Key Biology and Ecology Terms and Concepts

Periodic Table

A tabular arrangement of the chemical elements, organized by atomic number, electron configuration, and recurring chemical properties.

Atomic Number

The number of protons in the nucleus of an atom, determining its chemical properties.

Atomic Weight

The average mass of atoms of a particular element, typically measured in atomic mass units (amu).

Macronutrients

Nutrients required in large amounts by organisms, such as carbohydrates, proteins, and fats.

Micronutrients

Nutrients required in small amounts by organisms, such as vitamins and minerals.

Producers

Organisms that produce their own food through photosynthesis or chemosynthesis, such as plants and some bacteria.

Photosynthesis

The process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll.

Chloroplasts

Organelles found in plant cells that are responsible for photosynthesis.

Consumers

Organisms that obtain energy by consuming other organisms, such as animals.

Cellular Respiration

The process by which cells break down glucose to release energy in the form of ATP.

Mitochondria

Organelles found in most eukaryotic cells that are responsible for cellular respiration.

Grana

Stacks of thylakoids found within chloroplasts.

Thylakoid

Flattened sacs found within chloroplasts that contain chlorophyll and other pigments involved in photosynthesis.

Stomata

Small pores on the surface of leaves that allow for gas exchange.

Chlorophyll

A green pigment found in plants that is essential for photosynthesis.

Light Reactions

The first stage of photosynthesis, where light energy is converted into chemical energy in the form of ATP and NADPH.

Calvin Cycle

The second stage of photosynthesis, where carbon dioxide is fixed and used to synthesize glucose.

NADPH

A coenzyme that carries electrons and hydrogen ions, involved in energy transfer in photosynthesis and cellular respiration.

ATP

Adenosine triphosphate, the main energy currency of cells.

Artificial Selection

The process by which humans select and breed organisms with desired traits.

Prokaryotes

Single-celled organisms that lack a nucleus and other membrane-bound organelles.

Decomposers

Organisms that break down dead organisms and organic matter, such as bacteria and fungi.

Nitrogen Fixers

Bacteria that convert atmospheric nitrogen into a form usable by plants.

Nodules

Swellings on the roots of legumes that contain nitrogen-fixing bacteria.

Crop Rotation

The practice of planting different crops in a field each year to improve soil fertility and reduce pest and disease problems.

Organic Farming

A farming system that avoids the use of synthetic pesticides and fertilizers.

Angiosperms

Flowering plants that produce seeds enclosed within a fruit.

Leaf

The main photosynthetic organ of a plant, typically consisting of a blade and a petiole.

Blade

The flat, expanded part of a leaf.

Petiole

The stalk that attaches a leaf to a stem.

Stem

The main supporting structure of a plant, transporting water and nutrients between the roots and leaves.

Flower

The reproductive structure of a flowering plant.

Roots

The underground part of a plant that absorbs water and nutrients from the soil.

Monocots

Flowering plants with one cotyledon in their seeds, such as grasses and lilies.

Dicots

Flowering plants with two cotyledons in their seeds, such as beans and roses.

Petals

The colorful parts of a flower that attract pollinators.

Sepals

The outermost whorl of leaves in a flower, often green and protective.

Stigma

The sticky tip of the pistil that receives pollen.

Style

The stalk that connects the stigma to the ovary.

Anther

The part of the stamen that produces pollen.

Pollen

The male reproductive cells of a plant.

Filament

The stalk that supports the anther.

Pollen Tube

A tube that grows from a pollen grain to the ovule, allowing sperm cells to reach the egg cell.

Embryo Sac

The female gametophyte in a flowering plant, containing the egg cell.

Ovary

The part of the pistil that contains the ovules.

Ovule

The structure that contains the female gametophyte and develops into a seed after fertilization.

Cotyledon

The first leaf or leaves of a plant embryo.

Endosperm

The tissue that surrounds and nourishes the plant embryo in a seed.

Fruit

The mature ovary of a flowering plant, often containing seeds.

Exponential Growth

A pattern of growth in which the population size increases rapidly over time.

Limiting Factors

Factors that limit the growth of a population, such as food, water, and space.

