9.1-9.14 and 10.1-10.15 Flashcards
What are Mendels 4 Hypotheses
- Genes are found in alternative versions called alleles; a genotype is the listing of alleles an individual carries for a specific gene.
- For each characteristic, an organism inherits two alleles, one from each parent; the alleles can be the same or different
- If the alleles differ, the dominant allele determines the organism’s appearance, and the recessive allele has no noticeable effect
- Law of segregation: Allele pairs separate (segregate) from each other during the production of gametes so that a sperm or egg carries only one allele for each gene
Homozygous
genotype has identical alleles.
Heterozygous
genotype has two different alleles
What is the Law of Segregation
Allele pairs separate (segregate) from each other during the production of gametes so that a sperm or egg carries only one allele for each gene (One of Mendels Hypotheses)
Phenotype
is the appearance or expression of a trait
Genotype
Genetic makeup
Dominant
The allele that determines the phenotype of a gene when the individual is heterozygous for that gene
Recessive
An allele that has no noticeable affect on the phenotype of a gene when the individual is heterozygous for that gene
Law of independent assortment
Each pair of alleles segregates independently of the other pairs of alleles during gamete formation
What type of cross represents independent assortment?
Dihybrid
What do geneticists use of determine unknown genotypes
Testcross
What is a test cross
Mating between an individual of unknown genotype and a homozygous recessive individual
Results will show whether the unknown genotype includes a recessive allele
Used by Mendel to confirm true-breeding genotypes
How can genetic traits in humans be tracked?
Pedigrees
What is a pedigree
Shows the inheritance of a trait in a family through multiple generations
Demonstrates dominant or recessive inheritance
Can also be used to deduce genotypes of family members
What is incomplete dominance?
Neither allele is dominant over the other
Expression of both alleles is observed as an intermediate phenotype in the heterozygous individual
What is co dominance
Neither allele is dominant over the other
Expression of both alleles is observed as a distinct phenotype in the heterozygous individual
Where are COVALENT bonds located in DNA structure?
hold nucleotides next to one another along the sugar-phosphate backbones
Where are HYDROGEN bonds located in DNA structure?
link complementary base pairs (A-T, G-C)
Weak
Allow the strands to separate during replication
What does DNA replication allow for?
Semi conservative model
What is attached to the 5 prime end?
Phosphate Group
What is attached to the 3 prime end?
Hydroxyl Group
From top to bottom how is the chain oriented on the lef?
5’-> 3’
How is the chain oriented on the right?
3’->5’
What adds nucleotides to the 5’-3’
DNA Polymerase
What is the strand that is continuously synthesized?
Leading
What is the strand that is synthesized in fragments?
Lagging
What is the overall direction of replication?
Matches direction of leading strand
What joins the pieces in the lagging strand?
DNA ligase
DNA is _________ into RNA
Transcribed
RNA is __________ into protein
Translated
What are the stages of Transcription
- Initiation
- Elongation
- Termination
What is initiation?
RNA polymerase enzyme binds to a DNA sequence called the promoter, where the helix unwinds and transcription starts
What is elongation?
RNA nucleotides are added to the chain
What is termination?
RNA polymerase reaches a DNA sequence called a terminator and detaches
What are codons?
Triplets of bases on a RNA strand
What is translation?
is the link between genotype (DNA) and phenotype (proteins)
allows for cells to change from the language of nucleotides (DNA & RNA) to the language of amino acids (proteins)
tRNA molecules match an amino acid to the corresponding mRNA codon
What is the start code?
AUG
What does each tRNA carry?
A specific amino acid
an anticodon on the tRNA binds to a specific mRNA codon
What hold tRNA and mRNA close together?
Ribosome subunits
This allows the amino acids to connect into a polypeptide chain
What bases match with each other
A-T
C-G
What does a sugar, phosphate, and nitrogen base make up?
Nucleotides
What is the shape of a dna molecule most like?
A twisted rope ladder
Why does a dna strand grow only on the 5’ to 3’ direction
Because DNA polymerase can only add nucleotides to the 3’ end of the growing molecule
CGTACTTCAAAATCTG
Make a complementary base pair
Transcribe
strand 2: GCATGAAGTTTTAGAC
mRNA: GCAUGAAGUUUUAGAC
tRNA:CGUACUUCAAAAUCUG
Where does transcription occur?
Nucleus
Where does translation occur?
Cytoplasm
When one parent DNA molecule is copied to make two dna molecules the new daughter dna molecule contain
50% of the parent DNA
What is the transfer of genetic information from dna to rna
Transcription
The directions for each amino acid in a protein are indicated by a colon that consists of _____ nucleotide in an rna molecule
3
What enables the formation of an RNA molecule?
RNA Polymerase
Marks the end of a gene and causes transcription to stop?
A terminator
What is a testcross?
An individual of unknown genotype and an individual homozygous recessive for the trait of interest
Two heterozygous four way cross results in what?
9:3:3:1 ratio
When two traits are crossed and a completely new phenotype emerges that is called?
Incomplete dominance
A person with AB blood illustrates the principle of
Co dominance
