BIO 101: Lab 11 - Cell Division & Gametogenesis

anaphase

Phase of mitosis in which the chromosomes separate and move to opposite ends of the cell

anaphase I

tetrads separate and homologous chromosomes move apart to opposite sides of the cell

anaphase II

sister chromatids separate and spindle fibers pull chromosomes to opposite sides of the cell

bivalent

the four chromatids of the two homologous chromosomes that pair up during synapsis

cell cycle

stages from the first division of a cell to the time the resulting daughter cells divide

cell plate

A double membrane across the midline of a dividing plant cell, between which the new cell wall forms during cytokinesis.

centrioles

a pair of these make up the centrosome; these form the mitotic spindle

centromere

joins the sister chromatids together

centrosome

A structure in animal cells containing centrioles from which the spindle fibers develop.

chiasma

The X-shaped, microscopically visible region representing homologous chromatids that have exchanged genetic material through crossing over during meiosis.

chromatin

DNA that is unwound into a thin strand; appears this way during interphase, when the cell is actively engaged in its metabolic processes

cleavage furrow

The first sign of cytokinesis in an animal cell; a shallow groove in the cell surface near the old metaphase plate

crossing over

Process in which homologous chromosomes exchange portions of their chromatids during prophase I of meiosis

cytokinesis

Division of the cytoplasm during cell division

diploid

an organism or cell that has two of each type of chromosome (homologous pairs)

fertilization

Process in sexual reproduction in which male and female reproductive cells join to form a new cell

G1 phase

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

G2 phase

stage of interphase in which cell duplicates its cytosol and organelles and synthesizes proteins necessary for division

gametogenesis

production of gametes

haploid

an organism or cell that has only one of each type of chromosome

homologous chromosomes

Pair of chromosomes that are the same size, same appearance and contain genes that code for the same traits.

interkinesis

"resting" period between meiosis I and meiosis II (similar to interphase but NO DNA replication occurs)

interphase

period of the cell cycle between cell divisions; makes up 90% of the cell cycle; cell performs its usual functions during this stage

kinetochores

where the mitotic spindle attaches to a chromosome

meiosis

nuclear division that reduces the chromosome number by half

metaphase

Chromosomes line up in the middle of the cell

metaphase I

Pairs of homologous chromosomes move to the equator or middle of the cell.

metaphase II

chromosomes align at metaphase plate in a single file line (no homologous pairs)

mitosis

cell division in which the nucleus divides into nuclei containing the same number of chromosomes

mitotic spindle

An assemblage of microtubules and associated proteins that is involved in the movements of chromosomes during mitosis.

mitotic stage

includes mitosis and cytokinesis

oogenesis

the production, growth, and maturation of an egg, or ovum; occurs in females in the ovaries starting during fetal development, then stops and restarts once over 28 days from puberty to menopause

ova

female reproductive cells (eggs)

prometaphase

The second stage of mitosis, in which the nuclear envelope fragments and the spindle microtubules attach to the kinetochores of the chromosomes.

prophase

Chromosomes become visable, nuclear envelop dissolves, spindle forms

prophase I

The chromosomes condense, and the nuclear envelope breaks down, the mitotic spindle forms, homologous chromosomes synapse and crossing-over occurs.

prophase II

chromosomes condense, nuclear envelop breaks down if needed, mitotic spindle forms (NO pairing of homologous chromosomes)

S phase

The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated.

spermatids

four haploid cells produced as a result of spermatogenesis; eventually mature into viable sperm

spermatogenesis

production of sperm; occurs in males in the testes starting at puberty throughout the life span

synapsis

Pairing of homologous chromosomes during prophase I of meiosis

telophase

phase of mitosis in which the distinct individual chromosomes begin to spread out into a tangle of chromatin; nuclear envelope begins to reform; spindle fibers break down

telophase I

mitotic spindle breaks down, nuclear envelope may reform, chromosomes relax into chromatin (still have sister chromatids)

telophase II

spindle breaks down, nuclear envelop reforms, chromosomes relax into chromatin

zygote

fertilized egg (diploid)