MCAT BIOLOGY UPDATED FINAL EXAM QUESTIONS AND
ANSWERS SURE A+
✔✔Insertion mutations - ✔✔Occurs when a segment of DNA is moved from one
chromosome to another.
✔✔Translocation mutations - ✔✔Occurs when a segment of DNA is swapped with a
segment of DNA from another chromosome.
✔✔Genetic leakage - ✔✔The flow of genes between species through a hybrid offspring.
✔✔Genetic drift - ✔✔Occurs when the composition of the gene pool changes as a
result of chance.
✔✔Founder effect - ✔✔Results from a bottleneck that suddenly isolates a small
population, leading to inbreeding and increased prevalence of certain homozygous
genotypes.
✔✔Parent generation - ✔✔Represented by P1
✔✔Filial (offspring) generations - ✔✔Represented by F1, F2, and so on.
✔✔Monohybrid cross - ✔✔Accounts for one gene
*A cross between individuals that involves one pair of contrasting traits*
✔✔Phenotypic ratio for monohybrid cross? - ✔✔
✔✔Dihybrid cross - ✔✔Accounts for two genes
*Cross or mating between organisms involving two pairs of contrasting traits*
✔✔Phenotypic ratio for dihybrid cross? - ✔✔
✔✔Test cross - ✔✔Breeding the unknown parent with a homozygous recessive
✔✔Sex-linked crosses - ✔✔Sex chromosomes are usually used to indicate sex as well
as genotype
SeX linked is X linked
*X-linked trait is recessive*
,✔✔Recombination frequency - ✔✔The likelihood of two alleles being separated during
crossover by meiosis.
*Genes that are close to each other have low recombination frequency because they
are unlike to cross-over separately*
✔✔What is the maximum recombination frequency? - ✔✔50% because it is a random
process
✔✔Genetic maps - ✔✔Maps made using recombination frequencies as the scale, in
centimorgans.
✔✔Hardy-Weinberg principle - ✔✔States that if a population meets certain criteria
(aimed at a lack of evolution), then the allele frequencies will remain constant (Hardy-
weinberg equilibrium).
✔✔Hardy-weinberg equations - ✔✔
✔✔Hard-weinberg criteria - ✔✔5 criteria:
1) Population is large
2) No mutations
3) Mating is random
4) No migration into/out of the population
5) No natural selection
✔✔Hardy-weinberg problem - ✔✔
✔✔Natural selection - ✔✔States that the chance variations that exist between
individuals, and the advantageous variations-- those that increase an individuals fitness
for the environment-- afford the most opportunity for reproductive success.
✔✔Modern synthesis model (net-darwinism) - ✔✔Accounts for the mutation and
recombination as mechanisms for variation and considers differential reproduction to be
the mechanism for reproductive success.
✔✔Inclusive fitness - ✔✔Considers an organisms success to be based on:
1) Number of offspring
2) Success in supporting offspring
3) Ability of offspring to reproduce
4) Survival of offspring
✔✔Punctuated equilibrium - ✔✔Considers evolution to be a very slow process with
intermittent rapid burst of evolutionary activity.
,✔✔Evolution theories overview - ✔✔
✔✔Natural selection (types) - ✔✔Different types of selection lead to changes in
phenotype:
1) Stabilizing selection
2) Directional selection
3) Disruptive selection
4) Adaptive selection
✔✔Stabilizing selection - ✔✔Keeps the phenotypes in a narrow range, excluding
extremes.
✔✔Directional selection - ✔✔Moves the average phenotype toward one extreme.
✔✔Disruptive selection - ✔✔Moves toward two different phenotypes at the extremes
and can lead to speciation.
✔✔Adaptive radiation - ✔✔The rapid emergence of multiple species from a common
ancestor, each which occupies its own ecological niche.
✔✔Species - ✔✔The largest group of organisms capable of breeding to form a fertile
offspring.
1) Reproductively isolated from each other by pre- and post zygotic mechanisms.
✔✔Pre zygotic mechanisms - ✔✔Prezygotic reproductive isolation
Ecological, Temporal, Behavioral, Mechanical, Gametic
✔✔Isolation - ✔✔when 1 species is separated, different evolutionary pressures leads to
isolation, in which the progeny of these populations can no longer interbreed
✔✔Post zygotic mechanisms - ✔✔Postzygotic reproductive isolation
Hybrid inviability, sterility
✔✔Evolution (types) - ✔✔1) Divergent evolution
2) Convergent evolution
3) Parallel evolution
✔✔Divergent evolution - ✔✔Occurs when two species sharing a common ancestor
become more different.
