basics of dna todd rightmire mt. baker high school
TRANSCRIPT
Basics of DNABasics of DNATodd RightmireTodd Rightmire
Mt. Baker High SchoolMt. Baker High School
Cellular compositionCellular composition
DNA is contained in DNA is contained in nucleus of cellnucleus of cell
Phospho-lipids and Phospho-lipids and proteins combined to proteins combined to form cell membraneform cell membrane
Lipids are fatsLipids are fats
DNA (DeoxyriboNucleic Acid) is a DNA (DeoxyriboNucleic Acid) is a double helixdouble helix
Backbone is made of Backbone is made of sugar-phosphatesugar-phosphate
Base pairs bind the Base pairs bind the backbone togetherbackbone together
Adenine always pairs Adenine always pairs with Thyminewith Thymine
Guanine binds with Guanine binds with CytosineCytosine
Base pairsBase pairs
AA==T – T – double hydrogen bonddouble hydrogen bond
GG C – C – triple hydrogen bondtriple hydrogen bond
Nucleotide (3 chemical Nucleotide (3 chemical groups)groups) Sugar – deoxyriboseSugar – deoxyribose
contains 5 Carbon atomscontains 5 Carbon atoms
Phosphate groupPhosphate group A base (A, T, G, C)A base (A, T, G, C)
Extracting DNA from an onionExtracting DNA from an onion
Papain (enzyme) is found in meat Papain (enzyme) is found in meat tenderizertenderizer destroys cell membranedestroys cell membrane
Detergent – breaks down lipids in cell Detergent – breaks down lipids in cell membranemembrane
Ethanol and heat shock?Ethanol and heat shock?
DNA replication/synthesisDNA replication/synthesis
DNA has a lagging strand DNA has a lagging strand 3’-5’ and a leading strand 3’-5’ and a leading strand 5’-3’5’-3’
The 5’ end matches with The 5’ end matches with a 3’ end in a double helixa 3’ end in a double helix
DNA replication occurs DNA replication occurs every 20 minutes in E. every 20 minutes in E. coli (widely used to coli (widely used to reproduce DNA)reproduce DNA)
Copying DNA moleculeCopying DNA molecule Each DNA strand (double Each DNA strand (double
helix) unzips itselfhelix) unzips itself Happens before cell Happens before cell
division (mitosis and division (mitosis and meiosis)meiosis)
Done in PCR Done in PCR (polymerase chain (polymerase chain reaction) to make a lot of reaction) to make a lot of the same DNA (mass the same DNA (mass replication) for analysis replication) for analysis through fingerprinting.through fingerprinting.
DNA replicationDNA replication
MutationsMutations Caused by chance, genes, Caused by chance, genes,
and environmentand environment ultraviolet lightultraviolet light tobacco/alcoholtobacco/alcohol change in genetic coding of change in genetic coding of
amino acidsamino acids TypesTypes
insertioninsertion deletiondeletion substitutionsubstitution inversion (flipping)inversion (flipping)
Cystic fibrosisCystic fibrosis Some are beneficial – postitive Some are beneficial – postitive
traittrait Drought resistance, etc.Drought resistance, etc.
Sickle cell anemia
Use the Amino Acid Chart to Use the Amino Acid Chart to identify the mutationidentify the mutation
ATT CCG CTA CAA CGA TGC TAGATT CCG CTA CAA CGA TGC TAG
Insertion mutation (inserting a letter in Insertion mutation (inserting a letter in sequence)sequence)
ATT ATT AACC GCT ACA ACG ATG CTA ……CC GCT ACA ACG ATG CTA ……
http://learn.genetics.utah.edu/archive/mutations/http://learn.genetics.utah.edu/archive/mutations/
CancersCancers
Caused by Caused by abnormalities abnormalities (mutations) in genetic (mutations) in genetic material of the material of the transformed cellstransformed cells
Carcinogens – cancer Carcinogens – cancer causing (tobacco, causing (tobacco, smoke, chemicals, smoke, chemicals, radiation, alcohol, etc)radiation, alcohol, etc)
Mutagens – mutation Mutagens – mutation forming substanceforming substance
http://http://www.johnkyrk.com/www.johnkyrk.com/
meiosis.htmlmeiosis.html Aneupliody – change in number of Aneupliody – change in number of
chromosomes leads to chromosomal disorderschromosomes leads to chromosomal disorders Downs syndrome – extra 21Downs syndrome – extra 21stst chromosome chromosome Edwards syndrome – three chromosome 18 Edwards syndrome – three chromosome 18
50% die in uteuro50% die in uteuro 25% die by 2 months25% die by 2 months 5-10% survive 1 year.5-10% survive 1 year.
