Class 10 Science: Life Processes

A comprehensive vocabulary review of core terms and concepts covered in Chapter 5: Life Processes, including autotrophic and heterotrophic nutrition, cellular respiration pathways, circulatory and respiratory mechanisms, plant transport, and human excretion.

Life Processes

The essential maintenance processes that together keep an organism alive and prevent structural damage or breakdown, functioning continuously even when the organism is resting or asleep.

Nutrition

The process of transferring an external source of energy (food) into the body of an organism for growth, maintenance, and cellular repair.

Autotrophs

Organisms, including green plants and some bacteria, that fulfill their energy and carbon requirements by converting inorganic carbon dioxide and water into organic carbohydrates in the presence of sunlight and chlorophyll.

Heterotrophs

Organisms, such as animals and fungi, that cannot synthesize their own food and must survive by consuming complex organic substances prepared by other organisms and breaking them down with enzymes.

Chloroplasts

Microscopic green cell organelles located within photosynthetic plant cells that contain chlorophyll and serve as the site where sunlight is absorbed during photosynthesis.

Stomata

Tiny microscopic pores found on the surface of plant leaves through which large volumes of gas exchange take place for photosynthesis and respiration, and through which water is lost via transpiration.

Guard Cells

Specialized cells that flank and regulate each stomatal pore; they swell with water to open the pore and shrink when water is lost to close it.

Pseudopodia

Temporary finger-like extensions of the cell surface formed by Amoeba that engulf food particles to form an internal food vacuole for digestion.

Salivary Amylase

A biological catalyst present in human saliva that initiates digestion in the mouth by breaking down complex starch molecules into simple sugars.

Peristaltic Movements

Rhythmic, coordinated muscular contractions and relaxations of the alimentary canal lining that push food forward through the digestive tract.

Pepsin

A protein-digesting enzyme secreted by the gastric glands in the stomach wall that requires an acidic environment created by hydrochloric acid to function.

Villi

Tiny finger-like projections extending from the inner lining of the small intestine that greatly increase the surface area available for absorbing nutrients into the bloodstream.

Dental Plaque

A sticky mass of bacterial cells and food particles that covers teeth, preventing saliva from neutralizing acids produced by bacteria that cause tooth decay.

Pyruvate

A three-carbon intermediate molecule produced in the cytoplasm during the first stage of cellular respiration when a six-carbon glucose molecule is broken down.

Anaerobic Respiration

A pathway of cellular respiration occurring in the absence of oxygen, such as the fermentation of pyruvate to ethanol and carbon dioxide in yeast, or to lactic acid in human muscle cells.

Aerobic Respiration

A cellular respiration pathway taking place in mitochondria that uses oxygen to break down pyruvate into carbon dioxide, water, and a large quantity of energy.

ATP (Adenosine Triphosphate)

The primary energy currency for cellular processes; breaking its terminal phosphate linkage using water releases an energy equivalent of $30.5\,\text{kJ/mol}$ to drive endothermic cell reactions.

Alveoli

Extensively vascularized, balloon-like structures at the terminal ends of the respiratory bronchioles in the lungs that provide a surface of about $80\,\text{m}^2$ for gaseous exchange.

Haemoglobin

An iron-containing respiratory pigment located inside red blood corpuscles that exhibits a high affinity for binding and transporting oxygen from the lungs to oxygen-deficient tissues.

Double Circulation

A circulatory pattern found in birds and mammals where blood passes through the heart twice during each complete circuit of the body, preventing the mixing of oxygenated and de-oxygenated blood.

Blood Pressure

The hydrostatic force exerted by blood against the walls of blood vessels, characterized by a normal systolic pressure of about $120\,\text{mm of Hg}$ and a diastolic pressure of about $80\,\text{mm of Hg}$.

Lymph

A colorless fluid (tissue fluid) composed of plasma, proteins, and white blood cells that filters into intercellular spaces from blood capillaries, transporting absorbed fats and draining excess fluid back to the bloodstream.

Transpiration

The evaporative loss of water vapor from the aerial parts of a plant, creating a transpiration pull that drives the upward absorption and transport of water and dissolved minerals through xylem vessels.

Translocation

The active transport of soluble photosynthetic products, amino acids, and sucrose through the sieve tubes and companion cells of phloem tissue using energy from ATP.

Nephron

The microscopic structural and functional filtration unit of the kidney, consisting of a capillary cluster associated with a cup-shaped Bowman's capsule and a long tubular segment that forms urine via selective re-absorption.