Grade 11 Life Sciences Comprehensive Review

A comprehensive vocabulary flashcard set covering all 10 topics of the Grade 11 Life Sciences CAPS curriculum, including micro-organisms, plant and animal diversity, photosynthesis, animal nutrition, cellular respiration, gaseous exchange, excretion, population ecology, and human impact on the environment.

Bacteriophage

A virus that infects and replicates within a bacterial cell.

Nucleoid

The nuclear region in a bacterial cell where the genetic material (DNA) occurs freely without an enclosing nuclear membrane.

Binary fission

A form of asexual reproduction in bacteria and single-celled organisms where one cell divides into two identical cells with the same DNA.

Mycelium

The interwoven, vegetative body of a fungus composed of a mass of branched filaments called hyphae.

Opportunistic infections

Infections and conditions (such as tuberculosis and pneumonia) that attack the human body specifically when the immune system is compromised or weakened, as in advanced HIV infection.

Vector

An organism, such as the female Anopheles mosquito in malaria, that transmits a disease-causing pathogen from one host to another.

Antigens

Protein molecules that occur as markers on the surface of body cells, viruses, bacteria, protozoa, and fungi, which white blood cells recognize as foreign or self.

Phagocytosis

The process by which large, shape-changing white blood cells known as phagocytes engulf and destroy invading pathogens.

Alternation of generations

The phenomenon in a plant's life cycle where a sexual, gamete-producing generation (gametophyte) alternates with an asexual, spore-producing generation (sporophyte).

Thallus

A plant or vegetative body, typical of bryophytes and fungal mycelia, that shows no differentiation into true roots, stems, or leaves.

Rhizome

An underground stem from which tough, wiry adventitious roots arise to anchor fern plants and absorb water.

Sori (singular: Sorus)

Small structures that develop on the underside of fern leaves, each containing a cluster of spore-producing sporangia.

Prothallus

The small, green, heart-shaped haploid gametophyte structure produced when a fern spore germinates.

Gymnosperms

A division of vascular, cone-bearing seed plants whose seeds are not enclosed within an ovary or fruit, known as naked seeds.

Perigone

A floral whorl found in monocotyledonous flowers (such as Aloe) where the sepals (calyx) and petals (corolla) are fused together.

Cross-pollination

The transfer of ripe pollen from the anther of one flower to the receptive stigma of a flower on another plant of the same species.

Testa

The hard, resistant seed coat formed from the hardened tissue of the ovule that protects the plant embryo against unfavorable conditions.

Cephalisation

The concentration of nerve cells and sensory organs at the anterior end of a bilaterally symmetrical animal's body to form a definite head and central nervous system.

Diploblastic

Describing an animal embryo that develops from two primary germ layers (an outer ectoderm and an inner endoderm) separated by a non-cellular jelly layer called mesoglea.

Triploblastic

Describing an animal embryo that develops from three germ layers: an ectoderm, a middle mesoderm, and an inner endoderm.

Coelom

An internal, fluid-filled body cavity that develops entirely within the mesoderm of triploblastic animals, separating the body wall from the digestive tract.

Through gut

A complete digestive tract with two separate openings: a mouth for ingestion and an anus for egestion.

Photolysis

The light-dependent splitting of water molecules in the grana of chloroplasts into energy-rich hydrogen atoms and oxygen gas during photosynthesis.

Calvin cycle

The dark phase of photosynthesis occurring in the stroma of chloroplasts, where $CO_2$ combines with energy-rich hydrogen atoms using ATP to form glucose.

Peristalsis

The involuntary, rhythmic contractions and relaxations of circular and longitudinal muscles in the alimentary canal wall that push food forward.

Deamination

The metabolic process taking place in the liver where excess amino acids are broken down to form urea and glucose.

Hydrolysis

The chemical breakdown of large, insoluble food molecules into smaller, soluble molecules by the enzymatic addition of water.

Islets of Langerhans

Endocrine cell groups within the pancreas that secrete insulin (from beta cells) and glucagon (from alpha cells) to regulate blood glucose concentration.

