Life Processes

This set of vocabulary flashcards covers the fundamental life processes of nutrition, respiration, transportation, and excretion in both human beings and plants based on the Chapter 5 lecture notes.

Life Processes

The processes which together perform the maintenance job of living organisms, such as nutrition, respiration, transportation, and excretion.

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 use simple food material obtained from inorganic sources in the form of carbon dioxide and water, such as green plants and some bacteria.

Heterotrophs

Organisms that utilise complex substances which must be broken down into simpler ones before use, including animals and fungi.

Enzymes

Biological catalysts that help in the break-down of complex substances into simpler ones within organisms.

Photosynthesis

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

Starch

The form in which carbohydrates not used immediately are stored in plants, serving as an internal energy reserve.

Glycogen

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

Chloroplasts

Cell organelles that contain green dots called chlorophyll, which is essential for photosynthesis.

Stomata

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

Guard cells

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

Saprophytes (Fungi)

Organisms like bread moulds, yeast, and mushrooms that break down food material outside the body and then absorb it.

Parasites

Organisms that derive nutrition from plants or animals without killing them, such as Cuscuta, ticks, lice, leeches, and tape-worms.

Amoeba

A single-celled organism that takes in food using temporary finger-like extensions of the cell surface called pseudopodia.

Salivary amylase

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

Peristaltic movements

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

Pepsin

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

Villi

Finger-like projections on the inner lining of the small intestine that increase the surface area for the absorption of digested food.

Pyruvate

A three-carbon molecule produced by the break-down of the six-carbon glucose molecule in the cytoplasm.

Anaerobic respiration

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

Aerobic respiration

The process of breaking down the three-carbon pyruvate molecule using oxygen in the mitochondria to give three molecules of carbon dioxide and water.

Lactic acid

A three-carbon molecule formed in muscle cells during a lack of oxygen; its build-up during sudden activity causes cramps.

ATP (Adenosine triphosphate)

The energy currency for most cellular processes; its terminal phosphate linkage releases $30.5\,kJ\,mol^{-1}$ when broken using water.

Alveoli

Balloon-like structures within the lungs that provide a surface where the exchange of gases occurs.

Haemoglobin

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

Plasma

The fluid medium of blood in which cells are suspended; it transports 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.

Systolic pressure

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

Diastolic pressure

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

Arteries

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

Veins

Blood vessels that collect blood from different organs and bring it back to the heart; they have valves to ensure one-way flow.

Capillaries

The smallest blood vessels with walls only one-cell thick, where exchange of material between blood and cells takes place.

Platelets

Cells in the blood that circulate the body and plug leaks by helping to clot blood at points of injury.

Lymph

A colourless fluid, also known as tissue fluid, that escapes from capillaries into intercellular spaces and contains less protein than plasma.

Xylem

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

Phloem

Vascular tissue in plants used for the translocation of products of photosynthesis, amino acids, and other substances.

Transpiration

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

Translocation

The transport of soluble products of photosynthesis through the phloem tissue using energy from ATP.

Nephrons

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

Hemodialysis

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

Dental plaque

Masses of bacterial cells and food particles that stick to teeth and prevent saliva from neutralising acids, leading to tooth decay.