Patau Syndrome – trisomy (3) of chromosome 13Patau Syndrome – trisomy (3) of chromosome 13 All other chromosomal abnormalities are fatal in All other chromosomal abnormalities are fatal in
uteurouteuro
TranscriptionTranscription
DNA is copied to RNADNA is copied to RNA T is changed to a UT is changed to a U So then A bonds with a U So then A bonds with a U
(Uracil)(Uracil) Proceeds in the 5’-3’ Proceeds in the 5’-3’
positionposition mRNA – leaves nucleus mRNA – leaves nucleus
as a copy and codes for as a copy and codes for an amino acid an amino acid (translation)(translation)
TranslationTranslation
occurs within the occurs within the cytoplasm of cellcytoplasm of cell
tRNA – transfer RNAtRNA – transfer RNA decodes information decodes information
from mRNA to from mRNA to produce amino acidsproduce amino acids
3 codons translate to 3 codons translate to an amino acidan amino acid
Translation animationTranslation animation
Amino AcidAmino Acid
A chain of nucleotides A chain of nucleotides makes a codon (3 makes a codon (3 letter word such as letter word such as ATT, GCAATT, GCA
Each codon makes Each codon makes an amino acid (20 an amino acid (20 essential Amino essential Amino Acids)Acids)
““Stop” codons means Stop” codons means translation stops and translation stops and a gene is completea gene is complete
GenesGenes
A string of codons codes A string of codons codes for several amino acids to for several amino acids to form a geneform a gene
A gene can be as short A gene can be as short as 50 nucleotides and as as 50 nucleotides and as long as 250 million.long as 250 million.
Humans have over 3 Humans have over 3 billion nucleotides or 1 billion nucleotides or 1 billion codonsbillion codons
Each gene codes for a Each gene codes for a certain trait.certain trait.
Chromosome
Gene pairingGene pairing
Every gene is paired by the gene of the Every gene is paired by the gene of the opposite sexopposite sex
Dominant or recessive (R) or (r)Dominant or recessive (R) or (r) Heterozygous - carrier (different) - RrHeterozygous - carrier (different) - Rr Homozygous (same) – rr or RRHomozygous (same) – rr or RR Dominant gene is expressed as phenotypeDominant gene is expressed as phenotype Punnett SquarePunnett Square
Punnett SquarePunnett Square
ChromosomesChromosomes
Macromolecule of DNAMacromolecule of DNA Contains many genesContains many genes Usually contained in the Usually contained in the
nucleus. nucleus. Eukaryotic cells Eukaryotic cells
mitochondria and mitochondria and chloroplasts contain chloroplasts contain chromosomeschromosomes
Human cell – 23 pairs of Human cell – 23 pairs of chromosomes (23 from chromosomes (23 from dad, 23 from mom)dad, 23 from mom)
Males have XY Males have XY chromosomechromosome
Females have XX Females have XX chromosomechromosome
XYY has been attributed XYY has been attributed is a trait of several serial is a trait of several serial killerskillers
Sperm contains X or YSperm contains X or Y An X is always donated An X is always donated
by a female and an X or a by a female and an X or a Y is donated by the maleY is donated by the male
Meiosis (haploid)Meiosis (haploid)
formation of a new individual by combining two formation of a new individual by combining two haploid sex cells (gametes – sperm/egg)haploid sex cells (gametes – sperm/egg)
Fertilization – genetic info from two separate cells Fertilization – genetic info from two separate cells (1/2 of original genetic info)(1/2 of original genetic info)
both gametes are haploid – 1 set of both gametes are haploid – 1 set of chromosomeschromosomes
