Organisation of Living Things & Transport Systems

Vocabulary flashcards covering key terms and definitions related to cellular organisation, plant and animal structures, gas exchange, and circulatory systems as presented in the lecture notes.

Cell

Fundamental, self-contained unit that makes up all living organisms.

Unicellular Organism

Living thing composed of a single independent cell that carries out all necessary functions (e.g., bacteria).

Multicellular Organism

Organism made of specialised cells that cooperate; individual cells cannot survive if separated (e.g., animals, plants).

Colonial Organism

Group of single-celled organisms living together in a colony; members can survive if separated (e.g., Volvox, corals).

Volvox

Genus of freshwater green algae forming spherical, rolling colonies visible to the naked eye; nicknamed "fierce rollers."

Colonial Flagellate Hypothesis

Theory that unicellular flagellates formed colonies, then differentiated into specialised cells, leading to the first multicellular organisms.

Hierarchical Organisation of Cells

Structural levels in multicellular organisms: cell → tissue → organ → organ system, enabling division of labour and efficiency.

Stem Cell

Undifferentiated cell that gives rise to various specialised cell types through gene expression.

Gene Expression

Process by which information in genes directs production of specific proteins and structures, determining cell function.

Red Blood Cell

Biconcave, haemoglobin-filled cell specialised for efficient oxygen transport.

Organ System

Group of organs working together to deliver nutrients and remove wastes in an organism.

Autotroph

Organism that produces its own food (e.g., via photosynthesis).

Heterotroph

Organism that obtains nutrients by consuming other organisms.

Root System (Plant)

Underground plant structure with hair-like roots for water (osmosis) and mineral (active transport) absorption.

Stem (Plant)

Plant structure containing dermal, ground, and vascular tissues; supports plant and transports water, minerals, and sugars.

Leaf System

Plant’s photosynthetic structure consisting of blade, veins, mesophyll, stomata, etc., for gas exchange and sugar production.

Xylem

Dead, hollow vascular tissue transporting water and ions unidirectionally from roots to shoots.

Phloem

Living vascular tissue transporting photosynthetic sugars bidirectionally from leaves to the rest of the plant.

Waxy Cuticle

Leaf surface layer that reflects heat and reduces water loss.

Epidermis (Plant)

Protective outer leaf layer regulating interactions with environment and aiding UV protection and gas exchange.

Mesophyll Cell

Leaf cell rich in chloroplasts; primary site of photosynthesis.

Stomata

Tiny leaf pores that regulate gas exchange and water loss.

Petiole

Stalk attaching a leaf blade to the stem.

Leaf Vein

Vascular bundle that transports water and sugars within the leaf.

Leaf Blade

Broad, flat part of a leaf providing surface area for photosynthesis and gas exchange.

Cellular Respiration Equation

Glucose + O₂ → CO₂ + H₂O + energy (ATP).

Gas Exchange

Diffusion of O₂ and CO₂ across respiratory surfaces between internal and external environments.

Respiratory System

Organs and tissues enabling uptake of oxygen and removal of carbon dioxide.

Moist, Thin Membranes

Universal respiratory surface feature ensuring short diffusion distance and dissolved gases.

Rich Blood Supply

Dense capillary network that maintains concentration gradients for efficient gas exchange.

Large Surface Area (Respiration)

Structural adaptation (e.g., alveoli) that increases diffusion rate of gases.

Alveolus

Tiny balloon-shaped air sac in lungs where O₂ enters blood and CO₂ exits.

Epiglottis

Leaf-shaped cartilage that closes the trachea during swallowing to prevent aspiration.

Thoracic Cavity

Chest cavity housing lungs and heart; changes volume to move air during breathing.

Bronchiole

Small bronchial branch leading air to alveoli; final airway before gas exchange.

Diaphragm

Dome-shaped muscle whose contraction enlarges thoracic cavity for inhalation.

Pharynx

Muscular throat passage for air and food connecting nasal/oral cavities to larynx and esophagus.

Trachea

Windpipe carrying air from larynx to bronchi.

Bronchus

One of two main airways branching from trachea into each lung.

Transport System

Circulatory mechanism delivering nutrients/oxygen and removing wastes in multicellular organisms.

Closed Circulatory System

System in which blood is confined to vessels and pumped under high pressure (e.g., mammals, fish).

Open Circulatory System

System where haemolymph flows around organs, not just inside blood vessels,but organs directly under low pressure (e.g., insects, crabs).

Artery

Thick-walled vessel carrying blood away from the heart under high pressure.

Vein

Thin-walled vessel carrying blood toward the heart; contains valves to prevent backflow.

Capillary

Microscopic, one-cell-thick vessel where exchange of gases, nutrients, and wastes occurs with tissues.

Pulse

Expansion and recoil of arterial walls felt near skin surface with each heartbeat.

Haemolymph

Transport fluid in open circulatory systems, directly contacting cells.

Oxyhaemoglobin

Form of haemoglobin bound to oxygen for transport in the blood.

Chylomicron

Lipid droplet in blood transporting dietary lipids from intestine to body cells.