What are life processes in living organisms?
Activities like taking in food, deriving energy, removing waste, and responding to changes.
What does food provide for life processes?
Energy for life processes.
What else does food provide besides energy?
Raw materials for growth and tissue repair.
What materials does food provide for enzyme and hormone production?
Materials for producing enzymes and hormones.
What is nutrition?
The process of obtaining food, converting it into absorbable forms, and making needed substances.
How do autotrophic organisms obtain their food?
They manufacture their own food.
On what do heterotrophic organisms depend for food?
They depend on other organisms for food.
Which organisms are called producers in nutrition?
Green plants, algae, and certain bacteria.
Why are green plants, algae, and certain bacteria called producers?
Because other organisms depend on them for food.
What does holozoic nutrition involve?
Ingestion, digestion, and absorption of food.
What is parasitic nutrition?
Living on or inside another organism and deriving food from it.
Give examples of organisms with parasitic nutrition.
Cuscuta, leeches, and head lice.
From where do saprotrophic organisms obtain their food?
From dead and decaying organic matter.
What is photosynthesis in green plants?
A biochemical process making food from carbon dioxide and water using sunlight and chlorophyll.
What is the overall chemical equation of photosynthesis?
6CO2 + 12H2O → C6H12O6 + 6H2O + 6O2 under light and chlorophyll.
What are the two simultaneous steps of photosynthesis?
Light reaction captures light energy and dark reaction forms glucose in chloroplasts.
How is glucose from photosynthesis used by plants?
It is used by cells or converted and stored as starch.
How does oxygen produced in photosynthesis leave the plant?
It diffuses into the atmosphere through stomata.
How does photosynthesis contribute to atmospheric gas balance?
It uses carbon dioxide from respiration and supplies oxygen for respiration.
Which nutrients yield energy in the human diet?
Carbohydrates and fats yield energy.
What role do proteins play in human nutrition?
Proteins are body-building nutrients.
Which nutrients regulate growth in the human body?
Vitamins and minerals regulate growth.
How much energy does one gram of fat release on oxidation?
One gram of fat releases about 37 kilojoules or 9 kilocalories.
What is the main function of proteins in the body?
Proteins mainly support the growth of body tissues.
Which vitamins are water-soluble?
Vitamins B-complex and C are water-soluble.
What percentage of body weight does water form?
Water forms 65–70% of body weight.
What defines a balanced diet?
A balanced diet contains adequate amounts of nutrients and water in proper proportions.
What is digestion in human biology?
The conversion of complex food into smaller absorbable substances.
Which processes are included in human nutrition?
Ingestion, digestion, absorption, assimilation, and egestion.
What does salivary amylase do in the mouth?
It breaks starch into sugar.
How does the oesophagus contribute to digestion?
It moves food to the stomach by peristalsis without digesting it.
What role does hydrochloric acid play in the stomach?
It activates pepsinogen to pepsin and kills bacteria.
What is the function of pepsin in the stomach?
It breaks proteins into peptones.
How does bile aid digestion in the small intestine?
It emulsifies fats and creates an alkaline medium.
What is the function of villi in the small intestine?
They increase surface area for absorption of digested food.
What is malnutrition?
Malnutrition is the intake of an improper or inadequate diet.
Which condition does protein-energy malnutrition cause in children up to one year?
Marasmus.
Which condition does protein-energy malnutrition cause in children aged one to five years?
Kwashiorkor.
What does iodine deficiency cause?
Goitre.
What effect does iron deficiency have on the body?
It reduces haemoglobin production and causes anaemia.
What condition results from vitamin A deficiency?
Night blindness.
What is food adulteration?
The deliberate mixing of food with cheaper, substandard, edible, or inedible substances.
What do root hairs absorb from the soil?
Water and minerals.
Which plant structures transport water upward to leaves?
Xylem tracheids and vessels.
What causes the upward force called transpiration pull?