Homeostasis

The tendency of living organisms to maintain a constant internal environment within narrow physiological limits despite fluctuations in the external environment.

Kwashiorkor

A form of malnutrition in children caused by an insufficient intake of dietary protein.

Marasmus

A severe form of malnutrition caused by a general lack of energy-supplying foods, especially carbohydrates and fats.

Cellular respiration

The catabolic process by which organic compounds (glucose) are broken down with the gradual release of energy that is stored in ATP molecules.

Glycolysis

The anaerobic initial stage of cellular respiration that takes place in the cytosol, breaking down a 6-carbon glucose molecule into two 3-carbon pyruvic acid molecules.

Oxidative phosphorylation

The aerobic final phase of cellular respiration in the mitochondrial cristae where energy released by transferring hydrogen atoms across acceptors is used to bind ADP and phosphate into ATP.

Oxygen debt

The extra volume of oxygen required following anaerobic muscle exertion to convert accumulated lactic acid back into pyruvic acid.

Vital capacity

The total maximum volume of air that can be exhaled following a maximum inhalation, calculated as tidal volume plus inspiratory reserve volume plus expiratory reserve volume.

Residual volume

The volume of air that always remains inside the lungs after the most forceful exhalation and is never exhaled.

Oxyhaemoglobin

The compound formed when oxygen diffusing from the alveoli combines with haemoglobin inside red blood cells for systemic transport.

Emphysema

A chronic lung disease, primarily caused by smoking, in which the alveolar walls tear and form holes, severely impairing gaseous exchange.

Nephron

The microscopic, structural and functional urine-producing unit of the mammalian kidney.

Malpighian body

The filtration apparatus in the kidney cortex consisting of a double-walled Bowman's capsule enclosing a capillary network called the glomerulus.

Podocytes

Specialized epithelial cells with interdigitating projections and filtration slits that form the inner wall of Bowman's capsule.

Glomerular filtration

The non-selective movement of water and dissolved solutes out of the high-pressure glomerular capillaries through an ultrafine filter into the cavity of Bowman's capsule.

Tubular excretion

The active secretion of metabolic wastes, excess ions ($H^+$ and $K^+$), and foreign substances from peritubular capillaries into the renal tubule filtrate.

Aldosterone

A hormone secreted by the adrenal cortex that regulates blood electrolyte levels by promoting the reabsorption of sodium ions from the distal convoluted tubules into the blood.

Antidiuretic hormone (ADH)

A hormone produced by the pituitary gland (hypophysis) that increases the water permeability of the distal convoluted tubules and collecting ducts to conserve water in the blood.

Carrying capacity

The maximum number of individuals of a specific species that a given environment can support and sustain indefinitely.

Environmental resistance

The collective influence of all density-dependent and density-independent limiting factors that prevent a population from reproducing at its maximum biotic potential.

Competitive exclusion

The ecological principle stating that two species competing for the exact same limited resources cannot occupy the same ecological niche in the same habitat indefinitely.

Resource partitioning

The evolutionary adaptation where coexisting species divide resources by using them at different times, in different places, or across different plant structural layers to reduce competition.

Commensalism

A symbiotic relationship between two different species in which one organism benefits while the other is neither harmed nor benefited.

Ecological succession

The predictable, gradual sequence of communities replacing one another over time in an ecosystem until a stable climax community is established.

Greenhouse effect

The process by which greenhouse gases in the atmosphere absorb, reflect, and re-radiate infrared energy back to Earth, maintaining a warm surface temperature suitable for life.

Carbon footprint

The total amount of greenhouse gases, expressed as tons of carbon released as $CO_2$ per year, produced directly and indirectly by human activities.

Desertification

The degradation process by which human pressures such as overgrazing, deforestation, and poor irrigation transform semi-arid or arid land into barren desert.

Eutrophication

The process where excessive agricultural nutrients (nitrogen and phosphorus) enter water bodies, triggering explosive algal growth that blocks sunlight and depletes dissolved oxygen upon decomposition.

Food security

The ability of a country or region to ensure that all citizens have physical and economic access to sufficient, safe, and nutritious food to maintain a healthy life.