Ch 12

All the DNA in a cell

where DNA molecules in a cell are packaged into

joined copies of the original chromosome

the narrow “waist” of the duplicated chromosome, where the two chromatids are most closely attached

a complex of DNA and protein that condenses during cell division

nonredproductive, have two sets of chromosomes

reproductive (sperm and egg), have half as many chromosomes as somatic cells

1 because sister chromatids are still considered 1 chromosome before seperating

interphase and mitotic

cell growth and copying of chromosomes in preparation for cell division

mitosis and cytokinesis

interphase

G1 phase (“first gap”), S phase (“synthesis”), G2 phase (“second gap”)

the division of the genetic material in the nucleus

the division of the cytoplasm into taughter cells
-where cytoplasm that was already dividing the cell continues until there are 2 individual cells

cell grows by producing proteins and organells, where non replicating cells exit the cycle

DNA synthesis or replication.

- At the start each chromosome is single, at the end, after dna replication each chromosome has 2 sister chromatid

-where we duplicate the 23 chromosomes and end up with 46 pairs

the cell grows more as it completes preparation for cell division

-preparation for mitotic phase

when the cell physically divides

-division of the nucleus and its chromosomes

miotic phase

G1 growth phase

phrophase, phrometaphase, metaphase, anaphase, telaphase

chromatin condenses into chromosomes, mitotic spindle begins to form, microtubles begin to grow and push the centrosomes furthur apart

-before this phase the chromatids aren't in the familiar chromosome shape they are loosley spread. this phase causes the chromatin to become tightly coiled int the shape we're familiar to

anaphase

telophase

contains 2 centrioles, replicated before mitosis in G2 creating 2 pais of centrioles or 2 centrosomes

the 2 centrosomes and the microtubles that start to form between them

the nucleus breaks down and the sister chromatids are freed, the growing microtubles attatch to proteins called Kinetochores which have assembled on the centromere of the chromosome

cells align in the center, M checkpoint occurs to ensure that each chromatid is attacthed to opposite ends of a miotic spindle, once all Kinetochores are attatched to the spindle and are lined up they can pass the checkpoint

cohesive proteins that bind the chromatids together breaks down, the chromatids are now called chromosomes as they're pulled apart and seperated by the miotic spindle, thus generating the 2 seperate sets of the entire genome, lastly the cell elongates

anaphase

2 seperate nuclei are built from the fragments of the brocken down nucleus, chromosomes unwind into chromatin, microtubles finish coming apart and two identical nuclei which completes mitosis

-nuclear membranes form around the seperated chromosomes

crowded cells will stop dividing

the point at which the cell becomes committed to entering the cell cycle.
-determines if the cell will enter the S phase to replicate DNA and prepare for cell division

help maintain genomic stability
-prevents cells from entering mitosis when DNA is damaged

1 chromsome

a structure made of microtubules that controls chromosome movement during mitosis

the assembly of spindle microtubules begins

intherphase, opposite ends of the cell

G0 phase

to divide, they must be attached to a substratum

They may make their own growth factor

They may convey a growth factor’s signal without the presence of the growth factor

They may have an abnormal cell cycle control system

released by certain cells and stimulate other cells to divide
-natural proteins in our body that promote the growth, organization
-proteins that stimulate cell division