This document defines 20 key study terms related to biology including lipids, autotrophs, nondisjunction, interphase, prophase, metaphase, anaphase, telophase, cytokinesis, cytoplasm, flagellum, taxis, catalyst, enzyme, mutualism, gene therapy, helicase, genomics, and the Human Genome Project. Examples are provided for some terms.

1. 20 Study Terms

2. Lipids
Any of a class of organic compounds that are fatty
acids or their derivatives and are insoluble in water but
soluble in organic solvents. They include many natural
oils, waxes, and steroids.
Example: Butter

3. Autotrophs
An organism that is able to form nutritional organic
substances from simple inorganic substances such as
carbon dioxide.
Example: Plants

4. Nondisjunction
The failure of one or more pairs of homologous chromosomes or sister
chromatids to separate normally during nuclear division, usually resulting
in an abnormal distribution of chromosomes in the daughter nuclei.

5. Interphase
The resting phase between
successive mitotic divisions of
a cell, or between the first and
second divisions of meiosis.

6. Prophase
The first stage of cell division, before
metaphase, during which the
chromosomes become visible as
paired chromatids and the nuclear
envelope disappears. The first
prophase of meiosis includes the
reduction division.

7. Metaphase
The second stage of cell division,
between prophase and anaphase, during
which the chromosomes become
attached to the spindle fibers.

8. Anaphase
The stage of meiotic or mitotic
cell division in which the
chromosomes move away
from one another to opposite
poles of the spindle.

9. Telophase
The final phase of cell division, between
anaphase and interphase, in which the
chromatids or chromosomes move to
opposite ends of the cell and two nuclei
are formed.

10. Cytokinesis
The cytoplasmic division of a cell at
the end of mitosis or meiosis,
bringing about the separation into
two daughter cells.

11. Cytoplasm
The material or protoplasm within a
living cell, excluding the nucleus.

12. Flagellum
A slender threadlike structure, especially a microscopic appendage that
enables many protozoa, bacteria, spermatozoa, etc. to swim.

13. Taxis
The movement of an organism in response to a
stimulus such as light or the presence of food. Taxes
are innate behavioral responses.
Example: A moth attracted to the light.

14. Catalyst
The process by which a substance speeds up a
chemical reaction without being consumed or altered
in the process.

15. Enzyme
A substance produced by a living organism which acts
as a catalyst to bring about a specific biochemical
reaction.
Example: Lactase

16. Mutualism
Symbiosis that is beneficial to both organisms
involved.
Example: Flower giving a bee nectar and the bee
pollinating the flower.

17. Gene
Therapy
A treatment for genetic disorders that uses a functional gene to treat the
disease caused by a non-functioning gene or a malfunctioning gene.
Example: Adding a stem cells to treat SCID

18. Helicase
Helicases are enzymes that
bind and may even
remodel nucleic acid or
nucleic acid protein
complexes.

19. Genomics
The study of how genes work.

20. The Human
Genome
Project
An international effort that
resulted in mapping the
location of all of the genes
on the 46 human
chromosomes.