Part 2 - Eukaryotic cell division Flashcards
What are histones?
Proteins that DNA wraps around
What is chromatid?
Each arm of chromosome (Half of a chromosome)
What is centromere?
The ball in the middle between the chromatids that holds them together
How many chromosomes is there in humans?
46
What are somatic cells?
Any cell that is haploid and is not a gamete. It has two homologous chromosomes
What are homologous chromosomes?
It is two chromosomes of identical structure
What are gametes?
Haploid cells that are involved in sexual reproduction.
What are the steps of the cell cycle and what happens during each of them?
Mitosis - division of the cells
G1 (growth phase 1) - No DNA synthesis, production of organelles
S phase (Synthesis phase) - DNA/protein synthesis
G2 (growth phase 2) - the cells grows and continues its regular life cycle until gets to Mitosis and the process repeats
What is the duration of G2 phase?
From 24 hours to 1 year - resting phase
What is mitosis?
Division of the nuclear of the cell. Produces diploid cells
What are the stages of mitosis?
Prophase, Prometaphase, Metaphase, Anaphase, Telophase
What happens during Prophase?
Chromatin condenses making the chromosomes visible
What happens during Prometaphase?
Nuclear envelope breaks down
What happens during Metaphase?
The chromosomes become aligned at the equatorial plane
What happens during Anaphase?
Sister chromatids separate and the resultant daughter chromosomes move toward the poles
What happens during Telophase?
Daughter chromosomes reach the poles and form two new nuclei.
What happens during Cytokinesis in an animal cell?
Microfilaments wrap around the middle of the cell pulling on the edges of the cell eventually forming a cleavage furrow, which eventually splits the cell right in half producing two diploid cells
What happens during Cytokinesis in a plant cell?
The cell forms cellulose between the two separate areas. Cell plate formed between the two, and then the cell wall is formed between them as well. Later the cell wall cracks in two forming two separate cells.
What is Meiosis?
The division of the gametes
What are genes formed of?
Alleles. They lead to evolution
What are the stages of Meiosis?
Meiosis I: Prophase I, Metaphase I, Anaphase I, Telophase I
Interkinesis
Meiosis II: Prophase II, Metaphase II, Anaphase II, Telophase II
What happens during Prophase I?
Crossing over, nuclear membrane disappears. Kinetochore microtubules move to the sides of the cell
What happens during Metaphase I?
Both sets of homologous chromosomes are in the centre of the plate. Motor proteins move them there. Kinetochore microtubules contract, pulling the chromosomes in opposite direction. Non kinetochore microtubules continue to grow and push the cell apart
What happens during Anaphase I?
The homologous chromosomes are being pulled apart and in separate sides, cell continues to elongate.
