Stage 6 Year 11 Biology Vocabulary Flashcards

Comprehensive vocabulary flashcards covering Modules 1 through 4 of HSC Stage 6 Year 11 Biology.

Classical Cell Theory

The foundational biological principle stating that all living organisms are composed of one or more cells, the cell is the basic structural unit of life, and all new cells arise from pre-existing cells.

Prokaryotic Cell

A simple, single-celled organism that lacks a membrane-bound nucleus and membrane-bound organelles, containing circular double-stranded DNA within its cytoplasm.

Eukaryotic Cell

A complex cell containing a membrane-bound nucleus housing linear double-stranded DNA, along with specialized membrane-bound organelles.

Fluid Mosaic Model

A model describing cell membrane structure as a flexible phospholipid bilayer embedded with floating proteins, cholesterol, and carbohydrates that can move laterally.

Simple Diffusion

The passive movement of solute particles along a concentration gradient from a region of high concentration to a region of low concentration without metabolic energy.

Osmosis

The passive net movement of water molecules across a selectively permeable membrane from an area of high water concentration to an area of low water concentration.

Active Transport

The movement of substances across a cell membrane against their concentration gradient using energy in the form of ATP and carrier proteins.

Endocytosis

An active transport process in which the plasma membrane folds inward to engulf and internalise bulk materials or fluid into vesicles inside the cell.

Phagocytosis

A form of endocytosis in which a cell engulfs solid particles, such as a white blood cell engulfing a bacterium.

Surface Area to Volume Ratio (SA:V)

The relationship between the external surface area of a cell and its internal volume, where smaller cells have a higher ratio enabling faster diffusion and material exchange.

Catabolism

The metabolic pathway component that breaks down complex molecules into simpler ones, releasing chemical energy.

Anabolism

The metabolic pathway component that consumes energy to synthesise complex biological molecules from simpler building blocks.

Autotroph

An organism capable of synthesising its own organic nutrients from simple inorganic raw materials using an energy source such as sunlight.

Heterotroph

An organism that cannot synthesise its own organic nutrients and must obtain them by consuming other living or dead organisms.

Enzymes

Protein molecules that act as biological catalysts, accelerating metabolic reaction rates by lowering activation energy without being consumed in the process.

Induced Fit Model

An enzyme action model proposing that an enzyme's active site is flexible and alters its shape slightly upon substrate binding to form a precise, tighter fit.

Resolution

The minimum distance between two separate points at which they can still be distinguished as distinct, individual structures under a microscope.

Unicellular Organism

An organism composed of a single independent cell that carries out all life processes needed for survival.

Colonial Organism

A cluster of individual single-celled organisms living together in a group with shared advantages like protection, where individual cells remain capable of surviving alone if separated.

Multicellular Organism

An organism composed of many differentiated, specialised cells that depend on one another for survival and function hierarchically.

Cell Differentiation

The process by which an unspecialised stem cell becomes structurally and functionally specialised through selective gene expression.

Peristalsis

Involuntary, rhythmic muscle contractions that propel food along the digestive tract.

Alveoli

Microscopic, thin-walled, moist air sacs in lungs surrounded by capillaries where diffusion of oxygen and carbon dioxide takes place.

Transpiration-Cohesion-Tension Theory

The mechanism driving passive water movement in xylem, where leaf evaporation (transpiration) creates tension that pulls a cohesive and adhesive column of water upward from roots.

Translocation

The active bulk-flow transport of organic solutes, mainly sucrose, through phloem tissue from source tissues to sink tissues.

Casparian Strip

A waxy, waterproof strip in root endodermal cell walls that blocks the extracellular apoplast pathway, forcing water and minerals through selective cell membranes into xylem.

Selection Pressure

An environmental factor (abiotic or biotic) that influences the survival and reproduction of individuals, driving evolutionary change within a population over generations.

Structural Adaptation

A physical or anatomical body feature of an organism that increases its fitness and likelihood of survival in its environment.

Physiological Adaptation

An internal systemic process or biochemical function within an organism that aids survival in its environment.

Behavioural Adaptation

An inherited or learned action carried out by an organism to enhance its chances of survival and reproduction.

Natural Selection

The evolutionary mechanism by which organisms with favorable heritable traits survive and reproduce at higher rates, increasing the frequency of those traits in future generations.

Microevolution

Small-scale evolutionary changes in allele frequencies within a single population over a short period of time.

Speciation

The evolutionary process by which a single ancestral lineage splits into two or more distinct, reproductively isolated species.

Homologous Structures

Anatomical features in different species that share a common evolutionary origin and structural blueprint, though they may serve different functions (resulting from divergent evolution).

Analogous Structures

Structures in different species that perform similar functions but evolved independently from different ancestral lineages (resulting from convergent evolution).

Allopatric Speciation

Speciation that occurs when populations become geographically isolated by a physical barrier, preventing gene flow and allowing independent evolution.

Radiometric Dating

An absolute dating technique that calculates the exact numerical age of rocks or fossils by measuring the decay ratio of radioactive isotopes to stable daughter decay products.

Mutualism

A close ecological interaction between two organisms of different species where both individuals benefit (+/+).

Commensalism

A symbiotic relationship in which one species benefits while the other species is neither helped nor harmed (+/0).

Parasitism

A symbiotic relationship where one organism (parasite) benefits at the direct expense of another organism (host), causing harm (+/-).

Ecological Niche

The specific functional role, habitat, resource requirements, and species interactions an organism fulfills within an ecosystem.

Carrying Capacity (K)

The maximum population size of a species that a given ecosystem can sustainably support indefinitely based on available resources.

Trophic Level

A feeding level or position occupied by an organism within a food chain or ecological pyramid.