Modern Biology Chapter 8

Chromosomes

Rod-shaped structures made of DNA and proteins.

Histones

Maintain the shape of chromosomes and aid in the tight packing of DNA.

chromatid

Each half of the chromosomes.

Centromere

The point where two Chromatids are attached.

Chromatin

Less tightly coiled DNA-protein complex.

Sex Chromosomes

Determine the sex of the organism.

Autosomes

All the other chromosomes in the organism.

Homologous Chromosomes

Two copies of each Autosomes.

Karyotype

A photomicrograph of the chromosomes in a normal dividing cell found in a human.

Diploid

Two sets of chromosomes. Body Cells.

Haploid

Sperm Cells and Egg Cells.

Binary Fission

The division of a prokaryotic cell into two offspring cells.

Mitosis

Cell division that results in new cells.

Asexual Reproduction

Is the production of offspring from one parent.

Meiosis

Reduces the chromosome count by half in new cells.

Gametes

Haploid reproiductive cells.

Interphase

The time between cell division. (The Phase)

Cytokinesis

The division of the cells cytoplasm.

Prophase

The first phase of Mitosis.

Spindle Fiber

Radiate from the newly seperated centromeres to prepare for Metaphase.

Metaphase

The second phase of Mitosis, chromosomes are larger in this phase.

Anaphase

The third phase, chromatids of each chromosome seperate at the centromere and slowly move away from eachother.

Telophase

After the chromosome seperates, the cell seals off, Final Phase of Mitosis.

Cell Plate

In a plant cell, midline of dividing cells. Becomes the cell wall eventually.

Synapsis

The pairing of Homologous Chromosomes.

Tetrad

Each pair of Homologous Chromosomes.

Crossing-over

Chromotids may break off and connect to adjacent Homologous Chromosomes.

Genetic Recombination

A new mixture of genetic material is created.

Independant Assortment

The random seperation of the Homologous Chromosomes.

Spermatogensis

The production of sperm cells.

Oogenesis

The production of mature egg cells.

Polar Body

The other three products of meiosis that eventually degenerate.

Sexual Reproduction

The production of offspring through meiosis and the union of a sperm and an egg cell.