Cambridge IGCSE Biology Vocabulary Flashcards

Movement

An action by an organism or part of an organism causing a change of position or place.

Respiration

The chemical reactions in cells that break down nutrient molecules and release energy for metabolism.

Sensitivity

The ability to detect and respond to changes in the internal or external environment.

Growth

A permanent increase in size and dry mass.

Reproduction

The processes that make more of the same kind of organism.

Excretion

The removal of waste products of metabolism and substances in excess of requirements.

Nutrition

The taking in of materials for energy, growth and development.

MRS GREN

A mnemonic used to recall the seven characteristics of all living organisms: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, and Nutrition.

Species

A group of organisms that can reproduce to produce fertile offspring.

Genus

A taxonomic rank that groups closely related species together; the first part of a binomial scientific name.

Binomial System

An internationally agreed system in which the scientific name of an organism is made up of two parts showing the genus and species.

Generic Name

The first name in the binomial naming system, denoting the genus, which always starts with a capital letter.

Specific Name

The second name in the binomial naming system, denoting the specific species, which always starts with a lowercase letter.

Dendrelaphis

A genus of snakes comprising 45 closely related species of bronzeback snake.

Epipremnum aureum

The scientific botanical name for the wild plant commonly referred to as 'Money Plant' or 'Devil's Ivy'.

Copsychus fulicatus

The scientific name of the Indian robin, measuring about $17\,cm$ in length.

Erithacus rubecula

The scientific name of the British robin, measuring about $14\,cm$ in length with an orange-red breast.

Herpestes ichneumon

The scientific binomial name for the Egyptian mongoose.

Herpestes edwardsii

The scientific binomial name for the Indian grey mongoose.

Dichotomous Key

A tool used to identify unfamiliar organisms, composed of pairs of contrasting statements or questions leading to identification.

Vertebral Column

The spinal column or spine, consisting of a chain of cylindrical bones (vertebrae) joined end to end, which protects the spinal cord.

Humerus

The single upper limb bone of vertebrates that connects to the shoulder via a ball and socket joint and to the radius and ulna via a hinge joint.

Radius and Ulna

The two bones of the vertebrate forearm that articulate between the humerus and wrist bones.

Keratin

The protein substance that makes up human fingernails and the protective body scales of pangolins.

Pangolin

A mammal possessing body scales made of keratin, lacking teeth, and feeding on ants and termites with a long tongue.

Armadillo

A mammal with an armoured body covering made of hard bony plates, clawed feet for digging burrows, and enamel-less teeth.

DNA (Deoxyribonucleic Acid)

The chemical that forms chromosomes and genes, composed of a double-stranded sequence of nucleotide bases coding for proteins.

Genome

The complete set of genetic material of an organism.

Pongidae

The traditional taxonomic family in which apes (chimpanzees, gorillas, and orang-utans) were grouped separately from humans.

Bonobo

A primate species found in Zaire, identified as distinct from common chimpanzees in 1929, sharing a $1.2\%$ genomic difference with humans.

Kingdom

The largest taxonomic category of living organisms recognised in classification systems.

Animal Kingdom

Multicellular organisms whose cells lack cell walls and chloroplasts, and which ingest solid food and digest it internally.

Phylum

A primary classification subgroup within a kingdom; for example, Arthropods or Chordates.

Arthropods

Invertebrate animals characterized by jointed limbs, segmented bodies, and a firm external skeleton (cuticle).

Cuticle (Arthropod)

A hard, firm, external skeleton (exoskeleton) enclosing the segmented body of an arthropod.

Crustacea

A class of arthropods possessing an exoskeleton, two pairs of antennae, compound eyes, and five or more pairs of jointed limbs.

Compound Eye

An eye made up of tens or hundreds of separate lenses with underlying light-sensitive cells, sensitive to movement.

Insects

A class of arthropods whose bodies are divided into head, thorax, and abdomen, having three pairs of legs, one pair of antennae, and usually two pairs of wings.

Thorax

The middle body region of an arthropod or mammal, situated between the head/neck and the abdomen.

Abdomen

The posterior section of the body located behind the thorax in arthropods and vertebrates.

Arachnids

A class of arthropods with bodies divided into a cephalothorax and abdomen, having four pairs of legs, no antennae, and a pair of pedipalps.

Cephalothorax

The combined, fused head and thorax region found in arachnids and crustaceans.

Pedipalps

Two pairs of specialized appendages in arachnids used for reproduction or to pierce and paralyse prey with venom.

Myriapods

A class of arthropods including centipedes and millipedes, possessing a head, a segmented body with 10 or more pairs of legs, and one pair of antennae.

Centipede

A carnivorous myriapod that has one pair of legs per body segment and feeds on other animals.

Millipede

A herbivorous myriapod whose abdominal segments are merged in pairs, appearing to have two pairs of legs per segment.

Vertebrates

Animals that possess a vertebral column (spine) and a skull enclosing a brain.

Operculum

A bony protective plate covering and shielding the filamentous gills of fish.

Amphibia

Cold-blooded vertebrates with four limbs, moist scaleless skin, and external fertilisation, living partly on land and breeding in water.

Reptiles

Cold-blooded land-living vertebrates with dry scaly skin, four limbs (except snakes), internal fertilisation, and rubbery/leathery-shelled eggs.

Birds

Warm-blooded vertebrates possessing feathers, forelimbs modified into wings, beaks, scaly legs, and hard-shelled eggs.

Mammals

Warm-blooded vertebrates possessing hair or fur, mammary glands that secrete milk, a muscular diaphragm, and external ears (pinnae).

Pinna

The external ear flap characteristic of mammals.

