Chapter 12: The Cell Cycle

What is cell division?

the process a cell splits into two new cells

What is cell division used for?

Growth, Repair, Reproduction

What is the cell cycle?

the series of events a cell goes through as it grown and divides

Genome

complete set of DNA in a cell

Chromatin

loosely packed DNA and proteins; this is how DNA exist during interphase

Chromosome

tightly coiled DNA visible during cell division

Prokaryotes

single circular chromosomes

Eukaryotes

Multiple linear chromosomes

Somatic cells

(non reproductive cells) 2 sets of chromosomes

Gametes

(reproductive cells; sperm & egg) have 1 set of chromosomes

Sister chromatic

identical copies of a chromosomes, connected at the centromere

Centromere

the narrow “waist” of the duplicated chromosome; Region where sister chromatids are tightly joined

Mitosis

division of somatic cells; reproduces identical cells

Meiosis

division of gametes; reproduces chromosome number by half

Difference between eukaryotic cell division consists of…

Mitosis: the division of the genetic material in the nucleus

Cytokinesis: the division of the cytoplasm

Mitotic spindle

structure made of microtubules that control chromosome movement during mitosis

Kinetochores

protein complexes associated with centromeres

At metaphase the chromosomes are all lines up at the…

Metaphase plate: a plane midway between the splindle’s two poles

Cytokinesis; Animal cells

occur by a process known as cleavage, forming a cleavage furrow

Cytokinesis; Plant cells

a cell plate forms during cytokinesis

How do prokaryotes such as bacteria reproduce?  

reproduce by a type of cell division called binary fission  

Binary fission

1. The chromosome replicated (beginning at the origin of replication) 

2. 2 daughter chromosomes actively move apart  

3. The plasma membrane pinches inward, dividing the cell into two

How is the cell cycle control system regulated, Why is this important

by both internal and external controls

it ensures that cells divide safely and accurately, preventing errors that could lead to diseases like cancer

What are checkpoint in the cell cycle?

where the cell cycle stops until a go-ahead signal is received: G1, G2, M phases

What is the G0 phase

resting stage in the cell cycle where a cell stops dividing

What two general rules do normal cells exhibit when dividing

1. They only divide when needed

2. They stop dividing when they touch other cells

a normal cell is converted to a cancerous cell by a process called

transformation

If abnormal cells remain only at the original site, the lump is called a

benign tumor

Malignant tumors

invade surrounding tissues and can be metastasize exporting cancer cells to other parts of the body, where they may forms additional tumors

Mitotic (M) phase

mitosis and cytokinesis

Interphase

cell growth and copying of chromosomes in preparation for cell division

G1 phase

first gap

S phase

synthesis

G2 phase

second gap