Exam 1 Flashcards
(108 cards)
_________ is a change in allele or genotype frequency over time.
Evolution
How many homologous pairs of chromosomes in each somatic cell in your body?
23
How many total chromosomes in each somatic cell in your body?
46
What is the chromosome theory of inheritance?
A concept that explains how genetic information is transmitted from one generation to the next.
What is an allele?
Different version of the same gene.
What is a gene?
An instruction that tells your body what it needs to do.
Why is the pea wrinkled-seed allele a recessive allele?
The trait associated with the allele is not exhibited in htereozygotes.
Mendel’s experimental method involved using true breed parental plants for each of the traits he studied in the monohybrid cross. Why was this vital to the outcomes of the experiment?
By starting with a true breed pure line, Mendel could better understand the inheritance of the traits as only due to the result of the cross.
The alleles found in haploid organisms cannot be dominant or recessive. Why?
Dominance and recessiveness describe which of two possible phenotypes are exhibited when two different alleles occur in the same individual.
How did Mendel’s monohybrid cross with round and wrinkled seeds and other single traits tested, directly contradict the blending hypothesis?
The result of the cross between round and wrinkled pure breed cell lines was all round seeds in the F1 offspring, not partially round and wrinkled as blending theory would predict.
Mendel crossed plants that produced only round seeds to those that produced only wrinkled seeds. In the next generation, all the pea plants produced only round seeds. Which term describes how the round-seed allele is inherited?
Dominant
What is typically the purpose of drawing a forked-line diagram in genetics?
to determine what kinds of gametes an individual can produce
Name the fours evolutionary processes that change allele frequencies in populations.
Natural Selection.
Genetic Drift.
Gene Flow.
Mutation.
What is a “population”?
A group of individuals of the same species that live in the same area at the same time and can interbreed.
____________ changes the frequency of certain alleles if they influence reproductive success of organisms in a particular environment.
Natural Selction.
_______________ causes random changes in allele frequencies due to the chance survival and reproductive success in some individuals, even if they are less fit than other individuals.
Genetic Drift.
___________ occurs when individuals leave one population, join another, and breed.
Gene Flow.
___________ changes allele frequencies in a population when a random change in the DNA sequence creates a new allele of a gene.
Mutation.
Random Mating?
A model that assumes that gametes form the gene pool combine at random. This means individuals are mating by chance.
What are the five important assumptions about populations in the Hardy-Weinberg Equilibrium?
Random Mating.
No Natural Selection.
No Genetic Drift.
No gene flow.
No mutation.
In what sense is the Hardy-Weinberg Equilibrium a null hypothesis?
It defines what genotype and allele frequencies should be expected if evolutionary processes and nonrandom mating are NOT occurring.
what is a gene pool?
A hypothetical collection of all the genes that occur in a habitat.
Why isn’t inbreeding considered an evolutionary process?
It does not change allele frequencies.
What are the four main patterns, or modes, that affect genetic variation?
Directional selection.
Stabilizing Selection.
Disruptive selection.
Balancing selection.
