Honors When Good Cells Go Bad

Mutation

change in a DNA sequence that affects genetic information

missense mutation

A base-pair substitution that results in a codon that codes for a different amino acid.

nonsense mutation

A mutation that changes an amino acid codon a stop codon, resulting in a shorter and usually nonfunctional protein.

silent mutation

A mutation that changes a single nucleotide, but does not change the amino acid created.

frameshift mutation

involves the insertion or deletion of a nucleotide in the DNA sequence

cancer cells

Do not have a properly functioning cell-cycle system; instead, they divide excessively and can invade other tissues of the body

tumor suppressor genes

make proteins that stop cell division and kill cells

Proto-oncogenes

the corresponding normal cellular genes that are responsible for normal cell growth and division

Apoptosis

programmed cell death

DNA repair

Term for the processes that correct changes to a DNA molecule.

checkpoints

3 points (g1, G2, M) where regulatory proteins (enzymes) determine if cell is ready to proceed in cell cycle

G1 phase

stage of interphase in which cell grows and performs its normal functions

S phase

DNA is replicated during interphase

G2 phase

stage of interphase in which cell prepares to divide

Protein

A polymer made of monomers of amino acids.

multi-hit model

multiple mutations are usually required to convert a normal cell to a malignant one

cell cycle

series of events that cells go through as they grow and divide

Mitosis

division of the nucleus

Cytokinesis

division of the cytoplasm

G0 phase

a non dividing state occupied by cells that have left the cell cycle, sometimes reversibly

sister chromatids

Identical copies of a chromosome; full sets of these are created during the S subphase of interphase.

Chromatin

uncondensed DNA

chemotherapy

treatment of cancer with drugs that target rapidly dividing cells

spindle fibers

Protein structures which move the chromosomes during cell division.

causes of mutations

Copying Errors and Exposure to Chemicals & UV radiation

Prophase

Chromosomes become visable, nuclear envelop dissolves, spindle forms

Metaphase

phase of mitosis in which the sister chromatides line up across the center of the cell

Anaphase

the third phase of mitosis, during which the chromosome pairs separate and move toward opposite poles

Telophase

phase of mitosis in which the distinct individual chromosomes begin to spread out into a tangle of chromatin

Oncogenes

genes that cause cancer by blocking the normal controls on cell reproduction

Image of interphase

Image of prophase

Image of metaphase

Image of Anaphase

Image of telophase/cytokinesis

Image of sister chromatids