BIO1107 Exam 4 Study Guide 2025/2026
Which one of the following does not constitute an example of genetic exchange? -
ANSWER Endogenization of a retrovirus into the germline of a mammalian host species
Transfer of a plasmid from one bacterial species to another
Sexual reproduction producing offspring different from either parent
Correct Response
Transcriptional activation of genes in the nuclei of root cells of a plant after contact of
the roots with a bacterial pathogen in the soil (Change in gene expression).
Which of the following would not be considered a component of sexual reproduction? -
ANSWER Occasional production of diploids through fusions of cells of opposite mating
types in a yeast that largely reproduces through clonal mitotic divisions (Most yeast do
have a sexual phase)
Correct Response
Gradual acquisition of multiple mutations in a purely mitotically dividing eukaryotic
single celled organism
Production of eggs and sperm in separate sexes in an animal species
"Alteration of generations" between haploid and diploid organisms in a fern
Which one of the following situations is less likely to benefit from the high level of
genetic exchange accomplished by obligate sexual reproduction? - ANSWER A species
with a complex life history and a large number of genes
A comparatively rare species with a global population never exceeding 10,000
Large animal species like rhinos and elephants
Correct Response
A single cell organism with a generation time less than a hour (sexual reproduction
produces a great deal of genetic exchange, and that isn't needed for something that
doesn't live long)
Which statement is untrue about a eukaryotic species with no documented sexual
reproduction? - ANSWER Correct Response It would be expected to be composed of
individuals that were all genetically distinct from one another
It could be more capable of horizontal gene transfer than most sexually reproducing
species
,It could be a recent asexual derivative of a species with occasional sexual reproduction
It could well be a species with cryptic sexual forms that have not yet been discovered
Which form of genetic exchange is absent in prokaryotes? - ANSWER Integration of
virus (phage) genomes into host chromosomes
Correct Response
Meiosis
Uptake of naked DNA from outside the cell
Movement of plasmids from one species to another
Which one of the following is an inaccurate statement about sexual reproduction -
ANSWER It can both create and destroy particular combinations of gene forms (alleles)
Correct Response
It can never exist without a fully functional ability to carry out meiosis
It produces a very high level of genetic exchange relative to alternative processes
It can be an excellent mechanism for the efficient spread of a transposon into the
genome of a species
Which statement is untrue about horizontal gene transfer (HGT)? - ANSWER Correct
Response While HGT is common in prokaryotes and some lower eukaryotes, there is no
evidence to support that it has ever occurred bringing new genes into vertebrates
Retrovirus endogenization is an example of HGT
A horizontally transferred gene can much more closely resemble (in terms of DNA
sequence similarity) a gene from a distantly related organism than any gene from
closely related species
HGT is apt to be easier with single-celled organisms than multicellular organisms
Which feature is not a characteristic of meiosis? - ANSWER Correct Response
Ploidy remains the same from start to end
Pairing of homologs
Crossovers between homologs occur
DNA replication occurring in only one of two cell divisions
Which kind of event does not characterize the behavior of chromosomes at some point
in meiosis I? - ANSWER DNA double strand breaks occur in chromosomes
,Synaponemal complex forms
Correct Response
Sister kinetochores are not held close together but instead all held in opposing positions
on opposite sides of sister chromatids (They act like one so they are held close
together)
Clustering of telomeres of all chromosomes
Which statement is true about meiotic chromosomes? - ANSWER Correct Response
Crossovers exchange chromosome pieces between homologs
Synaptonemal complex holds homologs together at anaphase of meiosis I
Chiasmata contribute to holding sister chromatids together at anaphase of meiosis II
DNA double strand breaks in meiosis function to allow separation of sister chromatids in
meiosis II
Which statement is not true about chromosome non-disjunction in meiosis? - ANSWER
Chromosome non-disjunction in meiosis occurs at much higher frequencies in 40 year
old women relative to 25 year old women
Correct Response
There is no way to distinguish whether chromosome non-disjunction occurred in
meiosis I or in meiosis II
Chromosome non-disjunction in meiosis I will lead to a gamete with two different
homologs of a chromosome (as opposed to two copies of the same homolog)
Chromosome non-disjunction in meiosis is the major cause of Down syndrome
Which statement is true about human oogenesis? - ANSWER Meiotic cell divisions in
humans occur in many tissues throughout the body
, Human egg cells are approximately the same size as human sperm
One pair of meiotic divsions in women produces four viable haploid oocytes
Correct Response
The first meiotic division in oogenesis is arrested from before birth until after puberty
Which statement is not true about the parasexual life cycle of Candida albicans? -
ANSWER Incorrect Response
It occurs in the absence of a proper meiosis
It produces a wide variety of viable aneuploidy progeny
Correct Answer
It produces haploid gametes (It does not produce these.)
