Distinguish between the following pairs of terms:
a) somatic cell and gamete
b) autosome and sex chromosome
A) Somatic cell: Two chromosomes of each type, known as homologous chromosomes.
Gamete: Egg and sperm
B) Autosome: Chromosomes other than the sex chromosomes.
Sex chromosome: Determine the sex of a person: XX= Female, XY= Male
Explain how haploid and diploid cells differ from each other. State which cells in the human body are diploid cells differ from each other. State which cells in the human body are diploid and which are haploid.
Haploid cells: Gametes, egg and sperm (contain a single set of chromosomes).
Diploid cells: Somatic cells (one from each parent).
List the phases of meiosis I and meiosis II and describe the events characteristic of each phase.
– Prophase I: Replicated homologous chromosomes.
-Metaphase I: Chromosomes line up on the metaphase plate (horizontally).
-Anaphase I: Chromosomes separate on opposite poles of the cell.
-Telophase I/Cytokinesis: The cleavage furrow forms and the cell is split into two haploid cells.Meiosis II
– Prophase II: Sister chromatids are paired up
-Metaphase II: Sister chromatids line up on the metaphase plate (vertically)
-Anaphase II: Sister chromatids get pulled away by spindle apparatus to opposite poles of the cell.
-Telophase II/Cytokinesis: Nuclei form and the cell in split into four haploid cells.
Describe the process of synapsis during prophase I. What happens during this?
The pairing of two homologous chromosomes that occurs during meiosis. The genetic material is rearranged by crossing over between nonsister chromatids.
Describe two events that occur during Meiosis I but not during Mitosis.
In metaphase I, the metaphase plate is lined horizontally whereas the mitosis has their plate vertically.
One of two or more forms of a gene.
A single parent passes copies of all its genes to its offspring.
Chromosomes other than the sex chromosomes.
Crossovers are visible later in the stage, where sister chromatid cohesion holds the original sister chromatids together.
A group of genetically identical offspring.
The reciprocal exchange of genetic material between nonsister chromatids during prophase I of meiosis.
Somatic cells (one from each parent).
Gametes, egg and sperm (contain a single set of chromosomes).
Two chromosomes of each type, from each parent.
Separation of homologous chromosomes
Separation of sister chromatids
In prophase I, homologous chromosomes segments of nonsister chromatids are exchanged by crossing over, with genetic combinations of maternal and paternal genes on the same chromosome.
Determine the sex of a person: XX= Female, XY= Male
An individual receives a unique combination of genes inherited from two parents.
Two chromosomes of each type, known as homologous chromosomes.
The pairing of two homologous chromosomes that occurs during meiosis.
Contains both paternal and maternal sets of chromosomes (fusion of egg and sperm).