Meiosis
What is the overall goal of meiosis?
To produce haploid cells (4 haploid daughter cells)
How many traits does a monohybrid and a dihybrid cross follow?
Monohybrid = 1 trait
Dihybrid = 2 traits
What is the flow of information?
DNA --> RNA --> Protein
3 sites of a ribosome
E = Exit
P = Polypeptide chain
A = Admission
What is a heritable mutation?
A change in the DNA sequence.
Which stage does reduction division occur?
Anaphase I
Define the following terms:
1) Phenotype
2) Genotype
3) Homozygote
4) Heterozygote
1) Phenotype = Expression of the Genome (physical appearance)
2) Genotype = Genome (genetic makeup)
3) Homozygotes = two identical alleles in the genotype (express the phenotype for dominant or recessive traits)
4) Heterozygotes = two different alleles in the genotype (express the phenotype for ONLY the dominant trait)
What is synthesize during transcription?
Some form of RNA...
-mRNA
-tRNA
-rRNA
How do tRNAs gain/accept an amino acid?
A charged reaction
What are two ways mutation consequences are minimized?
-Smaller changes
-Non coding DNA
-Non translated mRNA
-3rd base wobble
-Unlikely change in phenotype
What occurs during anaphase I and anaphase II.
Anaphase I - homologous chromosomes separate
Anaphase II - sister chromatids separate
What is the phenotypic and genotypic ratios of a cross between Pp x Pp?
Phenotype = 3:1
Genotype = 1:2:1
3 requirements for Prokaryote transcription & main enzyme for synthesis
1) Promoter
2) Start site
3) Termination site
RNA polymerase
Cycle of elongation for translation
1) Matching of anti-codon to codon
2) Polypeptide bond
3) Ribosome translocation
3 sources of mutation?
1) DNA polymerase mistake
2) Radiation
3) Chemical mutagens
2 similarities and 2 differences between Meiosis & Mitosis
Same = separation of sister chromatids, same 5 stages of mitosis, 1 replication cycle of DNA, Creation of new cells, performed by eukaryotes,
Differences = Separation of homologous chromosomes, 2 cycles of meiosis, reduction division, identical/haploid, 2/4 cells created, somatic/germ cells
Is dominance always complete? Why or why not and provide examples.
No. Some organisms experience incomplete dominance or codominance.
List 3 differences in gene expression between prokaryotes and eukaryotes
-Initiation of transcription (sigma/transcription factors)
-Introns/Exons (only in EUK)
-Operons (only in PRO)
-mRNA splicing (only in EUK)
-mRNA modifications (only in EUK)
-Location of transcription (Cytoplasm/nucleus)
-Time of translation/transcription (coupled with translation or not)
The order of translation initiation
1) mRNA is available for translation
2) Small rRNA subunit binds
3) tRNA with start codon binds to P site
4) Large rRNA subunit binds
Define a reading frame and what type(s) of mutations could result in a frame shift.
-Specific start/stop points in the genetic code made of codons to encode for potential proteins.
Insertions and deletions
What error can occur during during meiosis and what gametes would be created?
Nondisjunction can occur to create aneuploid gametes.
For a cross between Rr Bb x Rr Bb, what % of possible offspring have the phenotype of Round brown eyes?
R = Round, r = oval
B = Blue, b = brown
R_bb = 18.75%
What are 3 characteristics of Genetic code?
-Made up of codons (triplets)
-Codons do not overlap
-Stop codons do not = amino acids
-Redundant
-Start codon = AUG
-mRNA strand is read 5'-->3'
-Mutations cause changes in protein structure
-Cytoplasm & rough endoplasmic reticulum
-Signal sequences at the beginning of the growing peptide chain
3 types of point mutations and their defining feature.
Silent - DNA change but no change in amino acid
Misense - DNA change with a change in amino acid
Nonsense - DNA change with a change to a premature stop codon