute, Edinburgh.

PROCEDURE FOR CLONINGPROCEDURE FOR CLONING

1. Remove nucleus1. Remove nucleus

from egg cellfrom egg cell

(discard nucleus)(discard nucleus)

2. Remove 2. Remove nucleus from nucleus from

cell of organismcell of organism

3. Insert 3. Insert nucleus from nucleus from

body cell into body cell into egg cellegg cell

4. Electric Shock to begin cell

division into embryo

5. Implant embryo 5. Implant embryo into uterusinto uterus

6. Embryo 6. Embryo develops into develops into

cloneclone Removing an egg's nucleus during nuclear transfer. Courtesy of Roslin Institute, Edinburgh.

NUCLEAR TRANSFERNUCLEAR TRANSFEREthical, legal and social issues.

�Ethical issues - consider the potential moral outcomes of cloning technologies.

�Legal issues - how should it be regulated by thegovernment.

�Social issues –impact on society as a whole.

Some questions to ponder.•Who has the right to have children, no matter how they are created?

•Is human cloning "playing with nature?“in vitro fertilization or hormone treatments?

•Does cloning to create stem cells, also called therapeutic cloning,

justify destroying a human embryo?•If a clone originates from an existing person, who is the parent?•What are some of the social challenges a cloned child might face?

•Do the benefits of human cloning outweigh the costs of human dignity?•Should cloning research be regulated? How, and by whom?

21

Gel ElectrophoresisGel Electrophoresis

�� A techniques to separate DNA fragments A techniques to separate DNA fragments by length (size) in an electrical field using by length (size) in an electrical field using a gel.a gel.

�� DNA is (DNA is (--) charged due to the ) charged due to the phosphatephosphatelocated on DNA strands.located on DNA strands.

�� DNA fragments will move towards the DNA fragments will move towards the POSITIVE POLE!POSITIVE POLE!

Smaller fragments

move faster than larger fragments

because of a lower

molecular weight.

ProcedureProcedure: : Gel ElectrophoresisGel Electrophoresis

1.1. Restriction enzymes cut DNA into Restriction enzymes cut DNA into

different length pieces.different length pieces.

2.2. DNA fragments are put into wells in gel.DNA fragments are put into wells in gel.

3.3. Electrical current causes fragments to Electrical current causes fragments to

travel towards the + pole.travel towards the + pole.

4.4. Smaller fragments are faster & travel Smaller fragments are faster & travel

further in gelfurther in gel

Larger fragments more slower.Larger fragments more slower.

UsesUses

1. Compare relatedness of individuals of 1. Compare relatedness of individuals of

some or different species.some or different species.

2. Paternity or maternity testing2. Paternity or maternity testing

3. Place suspects at a crime scene or not.3. Place suspects at a crime scene or not.

InterpretationInterpretation

�� Identical DNAIdentical DNA Band Pattern = Same IndividualBand Pattern = Same Individual

�� Similar DNASimilar DNA Band Pattern = Related IndividualBand Pattern = Related Individual

�� Different BandDifferent Band Pattern = Not Closely Related Pattern = Not Closely Related

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Genetic DisordersGenetic Disorders

Words To Know!Words To Know!

�� AllelesAlleles

–– An area of DNA on a chromosome.An area of DNA on a chromosome.

-- The different forms of a gene for a The different forms of a gene for a

specific trait.specific trait.

-- Humans have Humans have 2 alleles2 alleles

for each trait.for each trait.

-- Allows for Allows for

genetic variation..

Allele

Allele

�� DominantDominant-- the trait expressed (XX, Xx)the trait expressed (XX, Xx)

�� RecessiveRecessive-- the trait that’s hidden (xx)the trait that’s hidden (xx)

Cystic FibrosisCystic Fibrosis�� RecessiveRecessive disorder (inherited from 2 defective disorder (inherited from 2 defective

genes)genes)�� System AffectedSystem Affected: lung & digestive system: lung & digestive system

�� DiseaseDisease: : -- thick mucus in lungs = difficulty breathing thick mucus in lungs = difficulty breathing -- blocked pancreas = difficulty breaking down to blocked pancreas = difficulty breaking down to digest food (fats)digest food (fats)

�� SymptomsSymptoms: difficulty breathing, constipation, : difficulty breathing, constipation, lung infectionslung infections

TX: inhaler, percussion therapyTX: inhaler, percussion therapy

Chloride channeldefect- diffusion of

salt & water in the cell membrane doesn’t work.

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Sickle Cell AnemiaSickle Cell Anemia�� Recessive Recessive disorderdisorder�� System AffectedSystem Affected: RBC is : RBC is Sickle-shaped (defect in

hemoglobin)

�� Disease:Disease:-- blocked blood vessels blocked blood vessels -- decrease oxygendecrease oxygen

�� SymptomsSymptoms::

- fatigue, PAIN

Tx: fluids, restTx: fluids, rest

Sickle Cell AnemiaSickle Cell Anemia

�� Normal codon is GNormal codon is GAAA = glutamic acidA = glutamic acid

�� Abnormal codon is GAbnormal codon is GUUA = valineA = valine

DEFECTIVE GENE DEFECTIVE GENE

CHANGES AMINO ACID CHANGES AMINO ACID SEQUENCE SEQUENCE

CHANGES PROTEIN CHANGES PROTEIN SHAPESHAPE

CHANGES FUNCTION

TYPE= Substitution

Phenylketonuria (PKU)Phenylketonuria (PKU)

�� RecessiveRecessive disorder (inherited 2 defective genes)disorder (inherited 2 defective genes)

�� System AffectedSystem Affected: high levels of phenylalanine in : high levels of phenylalanine in blood due to the missing enzyme (protein) called blood due to the missing enzyme (protein) called Phenylalanine.Phenylalanine.

�� DiseaseDisease::

-- unable to break down amino acids so it breaks unable to break down amino acids so it breaks down into chemicals that damage the brain.down into chemicals that damage the brain.

�� Symptoms:Symptoms:

-- mental retardationmental retardation

Tx: special diet (low protein)Tx: special diet (low protein)

TayTay--SachsSachs�� RecessiveRecessive disorderdisorder

�� System AffectedSystem Affected: Nervous System due to lack of : Nervous System due to lack of enzyme needed to break down LIPIDSenzyme needed to break down LIPIDS


-- unable to break down lipids, important for unable to break down lipids, important for normal brain function.normal brain function.

�� SymptomsSymptoms: build up of lipids in brain tissue = : build up of lipids in brain tissue = brain damage, blindness, muscle paralysis.brain damage, blindness, muscle paralysis.

Tx: none, early deathTx: none, early death

Nerve Cell

damage

http://www.momsonthemove.com/show_detail.asp?id=9

Down’s SyndromeDown’s Syndrome

�� NondisjunctionNondisjunction (chromosomes do not separate (chromosomes do not separate during meiosis)during meiosis)

2424 (egg) + 23 (sperm) = 47 chromosomes(egg) + 23 (sperm) = 47 chromosomes

�� Systems AffectedSystems Affected: Brain, heart, kidney: Brain, heart, kidney


-- extra chromosome # on chrom. 21extra chromosome # on chrom. 21

�� SystemsSystems: mental disabilities: mental disabilities

physical problems, physical problems,

heart, kidneyheart, kidney

nucleus chromosome gene - living...

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