Mcat Biology (Chapter 12)

Front 1

________ is the proportion of a population with a given genotype.

Back 1

penetrance

Front 2

________ refers to the varying phenotypic manifestations of a given genotype.

Back 2

expressivity

Front 3

________ states that an organism has two alleles for each gene, which segregate during meiosis, resulting in gametes carrying only one allele for a trait.

Back 3

Medndel's first law (of segregation)

Front 4

________ states that the inheritance of one allele does not influence the probability of inheriting a given allele for a different trait.

Back 4

Mendel's second law (of independent assortment)

Front 5

Crossing two heterozygotes for a trait with complete dominance results in a ________ ratio of genotypes and a ________ ratio of phenotypes.

Dihybrid crosses between two heterozygotes with complete dominance results in ________ ratio of phenotypes.

Back 5

1:2:1

3:1

9:3:3:1

Front 6

Support for DNA as genetic material came through a number of experiments.

The ________ experiment demonstrated the transforming principle, converting non-virulent bacteria into virulent bacteria by exposure to heat-killed virulent bacteria.

The ________ experiment demonstrated that DNA is the genetic material because degradation of DNA led to a cessation of bacterial transformation.

The ________ experiment confirmed that DNA is the genetic material because only radiolabeled DNA could be found in bacteriophage-infected bacteria.

Back 6

Griffith

Avery-MacLeod-McCarty

Front 7

________ mutations occur when a segment of DNA is moved from one chromosome to another.

________ mutations occur when a segment of DNA is swapped with a segment of DNA from another chromosome.

Back 7

insertion

translocation

Front 8

________ is a flow of genes between species through hybrid offspring.

Back 8

genetic leakage

Front 9

________ occurs when the composition of the gene pool changes as a result of chance.

Back 9

genetic drift

Front 10

The ________ results from ________ that suddenly isolate a small population, leading to ________ and increased prevalence of certain homozygous genotypes.

Back 10

founder effect

bottlenecks

inbreeding

Front 11

The ________ is the likelihood of two alleles being separated during crossing over in meiosis. ________ can be made using recombination frequency as the scale, in ________.

Back 11

recombination frequency

genetic maps

centimorgans

Front 12

The ________ states that if a population meets certain criteria (aimed at a lack of evolution), then the allele frequencies will remain constant, which is called ________.

What equations are used to determine if this is the case? Explain what they mean.

Back 12

Hardy-Weinberg principle

Hardy-Weinberg equilibrium

p + q = 1

frequency of alleles in population

(p)2 + 2pq + (q)2 = 1

frequency of genotypes and phenotypes

(p)2 = frequency of homozygous dominant genotype

2pq = frequency of heterozygous dominant genotype

(q)2 = frequency of homozygous recessive genotype

Front 13

The ________ accounts for mutation and recombination as mechanisms of variation and considers ________ to be the mechanism of reproductive success.

Back 13

modern synthesis model (neo-Darwinism)

differential reproduction

Front 14

________ considers an organism's success to be based on the number of offspring, success in supporting offspring, and the ability of the offspring to then support others; survival of offspring or relatives ensures continuation of genes in subsequent generations.

Back 14

inclusive fitness

Front 15

________ considers evolution to be a very slow process with intermittent rapid bursts of evolutionary activity.

Back 15

punctuated equilibrium

Front 16

Different types of selection lead to changes in phenotypes.

________ keeps phenotypes in a narrow range, excluding extremes.

________ moves the average phenotype toward one extreme.

________ moves toward two different phenotypes at the extremes and can lead to ________.

________ is the rapid emergence of multiple species from a common ancestor, each of which occupies its own ecological niche.

Back 16

stabilizing selection

directional selection

disruptive selection

adaptive selection

speciation

adaptive radiation

Front 17

Species are reproductively isolated from each other by ________ mechanisms.

Back 17

prezygotic and postzygotic

Front 18

Two species can evolve with different relationship patterns.

________ occurs when two species sharing a common ancestor become more different.

________ occurs when two species sharing a common ancestor evolve in similar ways due to analogous selection pressures.

________ occurs when two species not sharing a recent ancestor evolve to become more similar due to analogous selection pressures.

Back 18

divergent evolution

parallel evolution

convergent evolution

Front 19

According to the ________, the degree of difference in the genome between two species is related to the amount of time since the two species broke off from a common ancestor.

Back 19

molecular clock model