mitosis Flashcards
What is mitosis?
A type of cell divison that results in two identical diploid daughter cells with same number of chromosomes as parent cells
What are the stages of mitosis?
The stages of mitosis are prophase, metaphase, anaphase, and telophase.
What happens in prophase?
- Chromatin material condenses to form visible chromosomes
- the nucleolus disappears
- Nuclear membrane begins to break down
- spindle fibres begins to form from centrosomes
What happens during metaphase?
Chromosomes line up across the equator of the cell and spindle fibres attach to the centromeres
What happens during anaphase?
the sister chromatids of each chromosome separated and are pulled to opposite ends of the cell by the spindle fibers.
What happens during telophase?
- two nuclei are formed
- spindle fibres break downs
- chromosomes unwinds chromatin
- nuclear membrane forms around each nucleus
* mitosis is complete
What is cytokinesis?
cytoplasm of a parent cell divides into two daughter cells, each containing a nucleus and other organelle
What is interphase?
The cell’s DNA is replicated. Each chromosome is duplicated, forming identical sister chromatids. This step ensures that each daughter cell, after cell division, will receive a complete set of genetic information.
G1 Phase (Gap 1):
Cell Growth: The cell grows in size and carries out its normal cellular functions.
What are the three stages of interphase?
- G1( gap phase 1 ) - cell growth and metabolic activity occurs. cells enlarge by absorbing new materials (end products of photosynthesis/digestion)
- S (synthesis phase)- DNA replication occurs- each cell has two identical copies of DNA
- G2 (gap phase 2)- enzymes check duplicated chromosomes for any errors and prepares for mitosis
Why is mitosis important?
- repair of damaged tissues and replacement of worn out cells
- asexual reproduction
- growth and development of multi cellular organisms- embryos, organs
- ensures chromosomes are evenly distributed between two daughter cells during cell division.- identical to parent cell
What are embryonic stem cells?
cells from early embryos that can differentiate into any type of cell
How does cytokinesis occur in animals and animal cells?
Why is cytokinesis important
- separates the two daughter nuclei and ensures each cell has one nucleus
- result is two daughter cells with identical chromosomes to each other and to parent cell (46)
Why is cytokinesis important
- separates the two daughter nuclei and ensures each cell has one nucleus
- result is two daughter cells with identical chromosomes to each other and to parent cell (46)
What are spindle fibres composed of?
Microtubules
What is the role of centrosomes in mitosis?
They contain the centrioles, which help to form the spindle fibers that attach to the chromatids and pull them apart
What is the difference between chromatids and chromosomes?
Chromosomes are the condensed, coiled-up form of DNA that can be seen during cell division. Each chromosome is composed of two identical copies of DNA called chromatids, which are held together by the centromere. During cell division, the chromatids separate
What are the stages of cell cycle?
- interphase
- mitosis
after cytokinesis, cell will enter G1 phase again
Do all cells enter enter G1 phase or continue to divide?
No some specialized cells do not enter cell cycle.
they are in a phase called G0 phase, and only reenter cell cycle when needed
eg.
* nerve cells do not divide
* stem cells can enter cell cycle and divide when needed but not frequently
What is the result in telophase
- Two nuclei with chromosomes identical to each other and to the the parent cell
What is the result of mitosis?
Mitosis results in the formation of two genetically identical diploid daughter cells, each with the same number of chromosomes as the original parent cell.
