Chromosome Theory of Inheritance ch 3&4 Flashcards
What are the 2 means of cell division?
Mitosis and Meiosis
What is mitosis
Mitosis is the nuclear cell division that generates two daughter cells.
- Chromosome number maintained
Mitosis Vs Meiosis. In which cells mitosis/meiosis occur?
Which cells undergo mitosis/meiosis?
What is Meiosis?
Meiosis is the nuclear cell division that generates gametes (egg and sperm) and results in 4 daughter cells
Diploid meaning? In which cells occur?
Diploid - is a cell that contains 2 complete sets (copies) of chromosomes, one from each parent. Most body cells (somatic cells) are diploid (2n).
Haploid means?
Haploid - is a cell that has a half of the set (one copy) of unpaired chromosomes.
Meiosis —> haploid (n) gametes –half chromosome number
How zygote is formed?
Two gametes fuse during fertilization to form a zygote. (2n)
Drosophila VS humans (number of diploid and haploid cells)
In Drosophila, 2n=8 - diploid cells , n=4 - haploid cells (gametes)
In humans , 2n=46 - diploid cells (46 chromosomes) and n=23 - haploid cells
(23 chromosomes in each of the gamete)
Chromosomes can be classified by centromere position. What are they?
> metacentric, submetacentric, acrocentric, and telocentric
Sister chromatids definition
Sister chromatids are identical copies of a replicated chromosome
What are the homologous chromosomes (homologs)?
Homologs contain the same set of genes, but can have different alleles for some genes
Nonhomologs chromosomes definition
Nonhomologs carry completely unrelated sets of genes
What is Karyotype?
Karyotype: Micrograph of stained chromosomes arranged in homologous pairs
Difference between sex chromosomes and autosomes.
The key difference between autosomes (22 pairs) and sex chromosomes (1 pair) is that the autosomes contain genes that are responsible for the determination of somatic characteristics while the sex chromosomes contain genes that determine sex and sex-related characteristics of an organism.
The primary determinant of maleness is a single gene called??
SRY gene
What are the phases (stages) of meiosis I?
Prophase I, Metaphase I, Anaphase I, Telophase I and
Interkinesis - (not actual stage)
What are the phases (stages) of meiosis II?
Prophase II, Metaphase II, Anaphase II, Telophase II and (Cytokinesis - division of cytoplasm, which ends with 4 non-identical haploid cells)
What is interphase?
Interphase is the phase of the cell cycle in which a typical cell spends most of its life prior to cell division. It’s the normal state of the cell.
(growth, metabolism, function)
What are the phases (stages) of the cell cycle (interphase)?
Describe the brief function of each.
1) G1 Phase, 2) S Phase, 3) G2 Phase,
4) M (Mitosis or Meiosis) phase - nucleus and cell divides
Late in G1, all cells follow one of two paths:
- they withdraw from cell cycle and become dormant in G0
2. they become committed to DNA synthesis, cell cycle.
What is G0 phase?
G0 - viable and metabolically active, but NO proliferation (no division)
What is chromatid
A chromatid is one half of a replicated (duplicated) chromosome
in preparation for cell division