It can feature mating of two diploid cells to produce a tetraploid
Which of the following is not an advantage of the pea plant that helped Mendel establish
the principle of genetics? - ANSWER The organism is normally self fertilizing but can
manually be cross fertilized
Correct Response
Unusually for a higher eukaryote, pea plants are haploid
Which one of the following does not constitute an example of genetic exchange? -
ANSWER Endogenization of a retrovirus into the germline of a mammalian host species
Transfer of a plasmid from one bacterial species to another
Sexual reproduction producing offspring different from either parent
Correct Response
Transcriptional activation of genes in the nuclei of root cells of a plant after contact of
the roots with a bacterial pathogen in the soil (Change in gene expression).
Which of the following would not be considered a component of sexual reproduction? -
ANSWER Occasional production of diploids through fusions of cells of opposite mating
types in a yeast that largely reproduces through clonal mitotic divisions (Most yeast do
have a sexual phase)
Correct Response
Gradual acquisition of multiple mutations in a purely mitotically dividing eukaryotic
single celled organism
Production of eggs and sperm in separate sexes in an animal species
"Alteration of generations" between haploid and diploid organisms in a fern
Which one of the following situations is less likely to benefit from the high level of
genetic exchange accomplished by obligate sexual reproduction? - ANSWER A species
with a complex life history and a large number of genes
A comparatively rare species with a global population never exceeding 10,000
Large animal species like rhinos and elephants
Correct Response
A single cell organism with a generation time less than a hour (sexual reproduction
produces a great deal of genetic exchange, and that isn't needed for something that
doesn't live long)
Which statement is untrue about a eukaryotic species with no documented sexual
reproduction? - ANSWER Correct Response It would be expected to be composed of
individuals that were all genetically distinct from one another
It could be more capable of horizontal gene transfer than most sexually reproducing
species
,It could be a recent asexual derivative of a species with occasional sexual reproduction
It could well be a species with cryptic sexual forms that have not yet been discovered
Which form of genetic exchange is absent in prokaryotes? - ANSWER Integration of
virus (phage) genomes into host chromosomes
Correct Response
Meiosis
Uptake of naked DNA from outside the cell
Movement of plasmids from one species to another
Which one of the following is an inaccurate statement about sexual reproduction -
ANSWER It can both create and destroy particular combinations of gene forms (alleles)
Correct Response
It can never exist without a fully functional ability to carry out meiosis
It produces a very high level of genetic exchange relative to alternative processes
It can be an excellent mechanism for the efficient spread of a transposon into the
genome of a species
Which statement is untrue about horizontal gene transfer (HGT)? - ANSWER Correct
Response While HGT is common in prokaryotes and some lower eukaryotes, there is no
evidence to support that it has ever occurred bringing new genes into vertebrates
Retrovirus endogenization is an example of HGT
A horizontally transferred gene can much more closely resemble (in terms of DNA
sequence similarity) a gene from a distantly related organism than any gene from
closely related species
HGT is apt to be easier with single-celled organisms than multicellular organisms
Which feature is not a characteristic of meiosis? - ANSWER Correct Response
Ploidy remains the same from start to end
Pairing of homologs
Crossovers between homologs occur
DNA replication occurring in only one of two cell divisions
Which kind of event does not characterize the behavior of chromosomes at some point
in meiosis I? - ANSWER DNA double strand breaks occur in chromosomes
,Synaponemal complex forms
Correct Response
Sister kinetochores are not held close together but instead all held in opposing positions
on opposite sides of sister chromatids (They act like one so they are held close
together)
Clustering of telomeres of all chromosomes
Which statement is true about meiotic chromosomes? - ANSWER Correct Response
Crossovers exchange chromosome pieces between homologs
Synaptonemal complex holds homologs together at anaphase of meiosis I
Chiasmata contribute to holding sister chromatids together at anaphase of meiosis II
DNA double strand breaks in meiosis function to allow separation of sister chromatids in
meiosis II
Which statement is not true about chromosome non-disjunction in meiosis? - ANSWER
Chromosome non-disjunction in meiosis occurs at much higher frequencies in 40 year
old women relative to 25 year old women
Correct Response
There is no way to distinguish whether chromosome non-disjunction occurred in
meiosis I or in meiosis II
Chromosome non-disjunction in meiosis I will lead to a gamete with two different
homologs of a chromosome (as opposed to two copies of the same homolog)
Chromosome non-disjunction in meiosis is the major cause of Down syndrome
Which statement is true about human oogenesis? - ANSWER Meiotic cell divisions in
humans occur in many tissues throughout the body
, Human egg cells are approximately the same size as human sperm
One pair of meiotic divsions in women produces four viable haploid oocytes
Correct Response
The first meiotic division in oogenesis is arrested from before birth until after puberty
Which statement is not true about the parasexual life cycle of Candida albicans? -
ANSWER Incorrect Response
It occurs in the absence of a proper meiosis
It produces a wide variety of viable aneuploidy progeny
Correct Answer
It produces haploid gametes (It does not produce these.)
It can feature mating of two diploid cells to produce a tetraploid
Which of the following is not an advantage of the pea plant that helped Mendel establish
the principle of genetics? - ANSWER The organism is normally self fertilizing but can
manually be cross fertilized
Correct Response
Unusually for a higher eukaryote, pea plants are haploid
