Ch. 10 Review

Telophase I

2 new cells, nuclear envelope reforms, cytokinesis takes place.

Cleavage Furrow

A constricted region of the cytoplasm that forms and progressively deepens during cytokinesis of animal cells, thereby separating the 2 daughter cells.

OOtid

A haploid cell formed by meiotic division of a secondary oocyte

Crossing Over

A process in which genetic material (DNA) is exchanged between paired, homologous chromosomes

polar bodies

A small n cell produced during oogenesis in female animals that does not develop into a functional ovum.

Centromere

A specialized constricted region of a chromatid; contains the kinetochore. In cells at prophase and metaphase, sister chromatids are joined at in the vicinity of their centromeres.

Centrosomes

An organelle in animal cells that is the main microtubule-organizing center; typically contains a pair of centrioles and is important in cell division

Anaphase II

Chromatids separate

Homologous Chromosomes

Chromosomes that are similar in morphology and genetic constitution.

Sex chromosomes

Chromosomes that play a role in sex determination.

Binary Fusion

Equal division of a prokaryotic cell into two; type of asexual reproduction

Telophase II

Nucleus forms & cytokinesis takes place

Centriole

One of a pair of small, cylindrical organelles lying at right angles to each other near the nucleus in the cytoplasm of animal cells and certain protists and plant cells; each centriole is in the form of a cylinder composed of nine triplets of microtubules.

Chromatid

One of the two identical halves of a duplicated chromosome; the two chromatids that make up a chromosome are referred to as sister chromatids

G2 Phase

Second gap phase within the interphase stage of the cell cycle. Time gap following the S phase and preceding cell division. Cell preps for division. Organelles are copied and proteins are made.

Histones

Small positively charged (basic) proteins in the cell nucleus that bind to the negatively charged DNA

S Phase

Stage in interphase of the cell cycle during which DNA and other chromosomal constituents are synthesized. Cells DNA is copied.

Cytokinesis

Stage of cell division in which the cytoplasm divides to form 2 daughter cells.

Anaphase

Stage of mitosis in which the chromosomes move to opposite poles of the cell. The chromatids of each chromosome separate at the centromere and move toward opposite poles.

Independent Assortment

The alleles of unlinked loci are randomly distributed to genes

Genetic Recombination

The appearance of new allele combinations. Recombination in eukaryotes generally results from meiotic events, wither crossing over or shuffling chromosomes

Haploid

The condition of having one set of chromosomes per nucleus.

Diploid

The condition of having two sets of chromosomes per nucleus.

G1 Phase

The first gap phase within the interphase stage of the cell cycle. Offspring cells grow to mature size

Prophase

The first stage of mitosis. During prophase the chromosomes become visible as distinct structures, the nuclear envelope breaks down, and a spindle forms. Copied DNA coils into rod shaped chromosomes, nucleolus and nuclear membrane breakdown. Centrosomes form and move toward opposite ends of the cell. Spindle fibers radiate from the centrosomes in prep of mitosis.

Telophase

The last stage of mitosis when, having reached the poles, chromosomes become decondensed, and a nuclear envelope forms around each group. Cytoplasm of cell divides by cytokinesis. A pinching occurs and creates a cleavage furrow.

Sperm cells

The motile male gamete of animals and some plants and protists

Metaphase

The stage of mitosis in which the chromosomes line up on the midplane of the cell. Occurs after prometaphase and before anaphase. Chromosomes are easy to identify, kinetochore fibers move the chromosomes to the center of the dividing cell.

Interphase

The stage of the cell cycle between successive mitotic divisions. Most of cell's life

Cell Plate

The structure that forms during cytokinesis in plants, separating the 2 daughter cells produced by mitosis

Secondary OOcyte

after it passes as part of ovulation

Prophase II

break down of nuclear envelope, no crossing over, chromosomes thicken

Metaphase I

chromosomes line up randomly in the middle, independent assortment takes place

Metaphase II

chromosomes meet in the middle

Primary Spermatocyte

diploid cells

Primary OOcyte

during fetal period

Anaphase I

entire chromosomes move to poles

Ovum

female gamete of animals

Secondary Spermatocyte

haploid cells

Tetrad

he chromosome complex formed by the synapsis of a pair of homologous chromosomes during meiotic prophase I.

Synapsis

he process of physical association of homologous chromosomes during prophase I of meiosis

Spermatids

immature sperm cells

Prophase I

loss of nuclear envelope, chromosomes thicken, homologs chemically find one another, crossing over occurs which allows for genetic diversity.

Gamete

sex cell

Spindle Fibers

structure consisting mainly of microtubules that provides the framework for chromosomes movement during cell division.