Chapter 10: Mitosis

Chromatin

DNA and its associated proteins

Chromosome

A single continuous molecule of DNA wrapped around a protein

Chromatid

One of the two identical attached copies that make up a replicated chromosome

Centromere

A small region of a chromosome where sister chromatids attach to each other

Karyotype

An individual’s complete set of chromosomes, and a laboratory-produced image of a person’s chromosomes

Diploid (2n)

The total number of chromosomes in a cell

Haploid (n)

Half the total number of chromosomes in a cell

Genotype

The genetic constitution of an individual organism

Phenotype

The set of observable characteristics of an individual

Homologous

The maternal and paternal copies of the same chromosome

Euchromatin

Domains of chromatids that are active

Heterochromatin

Domains of chromatids that are inactove

Autosome

Any chromosome that isn’t a sex chromosome

Gamete

a mature haploid male/female germ cell

Telomere

A protective cap at the end of a chromosome, preventing damage and fusion

Binary Fission

asexual reproduction, a single cell divides into two identical daughter cells

q Arm

The long end of a chromosome

p Arm

The short end of a chromosome

Mitosis

Division of a cell’s chromosomes into two identical nuclei

Prophase

Chromosomes condense and become visable

Prometaphase

The nuclear envelope breaks down and spindle fibers attach to the chromosomes

Metaphase

The chromosomes align along the center of the cell, forming the metaphase plate 

Anaphase

The chromosomes are pulled apart to opposite poles of the cell

Telophase

Two new nuclei form at opposite ends of the cell

Cytokinesis

distribution of cytoplasm to daughter cells following division of a cell’s chromosomes

Cleavage

Indentation in an animal cell’s membrane undergoing cytokinesis

Cell plate

Material that forms the beginning of the cell wall in a plant cell

Centrosome

Structure that organizes the microtubules that make up the spindle in animal cells

Spindle

Array of microtubule proteins that move chromosomes

Gap Phase 1 (G1)

The primary growth phase of the cell

Synthesis Phase (S)

The cell replicates its DNA genome

Gap Phase 2 (G2)

The second growth phase of the cell

Cyclins

One of the chemical controls of the cell cycle, the levels of the four proteins fluctuate throughout the cell cycle in a predictable pattern

G1 Checkpoint

Determines if conditions are favorable for cell division

G2 Checkpoint

Occurs before the cell goes into mitosis, the replicated DNA is checked for mutations

M(spindle) Checkpoint

The cell examines whether all sister chromatids are correctly attached to the spindle microtubules

Apoptosis

Programmed cell death

Cancer

A failure of Cell-Cycle control

Characteristics of cancer

Uncontrolled cell growth and the loss of cellular adhesion

Benign Tumors

Slow-growing and harmless tumors that can’t invade adjacent tissues

Metastases

The secondary tumors formed from cancer that has invaded somewhere else

Henrietta Lacks (1920-1951)

Cancer cells were taken from her body and used for decades without her or her family’s knowledge or permission

Proto-oncogenes

A healthy gene found in the cell that is responsible for making proteins responsible for cell growth, are cancerous if mutated

Tumor-Suppressor Genes (p53)

Work to stop and repair mutated genes if detected in the Cell-Cycle, if mutated the enzymes responsible for these repairs will no longer function

Retinoblastoma

Mutation of the tumor-suppressor gene found in the q arm of chromosome 13, cancer of the retina of the eye,

BRCA1

Mutation of the tumor-suppressor gene found in the q arm of chromosome 17, cancer of the breasts and ovaries

Physical Mutagens

Radiation (UV and X-ray)

Chemical Mutagens

Carcinogens(cigarettes), processed foods and preservatives, cosmetics and cleaning products

Biological Mutagens

Viruses and bacteria