Cell Cycle, Cancer & Meiosis

helicase

unzips dna

DNA polymerase

builds DNA strands

ligase

connects the small DNA fragments built on the lagging strands

chromatin

DNA in uncoiled state

chromosome

a structure of highly coiled DNA

interphase

G1 S G2

haploid

one copy of every chromosome

diploid

cell with 2 copies of every chromosome

gamete

haploid sex cell

somatic cell

diploid zygobody cell

zygote

fertilized egg

sister chromatids

identical copies of chromosomes from DNA replication

homologous chromosomes

pair of chromosomes that contain the same genes in the same locations

G1 checkpoint

checks for dna damage, nutrients and growth factors

G2 checkpoint

checks cell growth and dna replication

metaphase checkpoint

checks chromosome spindle attachment

tumor

mass of cells caused by uncontrolled cell division

protooncogene

genes that code for proteins that continue the cell cycle

tumor suppressor gene

genes that code for proteins that stop the cell cycle

histones

proteins DNA would tightly for chromosome shape

cell fate genes

codes for cell function

autosomes

chromosomes 1-22

crossing over

gene exchange between homologous chromosomes during prophase 1

independent assortment

different combinations of chromosomes pair up randomly during metaphase 1

nondisjunction

uneven separation of homologous chromosomes during anaphase 1 or sister chromatids during anaphase 2

trisomy

3 copies of a chromosome (kinefilter)

monosomy

one copy of a chromosome (turner)

carcinogens

substances that promote the formation of cancer cells

mutagens

damages DNA

spermatocyte

parent cell in spermatogenesis

oocyte

parent cell in oogenesis

alleles

a genetic sequence in a chromosome