Evaporation of water vapour from stomata creating a vacuum.
What is transpiration pull?
The upward force drawing water through xylem.
What does translocation transport in plants?
Sugars and other food molecules.
Through which plant structures does translocation occur?
Living phloem sieve tubes.
What components make up the circulatory system?
A muscular heart, blood vessels, and circulating fluids.
Which blood vessels carry blood away from the heart?
Arteries carry blood away from the heart.
Which blood vessels bring blood toward the heart?
Veins bring blood toward the heart.
What is the function of capillaries in the circulatory system?
Capillaries allow exchange between blood and tissues.
How many chambers does the human heart have?
Four chambers.
What is a normal healthy young person's blood pressure?
About 120/80 mm Hg.
What is the normal heart rate for a healthy young person?
About 72 beats per minute.
What type of blood does the pulmonary artery carry?
Carbon-dioxide-laden blood.
What do red blood cells contain and what do they transport?
They contain haemoglobin and transport oxygen to and carbon dioxide from tissues.
What is a key characteristic of white blood cells?
They are colourless, irregularly shaped cells that fight infection.
What role do blood platelets play?
They participate in blood clotting.
How does lymph differ from blood in circulation?
Lymph flows one way from tissues to the heart, unlike blood which circulates through heart and vessels.
Which blood group can donate to all ABO groups?
Group O can donate blood to all four groups.
Which blood group can receive blood from all ABO groups?
Group AB can receive blood from all four groups.
What is hypertension?
Hypertension is high blood pressure.
What causes anaemia and what characterizes leukemia?
Anaemia results from reduced haemoglobin; leukemia involves excessive white blood cells and few red blood cells.
What distinguishes breathing from cellular respiration?
Breathing exchanges gases physically, cellular respiration oxidizes food to release energy.
Through which plant structures does gas exchange occur?
Gas exchange occurs through root hairs, stomata, and lenticels.
What causes guard cells to open stomata?
Guard cells open stomata when they are turgid.
Name the main human respiratory passages.
Nostrils, nasal cavities, internal nostrils, pharynx, trachea, bronchi, bronchioles, and alveoli.
What supports the trachea and prevents its collapse?
Cartilage rings support the trachea.
Why do alveoli have thin walls and many capillaries?
To provide a large surface for oxygen and carbon dioxide diffusion.
What happens to the diaphragm during inhalation?
The diaphragm contracts and flattens.
How do the ribs move during inhalation?
They move upward and outward.
What occurs to thoracic volume and pressure during inhalation?
Thoracic volume increases and pressure decreases.
What happens to the diaphragm during exhalation?
The diaphragm relaxes into a dome shape.
How do the ribs move during exhalation?
They move downward and inward.
What is the typical breathing rate of an adult human at rest?
About 16–18 times per minute.
Where does oxygen diffuse during gas exchange in the lungs?
From alveoli into blood capillaries.
Where does carbon dioxide diffuse during gas exchange in the lungs?
From blood into the alveoli for exhalation.
What is excretion in the human body?
The removal of unnecessary or harmful chemical reaction products.
What organs make up the human urinary system?
Two kidneys, two ureters, a urinary bladder, and a urethra.
What is a nephron in the kidney?
The structural and functional unit of the kidney.
Which parts compose a nephron?
Bowman’s capsule, glomerulus, renal tubule, proximal convoluted tubule, loop of Henle, and distal convoluted tubule.
Where is blood filtered in the kidney?
In the glomerulus and Bowman’s capsule.
What forms urine after filtration and reabsorption in the nephron?
Mainly urea remains to form urine.
How does urine travel from the kidneys to outside the body?
Through ureters to the bladder, then through the urethra.
What is osmoregulation?
Maintaining correct water and mineral ion levels in blood and internal environment.
Test your knowledge with 39 questions on Life Processes and Human Physiology.
1. Which combination best describes the roles of food in living organisms?
2. What does nutrition involve in a living organism?
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