Mammary Glands

Milk-producing glands found in female mammals used to suckle and nourish their young.

Five-Kingdom Scheme

A classification scheme proposed by Whittaker grouping organisms into Animal, Plant, Fungus, Prokaryote, and Protoctist.

Three-Domain Scheme

A classification system proposed by Carl Woese in 1978 dividing life based on ribosomal RNA into Archaea, Eubacteria, and Eukarya.

Archaea

A domain of ancient, single-celled prokaryotes lacking a nuclear membrane, exhibiting unique biochemistry distinct from bacteria.

Eubacteria

A domain comprising true prokaryotic bacteria whose cells do not contain a membrane-bound nucleus.

Eukarya

A domain containing all organisms whose cells possess a membrane-bound nucleus, divided into Protoctist, Fungus, Plant, and Animal kingdoms.

Plant Kingdom

Multicellular organisms possessing cellulose cell walls and chloroplasts containing chlorophyll to synthesise food via photosynthesis.

Ferns

Non-flowering land plants with stems, leaves, roots, and vascular tissue, reproducing via single-celled spores released from sporangia.

Sporangia

Spore capsules located in compact brown patches on the undersides of fern leaves.

Flowering Plants

Vascular plants that reproduce by seeds enclosed within an ovary inside flowers.

Monocotyledons

Flowering plants whose seeds possess a single cotyledon, typically having long narrow leaves with parallel veins and floral parts in multiples of three.

Dicotyledons

Flowering plants whose seeds have two cotyledons, typically having broad leaves with branching vein networks and floral parts in multiples of five.

Cotyledon

An embryonic leaf inside a seed that often contains food stores for the developing seedling.

Hyphae

Microscopic thread-like filaments forming the body structure of multicellular fungi.

Mycelium

A branching network or mass of fungal hyphae.

Parasite

An organism that lives on or in another living organism (the host), gaining food and shelter while causing harm.

Prokaryote Kingdom

Unicellular organisms, including bacteria and blue-green algae, that lack a nuclear membrane enclosing their chromosomes.

Protoctist Kingdom

Unicellular organisms whose chromosomes are enclosed inside a distinct nuclear membrane; includes Amoeba, Paramecium, and Euglena.

Virus

A non-cellular microscopic particle containing a core of RNA or DNA enclosed in a protein capsid, capable of replicating only inside host cells.

Capsid

The outer protein coat of a virus made up of individual protein units called capsomeres.

Longitudinal Section

A slice cut along the vertical length of a biological specimen or organ.

Transverse Section

A cross-sectional slice cut across the width or diameter of a biological specimen.

Stains

Dyes, such as iodine solution or methylene blue, used in microscopy to increase contrast and make internal cell organelles visible.

Cytoplasm

The jelly-like material within the cell membrane, composed of $90\%$ water, dissolved salts, sugars, and proteins, where metabolic reactions occur.

Cell Membrane

A thin, partially permeable boundary surrounding the cytoplasm that controls which substances enter and exit the cell.

Nucleus

A membrane-bound cell organelle containing chromosomes, responsible for regulating cell activities, enzyme synthesis, and cell division.

Cell Wall

A tough, non-living, freely permeable layer of cellulose surrounding plant cells that prevents them from bursting.

Vacuole (Plant)

A large permanent fluid-filled compartment in mature plant cells containing cell sap, maintaining cell turgidity.

Cell Sap

The watery solution of sugars, mineral salts, and pigments located within the large central vacuole of a plant cell.

Chloroplast

An organelle in green plant cells containing chlorophyll, which absorbs light energy to drive photosynthesis.

Mitochondrion

A double-membraned organelle in eukaryotic cells responsible for releasing energy through aerobic respiration.

Ribosome

A tiny spherical organelle, located free in the cytoplasm or on membranes, responsible for protein synthesis.

Circular DNA

The single, closed-loop chromosome of a bacterium that floats freely in the cytoplasm without a nuclear membrane.

Plasmid

A small, circular, extra-chromosomal ring of DNA found in bacteria, frequently carrying antibiotic-resistance genes.

Flagellum (Bacterial)

A protein filament extending from the surface of certain bacteria that flicks or rotates to provide motility.

Ciliated Cell

A specialised epithelial cell lining the trachea and bronchi possessing cilia that beat to move mucus and trapped dust away from the lungs.

Root Hair Cell

A specialised epidermal plant cell with an elongated projection that provides a large surface area for water uptake and mineral ion absorption.

Palisade Mesophyll Cell

A columnar plant cell packed with numerous chloroplasts, located beneath the upper epidermis of a leaf to carry out photosynthesis.

Neurone (Nerve Cell)

A specialised cell with elongated cytoplasmic fibres adapted to conduct electrical impulses rapidly across the nervous system.

Red Blood Cell

A biconcave disc-shaped blood cell lacking a nucleus when mature, filled with haemoglobin to transport oxygen.

Sperm Cell

A flagellated male gamete containing a haploid nucleus, an acrosome, and a mid-piece packed with mitochondria to provide energy for swimming.

Acrosome

A vesicle at the tip of the sperm head containing digestive enzymes that break down the outer jelly coat of an egg cell.

Egg Cell (Ovum)

A spherical female gamete containing a haploid nucleus, nutrient-rich yolk droplets in its cytoplasm, and an outer protective jelly coat.

Tissue

A group of cells with similar structures working together to perform a shared function.

Organ

A structure made up of a group of different tissues working together to perform a specific function.

Organ System

A group of organs with related functions working together to perform a coordinated body function.

Organism

A living thing that has an organised structure, can react to stimuli, reproduce, grow, adapt, and maintain homeostasis.