Genetics:Genetics: Study of Study of HeredityHeredity

Aim:Aim: What is Genetics? What is Genetics?

http://www.youtube.com/watch?v=eOvMNOMRRm8

Sexual Reproduction:Sexual Reproduction:

•Two parentsTwo parents

•Half of the genetic information is Half of the genetic information is received from one parent, half received from one parent, half from the other.from the other.

•VariationVariation Evolution Evolution

Asexual Reproduction:Asexual Reproduction:

•One parentOne parent

•Offspring is identical to parent.Offspring is identical to parent.

•ClonesClones- identical genetic copies.- identical genetic copies.

Genetics:Genetics:

• Gregor Mendel- 1800’s Gregor Mendel- 1800’s • ““Father of Genetics”Father of Genetics”• Pea plants: easy to growPea plants: easy to grow• Contrasting traitsContrasting traits• Easily self and cross pollinate.Easily self and cross pollinate.• From his studies, Mendel arrived at From his studies, Mendel arrived at

conclusions that are the basis for conclusions that are the basis for genetics today!genetics today!

Additional VocabularyAdditional Vocabulary

• Genetics:Genetics: Study of heredity Study of heredity

• Heredity:Heredity: Passing of genetic Passing of genetic information from an organism to it’s information from an organism to it’s offspring.offspring.

• Genes:Genes: units of heredity units of heredity– Determines traits/ characteristics an Determines traits/ characteristics an

offspring will have.offspring will have.– Located on chromosomes.Located on chromosomes.– For each trait-> minimum of 2 genes. For each trait-> minimum of 2 genes.

One from mom, one from dad.One from mom, one from dad.

• There are many genes located on a There are many genes located on a Chromosome.Chromosome.

GenesGenes

Hereditary Information:Hereditary Information:

• DNA- deoxyribonucleic acidDNA- deoxyribonucleic acid

• Organic (C, H, O, N, P).Organic (C, H, O, N, P).

• Double strandedDouble stranded

• Organized in the form of genesOrganized in the form of genes located located on the chromosomes.on the chromosomes.

Hereditary Hereditary Information:cont.Information:cont.

• Homologous chromosomesHomologous chromosomes- are - are same size and shape (one from each same size and shape (one from each parent)parent)– This allows for crossing over and This allows for crossing over and

variation to occur.variation to occur.

http://www.youtube.com/watch?v=lJzZ7p-47P8

Genotype vs. Phenotype:Genotype vs. Phenotype:

Genotype- genes

Ex: B,b,S,s

Phenotype-Physical appearance

Ex: Fur Color, Fur Length

http://www.youtube.com/watch?v=jHWJqzlHl3w

Genetic Recombination:Genetic Recombination:

•Sperm and egg combine to form Sperm and egg combine to form a new cell.a new cell.

•New cell (offspring) has a New cell (offspring) has a complete set of genetic complete set of genetic information (DNA). Each information (DNA). Each offspring is unique.offspring is unique.

The Genetic Code:The Genetic Code:

– Structure of DNA Structure of DNA was discovered by was discovered by 2 scientists:2 scientists:

– 1953 James Watson 1953 James Watson and Francis Crickand Francis Crick

– Created a model Created a model known as the known as the Double HelixDouble Helix a a twisted ladder.twisted ladder.

What is the structure of What is the structure of DNA?DNA?

Structure of DNAStructure of DNA

• Long chain of repeating units ( polymer) Long chain of repeating units ( polymer) called nucleotides.called nucleotides.

• A nucleotide unit contains:A nucleotide unit contains:1. phosphate group O1. phosphate group O2. deoxyribose (sugar)2. deoxyribose (sugar)3. nitrogenous base: 3. nitrogenous base: – A- adenineA- adenine– T- thymineT- thymine– C- cytosineC- cytosine– G- guanineG- guanine

Structure of DNAStructure of DNA

One Strand of DNAOne Strand of DNA•The backbone The backbone

of the molecule of the molecule is alternating is alternating phosphatephosphate and and deoxyribosedeoxyribose, a , a sugar, parts.sugar, parts.

•The teeth are The teeth are nitrogenousnitrogenous basesbases..

phosphate

deoxyribose

bases

Two Stranded DNATwo Stranded DNA

•Remember, Remember, DNA has two DNA has two strands that strands that fit together fit together something something like a zipper.like a zipper.

Types of nitrogen basesTypes of nitrogen bases

• A= adenineA= adenine

• G= guanineG= guanine

• C= cytosineC= cytosine

• T= thymineT= thymine

Structure of a Double HelixStructure of a Double Helix

• Sides of the “ladder” are Sides of the “ladder” are alternating phosphate group alternating phosphate group and deoxyribose sugar.and deoxyribose sugar.

