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Describe the structure and function of nephrons in the human excretory system.
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Nephrons are the functional units of the kidneys that filter blood to remove metabolic wastes, regulate water and electrolyte balance, and produce urine.
What are the main roles of plasma, red blood cells, white blood cells, and platelets in the circulatory system?
Plasma transports nutrients, waste products, and gases. Red blood cells carry oxygen. White blood cells are involved in immune response and fighting infections. Platelets are responsible for blood clotting.
What are the five key life processes essential for the survival and maintenance of living organisms?
Digestion, respiration, circulation, excretion, and growth.
What is the difference between aerobic and anaerobic respiration?
Aerobic respiration occurs in the presence of oxygen and produces CO₂, H₂O, and energy (ATP). Anaerobic respiration occurs in the absence of oxygen and produces either ethanol and CO₂, or lactic acid, and energy.
What mechanisms do plants use for excretion?
Plants excrete wastes through stomata (removing gaseous wastes), transpiration (removing excess water), leaf fall (discarding wastes stored in leaves), and storing gums and resins in old xylem cells.
Describe the structure and function of the alveoli in the human respiratory system.
Alveoli are tiny air sacs in the lungs where gas exchange occurs. Oxygen from inhaled air passes through the alveolar walls into the blood, and CO₂ from the blood is expelled through exhalation.
How do xylem and phloem function in plant transportation?
Xylem transports water and minerals from roots to various parts of the plant. Phloem transports food from the leaves to other parts of the plant.
What is root pressure and how does it aid in water transportation in plants?
Root pressure is generated in the roots, pushing water upward through the xylem vessels, mostly effective at night when transpiration is low.
Describe the process of digestion in humans including the main stages.
Human digestion involves ingestion (intake of food), digestion (breakdown of food), absorption (movement of digested food into the bloodstream), assimilation (utilization of absorbed food for energy and growth), and egestion (removal of undigested food).
Explain the role of gastric glands in the human digestive system.
Gastric glands secrete gastric juice, which includes pepsin, hydrochloric acid (HCl), and mucus, contributing to the digestion of proteins in the stomach.
How do saprophytic and parasitic organisms differ in their nutritional methods?
Saprophytic organisms feed on dead organic matter while parasitic organisms feed on living hosts without killing them, deriving nutrients from your host.
What is the role of the diaphragm in respiration?
The diaphragm is a muscle that contracts and flattens during inhalation to increase thoracic cavity volume, allowing the lungs to expand and fill with air. It relaxes during exhalation, reducing thoracic cavity volume and helping to expel air from the lungs.
How do autotrophic organisms obtain their food and provide an example?
Autotrophic organisms make their own food from inorganic substances like CO₂ and water through processes like photosynthesis. Example: Green plants.
What are the main components and functions of the human respiratory system?
Major components: nose, nasal cavity, pharynx, larynx, trachea, bronchi, lungs, and alveoli. Functions include inhalation and exhalation of air, and gas exchange in alveoli.
How does double circulation work in humans?
In double circulation, blood passes through the heart twice during one complete cycle. It goes from the heart to the lungs for oxygenation, back to the heart, and then throughout the body.
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