Grade 10 biology – Nutrition Quiz
1. Which nutrient is the primary source of energy for the body of a Kenyan school student who eats ugali and vegetables?
Carbohydrates are the body's main energy source; foods like ugali (maize) are rich in starch which is digested to provide energy.
2. Which organ is the main site for chemical digestion and absorption of food in most animals including humans?
The small intestine completes chemical digestion with enzymes and absorbs most nutrients through villi into the bloodstream.
3. What is the role of bile in digestion?
Bile produced by the liver emulsifies fats, breaking them into small droplets so lipase can act more efficiently during fat digestion.
4. Which enzyme in saliva begins the digestion of starch in the mouth?
Salivary amylase (ptyalin) starts breaking down starch into simpler sugars in the mouth.
5. Which vitamin deficiency causes scurvy and is linked to poor intake of fruits like oranges or vegetables?
Vitamin C deficiency leads to scurvy, characterized by bleeding gums and poor wound healing; citrus fruits and some vegetables supply vitamin C.
6. What is the main function of dietary fibre in the animal digestive system?
Dietary fibre adds bulk to the gut contents, helping peristalsis and preventing constipation; it is not a major energy source.
7. Which of the following best describes a balanced diet for a 15-year-old in Kenya?
A balanced diet supplies all nutrient groups in suitable amounts for growth, energy, and health, including water.
8. Which mineral is most important for healthy bones and teeth and is found in milk and green leafy vegetables?
Calcium is essential for strong bones and teeth; dairy products and leafy greens are good sources.
9. What condition results from prolonged deficiency of protein in the diet of young children?
Kwashiorkor is caused by severe protein deficiency and presents with oedema, a swollen belly, and muscle wasting.
10. In ruminant animals like cows, which stomach compartment hosts microbial fermentation of cellulose?
The rumen contains microbes that ferment cellulose, allowing ruminants to digest plant material that monogastric animals cannot.
11. Which process moves food along the gut using coordinated muscle contractions?
Peristalsis consists of rhythmic contractions of gut muscles that push food along the digestive tract.
12. Which nutrient group provides the building blocks for growth and repair of body tissues?
Proteins supply amino acids used to build and repair tissues, making them essential during the growth of teenagers.
13. Which disease is mainly caused by deficiency of vitamin D or lack of sunlight exposure?
Rickets is caused by vitamin D deficiency (or insufficient sunlight), leading to poor bone mineralization and bone deformities in children.
14. Where are nutrients absorbed into the blood after digestion of food?
Villi in the small intestine increase surface area for absorption of digested nutrients into blood and lymphatic vessels.
15. Which food example is a good plant source of protein common in Kenya?
Beans are a major plant protein source in Kenya; the choice clarifies meat (nyama-choma) is animal protein while beans provide plant protein.
16. Which of the following best describes essential amino acids?
Essential amino acids cannot be synthesized by the body and must be provided in the diet for proper growth and maintenance.
17. What is the main function of the large intestine in nutrition?
The large intestine absorbs water from undigested food residues and compacts waste into faeces for egestion.
18. Which nutrient is most concentrated in cooking oil and avocado and is important for insulation and energy storage?
Fats are energy-dense molecules used for long-term energy storage and insulation; oils and avocados are rich sources.
19. Anaemia in teenagers is most commonly caused by deficiency of which mineral?
Iron is needed to make haemoglobin; iron deficiency leads to anaemia, causing tiredness and poor concentration.
20. Which process describes the breakdown of large food molecules into smaller molecules by enzymes?
Digestion is the enzymatic breakdown of complex foods (proteins, fats, carbohydrates) into absorbable smaller molecules.
21. What is meant by 'assimilation' in animal nutrition?
Assimilation is the incorporation and use of absorbed nutrients by body cells for growth, repair and metabolic activities.
22. Which of these foods provides a good source of vitamin A important for eyesight and immunity?
Carrots and orange sweet potatoes contain beta-carotene, a precursor of vitamin A, which supports vision and immune function.
23. What is the role of the pancreas in digestion?
The pancreas secretes enzymes (amylase, lipase, proteases) and bicarbonate into the small intestine to digest food and neutralize acidic chyme from the stomach.
24. Which feeding category describes animals that eat both plants and other animals?
Omnivores feed on both plant and animal matter, unlike herbivores (only plants) or carnivores (only animals).
