Genetics Flashcards
Gregor Mendel
He was a monk and the father of genetics who studied pea plants to create Mendels Laws
Mendels Laws
-Law of Dominance
-Law of Segregation
-Law of Independent Assortment
Law of Dominance
In a hybrid only the dominant trait is seen, there is no blending of traits
Law of Segregation
Alleles separate during meiosis and can come together in different pairings during fertilization
Law of Independent Assortment
Traits are usually inherited independently of each other
Linked Genes
Genes that often go together like freckles and red hair
Gene-Chromosome Theory
Different form of genes are Alleles and can be uppercase (dominant) and lowercase (recessive)
Locus
The spot on a chromosome where the gene is located
Allele
Different form of the same gene (brown hair/red hair)
Genotype
The genetic makeup of a person that you CANNOT SEE (TT, Tt, tt)
Homozygous Dominant
TT
Homozygous Recessive
tt
Heterozygous
Tt
Phenotype
The physical appearances we can see due to genes (tall/short)
Punnett Square
Used to see the possible allele assortments when crossing two organisms
t t
T🔲 🔲
t 🔲 🔲
Test Cross
Where you cross an unknows Genotype with a homozygous recessive to figure out that person genes
Incomplete Dominance
Both alleles and capitalized because they blend when put together (RW-pink)
Codominance
When both alleles are expressed equally because they both appear on the organism
Sex Linkage
When diseases or traits are connected to the X or Y chromosome
Dihybrid Cross
Tracking two genes with a punnet square
T.H. Morgan
Discovered sex-linked chromosomes by studying fruit flies
Sex Linked Disorders
-Colorblindness
-Hemophilia
-Muscular Dystrophy
Frederick Griffith
Bacteria transformation with “factors” discovered that bacteria share “factors” which were not yet known as DNA
Avery, MacLeod, and McCarty
Discovered that “factors” were actually DNA
Hershey and Chase
They worked with bacteriophages and discovered that DNA contains genetic information
Watson and Crick (Rose Franklin)
They discovered that DNA’s structure is an alpha helix
Helicase
Breaks open the two DNA strands
DNA Polymerase
Attaches to one strand of DNA and makes a complementary strand
DNA Transcription
How RNA is made
Codon
a group of three bases Ex. TGC
Promoter Region
The beginning of a gene
What Facilitates RNA Polymerase Binding
Transcription factors bind to the strand in order to facilitate the polymerase binding
What you need to do DNA Translation
Translating the mRNA into a protein you need:
-mRNA
-ribosome
-T-RNA
-amino acids
How Translation Happens
The small subunit binds to the first codon, the T-RNA connects to the codon, and the large subunit goes on top. The TRNA corresponds to the codon and has an amino acid on top. A new TRNA comes in and replaces the old one allowing the amino acids to form a polypeptide chain
Polysomes/Polyribosomes
Multiple ribosomes translating mRNA at the same time
5’–>3’
Operon
A grouping of DNA with the same function in BACTERIA
Types of Genes in an Operon
- regulator gene
- promoter
- operator
4a-c. structural genes
Regulator Genes of an Operon
Codes for a repressor protein
Promoter of an Operon
Site for RNA polymerase binding
Operator of an Operon
On/Off switch for structural genes
Structural Genes of an Operon
Code for enzymes to digest lactose (in this case)
Gene Regulation in Higher Organisms
-environment
-differential coilling
-transcription factors
-differential mRNA splicing
-epigenetics
Differential Coilling
DNA coils are looser so they can be read and tighter so they cannot
Transcription Factors
Things that must be in place in order for polymerase binding, if they aren’t there will be no copying of the DNA into mRNA
Differential mRNA Splicing
Taking away the introns in a gene code so the extrons are in a better order for different proteins to be made
Introns
Regions of DNA that are spliced out because they code for nonsense
Extrons
Pieces of DNA that are expressed and that do code for proteins
Epigenetic Tags
Groups that bond to genes and can effect how they are expressed (turning them on/off) they are passed down through your genetics
Genetic Mutation
A change in DNA
Chromosomal Mutations
Mutations in a whole chromosome number or structure
Gene Mutations
Mutations in the sequence of a specific gene
Causes of Mutation
-random errors
-mutagens
Types of Chromosomal Mutations
-translocations
-inversions
-additions
-deletions
-nondisjunction
-polyploidy
Translocation
A chunk of information from one chromosome moves to a nonhomologous chromosome
Inversion
A chunk of the chromosome gets inverted
Addition
Genes get added from a homologous chromosome
Deletion
A section of the chromosome is lost/deleted
Nondisjunction
Chromosomes don’t separate during meiosis so the child is born with extra or missing chromosomes
Polyploidy
A form of nondisjunction in plants where they end up with 3n-5n chromosomes (enlarged fruit) farmers purposely do it using mutagens
Types of Gene Mutations
-point mutation
-deletion
-addition
-substitution
-missense mutation
-nonsense mutation
-silent mutation
Pont Mutation
A change in a single nucleotide
Addition/Deletion
This causes a frameshift and the codons to be read in the wrong groups
Missense Mutation
The altered nucleotide causes an altered codon and an altered protein
Nonsense Mutation
The altered nucleotide causes for a premature stop codon
Silent Mutation
There is no change in the protein
Barbra McClintock
She discovered transposons (jumping genes)
Transposons
Also known as jumping genes, they cut out and reinsert a piece of genetic information into a different place
Pedigree Chart
Allows people to track family diseases
circle = girl
square = guy
dark = has the disease
half dark = carrier
Sickle Cell Anemia
-altered hemoglobin
-African people
-die early
PKU
-cannot break down phenylalanine
-diagnosed with baby urine
-need diet so you don’t get brain damage
Tay-Sachs
-cannot break down lipids in brain
-affects jews
-no cure
Cystic Fibrosis
-mucus builds up in the lungs
-affects europeans
Huntington’s Disease
-DOMINANT
-break down of brain cells and death in 30s/40s
Down Syndrome
-extra 21st chromosome
-causes mental and physical abnormalities
Turner Syndrome
-girl with only one X (XO)
-undeveloped physical features
Klinefelters Syndrome
-XXY
-considered male
-underdeveloped physical features
Karyotyping
Getting a picture of someones genes (can include sorting them)
Amniocentesis
Extracting amniotic fluid out of the uterus and using the baby skin cells in it to look for disease
Chorionic Villus Sampling
Taking a portion of the placenta to look for chromosomal diseases in the baby
Genetic Counseling
Someone creates a pedigree chart for the family to explain possible diseases
Ultrasound
Blasting soundwaves at the baby in order to develop an image of them
Fetoscopy
The camera looks into the uterus and can have an attachment for sample collection
Types of Genetic Engineering
- Selective breeding
- Inbreeding
- Outbreeding
- Creating mutations
- Cloning
- Recombinant DNA technology
How to Create Recombinant DNA
Extract a bacterias plasmid DNA and replace it with desired gene. Cut it open using restriction enzymes
Plasmid
A small accessory circle of DNA in a bacteria that is not vital for survival but helps it to survive