Life Processes: Nutrition, Digestion, Respiration, and Transportation (BYJU'S Notes)

Vocabulary flashcards covering key terms and definitions from the Life Processes, Nutrition, Digestion, Respiration, and Transportation topics presented in the notes.

Life processes

The essential functions that maintain life in living organisms (e.g., nutrition, respiration, circulation, excretion, growth, reproduction, response to stimuli).

Homeostasis

Maintenance of stable internal conditions through coordinated life processes.

Nutrition

Process of acquiring food for nourishment and growth; includes autotrophic and heterotrophic modes.

Autotrophic nutrition

Organisms make their own food using light or chemical energy (photosynthesis or chemosynthesis).

Photoautotrophs

Organisms that use light energy to synthesize food (e.g., plants, algae).

Chemoautotrophs

Organisms that derive energy from chemical reactions to synthesize food (certain bacteria).

Heterotrophic nutrition

Organisms obtain energy by consuming preformed organic matter; includes holozoic, saprophytic and parasitic modes.

Holozoic nutrition

Animals take in complex food and digest it inside the body.

Saprophytic nutrition

Feeding on dead or decaying organic matter with external digestion.

Parasitic nutrition

Feeding on a living host, deriving nutrients at the host's expense.

Amoeba

Unicellular organism that ingests food by holozoic nutrition via phagocytosis.

Phagocytosis

Engulfing of a particle by the cell membrane to form a food vacuole.

Paramecium

Ciliate protozoan with holozoic nutrition; uses oral groove and food vacuole.

Cyclosis

Cytoplasmic movement that transports nutrients within the cytoplasm.

Anal pore (cytopyge)

Opening through which undigested material is expelled in Paramecium.

Alimentary canal

Long tube from the mouth to the anus where digestion and absorption occur.

Ingestion

Process of taking in food into the digestive system.

Digestion

Breakdown of food into smaller, absorbable molecules.

Absorption

Uptake of digested nutrients into the bloodstream or lymphatic system.

Assimilation

Use of absorbed nutrients by body cells for growth and maintenance.

Egestion

Elimination of indigestible substances from the body.

Mouth (buccal cavity)

Entry point for food; contains teeth for mastication and tongue with taste buds; salivary glands begin digestion.

Teeth

Hard structures for cutting, tearing, and chewing; enamel, dentine, cement, and dental pulp.

Enamel

Outermost, highly mineralized, hardest part of the tooth.

Dentine

Bulk of the tooth beneath enamel; about 70% inorganic salts.

Cement

Covering of the tooth root and lining of the bony socket.

Dental pulp

Central soft tissue containing nerves, blood vessels, and connective tissue.

Incisors

Teeth that cut food.

Canines

Teeth that tear food.

Molars

Teeth that crush food.

Premolars

Teeth that help grind/crush food.

Dental formula

Adult human tooth pattern: 2:1:2:3 (incisors: canines: premolars: molars).

Esophagus

Muscular tube that transports food to the stomach via peristaltic movements.

Peristalsis

Wave-like rhythmic contractions that push contents along the digestive tract.

Stomach

J-shaped organ where gastric juice digests food; forms chyme.

Gastric juice

Secretions in the stomach including hydrochloric acid and pepsin.

Hydrochloric acid (HCl)

Acidic stomach fluid that activates pepsin and kills bacteria (pH ~1.5–3.5).

Mucus

Protective lining in the stomach against acid damage.

Pepsin

Protease that digests proteins into peptides in the stomach.

Chyme

Semi-solid mass of partly digested food in the stomach.

Small intestine

Longest part of the alimentary canal where most digestion and absorption occur; sections: duodenum, jejunum, ileum.

Villi

Finger-like projections in the small intestine that increase surface area for absorption.

Microvilli

Microscopic folds on enterocytes that further increase absorptive surface area.

Pancreas

Gland that produces pancreatic juice and, as an endocrine organ, insulin and glucagon.

Pancreatic juice

Digestive enzymes secreted by the pancreas (e.g., trypsin, chymotrypsin, amylase, lipase).