• ““rungs” of the ladder are rungs” of the ladder are made of 2 nitrogenous bases.made of 2 nitrogenous bases.

• Specific pairings:Specific pairings:– There is a weak Hydrogen There is a weak Hydrogen

bondbondBetween the base pairs.Between the base pairs.

– Structure as a double Structure as a double helixhelix

– When a cell goes through When a cell goes through mitosis(cell division) the mitosis(cell division) the DNA must also make a DNA must also make a copy of itself.copy of itself.

DNA by the numbersDNA by the numbers

• Each cell has about 2 Each cell has about 2 m of DNA.m of DNA.

• The average human The average human has 75 trillion cells.has 75 trillion cells.

• The average human The average human has enough DNA to go has enough DNA to go from the earth to the from the earth to the sun more than 400 sun more than 400 times.times.

• DNA has a diameter of DNA has a diameter of only 0.000000002 m.only 0.000000002 m.

The earth is 150 billion mor 93 million miles from the sun.

Aim:Aim: How does DNA How does DNA replicate?replicate?Do Now:Do Now: Please answer the Please answer the

questions on the handout found on questions on the handout found on the front desk, omit questions 5-7.the front desk, omit questions 5-7.

GGenetics enetics CCan an TTell ell AAllll G-GuanineG-Guanine

C-CytosineC-Cytosine

T-ThymineT-Thymine

A-AdenineA-Adenine

Base PairingBase Pairing

• Which bases Which bases always match up?always match up?

• A-TA-T

• G-CG-C

• Adenine always Adenine always binds with Thyminebinds with Thymine

• Cytosine always Cytosine always binds with Guaninebinds with Guanine

Steps of Replication:Steps of Replication:

1.1. DNA unwinds

2. DNA unzips

3. Old strands become templates for new strands

4. Result- 2 identical DNA molecules

Characteristics of a Double Characteristics of a Double HelixHelix

• Proteins and Cell Functioning:Proteins and Cell Functioning:– Proteins-Proteins- long chains formed long chains formed

from 20 kinds of amino acids.from 20 kinds of amino acids.– Sequence(order) of the amino Sequence(order) of the amino

acids influences the shape of the acids influences the shape of the molecule.molecule.

– Proteins include: enzymes, Proteins include: enzymes, insulin, eye color, and skin color.insulin, eye color, and skin color.

DNA- Protein Connection:DNA- Protein Connection:

– Genes contain coded information.Genes contain coded information.– This information is used to make This information is used to make

proteins that are required for it’s proteins that are required for it’s function and structure.function and structure.

– Ribosomes construct proteins based on Ribosomes construct proteins based on the cell’s DNA code (combo of A, C, T, the cell’s DNA code (combo of A, C, T, G’s).G’s).

– Parent and offspring produce similar Parent and offspring produce similar traits that is why there is resemblance traits that is why there is resemblance between them. They produce similar between them. They produce similar proteins.proteins.

Aim: How does protein Aim: How does protein synthesis Work?synthesis Work?

Protein Synthesis:Protein Synthesis:

•The building of protein The building of protein molecules.molecules.

•Synthesizing protein from Synthesizing protein from DNA.DNA.

•Proteins are chains of Proteins are chains of amino acids.amino acids.

Steps:Steps:

– Begins in the nucleus with DNA.Begins in the nucleus with DNA.– DNA code is read by a “ DNA code is read by a “

messenger molecule” messenger molecule” messenger RNA; ; messenger RNA; ;

– mRNA.mRNA.– ““messenger molecule: travels messenger molecule: travels

into the cytoplasm of the cell to into the cytoplasm of the cell to the ribosome.the ribosome.

Steps cont.:Steps cont.:

– With the help of “transfer With the help of “transfer molecules” tRNA amino acids move molecules” tRNA amino acids move to the ribosomes to make proteins.to the ribosomes to make proteins.

– The ribosomes “reads” the code The ribosomes “reads” the code and a chain of amino acids is and a chain of amino acids is produced forming a protein.produced forming a protein.

– ***Protein structure is determined ***Protein structure is determined by DNA***by DNA***

RNA:RNA:

• Ribonucleic AcidRibonucleic Acid

• Single strandedSingle stranded

• Nitrogenous basesNitrogenous bases– A- adenineA- adenine– U- uracilU- uracil– C- cystosineC- cystosine– G- guanineG- guanine

Types of RNATypes of RNA

– Messenger RNA (mRNA)Messenger RNA (mRNA)Copies code from DNACopies code from DNABrings to ribosomeBrings to ribosome

– Transfer RNA (tRNA)Transfer RNA (tRNA)Brings amino acids to ribosome for Brings amino acids to ribosome for protein assemblyprotein assembly

– Mutations:Mutations:Alteration of DNA sequence.Alteration of DNA sequence.Causes a change in code carried Causes a change in code carried for by the gene.for by the gene.Random, but can be increased Random, but can be increased because of chemicals, radiation.because of chemicals, radiation.

