Biology EOC Concepts

Homeostasis

Maintaining stable internal conditions despite external changes.

Osmosis

The movement of water across a selectively permeable membrane from high to low concentration.

Diffusion

The movement of molecules from high to low concentration without using energy.

Active Transport

Movement of substances against a concentration gradient; requires energy (ATP).

Enzyme

A protein that speeds up chemical reactions by lowering activation energy.

Lock and Key Model

Explains how enzymes fit specific substrates to catalyze reactions.

Photosynthesis

Process by which plants use sunlight to make glucose (sugar). Occurs in chloroplasts.

Photosynthesis Equation

6CO₂ + 6H₂O + sunlight → C₆H₁₂O₆ + 6O₂

Cellular Respiration

Breaks down glucose to make ATP (energy); occurs in mitochondria.

Cell Respiration Equation

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP

ATP

Energy molecule of the cell.

DNA

Genetic material that carries instructions for life.

DNA Replication

Process of making an identical copy of DNA; happens before cell division.

Mitosis

Type of cell division that produces two identical diploid body cells.

Meiosis

Type of cell division that makes four genetically unique haploid gametes.

Haploid

Half the number of chromosomes (n); found in sperm and egg cells.

Diploid

Full set of chromosomes (2n); found in body (somatic) cells.

Punnett Square

Tool used to predict genetic outcomes of a cross.

Phenotype

The physical trait shown (e.g., brown eyes).

Genotype

The genetic makeup (e.g., Bb, AA).

Dominant Allele

Stronger gene that shows up if present (A).

Recessive Allele

Weaker gene; only shows up when paired with another recessive allele (a).

Natural Selection

Process by which organisms better adapted to their environment survive and reproduce.

Evolution

Change in a species over time due to natural selection and genetic variation.

Ecological Succession

Natural process of ecosystem recovery after disturbance.

Carrying Capacity

Maximum number of individuals an environment can support long-term.

Producer

Organism that makes its own food through photosynthesis (plants).

Consumer

Organism that eats other organisms for energy.

Decomposer

Breaks down dead organisms and recycles nutrients (e.g., fungi, bacteria).

Biotic Factor

Living part of the environment (e.g., plants, animals).

Abiotic Factor

Nonliving part of the environment (e.g., water, sunlight, temperature).

Biodiversity

Variety of life in an ecosystem; more biodiversity = more stability.

Human Impact

Deforestation, pollution, climate change, habitat destruction — all affect ecosystems.