10.5 M Phase: chromosome segregation and division of cytoplasmic contents Flashcards
Phases of Mitosis (M Phase)
- Prophase
- Prometaphase (late prophase)
- Metaphase
- Anaphase
- Telophase
Prophase
- disassembling of nucleus,cytoskeleton,Golgi, ER
- spindle apparatus forms
- chromosomes are visible, coiled
Prometaphase
- condensed chromosomes attach to spindle by kinetochores;
- attached to centromere region of each sister chromatid
- microtubules at opposite poles of spindle
Metaphase
- all chromosomes aligned in middle (metaphase plate)
- chromosomes attached to opposite poles
- loss of cohesin between sister chromatids brings cell into anaphase
- preparation for separation of sister chromatids checked before continuing cycle
Anaphase
- begins when centromeres split down middle
- separation of sister chromatids resulting in genetic material
- key:removal of cohesin proteins from all chromosomes
- chromosomes pull to opposite poles
- spindle poles move apart
Telophase
- chromosomes uncoil and become invisible(decondense)
- nucleus,Golgi,ER reform
- spindle apparatus is broken down
- prophase in reverse
Cytokinesis
- cleavage of cell into two halves (cell division)
- division of cytoplasm to produce two daughter cells
Mitosis is used for what
- Asexual reproduction (one parent)
- Growth
- Repair
After mitosis (PMAT) is complete what is the outcome?
-two identical daughter cells
Cytokinesis in plant cells
- form internal membrane called cell plate states at interior and extends out to plasma membrane
- form spindle apparatus during division
- do NOT use centrioles
Aster
- array of microtubules that extend toward plasma membrane
- in animal cells
During mitosis in human cells, what are separated and sorted so daughter cells receive 46 chromosomes?
-chromatids
metaphase plate
- during metaphase
- half way between the poles
- kinetochore microtubules move chromosomes to middle of cell (metaphase plate) where they are lines up
When does cell division take place?
-after mitosis is completed
Mitosis
- division of the nucleus
- chromatids are separated and sorted to each daughter cell has 46 chromosomes
Cytokinesis in animal cells
- cleavage furrow pinches cell until it divides in two
- aster
Anaphase A
- sister chromatids pulled toward opposite poles
- kinetochore microtubules attached to poles are shortened
Mitosis(nuclear division) occurs in what organisms?
- plants
- animals
- most protists
Cells divide into two equal halves during what phase in the cell cycle?
-cytokinesis
Anaphase B
- poles move apart
- flexible membrane is elongated
Cell plate
- in plants
- expanding membrane partition that grows outward
- fuses with plasma membrane
Middle lamella
- in plants
- the space between daughter cells filled with pectins
Separation of sister chromatids occurs during what phase?
Anaphase
