Aim: Aim: How do your How do your genetics play a role in genetics play a role in the person you are the person you are today?today? Do Now: Do Now: What similarities do you What similarities do you
have with your parents or have with your parents or siblings? siblings?
Homework:Textbook 126-132 #1-5 Homework:Textbook 126-132 #1-5
What is Heredity?What is Heredity?
The transfer of characteristics from one The transfer of characteristics from one generation to the nextgeneration to the next
What are Traits?What are Traits? A characteristic that is determined by A characteristic that is determined by
your genesyour genes A pair of genes will determine the traitA pair of genes will determine the trait
Examples:Examples: Tongue rollingTongue rolling EarlobesEarlobes Widow’s PeakWidow’s Peak Hair WhorlHair Whorl DimplesDimples
What is genetics?What is genetics?
The science of how traits are inheritedThe science of how traits are inherited
How are traits determined?How are traits determined? Dominant GenesDominant Genes – the traits that will – the traits that will
usually appear in the individual usually appear in the individual (represented by an uppercase letter)(represented by an uppercase letter) If an organism has a gene for blue or If an organism has a gene for blue or
brown eyes, usually it will have brown brown eyes, usually it will have brown eyes because it is the dominant geneeyes because it is the dominant gene
Recessive GenesRecessive Genes – The gene hidden by – The gene hidden by the dominant gene the dominant gene (represented by a lowercase letter)(represented by a lowercase letter) Blue-eyed people need two recessive Blue-eyed people need two recessive
genes to show the blue-eyed traitgenes to show the blue-eyed trait
Who is Gregor Mendel?Who is Gregor Mendel?
““Father of Genetics”Father of Genetics” Studied pea plantsStudied pea plants He crossed pea plants with different He crossed pea plants with different
characteristics and studied their offspringcharacteristics and studied their offspring He was able to determine how He was able to determine how
traits get passed on from traits get passed on from
generation to generationgeneration to generation
What is a Punnett What is a Punnett Square?Square? A table that shows A table that shows
the possible results the possible results when the genes of when the genes of two parents are two parents are crossedcrossed
It shows the It shows the probability of a trait to probability of a trait to be expressed in the be expressed in the offspring offspring
BB BB
BB BBBB BBBB
bb BbBb BbBb
B – Brown Eyes
b – Blue Eyes
What is a genotype?What is a genotype?
The genetic code or make up of the The genetic code or make up of the individualindividual
Examples: Examples: BB, Bb, bbBB, Bb, bb
What is a genotype?What is a genotype?
Homozygous dominantHomozygous dominant
– – a pair of dominant genes (BB)a pair of dominant genes (BB) Homozygous recessiveHomozygous recessive
– – a pair of recessive genes (bb)a pair of recessive genes (bb) Heterozygous or hybridHeterozygous or hybrid
– – a mixed pair of one dominant gene and a mixed pair of one dominant gene and one recessive gene (Bb)one recessive gene (Bb)
What is a phenotype?What is a phenotype?
The way an organism looks or behavesThe way an organism looks or behaves Examples:Examples:
GenotypeGenotype PhenotypePhenotype
BBBB Brown HairBrown Hair
BbBb Brown HairBrown Hair
Lets try some Punnett Lets try some Punnett Squares!Squares!
Examples:Examples: BB x bbBB x bb Bb x bb Bb x bb Bb x BbBb x Bb bb x bbbb x bb BB x BBBB x BB BB x BbBB x Bb
B = Brown EyesB = Brown Eyes
b = Blue Eyesb = Blue Eyes
What we are looking for:What we are looking for:
1.1. GenotypesGenotypes
2.2. PhenotypesPhenotypes
3.3. Percentage Brown eyesPercentage Brown eyes
4.4. Percentage Blue EyesPercentage Blue Eyes
Pedigree ChartsPedigree Charts
Allow us to trace certain traits. Helpful for tracking genetic disorders passed down through generations. Ex: Colorblindness
DNA StructureDNA StructureA double helix made of a sugar-phosphate backbone bound in the middle by nucleotide base pairs-The backbone is made up of molecules that have phosphates and sugars – basically the sides of the ladder-The nucleotides,which come in pairs, make up each step of the ladder
NucleotidesNucleotidesEverything that determines what we look like, our likes, our dislikes, whether we’re a morning person or we like to sleep in is largely determined by four nucleotides that are repeated over and over again inside each and of one of our cells.
Adenine
Cytosine
Guanine
Thymine
These four molecules hold our DNA together by binding together in pairs. Adenine and Thymine will always be paired. Cytosine and Guanine will always be paired.
**Guanine will not pair with Adenine, nor Thymine with Cytosine!!!!
Protein BuildingProtein Building
So how does our DNA actually determine why we are made this way?
Earlier in the year, we learned about ribosomes – who synthesize proteins. They get their orders from the DNA.
How??How??The ribosomes will read sections of DNA, and every time it reads three nucleotides, it goes and gets an amino acid. Once it has a few amino acids lined up, it chains them together, forming a protein. That protein then goes out to do it’s job, building your body from the ground up!
Remember – proteins come in many different forms, think of them like tools – many shapes and sizes, all with very different jobs.
ReplicationReplicationWhen DNA is copied, it is “unzipped”, separating the two strands of DNA.
Once separated, ribosomes work to create a complementary strand.
As the complementary strand is formed, the DNA and the new strand are “zipped” together, creating two separate strands of the same DNA.
Sometimes, errors occurs. These errors are called mutations
MutationMutationMutations can happen for a variety of reasons. Some are good, some are bad. Our DNA has methods built in to find and correct mutations, but not all of them are corrected in time.
If mutations are good, helping the organism to survive, there is a chance that they will be passed on to the offspring. This is a gradual change, that ultimately results in evolution over several generations of a species.
Restriction EnzymesRestriction Enzymes
Enzymes that cut DNA at specific Enzymes that cut DNA at specific locations.locations.
Genetically Engineered Genetically Engineered BacteriaBacteria
PlasmidPlasmid (loop of DNA) is (loop of DNA) is removed from bacterial removed from bacterial
cellcell A specific gene is removed A specific gene is removed
from an animal cellfrom an animal cell Animal gene is spliced into Animal gene is spliced into
plasmidplasmid Recombinant DNARecombinant DNA is inserted is inserted
into into bacterial cellbacterial cell Bacteria and it’s descendants will Bacteria and it’s descendants will
now produce an animal now produce an animal proteinprotein
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