Exam 3 Flashcards
Substitution
Replacement of one nucleotide (A,T,C,G) for another
Insertion
Addition of one or more nucleotides to a gene. Results in “frame-shift” mutations
Deletion
Removal of one or more nucleotides from a gene. Results in a frame-shift mutation
Silent
No change in the sequence of amino acids
Missense
An amino acid becoming another amino acid. change in primary structure of the protein
Nonsense
Change in amino acid to STOP codon
Frameshift
Caused by insertions or deletions. Reading frame to shift
Consequence of Silent
No change in phenotype
Consequence of Missense
Change in primary structure of protein; may be beneficial, neutral, or deleterious
Consequence of Nonsense
Leads to mRNA breakdown or shortened polypeptide chain, usually deleterious
Incomplete Dominance
The heterozygote has a phenotype that is intermediate to both homozygous phenotypes. Here we see that the heterozygote (Rr) is pink, which is the intermediate of red (RR) and white (rr).
Codominance
The heterozygote has a phenotype that express both homozygous phenotypes. Here we see that the heterozygote (Rr) expresses BOTH red and white petals. Remember that blood type AB is an example of codominance! The phenotype expresses contains both A and B antigens
What are the three situations in which mitotic cell division occurs
development of multicellular organisms, maintenance, and repair of organs and tissues
what are the 5 stages of mitosis
prophase, prometaphase, metaphase, anaphase, telophase
what would be the consequences if a cell underwent mitosis but not cytokinesis
the two cells do not fully separate - single cell with two nuclei
what determines a genotype
genotype is the genetic composition of a cell or organism
Define a phenotype
the observable factors
with regard to mutations, what is the meaning of harmful
it does something harmful to the individual
with regard to mutations, what is the meaning of beneficial
provides some sort of advantage to the organism in its environment
with regard to mutations, what is the meaning of neutral
you can’t tell that it did anything, no benefit or harm
what is the purpose of a test cross
to determine the genotype of an unsure dominant phenotype
why are some complex traits also called quantitative traits
because the phenotype is measured on a scale with only small intervals between similar indivividuals
examples of complex traits
height, weight, hair color, blood pressure
what are some factors that influence variation in complex traits
Environmental factors: sunlight, moisture, or nutrition. Genetic: multiple genes affecting a single trait
why does it not make sense to try to separate the effects of genes and the environment
the effects of genes and the environment in a single individual are so intimately related
what is twin concordance
the percentage of cases in which both members of a pair of twins show the trait when it is known that at least one member shows it
