Science 9 - Reproduction Unit Study Guide

Cell Theory

The three components are: 1) All living organisms are composed of one or more cells. 2) The cell is the basic unit of life. 3) All cells arise from pre-existing cells.

Organelle

Small specialized structures within a cell that perform specific functions.

Prokaryotic Cells

Cells that do not have a nucleus, such as bacteria.

Eukaryotic Cells

Cells that have a nucleus and organelles, including animal and plant cells.

Nucleus

The part of the cell that contains genetic material (DNA) and controls cell activities.

DNA

The molecule that carries genetic information, determining traits and controlling cell functions.

Double Helix

The structure of DNA, resembling a twisted ladder.

Nucleotide

The building block of DNA, consisting of a sugar (deoxyribose), a phosphate group, and a nitrogenous base.

Chromatin

Loose DNA in the nucleus, present when the cell is not dividing.

Chromosomes

Condensed DNA that is formed during cell division.

Karyotype

A picture of chromosomes used to check for genetic disorders.

Genes

Segments of DNA that code for proteins.

Cell Division

The process for growth, repair, and reproduction, including mitosis and meiosis.

Mitosis

The process of cell division that produces two identical daughter cells.

Cytokinesis

The splitting of the cytoplasm to form two identical daughter cells.

Diploid

A cell with a full set of chromosomes (46 in humans).

Haploid

A cell with half the number of chromosomes (23 in gametes).

Meiosis I

The phase of meiosis where homologous chromosomes separate.

Meiosis II

The phase of meiosis where sister chromatids separate.

Spermatogenesis

The process by which male gametes (sperm cells) are produced.

Oogenesis

The process by which female gametes (egg cells) are produced.

Crossing Over

A process during Prophase I of meiosis that increases genetic variation.

Trimesters of Human Development

The three stages of pregnancy: First (organ formation), Second (growth and movement), Third (final development and fat storage).

Prophase I (Meiosis)

The first phase of meiosis where homologous chromosomes pair and crossing over occurs, increasing genetic variation.

Metaphase I (Meiosis)

The stage where homologous chromosome pairs align at the center of the cell before being separated.

Anaphase I (Meiosis)

The phase where homologous chromosomes are pulled apart to opposite poles of the cell.

Telophase I (Meiosis)

The stage where the cell divides into two daughter cells, each with half the number of chromosomes.

Prophase II (Meiosis)

The stage where the chromosomes condense again in each of the two daughter cells, preparing for a second division.

Metaphase II (Meiosis)

The stage where chromosomes align at the center of each daughter cell before being separated.

Anaphase II (Meiosis)

The phase where sister chromatids are pulled apart to opposite poles of the daughter cells.

Telophase II (Meiosis)

The stage where the nuclear membranes re-form and the cell divides, resulting in four haploid daughter cells.

Prophase (Mitosis)

The phase where chromosomes condense and become visible; the nuclear membrane starts to break down.

Metaphase (Mitosis)

The stage where chromosomes align at the cell's equatorial plane, ensuring equal separation.

Anaphase (Mitosis)

The phase where sister chromatids are pulled apart and moved toward opposite poles of the cell.

Telophase (Mitosis)

The final stage where the nuclear membranes re-form around the separated sister chromatids, and the cell prepares to divide.

Cytokinesis (Mitosis)

The process where the cytoplasm splits, resulting in two genetically identical daughter cells.