, ✔✔Convergent evolution - ✔✔Occurs when two species not sharing a recent ancestor
evolve to become more similar due to analogous selection pressures.
✔✔Parallel evolution - ✔✔Occurs when two species sharing a common ancestor evolve
in similar ways due to analogous selection pressures.
✔✔Molecular clock model - ✔✔States that the degree of difference in the genome
between two species is related to the amount of time since the two species broke from a
common ancestor.
carry genetic information in the form of DNA
✔✔Eukaryotic Cells - ✔✔Contain a true nucleus enclosed in a membrane.
✔✔Prokaryotic Cells - ✔✔Do not contain a nucleus.
✔✔Organelles - ✔✔Suspended in semifluid cytosol. In eukaryotic cells they are
membrane bound, allowing for compartmentalization of functions. The membranes are
made of a phospholipid bilayer, surfaces are hydrophilic, they interact with the
environment.
✔✔Cytosol - ✔✔Allows for diffusion of molecules throughout the cell.
✔✔Nucleus - ✔✔Genetic material is encoded in DNA, organized in chromosomes. This
DNA provides all the genetic material needed for replication of the cell. It is surrounded
by the nuclear membrane or envelope, which forms a double membrane. Nuclear pores
allow for selective exchange of material between cytoplasm and the nucleus.
✔✔Genetic Material of the Nucleus - ✔✔DNA contains coding regions called genes.
Linear DNA is wound around organizing proteins known as histones, and further wound
into chromosomes.
✔✔Nuclear Membrane - ✔✔Contains nuclear pores that allow for selective 2-way
exchange of material between the cytoplasm and the nucleolus
✔✔Nucleolus - ✔✔-Subsection of the nucleus
-Where ribosomal RNA is synthesized
-The darker spot that is 25% of the nucleus
✔✔Mitochondria - ✔✔Power plant of the cell. Two layers, inner and outer membrane.
The outer membrane is a barrier between the cytosol and the inner environment of the
mitochondria. The inner membrane, made up of infoldings called cristae, contains the
molecules and enzymes necessary for the electron transport chain. The intermembrane
space separates them, creating a matrix between them.
ANSWERS SURE A+
✔✔Insertion mutations - ✔✔Occurs when a segment of DNA is moved from one
chromosome to another.
✔✔Translocation mutations - ✔✔Occurs when a segment of DNA is swapped with a
segment of DNA from another chromosome.
✔✔Genetic leakage - ✔✔The flow of genes between species through a hybrid offspring.
✔✔Genetic drift - ✔✔Occurs when the composition of the gene pool changes as a
result of chance.
✔✔Founder effect - ✔✔Results from a bottleneck that suddenly isolates a small
population, leading to inbreeding and increased prevalence of certain homozygous
genotypes.
✔✔Parent generation - ✔✔Represented by P1
✔✔Filial (offspring) generations - ✔✔Represented by F1, F2, and so on.
✔✔Monohybrid cross - ✔✔Accounts for one gene
*A cross between individuals that involves one pair of contrasting traits*
✔✔Phenotypic ratio for monohybrid cross? - ✔✔
✔✔Dihybrid cross - ✔✔Accounts for two genes
*Cross or mating between organisms involving two pairs of contrasting traits*
✔✔Phenotypic ratio for dihybrid cross? - ✔✔
✔✔Test cross - ✔✔Breeding the unknown parent with a homozygous recessive
✔✔Sex-linked crosses - ✔✔Sex chromosomes are usually used to indicate sex as well
as genotype
SeX linked is X linked
*X-linked trait is recessive*
,✔✔Recombination frequency - ✔✔The likelihood of two alleles being separated during
crossover by meiosis.
*Genes that are close to each other have low recombination frequency because they
are unlike to cross-over separately*
✔✔What is the maximum recombination frequency? - ✔✔50% because it is a random
process
✔✔Genetic maps - ✔✔Maps made using recombination frequencies as the scale, in
centimorgans.
✔✔Hardy-Weinberg principle - ✔✔States that if a population meets certain criteria
(aimed at a lack of evolution), then the allele frequencies will remain constant (Hardy-
weinberg equilibrium).
