D2.1 - Cell and Nuclear Division Flashcards
What happens during chromosome condensation?
Chromosomes undergo supercoiling of DNA, becoming more compact and visible under a microscope.
What occurs during metaphase?
Chromosomes align at the cell’s equator, and spindle fibers attach to their centromeres.
What factors can lead to cancer?
Mutagens, oncogenes, and metastasis.
What is the role of CDKs in the cell cycle?
CDKs drive the cell through various stages of the cell cycle when activated by cyclins.
What are cyclins?
Proteins that regulate the cell cycle by acting as subunits of cyclin-dependent kinases (CDKs).
What are the four main phases of mitosis?
Prophase, metaphase, anaphase, and telophase.
What occurs during interphase?
Cell growth, DNA replication, and preparation for mitosis.
What is the mitotic index?
The ratio of cells in mitosis to the total number of cells, expressed as a percentage.
How is the mitotic index calculated?
$$ ext{Mitotic Index} = \frac{\text{Number of cells in mitosis}}{\text{Total number of cells}} \times 100\%$$
What occurs during telophase?
Chromosomes decondense, the nuclear envelope reforms, and cytokinesis begins.
What are sister chromatids?
Identical copies of a chromosome, attached at the centromere, seen from prophase to metaphase.
What is mitosis?
A process in cell division where the nucleus divides into two genetically identical daughter nuclei.
How does cytokinesis differ in plant and animal cells?
In animal cells, a contractile ring pinches the cell; in plant cells, a cell plate forms to create a new cell wall.
What happens during anaphase?
Sister chromatids separate and move to opposite poles of the cell.
What happens during prophase?
Chromosomes condense, the nuclear envelope breaks down, and centrosomes move to opposite poles.