25. Which household practice helps preserve vitamin content in foods commonly eaten in Kenya?
Less cooking time and using cooking water preserves water-soluble vitamins (like vitamin C and B vitamins); prolonged boiling and discarding water causes losses.
26. What is the main purpose of nutrition in animals?
Nutrition supplies energy and the building blocks (like proteins and minerals) animals need for growth, repair and normal functioning.
27. Which term describes an animal that eats both plants and other animals?
Omnivores eat a mix of plant and animal foods (for example humans and pigs), while herbivores eat plants and carnivores eat mainly animals.
28. Which chamber of a cow's stomach is mainly responsible for absorbing water and minerals?
The omasum has many folds that absorb water and some minerals from the partially digested food in ruminants like cattle.
29. Which structure in birds temporarily stores food before digestion?
The crop is an enlarged part of the oesophagus in many birds where food is stored and softened before moving to the gizzard.
30. What is the main function of the gizzard in birds like chickens?
The muscular gizzard grinds food, often with the help of swallowed stones, assisting physical breakdown before chemical digestion.
31. Which enzyme begins protein digestion in the stomach?
Pepsin is a stomach enzyme that breaks proteins into smaller peptides; amylase digests starch, lipase digests fats.
32. Where does most nutrient absorption occur in the digestive system of mammals?
The small intestine has a large surface area (villi and microvilli) specialised for absorbing nutrients into the blood.
33. How are ruminant animals like cows able to digest cellulose from grass?
Bacteria and protozoa in the rumen produce enzymes that break cellulose into simpler compounds the animal can use.
34. Which nutrient is the main immediate source of energy for animals?
Carbohydrates (like glucose) are the primary and quickest source of energy used in respiration to make ATP.
35. A balanced diet for farm animals should include which combination?
Animals need energy sources (carbs, fats), building materials (proteins), and vitamins/minerals for proper growth, health and productivity.
36. What is the special name for the process when a cow brings up and chews its partly digested food again?
Rumination is the process where ruminants regurgitate cud to chew it again; mastication is chewing generally, peristalsis moves food along.
37. Which feature is typical of a hindgut fermenter such as a horse or rabbit?
Hindgut fermenters ferment plant fibres in the caecum and colon, unlike ruminants that ferment in the foregut (rumen).
38. Which vitamin is most important for blood clotting in animals?
Vitamin K is required for the synthesis of clotting factors that help blood to clot and prevent excessive bleeding.
39. Which mineral is especially important for strong bones and eggshell formation in poultry?
Calcium is a major component of bone and eggshell; deficiency leads to weak bones and thin eggshells.
40. Which enzyme in saliva begins the digestion of starch in animals and humans?
Salivary amylase (ptyalin) starts breaking down starch into simpler sugars in the mouth before food reaches the stomach.
41. What does assimilation mean in animal nutrition?
Assimilation is the process where absorbed nutrients are used to build and repair body cells and tissues.
42. Which group of animals typically has a beak and a muscular gizzard?
Birds commonly have beaks (no teeth) and a gizzard to grind food, examples include chickens and ostriches.
43. Which animal is an example of a filter feeder in aquatic environments?
Baleen whales feed by filtering small organisms from water using baleen plates; this is a classic example of filter feeding.
44. What name is given to the wave-like muscular movements that push food along the gut?
Peristalsis are coordinated contractions of gut muscles that move food along the digestive tract.
45. What is the role of bile in digestion?
Bile produced by the liver breaks large fat droplets into smaller ones (emulsification), increasing surface area for lipase action.
46. Which of the following animals is a specialised carnivore?
Lions are specialised carnivores that feed mainly on other animals, with teeth and digestive systems adapted for meat-eating.
47. Proteins in an animal's diet are made up of smaller building blocks called what?
Proteins are polymers of amino acids; digestion breaks proteins into amino acids which are absorbed and used to build body proteins.
48. Which vitamin listed below is fat-soluble and stored in the body's fatty tissues?
Vitamin A is fat-soluble (along with D, E and K) and can be stored in body fat; vitamin C and most B vitamins are water-soluble.
49. What is the main function of the large intestine in animals?
The large intestine reabsorbs water from indigestible food residues and compacts them into faeces for elimination.
50. What mouthpart adaptation do nectar-feeding insects like butterflies have for taking up liquid food?
A proboscis is a long tubular mouthpart used by butterflies and some other insects to suck nectar from flowers.