Tag: nutrients and foodstuffs

Nutrients are compounds in food, essential to life and health, providing us with energy, a building block for repair and growth and substance necessary to regulate the chemical process.

Nutrients are essential to survive and grow for an organism. A balanced diet provides the body nutrients it needs to function properly. Hence, a balanced diet is a good source of nutrients.

The process of nourishing or being nourished, especially the process by which a living organism assimilates food and uses it for growth and for replacement of tissues

•  The four major structural elements in the human body by weight  (oxygen, hydrogen, carbon, and nitrogen), are usually not included in lists of major nutrient minerals.
• As a group, minerals are one of the four groups of essential nutrients, the others of which are vitamins, essential fatty acids, and essential amino acids
• The five major minerals in the human body are calcium, phosphorus, potassium, sodium, and magnesium All of the remaining elements in a human body are called "trace elements". The trace elements are sulfur, iron, chlorine, cobalt, copper, zinc, manganese, molybdenum, iodine and selenium. Hence, silicon is not a major nutrient for the body.
  

• Physiological calories obtained from different food substances are - Carbohydrates give 4.0Kcal/g, Proteins give 4.0Kcal/g while fats give 9.0Kcal/g.
• So, energy from 5g sugar = 5 x 4Kcal = 20Kcal
• Energy from 4g albumin = 4 x 4Kcal = 16Kcal
• energy from 10g+2g fat = 12 x 9Kcal = 108Kcal
• lignin cannot be digested by humans because of the absence of digestive enzyme for lignin so no calories will be obtained from them. Ruminants are capable of digesting lignin.
• Adding all the above-obtained values we get 144Kcal.

So, the correct answer is '144'.

The leaf on the right shows a positive test for starch in the areas which contained chlorophyll, and a negative test for starch in the areas which lack chlorophyll. This is evidence that chlorophyll is required for photosynthesis. A plant can be 'de-starched' by leaving it in the dark for a few hours. So, the correct option is "C" (Starch will be found only in the part of the leaf exposed to light).

The iodine test is used for the determination of the presence of starch in a sample. Molecular iodine is not soluble in water and hence potassium iodide is added to it. Together they form polyiodide complex which upon addition of starch turns intense blue-black colour. Starch is a polymer of amylose and amylopectin, of which amylose is responsible for the blue colour of the reaction. In the absence of starch solution remain as light brown colour which is the colour of iodine solution.

Gastric acid is a digestive fluid, formed in the stomach. It is composed of hydrochloric acid (HCl) 0.05–0.1 M (roughly 5,000–10,000 parts per million) potassium chloride (KCl) and sodium chloride (NaCl). The acid plays a key role in digestion of proteins, by activating digestive enzymes, and making ingested proteins unravel so that digestive enzymes break down the long chains of amino acids. The highly acidic environment in the stomach lumen causes proteins from food to lose their characteristic folded structure (or denature). This exposes the protein's peptide bonds. The gastric chief cells of the stomach secrete enzymes for protein breakdown (inactive pepsinogen, and in infancy rennin). Hydrochloric acid activates pepsinogen into the enzyme pepsin, which then helps digestion by breaking the bonds linking amino acids, a process known as proteolysis. In addition, many microorganisms have their growth inhibited by such an acidic environment, which is helpful to prevent infection. HCl is digestive juice. Fatty acids are digested by bile acids.

Iodine test is used to distinguish between the presence of starch and glycogen and other saccharides.
When starch solution is treated with iodine, it gives a blue color. The blue color develops because of the trapping of iodine in the helical coils of amylose. When this test solution is heated, the color disappears due to disruption of the helical coils of amylose and the color reappears upon cooling, due to the reformation of helical coils. Glycogen however gives red color with iodine.
Therefore, the correct answer is option B.