Q10. Excess fluoride in drinking water causes:
[WBCS Prelims 2020]
(A) Lung disease
(B) Intestinal infection
(C) Fluorosis
(D) Rickets
Answer: (C) Fluorosis
Explanation: Prolonged intake of excessive fluoride can cause dental or skeletal fluorosis. Dental fluorosis changes the appearance of developing tooth enamel, while severe skeletal fluorosis affects bones and joints. The effect depends on dose, exposure duration and other factors.
Q9. Which of the following chemical compound is used as a preservative in pickle?
[SSC MTS, 14 August 2019, Shift 3]
(A) Calcium metabisulphate
(B) Sodium nitrate
(C) Sodium benzoate
(D) Calcium carbonate
Answer: (C) Sodium benzoate
Explanation: Sodium benzoate helps suppress microorganisms in acidic preserved foods, including certain pickles. Its antimicrobial action depends strongly on the product pH. Pickles may additionally rely on salt, vinegar and hygienic packaging to achieve their desired shelf life.
Q8. The food that gives more calories per unit mass of food is:
[WBCS Prelims 2019]
(A) Protein
(B) Carbohydrates
(C) Fat
(D) Water
Answer: (C) Fat
Explanation: Dietary fat provides approximately nine kilocalories per gram, compared with about four kilocalories per gram from digestible protein or carbohydrate. Water supplies no food energy. Therefore, fat is the most energy-dense nutrient among these alternatives.
Q7. In medicine bottles containing capsules and tablets, a pouch of silica gel is kept:
[WBCS Mains Science, 2018]
(A) To kill bacteria
(B) To absorb bacteria
(C) To keep bottle warm
(D) To absorb moisture
Answer: (D) To absorb moisture
Explanation: Silica gel is a desiccant that adsorbs water vapour from the surrounding air. Moisture control helps protect humidity-sensitive tablets and capsules from deterioration. Silica gel is not an antibiotic and its primary purpose is not to keep medicines warm.
Q6. Which of the following substance is extensively used for food preservation?
[West Bengal Police Constable, 2018, Official Paper 2]
(A) Acetic acid
(B) Benzoic acid
(C) Tartaric acid
(D) Sodium bicarbonate
Answer: (B) Benzoic acid
Explanation: Benzoic acid inhibits various spoilage microorganisms, particularly in acidic foods, and is frequently used as its more soluble sodium salt. Acetic acid is also used in preservation, especially vinegar-based pickling, but benzoic acid was the stated answer in this paper.
Q5. The well known antibiotic penicillin is obtained from this plant group:
[WBCS Prelims 2017]
(A) Algae
(B) Fungi
(C) Lichen
(D) Angiosperm
Answer: (B) Fungi
Explanation: Penicillin was originally derived from Penicillium moulds, which belong to the kingdom Fungi rather than plants. This antibiotic targets bacterial cell-wall synthesis. Alexander Fleming identified its antibacterial action, and subsequent development made penicillin an important clinical medicine.
Q4. Precursor of which one of the following vitamins comes from beta-carotene?
[UPSC NDA General Ability Test, 19 April 2015]
(A) Vitamin A
(B) Vitamin C
(C) Vitamin D
(D) Vitamin K
Answer: (A) Vitamin A
Explanation: Beta-carotene is a provitamin A carotenoid found in carrots and other orange or green vegetables. The body can convert it to retinal and related vitamin A compounds. Vitamin A is essential for vision, cellular differentiation and immune function.
Q3. The Government of India encourages the cultivation of sea buckthorn. What is the importance of this plant?
1. It helps in controlling soil erosion and in preventing desertification.
2. It is a rich source of biodiesel.
3. It has nutritional value and is well-adapted to live in cold areas of high altitudes.
4. Its timber is of great commercial value.
Which statements are correct?
[UPSC Civil Services Prelims 2012]
(A) 1 only
(B) 2, 3 and 4 only
(C) 1 and 3 only
(D) 1, 2, 3 and 4
Answer: (C) 1 and 3 only
Explanation: Sea buckthorn can stabilise soils in fragile cold, high-altitude areas and produces berries valued for their nutritional constituents. Its extensive roots assist erosion control. The other assertions overstate its commercial usefulness as biodiesel feedstock or timber.
Q2. Which of the following vitamin is most easily destroyed by heat and air?
[WBCS Prelims 2002]
(A) A
(B) B
(C) C
(D) D
Answer: (C) C
Explanation: Vitamin C, or ascorbic acid, is sensitive to heat and oxidation in air, especially during prolonged cooking and storage. Food preparation methods that reduce exposure to heat, water and oxygen can help preserve this important water-soluble vitamin.
Q1. Refrigeration helps in food preservation by:
[WBCS Prelims 2002]
(A) Killing bacteria and germs
(B) Greatly retarding the rates of biochemical reaction
(C) Providing a cover of ice over food
(D) Stopping enzyme action
Answer: (B) Greatly retarding the rates of biochemical reaction
Explanation: Lower temperatures slow many chemical and enzyme-mediated reactions and reduce the growth rates of numerous spoilage microorganisms. Refrigeration usually does not sterilise food or stop all enzyme activity. Proper hygiene and suitable storage time therefore remain necessary.
