3.7 Mitosis Flashcards
What is Mitosis?
Division of a cell that results in each of the daughter cells having an exact copy of DNA of the parent cell.
What is the difference of Mitosis and Meiosis?
Mitosis produces 2 daughter cells that have the same number of chromosomes as the parent cell and each other.
Meiosis produces 4 daughter cells each with half the number of chromosomes as the parent cell.
How many stages are in Cell Division?
4: Prophase, Metaphase, Anaphase, Telophase
What happens during Prophase?
The chromosomes condense
(get shorter and fatter)
Tiny bundles of protein called centrioles start moving to opposite ends of the cell forming a network of protein fibres across it called the spindle
The nuclear envelope breaks down and chromosomes lie free in the cytoplasm
What happens during Metaphase?
The chromosomes (each with two chromatids) line up along the middle of the cell
The chromosomes become attached to the spindle by their centromere
What happens during Anaphase?
The centromeres divide, seperating each pair of sister chromatids
The spindles contract, pulling chromatids to opotisite ends of the cell, centromere first
What happens during Telophase?
The chromatids reach the opposite poles on the spindle
They uncoil and become long and thin again
A nuclear envelope forms around each group of chromosomes so now there are two nuclei
Cytokinesis is the end of the cell cycle where the cell divides into two
By what process do Prokaryotic cells divide by?
Binary Fission
How is Binary Fission carried out?
Circular DNA molecule replicates and both copies attach to the cell membrane,
Plasmids also replicate,
Cell membrane begins to grow between the two DNA molecules and begins to pitch inward, dividing the cytoplasm in two,
A new cell wall forms between the two molecule of DNA, diving the original cell into two identical daughter cells, each with a single copy of circular DNA and a variable number of copies of plasmids.
Why are Spindle Fibres important?
Attached to the centromere of the chromosome
Separate the chromosomes into chromatids at opposite poles of the cell
Why are Centromeres important?
Holds the chromatids together
Attaches the chromatids to the spindle
Allows the chromatids to be separated to opposite poles
