Life Processes Practice Flashcards

Flashcards covering the essential concepts of life processes, including nutrition, respiration, transportation, and excretion in plants and humans based on Chapter 5.

What is the defining characteristic of life that professional biologists consider necessary, even if it is invisible to the naked eye?

Invisible molecular movement.

Why is molecular movement necessary for living organisms?

Living organisms are well-organised structures that are likely to break down over time due to environmental effects; molecular movement is needed to repair and maintain these structures.

What is the definition of life processes?

The processes which together perform the maintenance job of preventing damage and break-down in living organisms, even when they are not doing anything particular.

What is the process of transferring a source of energy (food) from outside the body to the inside called?

Nutrition.

What process do many organisms use to acquire oxygen from outside the body and use it to break down food sources for cellular needs?

Respiration.

Why is simple diffusion insufficient to meet the oxygen requirements of multi-cellular organisms?

Because in multi-cellular organisms, all the cells may not be in direct contact with the surrounding environment.

What are the biological catalysts used by heterotrophs to break down complex substances into simpler ones for growth and upkeep?

Enzymes.

In what form do plants store carbohydrates that are not used immediately?

Starch.

In humans, some of the energy derived from food is stored in the body in what form?

Glycogen.

What are the three main events that occur during the process of photosynthesis?

(i) Absorption of light energy by chlorophyll, (ii) Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen, (iii) Reduction of carbon dioxide to carbohydrates.

What are chloroplasts?

Cell organelles that contain chlorophyll and appear as green dots in leaf cells under a microscope.

How do plants regulate the opening and closing of stomatal pores?

The opening and closing is a function of the guard cells, which swell when water flows into them (opening the pore) and shrink when water is lost (closing the pore).

Beyond carbon dioxide and water, what other raw materials do terrestrial plants take up from the soil?

Nitrogen, phosphorus, iron, and magnesium.

What is the parasitic nutritive strategy?

A strategy where organisms derive nutrition from plants or animals without killing them, such as in cuscuta (amar-bel), ticks, lice, leeches, and tape-worms.

How does Amoeba obtain nutrition?

Amoeba uses temporary finger-like extensions of the cell surface to fuse over food particles, forming a food-vacuole where complex substances are broken down into simpler ones.

What is the role of salivary amylase in the human mouth?

It is an enzyme that breaks down starch, which is a complex molecule, to give simple sugar.

What are the rhythmic contraction movements that push food along the digestive tube called?

Peristaltic movements.

What are the three substances released by the gastric glands in the stomach?

Hydrochloric acid, a protein-digesting enzyme called pepsin, and mucus.

What is the function of mucus in the stomach?

It protects the inner lining of the stomach from the action of hydrochloric acid under normal conditions.

Why do herbivores need a longer small intestine compared to carnivores like tigers?

Herbivores need a longer small intestine to allow cellulose to be digested, whereas meat is easier to digest.

What is the role of bile salts in digestion?

Bile salts break down large fat globules into smaller globules to increase the efficiency of enzyme action.

Which enzymes are found in pancreatic juice for the digestion of proteins and emulsified fats?

Trypsin for digesting proteins and lipase for breaking down emulsified fats.

What is the primary function of villi in the small intestine?

They increase the surface area for the absorption of digested food into the blood vessels.

What occurs during the first step of glucose breakdown in all cases of respiration?

Glucose (a six-carbon molecule) is broken down into pyruvate (a three-carbon molecule) in the cytoplasm.

What are the products of anaerobic respiration in yeast during fermentation?

Ethanol, carbon dioxide, and energy.

What causes muscle cramps during sudden activity?

The build-up of lactic acid, which occurs when pyruvate is converted to lactic acid due to a lack of oxygen in muscle cells.

How much energy is released when the terminal phosphate linkage in ATP is broken using water?

$$30.5\,kJ/mol$$

Why is the rate of breathing in aquatic organisms much faster than in terrestrial organisms?

Because the amount of dissolved oxygen in water is fairly low compared to the amount of oxygen in the air.

What are the balloon-like structures in the lungs that provide a surface for gas exchange?

Alveoli.

What is the respiratory pigment in human beings that carries oxygen to tissues?

Haemoglobin.

Which blood component carries oxygen, and which component transports food, carbon dioxide, and nitrogenous wastes?

Red blood corpuscles carry oxygen; plasma transports food, $CO_2$, and nitrogenous wastes.

Why does the heart have different chambers?

To prevent oxygen-rich blood from mixing with blood containing carbon dioxide.

What is double circulation?

A process in which blood goes through the heart twice during each cycle of passage through the body, common in vertebrates other than fish.

What is the difference between systolic pressure and diastolic pressure?

Systolic pressure is the pressure inside the artery during ventricular contraction (normal $120\,mm$ of Hg), and diastolic pressure is the pressure during ventricular relaxation (normal $80\,mm$ of Hg).

What is the role of platelets in the circulatory system?

Platelets circulate around the body and plug leaks by helping to clot the blood at points of injury.

What is lymph?

A colourless fluid containing less protein than plasma that escapes into intercellular spaces; it carries digested fat and drains excess fluid back into the blood.

What are the two independent conducting tubes in plant transport systems and what do they move?

Xylem moves water and minerals from the soil, and phloem transports products of photosynthesis from the leaves.

What is transpiration?

The loss of water in the form of vapour from the aerial parts of the plant.

What is translocation in plants?

The transport of soluble products of photosynthesis (such as sucrose) and amino acids through the phloem using energy from ATP.

What is the basic filtration unit of the human kidney?

Nephron.

What is the function of the Bowman's capsule?

It is the cup-shaped end of a coiled tube in the nephron that collects the filtrate from the capillary cluster.

What is hemodialysis?

A process using an artificial kidney to remove nitrogenous waste products from the blood through a semi-permeable lining when kidneys fail.