Life Processes Lecture Notes

Comprehensive vocabulary flashcards covering the key concepts, biological processes, and definitions from Chapter 5: Life Processes.

Life Processes

The processes which together perform the maintenance job of living organisms even when they are not doing any particular activity.

Nutrition

A process to transfer a source of energy (food) from outside the body of the organism to the inside.

Respiration

The process of acquiring oxygen from outside the body and using it in the process of break-down of food sources for cellular needs.

Excretion

The biological process involved in the removal of harmful metabolic waste products from the body.

Autotrophs

Organisms that utilize simple food material obtained from inorganic sources in the form of $CO_2$ and water, such as green plants and some bacteria.

Enzymes

Biological catalysts used by organisms to break down complex substances into simpler ones for upkeep and growth.

Photosynthesis

The process by which autotrophs take in carbon dioxide and water and convert them into stored forms of energy (carbohydrates) in the presence of sunlight and chlorophyll.

Starch

The internal energy reserve in plants, formed from carbohydrates that are not used immediately.

Glycogen

The form in which energy derived from food is stored in the human body.

Chloroplasts

Cell organelles that contain chlorophyll and appear as green dots in a cross-section of a leaf.

Stomata

Tiny pores present on the surface of the leaves through which massive amounts of gaseous exchange take place.

Guard cells

Cells that regulate the opening and closing of the stomatal pore by swelling when water flows into them or shrinking.

Salivary amylase

An enzyme in saliva that breaks down starch, a complex molecule, into simple sugar.

Peristaltic movements

Rhythmic contractions of muscles along the lining of the alimentary canal that push food forward.

Pepsin

A protein-digesting enzyme released by gastric glands in the stomach.

Villi

Numerous finger-like projections on the inner lining of the small intestine that increase surface area for absorption and are richly supplied with blood vessels.

Dental caries

Tooth decay caused by the gradual softening of enamel and dentine due to acids produced by bacteria acting on sugars.

Pyruvate

A three-carbon molecule produced during the first step of glucose break-down in the cytoplasm.

Anaerobic respiration

The process of breaking down pyruvate in the absence of oxygen, resulting in ethanol, carbon dioxide, and energy (as seen in yeast fermentation).

Aerobic respiration

The break-down of pyruvate using oxygen in the mitochondria, producing carbon dioxide, water, and a greater amount of energy.

ATP (Adenosine triphosphate)

The energy currency for most cellular processes, synthesized from ADP and inorganic phosphate during respiration.

Alveoli

Balloon-like structures at the end of the respiratory passage in lungs that provide a surface for the exchange of gases.

Haemoglobin

The respiratory pigment in human beings found in red blood corpuscles that has a very high affinity for oxygen.

Plasma

The fluid medium of blood in which cells are suspended, transporting food, carbon dioxide, and nitrogenous wastes in dissolved form.

Double circulation

A circulatory system where blood goes through the heart twice during each cycle of passage through the body (common in vertebrates).

Systolic pressure

The pressure of blood inside the artery during ventricular contraction (ventricular systole), normally about $120\,mm$ of Hg.

Diastolic pressure

The pressure in an artery during ventricular relaxation (ventricular diastole), normally about $80\,mm$ of Hg.

Arteries

Thick-walled, elastic vessels that carry blood away from the heart to various organs under high pressure.

Veins

Vessels that collect blood from different organs and bring it back to the heart, featuring valves to ensure one-way blood flow.

Capillaries

The smallest blood vessels with walls one-cell thick that bring blood in contact with individual cells for material exchange.

Lymph

A colourless tissue fluid containing less protein than plasma that drains into lymphatic capillaries from intercellular spaces.

Xylem

Vascular tissue in plants responsible for moving water and minerals obtained from the soil.

Phloem

Vascular tissue in plants that transports products of photosynthesis from the leaves to other parts of the plant.

Transpiration

The loss of water in the form of vapour from the aerial parts of the plant, which helps in the upward movement of water and minerals.

Translocation

The transport of soluble products of photosynthesis, amino acids, and other substances through the phloem.

Nephrons

The basic filtration units in the kidneys, consisting of a capillary cluster (glomerulus) and a cup-shaped Bowman’s capsule.

Hemodialysis

A procedure using an artificial kidney to remove nitrogenous waste products from the blood of patients with kidney failure.