BISC120 Midterm 1 Exam | Questions Solved
100% Correct |Verified Answers
Fertilization
the union of gametes (the sperm and the egg)
What are fertilized egg called?
zygote (2n)=46
What does zygote produce?
somatic cells by mitosis and develops into an adult
What are the two consecutive cell divisions in meiosis called?
Meiosis I and meiosis II
How many daughter cells are produced in meiosis?
Four daughter cells
How do the number of chromosomes in daughter cells compare to the parent cell in meiosis?
Each daughter cell has only half as many chromosomes
What are the key events during Meiosis I - Prophase I?
Centrosome movement, spindle formation, nuclear envelope breakdown, chromosome
condensation
What is the role of the centrosome during Meiosis I - Prophase I?
The mitotic spindle is a structure made of microtubules that controls chromosome movement
It is involved in spindle formation and serves as a microtubule-organizing center
In early prophase 1, each chromsome pairs w/ homolog and it crosses over. What is Crossing
over
,the exchange of genes between two chromosomes, resulting in non - identical chromatids that
comprise the genetic material of gametes.
What are chiasmata?
Sites of crossovers
What happens in metaphase I of meiosis?
Pairs of homologous chromosomes line up at the metaphase plate with microtubules attached
to kinetochores.
How do microtubules attach in metaphase I of meiosis?
Microtubules from one pole attach to one chromosome of each homologous pair, while
microtubules from the other pole attach to the other chromosome.
The centromeres are___.
specific DNA regions centromere on a chromosome where sister chromatids are attached
• serve as the platform on which kinetochores assemble
The kinetochores are _____.
are the macromolecular protein complexes that govern chromosome movement by binding
spindle microtubules during mitosis and meiosis.
What happens during Anaphase I of Meiosis I?
Breakdown of proteins allows homologous pairs of chromosomes to separate
How do homologous pairs of chromosomes move during Anaphase I of Meiosis I?
Homologs move toward opposite poles guided by the spindle apparatus
What enables the two chromatids of each chromosome to move as a unit towards the same
pole in Anaphase I of Meiosis I?
Sister chromatid cohesions persist at the centromere
, What happens at the beginning of telophase I in meiosis?
Each half of the cell has a haploid set of duplicated chromosomes
What is the structure of chromosomes in telophase I of meiosis?
Each chromosome still consists of two sister chromatids
What occurs simultaneously with telophase I in meiosis?
Cytokinesis, forming two haploid daughter cells
What happens during Prophase II of meiosis II?
Spindle apparatus forms again.
How are chromosomes structured in Prophase II of meiosis II?
Chromosomes are still composed of two sister chromatids attached at the centromere.
What is the characteristic of chromosome movement in Prophase II of meiosis II?
Chromosomes begin migrating toward the metaphase II plate.
Does crossing over occur in Prophase II of meiosis II?
No, crossing over does not occur in Prophase II of meiosis II.
What type of pairing occurs in Prophase II of meiosis II?
Prophase II of meiosis II only happens between homologous pairs.
What happens during Metaphase II of meiosis II?
Chromosomes are placed at the metaphase plate
How are sister chromatids different in Metaphase II due to crossing over in Prophase I?
The two sister chromatids are not genetically identical
What are kinetochores attached to in Metaphase II of meiosis II?
Microtubules extending from opposite poles
100% Correct |Verified Answers
Fertilization
the union of gametes (the sperm and the egg)
What are fertilized egg called?
zygote (2n)=46
What does zygote produce?
somatic cells by mitosis and develops into an adult
What are the two consecutive cell divisions in meiosis called?
Meiosis I and meiosis II
How many daughter cells are produced in meiosis?
Four daughter cells
How do the number of chromosomes in daughter cells compare to the parent cell in meiosis?
Each daughter cell has only half as many chromosomes
What are the key events during Meiosis I - Prophase I?
Centrosome movement, spindle formation, nuclear envelope breakdown, chromosome
condensation
What is the role of the centrosome during Meiosis I - Prophase I?
The mitotic spindle is a structure made of microtubules that controls chromosome movement
It is involved in spindle formation and serves as a microtubule-organizing center
In early prophase 1, each chromsome pairs w/ homolog and it crosses over. What is Crossing
over
,the exchange of genes between two chromosomes, resulting in non - identical chromatids that
comprise the genetic material of gametes.
What are chiasmata?
Sites of crossovers
What happens in metaphase I of meiosis?
Pairs of homologous chromosomes line up at the metaphase plate with microtubules attached
to kinetochores.
How do microtubules attach in metaphase I of meiosis?
Microtubules from one pole attach to one chromosome of each homologous pair, while
microtubules from the other pole attach to the other chromosome.
The centromeres are___.
specific DNA regions centromere on a chromosome where sister chromatids are attached
• serve as the platform on which kinetochores assemble
The kinetochores are _____.
are the macromolecular protein complexes that govern chromosome movement by binding
spindle microtubules during mitosis and meiosis.
What happens during Anaphase I of Meiosis I?
Breakdown of proteins allows homologous pairs of chromosomes to separate
How do homologous pairs of chromosomes move during Anaphase I of Meiosis I?
Homologs move toward opposite poles guided by the spindle apparatus
What enables the two chromatids of each chromosome to move as a unit towards the same
pole in Anaphase I of Meiosis I?
Sister chromatid cohesions persist at the centromere
, What happens at the beginning of telophase I in meiosis?
Each half of the cell has a haploid set of duplicated chromosomes
What is the structure of chromosomes in telophase I of meiosis?
Each chromosome still consists of two sister chromatids
What occurs simultaneously with telophase I in meiosis?
Cytokinesis, forming two haploid daughter cells
What happens during Prophase II of meiosis II?
Spindle apparatus forms again.
How are chromosomes structured in Prophase II of meiosis II?
Chromosomes are still composed of two sister chromatids attached at the centromere.
What is the characteristic of chromosome movement in Prophase II of meiosis II?
Chromosomes begin migrating toward the metaphase II plate.
Does crossing over occur in Prophase II of meiosis II?
No, crossing over does not occur in Prophase II of meiosis II.
What type of pairing occurs in Prophase II of meiosis II?
Prophase II of meiosis II only happens between homologous pairs.
What happens during Metaphase II of meiosis II?
Chromosomes are placed at the metaphase plate
How are sister chromatids different in Metaphase II due to crossing over in Prophase I?
The two sister chromatids are not genetically identical
What are kinetochores attached to in Metaphase II of meiosis II?
Microtubules extending from opposite poles
