Biology Lecture Notes

Vocabulary flashcards from biology lecture notes.

Abiotic

Non-living parts of the environment like sunlight, water, and temperature.

Active transport

Movement of substances across a cell membrane using energy.

Adenosine triphosphate (ATP)

The main energy-carrying molecule in cells.

Adhesion

Water molecules sticking to other surfaces.

Allele

Different forms of a gene (like blue eyes or brown eyes).

Analogous structure

Body parts with similar function but different structure (like bird wings and insect wings).

Aquatic

Living in or related to water.

Artificial selection

Humans breeding plants or animals for specific traits.

Asexual reproduction

Reproduction without sex, producing identical offspring.

Biology

The study of living things.

Biome

A large area with a specific climate and types of living things (like a desert or rainforest).

Biosphere

All parts of Earth where life exists.

Biotechnology

Using living things to make products or solve problems.

Biotic

Living parts of the environment (like animals, plants, fungi).

Carbohydrate

Sugars and starches used for energy.

Carnivore

An animal that eats only meat.

Carrier (transport) proteins

Proteins that help move substances across a cell membrane.

Catalyst

A substance that speeds up a chemical reaction.

Cell

The basic unit of life.

Cell cycle

The process a cell goes through to grow and divide.

Cellular respiration

The process of breaking down food to make energy (ATP).

Chlorophyll

The green pigment in plants that captures sunlight.

Chloroplast

The part of a plant cell where photosynthesis happens.

Chromosomal mutation

A change in the structure or number of chromosomes.

Chromosomes

Structures that carry genetic information (DNA).

Cloning

Making a genetically identical copy of an organism or cell.

Co-dominance

When both alleles show up equally in a trait (like AB blood type).

Cohesion

Water molecules sticking to each other.

Commensalism

A relationship where one organism benefits and the other is unaffected.

Community (ecological)

All living things in a particular area.

Competition

When organisms fight for the same resources.

Concentration gradient

A difference in the amount of a substance across a space.

Consumer (ecological)

An organism that eats other organisms.

Crossing-over

Exchange of genes between chromosomes during meiosis.

Cytokinesis

The final step of cell division when the cell splits into two.

Decomposer

An organism that breaks down dead matter.

Deoxyribonucleic acid (DNA)

The molecule that holds genetic instructions.

Diffusion

Movement of substances from high to low concentration.

DNA mutation

A change in the DNA sequence.

DNA replication

Copying DNA before a cell divides.

Dominant inheritance

A trait that shows up if at least one dominant allele is present.

Ecology

The study of how living things interact with each other and their environment.

Ecosystem

A community of organisms and their non-living environment.

Embryology

The study of how embryos develop.

Endemic species

A species found only in one specific place.

Endocytosis

A process where cells take in large materials by engulfing them.

Endoplasmic reticulum (ER)

A cell structure that helps with protein and fat production.

Endosymbiosis

A theory that some cell parts came from one cell living inside another.

Energy pyramid

A diagram showing how energy flows through a food chain.

Enzyme

A protein that speeds up chemical reactions.

Eukaryote

A cell with a nucleus and organelles.

Evolution

Change in species over time.

Exocytosis

A process where a cell releases substances to the outside.

Extinction

When a species no longer exists.

Extracellular

Located outside a cell.

Facilitated diffusion

Diffusion with the help of transport proteins.

Food chain

A simple path of energy flow from one organism to another.

Food web

A complex network of food chains in an ecosystem.

Fossils

Remains or imprints of ancient organisms.

Founder effect

Genetic changes that happen when a new population starts from a few individuals.

Frame-shift mutation

A mutation that shifts the way the genetic message is read.

Gamete

A sex cell (egg or sperm).

Gene

A segment of DNA that codes for a trait.

Gene recombination

Mixing of genes during reproduction that increases variety.

Gene splicing

Cutting and joining DNA segments.

Gene therapy

Treating disease by fixing or replacing genes.

Genetic drift

Random changes in a population’s genes.

Genetic engineering

Changing genes on purpose.

Genetically modified organism (GMO)

An organism whose genes were altered by humans.

Genotype

The genetic makeup of an organism.

Golgi apparatus

A cell part that packages and ships proteins.

Gradualism

The idea that evolution happens slowly over time.

Habitat

The natural home of an organism.

Herbivore

An animal that eats only plants.

Homeostasis

Keeping a stable internal environment.

Homologous structure

Similar structures with different functions, showing common ancestry.

Impermeable

Not allowing substances to pass through.

Incomplete dominance

A mix of two traits (like red + white = pink).

Inheritance

Passing traits from parents to offspring.

Interphase

The phase of the cell cycle when the cell grows and prepares to divide.

Intracellular

Located inside a cell.

Isolating mechanisms

Features that prevent species from mating.

Limiting factor

Something that controls the size of a population.

Lipids

Fats used for energy storage and making cell membranes.

Macromolecule

A large molecule like a protein, carbohydrate, or DNA.

Meiosis

Cell division that makes gametes with half the DNA.

Migration

Movement of organisms from one place to another.

Mitochondrion

The powerhouse of the cell where energy is made.

Mitosis

Cell division that creates two identical cells.

Monomer

A small building block of a larger molecule.

Multicellular

Made up of many cells.

Multiple alleles

More than two allele options for a gene.

Mutualism

A relationship where both organisms benefit.

Natural selection

Organisms with better traits survive and reproduce more.

Niche

The role an organism plays in its environment.

Nondisjunction

When chromosomes fail to separate properly.

Nonnative species

A species that doesn’t naturally belong in an area.

Nucleic acid

Molecules like DNA and RNA that store genetic info.

Nucleus

The cell part that holds DNA.

Omnivore

An organism that eats both plants and animals.