Aim: What are different genetic Aim: What are different genetic mutations?mutations?

• Do Now: Please complete the Do Now: Please complete the handout on the front desk.handout on the front desk.

Different Types of Different Types of Mutations:Mutations:

• Original DNA Template Original DNA Template C A A T G C T C A A T G C T A CA C– 1. 1. Substitution:Substitution: one base pair for another. one base pair for another.

C A A C G C T A CC A A C G C T A C– 2. 2. Deletion: Deletion: missing a base.missing a base.

C A A T O C T A CC A A T O C T A C– 3. 3. Addition:Addition: adding an extra base adding an extra base

C A A T A G C T A CC A A T A G C T A C– 4. 4. Inversion:Inversion: bases are rearranged. bases are rearranged.

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

Causes of MutationsCauses of Mutations

• Environmental ConditionsEnvironmental Conditions can affect can affect how genes are expressed.how genes are expressed.– Ex. Himalayan rabbitEx. Himalayan rabbit– Warmer body temperatureWarmer body temperature white fur white fur– Colder body temperatureColder body temperature black fur black fur

• ** Identical twins- separated- different ** Identical twins- separated- different personalitiespersonalities

• Chemicals, hormones can activate a gene, Chemicals, hormones can activate a gene, causing certain proteins to be produced.causing certain proteins to be produced.

Genetic EngineeringGenetic Engineering

• Used to alter instructions in Used to alter instructions in organisms.organisms.

• Produce more desirable traits.Produce more desirable traits.

Selective Breeding:Selective Breeding:

•Produces animals and plants Produces animals and plants with desirable traits. with desirable traits.

•Horse & donkey= mule. Horse & donkey= mule. (outbreeding)(outbreeding)

•Ex. Larger, juicier fruits…Ex. Larger, juicier fruits…•Pure dog, pure cat. Pure dog, pure cat. (inbreeding)(inbreeding)

Inbreeding/ OutbreedingInbreeding/ Outbreeding

Breeding continued:Breeding continued:

•** In sexually reproducing ** In sexually reproducing organismsorganisms only mutations only mutations found on sex cells can be found on sex cells can be inherited by the offspring.inherited by the offspring.

•Mutations occurring in body Mutations occurring in body cells will only affect that cells will only affect that organism.organism.

DNA and Individuality:DNA and Individuality:

• The order of the nitrogenous base pairs, The order of the nitrogenous base pairs, A,T,C,G’s are what makes each person an A,T,C,G’s are what makes each person an individual and unique. This is because the individual and unique. This is because the order allows for certain proteins to be order allows for certain proteins to be produced.produced.

• In an organism every cell contains the In an organism every cell contains the same genetic code.same genetic code.

• However, each cell is different: hair cells, However, each cell is different: hair cells, skin cells, liver cells, stomach cells.skin cells, liver cells, stomach cells.

Gene Expression.Gene Expression.

•Each cell only uses some of Each cell only uses some of the genetic information from the genetic information from the chromosomes. the chromosomes.

•Certain parts of the Certain parts of the chromosomes get “turned chromosomes get “turned on” or “turned off.” on” or “turned off.”

Gene Manipulation:Gene Manipulation:

•Altering genes using enzymesAltering genes using enzymes

•By manipulating the DNA in By manipulating the DNA in plant cells or animal cells; plant cells or animal cells; favorable offspring can be favorable offspring can be producedproduced

•Produce bacteria that can be Produce bacteria that can be beneficial.beneficial.

Steps:Steps:

• Cut DNA segment with enzymesCut DNA segment with enzymes

• This segment can be spliced (moved) This segment can be spliced (moved) and attached to DNA of a new and attached to DNA of a new organism.organism.

• New organism will make the protein New organism will make the protein coded for by DNA code.coded for by DNA code.

Gene ManipulationGene Manipulation

Biotechnology:Biotechnology:

•Apply technology to biology.Apply technology to biology.•Applications of Applications of

Biotechnology:Biotechnology:– By using gene therapy and By using gene therapy and

applying it to modern medicine applying it to modern medicine scientists may:scientists may:

– Produce hormones, enzymes Produce hormones, enzymes and other body chemicals.and other body chemicals.

– Provide at a low cost.Provide at a low cost.– Provide a purer form.Provide a purer form.