General Biology I - Mitosis

Asexual Reproduction

Give rise to new organisms that are prokaryotic and unicellular

Growth and Development

Enables organism to develop from single cell to many cells

Tissue Renewal

replace cells that are injured

Genome

All the DNA in the cell

DNA gets packaged in chromosomes which

carry lots of genes

Prokaryotic Chromosomes

Consists of a single, circular DNA molecule associated with small amounts of protein

Binary Fission

Reproduce entire organism asexually and produces 2 identical cells

Binary Fission Steps

1. Chromosome will replicate

2. Each copy is at the end of the cells

3. Cell elongates and the cells will split apart

Eukaryotic chromosomes

consist of several linear DNA molecules with proteins which are made of chromatin and histones

histones

help fit DNA and nucleus and help maintain structure of the chromosome

Somatic cells

All body cells except gametes

Diploid Cells

contain 2 sets of chromosomes

Haploid Cells

Contain 1 set of chromosomesH

Homologus chromosomes

pairs type of chromosome

Homologs will be the same size and

have the same centromere position

Centromere

pinched in region of a chromosome that has the same banding patterns

The same genes are at

the same loci

Loci

location of a gene

Alleles

variation in a gene

Cell cycly has replication and sorting process which is

time from when a cell is first formed until its own division into two daughter cells

Interphase

90% of cell cycle and a prep for mitosis

G1

Metabolic activity and growth

S

Metabolic activity, growth and DNA synthesis

G2

Metabolic activity and growth and preparation for division

Mitotic Phase

10% of cell cycle consists of mitosis and cytokinesis

S Phase

Every chromosome will make a copy and made of 2 sister chromatids that are identical

G1 Phase,

they are unduplicated and made of 1 chromatid

G2 Phase

Centrosome divices and chromosomes are decondensed

Centrosomes

found only in animal cells and organizes microtubules into spindle

Spindle

composed of centrosomes, microtubules and asters and attach to the chromosomes

Aster

short radial arrangements of microtubules that exchange to form central tubules

Prophase

• Nuclear envelope will dissociate

• Nucleolus is less visible

• Chromatids become more contracted

• Centrosomes will move apart

2n =

6

Each chromosome is mad eof

2 sister chromatids

Prometaphase

Centrosomes will move to opposite ends and form spindles

• nuclear envelope will be completely fragmented

• Releases chromosomes into cytosol

Nonkinetochore MT

Part of spindle and do not attach to chromosomes

Kinetochore

made of proteins and will attach

Metaphase

Sister chromatids will align themselves on the metaphase plate, chromosomes get to the middle by using the cellA

Anaphase

connection is broken and each chromosome will be made of 1 chromatid

Telophase

Chromoseomes will compress and decompress

• nucleoli will reform

• nuclear envelope forms

Cytokinesis

Divides the cytoplasm of the cell

• starts shortly after anaphase

• occurs differently in plants and animals

Animal Cytokinesis

Ring of actin and myosin will form the clevage furrow

Plant Cytokinessi

Cell plate will divide the two daughter cells

G0

cell does not divide and cell resp takes place

Cell Cycle control system

Cyclically operating set of molecules in the cell that triggers and controls key events and contains where stop and go signals occur

G1 checkpoint

Checks for cell size accuracy of previous divisions

Growth factor

Made from cells around the dividing cell to say all checks are good

M Checkpoints

Before anaphase, checks chromosome atttach to spindle

G2 checkpoint

Between G2 and prophase, checks for DNA replication accuracy.