✔✔Hardy-weinberg equations - ✔✔
✔✔Hard-weinberg criteria - ✔✔5 criteria:
1) Population is large
2) No mutations
3) Mating is random
4) No migration into/out of the population
5) No natural selection
✔✔Hardy-weinberg problem - ✔✔
✔✔Natural selection - ✔✔States that the chance variations that exist between
individuals, and the advantageous variations-- those that increase an individuals fitness
for the environment-- afford the most opportunity for reproductive success.
✔✔Modern synthesis model (net-darwinism) - ✔✔Accounts for the mutation and
recombination as mechanisms for variation and considers differential reproduction to be
the mechanism for reproductive success.
✔✔Inclusive fitness - ✔✔Considers an organisms success to be based on:
1) Number of offspring
2) Success in supporting offspring
3) Ability of offspring to reproduce
4) Survival of offspring
✔✔Punctuated equilibrium - ✔✔Considers evolution to be a very slow process with
intermittent rapid burst of evolutionary activity.
,✔✔Evolution theories overview - ✔✔
✔✔Natural selection (types) - ✔✔Different types of selection lead to changes in
phenotype:
1) Stabilizing selection
2) Directional selection
3) Disruptive selection
4) Adaptive selection
✔✔Stabilizing selection - ✔✔Keeps the phenotypes in a narrow range, excluding
extremes.
✔✔Directional selection - ✔✔Moves the average phenotype toward one extreme.
✔✔Disruptive selection - ✔✔Moves toward two different phenotypes at the extremes
and can lead to speciation.
✔✔Adaptive radiation - ✔✔The rapid emergence of multiple species from a common
ancestor, each which occupies its own ecological niche.
✔✔Species - ✔✔The largest group of organisms capable of breeding to form a fertile
offspring.
1) Reproductively isolated from each other by pre- and post zygotic mechanisms.
✔✔Pre zygotic mechanisms - ✔✔Prezygotic reproductive isolation
Ecological, Temporal, Behavioral, Mechanical, Gametic
✔✔Isolation - ✔✔when 1 species is separated, different evolutionary pressures leads to
isolation, in which the progeny of these populations can no longer interbreed
✔✔Post zygotic mechanisms - ✔✔Postzygotic reproductive isolation
Hybrid inviability, sterility
✔✔Evolution (types) - ✔✔1) Divergent evolution
2) Convergent evolution
3) Parallel evolution
✔✔Divergent evolution - ✔✔Occurs when two species sharing a common ancestor
become more different.
, ✔✔Convergent evolution - ✔✔Occurs when two species not sharing a recent ancestor
evolve to become more similar due to analogous selection pressures.
✔✔Parallel evolution - ✔✔Occurs when two species sharing a common ancestor evolve
in similar ways due to analogous selection pressures.
✔✔Molecular clock model - ✔✔States that the degree of difference in the genome
between two species is related to the amount of time since the two species broke from a
common ancestor.
carry genetic information in the form of DNA
✔✔Eukaryotic Cells - ✔✔Contain a true nucleus enclosed in a membrane.
✔✔Prokaryotic Cells - ✔✔Do not contain a nucleus.
✔✔Organelles - ✔✔Suspended in semifluid cytosol. In eukaryotic cells they are
membrane bound, allowing for compartmentalization of functions. The membranes are
made of a phospholipid bilayer, surfaces are hydrophilic, they interact with the
environment.
✔✔Cytosol - ✔✔Allows for diffusion of molecules throughout the cell.
✔✔Nucleus - ✔✔Genetic material is encoded in DNA, organized in chromosomes. This
DNA provides all the genetic material needed for replication of the cell. It is surrounded
by the nuclear membrane or envelope, which forms a double membrane. Nuclear pores
allow for selective exchange of material between cytoplasm and the nucleus.
✔✔Genetic Material of the Nucleus - ✔✔DNA contains coding regions called genes.
Linear DNA is wound around organizing proteins known as histones, and further wound
into chromosomes.
✔✔Nuclear Membrane - ✔✔Contains nuclear pores that allow for selective 2-way
exchange of material between the cytoplasm and the nucleolus
✔✔Nucleolus - ✔✔-Subsection of the nucleus
-Where ribosomal RNA is synthesized
-The darker spot that is 25% of the nucleus
✔✔Mitochondria - ✔✔Power plant of the cell. Two layers, inner and outer membrane.
The outer membrane is a barrier between the cytosol and the inner environment of the
mitochondria. The inner membrane, made up of infoldings called cristae, contains the
molecules and enzymes necessary for the electron transport chain. The intermembrane
space separates them, creating a matrix between them.