combine as a zygote with 2 sets of chromosomescombine as a zygote with 2 sets of chromosomes meiosis is a process to convert a diploid to a meiosis is a process to convert a diploid to a
haploid gamete causing a change in genetic haploid gamete causing a change in genetic information to increase the diversity of offspringinformation to increase the diversity of offspring
Meiosis Meiosis
Meiosis (haploid)Meiosis (haploid)
Meiosis I and IIMeiosis I and II
Mitosis AnimationMitosis Animation
MitosisMitosis
Natural Cloning Natural Cloning (replicates parent cell)(replicates parent cell)
Cell divisionCell division
Law of SegregationLaw of Segregation
alleles are alleles are responsible for traits responsible for traits from each parent are from each parent are separated and are separated and are randomly combined randomly combined with the other parent with the other parent at fertilization.at fertilization.
Parent provides one Parent provides one of the two genes for of the two genes for each traiteach trait
Law of SegregationLaw of Segregation
1.1. Alternative forms for Alternative forms for genesgenes
2.2. Each trait inherits one Each trait inherits one alternative forms from alternative forms from each parent. Called each parent. Called alleles.alleles.
3.3. Gametes- allele pairs Gametes- allele pairs separate or separate or segregate segregate leaving only 1 allele for leaving only 1 allele for each trait.each trait.
4.4. When 2 alleles of a pair When 2 alleles of a pair are different, one is are different, one is dominant, one is dominant, one is recessive.recessive.
Law of Independent AssortmentLaw of Independent Assortment
allele pairs separate allele pairs separate independently during independently during formation of gametes. formation of gametes.
Traits are transmitted to Traits are transmitted to offspring independent of offspring independent of each other. each other.
Reason why there is Reason why there is diversity among siblings diversity among siblings and organismsand organisms
G – green pod, g – yellowG – green pod, g – yellow Y – Yellow seeds, g - Y – Yellow seeds, g -
greengreen
9:3:3:1 ratio when breeding 2 heterozygous traits (Dihybrid cross)
Genotype and PhenotypeGenotype and Phenotype
Genotype – genetic make up Genotype – genetic make up Phenotype – physical traitsPhenotype – physical traits Phenotype is expressed always by Phenotype is expressed always by
dominant allele. dominant allele. Phenotype = Genotype + EnvironmentPhenotype = Genotype + Environment
means that what something looks like means that what something looks like depends on genetics AND environment!!!depends on genetics AND environment!!!
Gel ElectrophoresisGel Electrophoresis
What is it?What is it? Electrophoresis separates DNA and Electrophoresis separates DNA and
Proteins using electricity through a porous Proteins using electricity through a porous
material.material.
Movement of the DNA and Protein is a Movement of the DNA and Protein is a
function of size.function of size.
• DNA speed is based on size. DNA speed is based on size.
• Smaller is Faster and Bigger is slower.Smaller is Faster and Bigger is slower.
It’s like McDonalds on a busy weekend. It’s like McDonalds on a busy weekend.
Porous Material UsedPorous Material Used Agarose (Natural Polysaccharide)Agarose (Natural Polysaccharide)
Most commonly used material in research.Most commonly used material in research. Polyacrylamide (Synthetic Material)Polyacrylamide (Synthetic Material)
Ideal when accuracy and precision are important. Ideal when accuracy and precision are important.
DNA VisualizationDNA VisualizationAutoradiographyAutoradiography
RadioisotopesRadioisotopes Intercalating Dyes
Ethidum Bromide