3.7 - Mitosis Flashcards
(20 cards)
What is the simple definition of mitosis?
Division of a cell that results in each of the daughter cells having an exact copy of the DNA of the parent cell.
Mitosis is always preceded by a period which the cell is not dividing, what is this period called?
Interphase
The two copies of DNA after replication remain joined at a place called?
Centromere
What are the four stages of mitosis?
- prophase
- metaphase
- anaphase
- telophase and cytokinesis
In prophase the chromosomes first become what?
Visible
Animal cells contain two cylindrical organelles called?
Centrioles
From each of the centrioles what develops?
Spindle fibres
The spindle fibres span the cell from pole to pole, collectively, these spindle fibres are called what?
Spindle apparatus
What do plant cells lack but still have?
Lack centrioles, but still develop a spindle apparatus.
By metaphase the chromosomes are seen to what?
Be made up of two chromatids
The chromatids are joined by the?
Centromere
Where do the chromosomes arrange themselves in metaphase?
Across the equator of the cell.
What happens in anaphase?
The centromeres divide into two and the spindle fibres pull the individual chromatids making up the chromosome apart to opposite poles of the cell
Where does the energy come from to pull the chromatids to opposite poles?
Mitochondria, which gather around the spindle fibres.
What happens to the chromosomes in telophase and cytokinesis?
The chromosomes reach their respective poles and become longer and thinner, finally disappearing altogether, leaving only wide spread chromatin.
What is it called when the cytoplasm divides?
Cytokinesis
What happens to the spindle fibres and nuclear envelope in telophase?
The spindle fibres disintegrate and the nuclear envelope and nucleolus re - form
What is the cell division process that happens in prokaryotic cells?
Binary fission
What happens in binary fission?
- The circular DNA molecule replicates and both copies attach to the cell membrane
- The plasmids also replicate
- The cell membrane begins to grow between the tow DNA molecules and begin to pinch inward, dividing the cytoplasm in two
- A new cell wall forms between the two molecules of DNA, dividing the original cell into the two identical daughter cells, each with a single copy of the circular DNA and a variable number of copies of the plasmids.
How do viruses replicate?
By attaching to their host cell with the attachment proteins on their surface, they inject their nucleic acid into the host cell, the genetic information on the injected viral nucleic acid the provides the ‘instructions’ for the host cells metabolic processes to start producing the viral components.