Logistic Growth

A pattern of growth in which the population size increases rapidly at first, then slows down and eventually levels off.

Carrying Capacity

The maximum number of individuals that an environment can support.

Biogeochemical Cycle

The movement of elements and compounds through the biosphere, geosphere, hydrosphere, and atmosphere.

Abiotic Reservoir

A nonliving component of the environment that stores a particular element or compound, such as the atmosphere or the ocean.

Biotic Components

Living organisms in an ecosystem, such as plants, animals, and microorganisms.

Ecological Footprint

The impact of human activities on the environment, measured in terms of the amount of land and resources required to support those activities.

Deforestation

The clearing of forests for other land uses.

Cloning

The process of producing genetically identical copies of an organism.

Biotechnology

The use of living organisms and their products to solve problems and make products.

DNA Technology

The manipulation of DNA for various purposes, such as genetic engineering.

Genetic Engineering

The direct manipulation of an organism's genome to introduce new traits.

Restriction Enzymes

Enzymes that cut DNA at specific sequences.

Restriction Site

The specific sequence of DNA that is recognized and cut by a restriction enzyme.

Restriction Fragments

Pieces of DNA produced by the action of restriction enzymes.

Sticky Ends

Short, single-stranded ends of DNA fragments that can be joined together by DNA ligase.

DNA Cloning

The process of making multiple copies of a specific DNA fragment.

Plasmid

A small, circular piece of DNA found in bacteria.

DNA Ligase

An enzyme that joins DNA fragments together.

Recombinant Plasmid

A plasmid that contains DNA from two or more different sources.

Recombinant DNA

DNA that has been formed artificially by combining DNA sequences from different organisms.

Genome

The complete set of genetic material in an organism.

Genomic Library

A collection of DNA fragments that represent the entire genome of an organism.

Nucleic Acid Probe

A single-stranded DNA or RNA molecule that is labeled with a radioactive or fluorescent tag and used to detect specific DNA sequences.

CRISPR-Cas9

A gene editing tool that allows scientists to precisely modify the DNA of an organism.

Reverse Transcriptase

An enzyme that synthesizes DNA from an RNA template.

Complementary DNA (cDNA)

DNA that is synthesized from an RNA template using reverse transcriptase.

Genetically Modified Organisms (GMOs)

Organisms whose genetic material has been altered using genetic engineering techniques.

Transgenic Organism

An organism that contains genes from another species.

DNA Synthesizer

A machine that can synthesize short strands of DNA.

Critical Thinking

The ability to think clearly and rationally, to analyze information, and to form sound judgments.

Pseudoscience

A claim or belief that is presented as scientific but is not based on scientific evidence.

Anecdotal Evidence

Evidence based on personal experiences or observations, rather than on scientific research.

Sample Size

The number of individuals or observations included in a study.

Control Group

A group in an experiment that is not exposed to the experimental treatment and is used as a comparison.

Reproducibility

The ability of a scientific experiment or study to be repeated by others with similar results.

Biology

The study of life.

Life

The quality that distinguishes living organisms from non-living matter.

Taxonomy

The science of classifying organisms.

Domains

The highest level of classification, dividing life into three major groups: Bacteria, Archaea, and Eukarya.

Taxonomic Hierarchy

A hierarchical system of classifying organisms, from broad to specific: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

Three-Domain System

A classification system that divides life into three domains: Bacteria, Archaea, and Eukarya.

Kingdoms

A major taxonomic rank below domain, traditionally including six kingdoms: Bacteria, Archaea, Protista, Fungi, Plantae, and Animalia.

Scientific Name

A two-part name assigned to each species, consisting of the genus and species names (e.g., Homo sapiens).

Protist

A diverse group of eukaryotic organisms that are not fungi, plants, or animals.

Protozoans

Protists that are heterotrophic and often motile.

Amoebas

Protozoans that move and feed using pseudopodia.

Slime Molds

Protists that can exist as single-celled or multicellular organisms.

Algae

Protists that are photosynthetic and produce oxygen.

Seaweeds

Large, multicellular algae that live in marine environments.