Year 11 Biology Modules 1-4 Vocabulary Flashcards

Comprehensive vocabulary flashcards covering key definitions, cell structures, biochemical pathways, evolutionary concepts, and ecological dynamics across Year 11 Biology Modules 1 to 4.

Cell Theory

A fundamental biological principle stating that all living organisms are made of one or more cells, the cell is the fundamental unit of life, and all cells arise from pre-existing cells.

Prokaryotic Cell

A smaller, simpler cell type that lacks a true nucleus and membrane-bound organelles, featuring circular DNA in a nucleoid and plasmids (e.g., bacteria and archaea).

Eukaryotic Cell

A larger, more complex cell type containing a true nucleus with linear chromosomes and membrane-bound organelles (e.g., animals, plants, fungi, protists).

Mitochondria

Organelles that serve as the site of aerobic cellular respiration to produce $ATP$; they contain a highly folded inner membrane called cristae to maximize surface area.

Chloroplasts

Organelles found in plant cells and some protists that contain chlorophyll and serve as the site of photosynthesis.

Magnification

How much larger an image appears compared with the actual specimen, calculated as $\text{Total magnification} = \text{Eyepiece magnification} \times \text{Objective magnification}$.

Resolution

The ability of a microscope to distinguish two close points as separate, making image detail clearer.

Scanning Electron Microscope (SEM)

An electron microscope that scans the surface of a specimen to produce detailed three-dimensional surface images.

Transmission Electron Microscope (TEM)

An electron microscope in which electrons pass through a specimen to reveal internal ultrastructure.

Fluid Mosaic Model

A structural model of the cell membrane consisting of a flexible phospholipid bilayer ('fluid') embedded with proteins, cholesterol, and carbohydrates ('mosaic').

Passive Transport

The movement of substances across a cell membrane down their concentration gradient ($\text{High concentration} \rightarrow \text{Low concentration}$) without the expenditure of $ATP$.

Osmosis

The movement of water across a selectively permeable membrane from high water concentration ($\text{low solute}$) to low water concentration ($\text{high solute}$).

Active Transport

The movement of substances across a cell membrane against their concentration gradient ($\text{Low} \rightarrow \text{High}$) requiring $ATP$ and transport proteins.

Endocytosis

A cellular transport process where the cell membrane encloses external material to form a vesicle and bring it into the cell (e.g., phagocytosis, pinocytosis).

Exocytosis

A transport process where an internal vesicle fuses with the cell membrane to release its contents outside the cell.

Surface Area : Volume Ratio (SA:V)

The relationship between a cell's exterior surface area and its internal volume; higher ratios in smaller cells allow for more efficient cellular exchange.

Photosynthesis

The biochemical process in autotrophs that converts light energy into chemical energy, represented by $6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$.

Cellular Respiration

The biochemical process breaking down glucose to produce $ATP$, represented aerobically by $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{ATP}$.

Catabolism

A category of metabolic reactions that break complex molecules down into smaller ones, releasing energy.

Anabolism

A category of metabolic reactions that construct complex molecules from simpler ones, requiring energy.

Enzyme

A biological catalyst (usually a protein) that accelerates biochemical reactions by lowering their activation energy.

Induced-Fit Model

An enzyme action model stating that the active site is flexible and alters its shape slightly upon binding to the substrate.

Unicellular Organism

An organism composed of a single cell that independently performs all life processes.

Multicellular Organism

An organism composed of many specialized cells organized into tissues, organs, and systems that depend on each other for survival.

Stem Cells

Undifferentiated cells capable of developing into various specialized cell types through regulated gene expression.

Xylem

Vascular tissue composed of dead, hollow, lignified cells that transports water and mineral ions unidirectionally from roots to shoots ($\text{Roots} \rightarrow \text{Shoots}$).

Phloem

Living vascular tissue that transports sugars and organic nutrients in multiple directions between source and sink regions.

TACT Model

The mechanism explaining xylem transport via Transpiration, Adhesion, Cohesion, and Tension working together to draw water upwards.

Pressure-Flow Hypothesis

The model describing phloem transport, where active sugar loading at the source causes osmotic entry of water, generating hydrostatic pressure that moves sap toward the sink.

Counter-Current Exchange

An arrangement in fish gills where water and blood flow in opposite directions to maintain a concentration gradient and maximize oxygen diffusion.

Alveoli

Tiny air sacs in human lungs with thin walls, high surface area, and rich capillary networks where gas exchange takes place.

Open Circulatory System

A circulatory system found in invertebrates where hemolymph is pumped into an open body cavity to directly bathe internal tissues.

Double Circulation

A cardiovascular pathway consisting of separate pulmonary circulation ($\text{Heart} \rightarrow \text{Lungs} \rightarrow \text{Heart}$) and systemic circulation ($\text{Heart} \rightarrow \text{Body} \rightarrow \text{Heart}$).

Selection Pressure

An abiotic or biotic environmental factor that influences an organism's ability to survive and reproduce in its environment.

Natural Selection

The evolutionary process through which advantageous heritable traits become more common in a population over successive generations.

Structural Adaptation

A physical or anatomical feature of an organism's body that enhances its survival and reproduction.

Behavioural Adaptation

An action or activity performed by an organism that increases its chances of survival and reproduction.

Physiological Adaptation

An internal biological process or metabolic function within an organism that aids survival.

Divergent Evolution

The evolutionary pattern where closely related species sharing a recent common ancestor accumulate differences due to different selection pressures.

Convergent Evolution

The evolutionary pattern where distantly related species independently develop similar features due to experiencing similar selection pressures.

Allopatric Speciation

The formation of new species resulting from populations becoming geographically isolated by physical barriers.

Punctuated Equilibrium

An evolutionary model proposing long periods of stability (stasis) interrupted by short periods of rapid evolutionary change and speciation.

Homologous Structures

Anatomical features in different species that share a common underlying structural plan due to shared ancestry, such as the vertebrate pentadactyl limb.

Transitional Fossils

Fossils that exhibit traits common to both an ancestral group and its derived descendant group (e.g., Archaeopteryx), demonstrating evolutionary pathways.

Ecological Niche

The specific role, position, and functional resource usage of a species within its ecosystem.

Carrying Capacity ($K$)

The maximum sustainable population size of a species that a given environment can support.

Density-Dependent Factors

Environmental factors whose influence on population growth changes proportionally with population density (e.g., competition, predation, disease).

Symbiosis

A close ecological interaction between individuals of two different species, including mutualism ($+/+$), commensalism ($+/0$), and parasitism ($+/-$).

Capture-Mark-Recapture

A ecological sampling method used to estimate mobile animal population sizes using the formula $N \approx \frac{M \times C}{R}$.

Primary Succession

The gradual establishment of an ecological community on previously uninhabited, bare substrate lacking organic soil.