Bile

Digestive fluid from the liver that emulsifies fats; stored in the gallbladder.

Liver

Largest gland; produces bile, detoxifies, stores glucose, and processes various substances.

Gallbladder

Sac that stores bile until it is needed for fat digestion.

Intestinal juice (succus entericus)

Digestive secretions from intestinal glands aiding digestion in the small intestine.

Digestive glands

Glands involved in digestion: salivary glands, gastric glands, liver, gallbladder, and pancreas.

Digestive enzymes

Enzymes that break down carbohydrates, proteins, and fats (e.g., amylase, proteases, lipases).

Trypsin

Protease from pancreatic juice that digests proteins.

Chymotrypsin

Protease from pancreatic juice that digests proteins.

Amylase

Enzyme that digests starch into sugars (salivary and pancreatic).

Lipase

Enzyme that digests fats into fatty acids and glycerol.

Respiration

Gas exchange and energy production; can be aerobic or anaerobic.

Diffusion

Movement of molecules from high to low concentration without energy expenditure.

Cellular respiration

Metabolic processes inside cells to convert glucose into ATP (energy).

ATP

Adenosine triphosphate; main energy currency of the cell.

Aerobic respiration

Glucose is fully oxidized to CO2 and H2O in the presence of oxygen to release energy.

Glycolysis

Initial breakdown of glucose in the cytoplasm during cellular respiration.

Krebs cycle

Citric acid cycle in mitochondria that processes acetyl-CoA to CO2 and high-energy electrons.

Electron transport chain

Series of proteins in membranes that produce ATP via oxidative phosphorylation.

Lactic acid fermentation

Anaerobic glucose breakdown in muscles producing lactic acid and limited ATP.

Respiration in plants

Gas exchange through stomata and lenticels; plants respire at a lower rate than animals.

Transpiration

Loss of water vapor from aerial parts of plants, mainly through stomata; aids water transport.

Xylem

Plant tissue that transports water and minerals from roots to shoots; unidirectional.

Phloem

Plant tissue that translocates sugars and nutrients through the plant; bidirectional flow.

Translocation

Movement of food within the phloem using mass flow driven by osmotic pressure.

Root pressure

Osmotic pressure in root cells that pushes sap upward through the plant.

Imbibition

Uptake of water by solids (e.g., seeds swelling when soaked).

Osmosis

Diffusion of water across a semipermeable membrane from low to high solute concentration.

Excretion

Removal of metabolic wastes from the body.

Excretory system (humans)

Kidneys, ureters, urinary bladder, and urethra responsible for urine production and removal.

Kidneys

Pair of organs that filter the blood and produce urine; contain nephrons as functional units.

Nephron

Structural and functional unit of the kidney; includes Bowman's capsule, glomerulus, tubules.

Bowman's capsule

Cup-like structure surrounding the glomerulus; site of initial filtration.

Glomerulus

Tangled capillaries in the nephron where filtration occurs.

Proximal convoluted tubule

Segment of nephron where most reabsorption of filtrate occurs.

Loop of Henle

Nephron segment that concentrates urine by creating a salt gradient.

Distal convoluted tubule

Nephron segment involved in selective reabsorption and secretion.

Urine

Filtrate that has been processed by the kidneys and collected in the bladder.

Haemodialysis

Dialysis treatment that removes waste and excess water from blood using a dialysis machine.

Dialyzer

Artificial kidney used in haemodialysis to filter blood.

Ureter

Tube carrying urine from kidneys to the urinary bladder.

Urinary bladder

Organ that stores urine before it is excreted through the urethra.

Urethra

Duct through which urine leaves the bladder to the outside.

Excretion in plants

Gaseous wastes (O2 from photosynthesis, CO2 from respiration) and excess water are managed; storage of organic wastes in plant parts.

Stomata

Pores on leaf surfaces for gas exchange; guard cells regulate opening and closing.

Guard cells

Cells surrounding stomata that control pore opening by turgor.

Transpiration (plant)

Water loss through stomata that also drives water transport from roots to shoots.

Gums, oils, resins, latex

Excretory plant products stored in various parts and sometimes shed seasonally.