chapter 8: intro to reproduction at the cellular level

allosome

chromosomes that play a role in sex determination

anaphase

mitosis, sister chromatids are separated from each other

aneuploid

individual with an error in choromosome number, deletions and duplications

asexual reproduction

produces genetically identical clones to the parent organism

autosome

any non-allosome

binary fission

process of prokaryotic cell division

cell cycle checkpoints

mechanisms that monitor the preparedness of a eukaryotic cell to advance through cell cycle stages

cell plate

formation of a cell wall to seperate the 2 daughter cells

centrosomes

microtubule organizing centers that give rise to the mitotic spindle

chiasmata

structure that forms at the crossover points after genetic material is exchanged

chromatin

dna wound around proteins forming long fiber like strands

chromosome

structire made of chromatic and are visible when the cell is dividing

crossing over

exchange of genetic material

cytokinesis

division of the cytoplasm following mitosis to form 2 daughter cells

diploid

describes a cell, nucleus, or organism containing TWO sets of chromosomes

euploid

individual with the appropiate number of chromosomes

G0 (gap 0) phase

here a cell is not preparing to divide

G1 (gap 1) phase

first phase of interphase, centered on cell growth during mitosis

G2 (gap 2) phase

third phase of interphase, cell undergoes the final preparations for mitosis

gamete

haploid reproductive cell or sex cell= sperm or egg

genome

entire genetic dna of an organism

germline cell

specialized cell line that produces gametes such as eggs or sperm

haploid

describes a cell, nucleus, or organism containing ONE set of chromosomes

homologous chromosomes

randomness of how pairs align at the metaphase plate during metaphase 1 of meiosis 1

independent assortment

composed of genetic material from 2 sources, both maternal and paternal segments of dna

interkinesis

period of rest, no replication of dna

inversion

detachment, 180 rotation, and reinsertion of chromosome arm

karyogram

photographic image of a karyotype

karyotype

number and appearance of individuals chromosomes, size, pattern, position

kinetochore

protein structure that attracts and binds spindle microtubules during prometaphase

locus

posotion of a gene on a chromosome

meiosis 1

meiosis 2

sister chromatids are separated from each other and result in 4 unique haploid cells

metaphase

stage of mitosis during which chromosomes are lined up at the metaphase plate

metaphase plate

where chromosomes align during metaphase

mitosis

duplicated chromosomes are separated into identical nuclei,prophase, prometaphase, metaphase, anaphase, telophase

mitotic phase

period of cell cycle when duplicted chromosomes are distributed into 2 nuclei, cytoplasmic contents are divided, include mitosis and cytokinesis

mitotic spindle

microtuule apparatus that orchestrates the movement of chromosomes during mitosis

monosomy

diploid genotype where one chromosome is missing

nondisjunction

sister chromatids that fail to seperate during meiosis 1 or 2

polyploid

individual with incorrect number of chromosome sets

prometaphase

mitosis, mitotic spindle fibers attach to kinetochores

prophase

mitosis, chromosomes condense and the mitotic spindle begins to form

S (synthesis) phase

dna replication occurs

septum

wall formed between bacterial daughter cells as a precursor to cell separation

sister chromatids

2 identical chromosomes attached to one another in the centromere region

somatic cell

all cells of a multicellular organism except the gamete forming cells

telophase

chromosome arrive at opposite poles, decondense, and are surrounded by new nuclear envelopes

tetrad

2 duplicated homologous chromosomes=4 bound together by chiasmata during prophase 1

translocation

where one segment of chromosome dissociates and reattaches to a different nonhomologous chromosome

trisomy

diploid genotype where one entire chromosome is duplicated

zygote

produced when fertilized egg and sperm fuse