Chapter 10 BIO MITOSIS

binary fission

Binary fission starts with origin of replication on one circular chromosome, grow in two opposite directions, forms two strands of DNA. FtsZ proteins scattered around the cell, form a ring structure bringing in material from cell wall and cell membrane to form separation. Separation forms septum. Two daughter cells are the result.

interphase

cell growth and copying chromosomes in preperation for cell division (spends most of its time there)

mitotic phase

mitosis and cytokinesis

G1 phase

cell is biochemically active, cell is growing, obtaining nutrients, preparing organelles for s phase

S phase

dna replication, histone production, centrosome production

G2 phase

cell continues to grow, energy replenished, cytokeleton begins to breaks, organelles replicate

nucleosomes are composed of -----

8 histones

nucleosomes are separated by

linker DNA

prophase

-nuclear envelope begins to break down,
-spindle fibers begin to form,
-nucleolus disappears,
-chromosomes start condensing

prometaphase

-centrosomes continue to condense,
-kinetochores appear,
-mitotic spindle begins to form at centromeres,
-centrosomes move to opposite poles

metaphase

-spindle fibers are fully forms,
-chromosomes line up at metaphase plate,
-nuclear envelope is absorbed in er,
-sister chromatids are attached to spindle fibers on opposite ends

anaphase

-sister chromatids are puled apart,
-cohesions begin to break down,
-nonkinetochores glide against each other to help elongate the cell

Telophase

-nuclear envelope reforms,
-mitotic spindle break down,
-chromosomes are at opposite ends and are decondensing

Cytokinesis

division of the cytoplasm, forming two new cells

kinetochore

A structure of proteins attached to the centromere that links each sister chromatid to the mitotic spindle.

Centromere

the region of the chromosome that holds the two sister chromatids together during mitosis

Centrosomes in Mitosis

organize microtubules of the mitiotic spindle

centrioles in mitosis

barrel shape organnelle that lives within the centrosome

clevage furrow

-formation of contractile ring made up of actin fiilaments are going to squeeze middle part and pinch it in the center --> get two separate cells
* only works in animals and some protists because plants have cell walls so cant pinch it

cell plate formation

Golgi vesicles align together and fuse to create the cell plate bringing in material from the cell wall and cell membrane. The membranes of these vesicles then form the new plasma membrane.

levels of packaging DNA in chromatin

-most DNA is at 30nm fiber stage
-at 300 nm: loop because scaffolding proteins that can hold loops together--> more condensed
-at 700nm they are fully condensed
- we condense because it makes it easier to move things around, need condesing of chromosome to replicate
-each region of nucleus has a specific chromosomes (they are not just tangled and floating)

functions of mitosis

growth and development of embryo and tissue renewal