PORTAGE LEARNING BIOD 101 COMPREHENSIVE EXAM
QUESTIONS AND ANSWERS GRADED A+
✔✔Meiosis I - ✔✔process of separation of homologous chromosomes
✔✔Meiosis II - ✔✔process of separation of sister chromatids
✔✔crossing-over - ✔✔the exchange of genes between homologous chromosomes,
resulting in a mixture of parental characteristics in offspring.
✔✔cohesins - ✔✔cohesion proteins pairing together sister chromatids
✔✔synaptonemal complex - ✔✔zipper-like protein complex bringing non-sister
chromatids together into synapsis
✔✔chiasmata - ✔✔crossing over points between sister chromatids
✔✔recombinant chromosomes - ✔✔distinct chromosomes created by crossover,
carrying genetic info from both parents but not identical to parents
✔✔Metaphase I - ✔✔Difference from mitosis is that both chromatids of one homolog
(maternal) are attached and line up to both chromatids of other homolog (paternal) to
one kinetochore along plate
✔✔Anaphase I - ✔✔Difference is sister chromatids remain attached at centromere.
Chromatid pair is getting pulled toward its centrosome pole.
✔✔Telophase I and cytokinesis - ✔✔Difference is nuclear envelope and nucleoli do not
reassemble yet. Cell is haploid but must be reduced
✔✔Non-disjunction - ✔✔failure of sister chromatids to separate properly
✔✔Trisomy 21 - ✔✔Carrying an extra copy of chromosome 21; also known as Down
syndrome.
✔✔True breeding plants - ✔✔will continue to display characteristics of parent plant over
several generations of offspring
✔✔hybridization - ✔✔crossing two true-breeding plants
✔✔Alleles - ✔✔Different versions of the same gene. ex: eye color and blood type
✔✔Locus - ✔✔location of alleles (one from each parent) on a chromosome
, ✔✔dominant allele - ✔✔occurs more frequently
✔✔recessive allele - ✔✔is present but has no observable effect on appearance
✔✔Law of Segregation - ✔✔alleles for different traits become separated during gamete
formation (meiosis)
✔✔Homozygous - ✔✔when an organism has the same alleles for a particular trait. ex:
PP
✔✔Heterozygous - ✔✔when an organism has different alleles for a particular trait. ex:
Pp
✔✔Genotype - ✔✔An organism's genetic makeup, or allele combinations (homozygous
vs. heterozygous)
✔✔Phenotype - ✔✔An organism's physical appearance, or visible traits.
✔✔monohybrid cross - ✔✔when only a single trait is studied during a cross
✔✔dihybrid cross - ✔✔A cross between two individuals, concentrating on two definable
traits
✔✔dihybridization - ✔✔when two traits from true-breeding parents are followed in F2
generation to see if traits will be inherited together or separately
✔✔law of independent assortment - ✔✔two or more genes are independent of each
other
✔✔Ratio of independent assortment in F2 (4 sperm x 4 eggs) - ✔✔9:3:3:1
✔✔complete dominance - ✔✔when phenotype for a dominant trait is exhibited
regardless of genotype
✔✔incomplete dominance - ✔✔when offspring have different phenotypes than parents
✔✔codominance - ✔✔when traits for both alleles are expressed in the phenotype
✔✔pleiotropy - ✔✔when one gene has multiple phenotypic effects
✔✔CFTR gene - ✔✔a gene that codes for a protein involved in chloride and water
transport across membranes. In patients with cystic fibrosis, a mutation in this gene
disrupts chloride and water transport across membranes. The end result is production of
QUESTIONS AND ANSWERS GRADED A+
✔✔Meiosis I - ✔✔process of separation of homologous chromosomes
✔✔Meiosis II - ✔✔process of separation of sister chromatids
✔✔crossing-over - ✔✔the exchange of genes between homologous chromosomes,
resulting in a mixture of parental characteristics in offspring.
✔✔cohesins - ✔✔cohesion proteins pairing together sister chromatids
✔✔synaptonemal complex - ✔✔zipper-like protein complex bringing non-sister
chromatids together into synapsis
✔✔chiasmata - ✔✔crossing over points between sister chromatids
✔✔recombinant chromosomes - ✔✔distinct chromosomes created by crossover,
carrying genetic info from both parents but not identical to parents
✔✔Metaphase I - ✔✔Difference from mitosis is that both chromatids of one homolog
(maternal) are attached and line up to both chromatids of other homolog (paternal) to
one kinetochore along plate
✔✔Anaphase I - ✔✔Difference is sister chromatids remain attached at centromere.
Chromatid pair is getting pulled toward its centrosome pole.
✔✔Telophase I and cytokinesis - ✔✔Difference is nuclear envelope and nucleoli do not
reassemble yet. Cell is haploid but must be reduced
✔✔Non-disjunction - ✔✔failure of sister chromatids to separate properly
✔✔Trisomy 21 - ✔✔Carrying an extra copy of chromosome 21; also known as Down
syndrome.
✔✔True breeding plants - ✔✔will continue to display characteristics of parent plant over
several generations of offspring
✔✔hybridization - ✔✔crossing two true-breeding plants
✔✔Alleles - ✔✔Different versions of the same gene. ex: eye color and blood type
✔✔Locus - ✔✔location of alleles (one from each parent) on a chromosome
, ✔✔dominant allele - ✔✔occurs more frequently
✔✔recessive allele - ✔✔is present but has no observable effect on appearance
✔✔Law of Segregation - ✔✔alleles for different traits become separated during gamete
formation (meiosis)
✔✔Homozygous - ✔✔when an organism has the same alleles for a particular trait. ex:
PP
✔✔Heterozygous - ✔✔when an organism has different alleles for a particular trait. ex:
Pp
✔✔Genotype - ✔✔An organism's genetic makeup, or allele combinations (homozygous
vs. heterozygous)
✔✔Phenotype - ✔✔An organism's physical appearance, or visible traits.
✔✔monohybrid cross - ✔✔when only a single trait is studied during a cross
✔✔dihybrid cross - ✔✔A cross between two individuals, concentrating on two definable
traits
✔✔dihybridization - ✔✔when two traits from true-breeding parents are followed in F2
generation to see if traits will be inherited together or separately
✔✔law of independent assortment - ✔✔two or more genes are independent of each
other
✔✔Ratio of independent assortment in F2 (4 sperm x 4 eggs) - ✔✔9:3:3:1
✔✔complete dominance - ✔✔when phenotype for a dominant trait is exhibited
regardless of genotype
✔✔incomplete dominance - ✔✔when offspring have different phenotypes than parents
✔✔codominance - ✔✔when traits for both alleles are expressed in the phenotype
✔✔pleiotropy - ✔✔when one gene has multiple phenotypic effects
✔✔CFTR gene - ✔✔a gene that codes for a protein involved in chloride and water
transport across membranes. In patients with cystic fibrosis, a mutation in this gene
disrupts chloride and water transport across membranes. The end result is production of
