D2.1 Cell and nuclear division SL Flashcards
Cytokinesis
The process of cytoplasmic division to form two daughter cells
How do animal cells achieve cytokinesis?
By forming a contractile ring that creates a cleavage furrow
How do plant cells achieve cytokinesis?
By forming a cell plate from fused vesicles that merges with the cell wall
What is an example of unequal cytokinesis?
Oogenesis in humans
How does cytokinesis differ in yeast budding?
It involves unequal division, where the bud receives less cytoplasm
What is common to both mitosis and meiosis?
Both require DNA replication before division
How do chromosomes form during mitosis and meiosis?
DNA condenses into two sister chromatids joined at a centromere
What role do microtubules play in mitosis and meiosis?
They assist in the separation of DNA
What marks the start of mitosis and meiosis?
Condensation of DNA into chromosomes
How is DNA organized for mitosis and meiosis?
As chromosomes composed of two sister chromatids
What is the result of mitosis?
Two genetically identical daughter nuclei
What are the stages of mitosis?
Prophase, metaphase, anaphase, telophase
What happens during prophase?
Chromatin condenses, nuclear membrane breaks down, spindle fibers form
Anaphase
Sister chromatids are separated to opposite poles of the cell
What occurs in telophase?
Chromosomes decondense, nuclear membrane reforms
Meiosis
A reduction division generating four genetically unique haploid daughter nuclei
Phases of meiosis
Meiosis I (prophase I, metaphase I, anaphase I, telophase I) and Meiosis II
What is crossing over?
The exchange of genetic material between non-sister chromatids during prophase I
What is non-disjunction?
Improper separation of chromosomes during anaphase
How does meiosis contribute to genetic diversity
Through crossing over and independent assortment
