Mitosis Flashcards
what are the types of cell division?
-mitosis and meiosis
what is mitosis?
-mitosis produced two daughter cells that have the same number of chromosomes ad the parent cell and each other
what is meiosis?
-meiosis produces four daughter cells each with half the number of chromosomes of the parent cell
what is mitosis?
- the division of a cell that results in each of the daughter cells having an exact copy of the DNA of the parent cell (unless there’s a mutation)
- mitosis is always preceded by a period during which the cell is not dividing Known as interphase
what are the stages of mitosis?
- interphase
- prophase
- metaphase
- anaphase
- telophase
- cytokinesis
what is prophase?
- the chromosomes first become visible as long thin threads which shorten and thicken
- animal cells contain two cylindrical organelles called centrioles which move to opposite end is if the cell
- spindle fibres firm ah each centrioles which span from pole to pole they are collectively known at spindle apparatus
- the nucleolus disappears and RE nuclear envelope breaks down leaving the chromosomes after in the cytoplasm where they are drawn towards the equator of the cell by spinel divides attached to the centromere
what is metaphase?
- chromosomes are seen to be made up of two chromatids each is an identical Copt of DNA from the parent cell
- chromatids are joined by the centromere which some microtubules from the poles are attached and the chromosomes are pulled along the spindle apparatus and arrange themselves along the equator of the cell
what is anaphase?
- the centromere divide into two and the spindle fibres pull the individual chromatids apart
- the chromatids move rapidly to their respective opposite poles and are now chromosomes
- energy for this comes from mitochondria which gather around the spindle fibres
what is telophase?
- the chromosomes reach their respective opposite poles and become longer and thinner finally disappearing altogether leaving only widely spread chromatin
- spindle fibres disintegrate and the nuclear envelope and nucleolus re-form
- the cytoplasm then divides during cytokinesis
What is binary fission?
-binary fission is how cell division occurs in prokaryotic cells
What so the process of binary fission?
- the circular DNA molecule replicated and both copies attach to the cell membrane
- the plasmids replicate
- the cell membrane begins to grow between the two DNA molecules and begins tie pinch inward dividing the cytoplasm in two
- a new cell wall forms between the two molecules if DNA dividing the original cell into 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?
- they replicate by attaching to their host cell with the attachment proteins in their surface they then inject their nucleic acid into the host cell
- the emetic information in the injected viral nucleic acid provide the instructions for the host cells metabolic processes to start producing the viral components like nucleic acid to be assembled into the new virus
what is the importance of mitosis?
-it produces two genetically identical daughter cells to the parent cell which allows for growth repair and reproduction
why is mitosis important for growth?
- when two haploid cells fuse together to form a diploid cell it has all the genetic information needed to form the new organism
- if the new organism is to resemble its patents all the cells that grow from this original cell must be genetically identical
What is interphase?
- a period of considerable cellular activity that includes a very important event (DNA replication)
- after replication the two copies of DNA after replication remain joined at the centromere
