Introduction to Nutrients - Class X Biology

An essential nutrient is a nutrient that the body cannot synthesize on its own  or not to an adequate amount and must be provided by the diet. These nutrients are necessary for the body to function properly. The six essential nutrients include carbohydrates, protein, fat, vitamins, minerals and water. Carbohydrates are the main energy source for the brain. Protein is the major structural component of cells and is responsible for the building and repair of body tissues. Fat is an energy source that when consumed, increases the absorption of fat-soluble vitamins including vitamins A, D, E and K. 

Biological particles in the atmosphere often lack the necessary nutrients required to sustain metabolic activity or reproduction, limiting their survival time.

Nutrients give energy and keep your body running. Nutrients help build and strengthen bones, muscles, and tendons and also regulate body processes. Therefore, (d) is the correct answer.

For various interconnected activities taking place in the body, the energy and raw material is provided in the form of food. Therefore, (a) is the correct answer.

The meal that includes all the nutrients namely, carbohydrates, proteins, fats, vitamins and minerals in a required balanced proportion is known as a balanced diet.

Nutrients are substance present in food and essential to life and health. They provide energy, building blocks for repair and growth and are necessary to carry out a chemical process.

Nutrients are substance present in food essential to survive, growth and health. They include macronutrients i.e, consumed in large amounts like carbohydrates, proteins and fats. And micronutrients i.e consumed small amounts like vitamins and minerals.

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 recommended daily intake of carbohydrates for an average adult is typically around 45 to 65 percent of total daily calories, which translates to roughly 225 to 325 grams, but in many educational contexts, 500 grams is cited as a high-end or specific dietary standard.

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.

• Raw potato contains approximately 17% starch. when iodine solution added to the raw potato sample, it turns blue-black. Iodine reacts with the starch present in the raw potato which results in the formation of blue-black colored complex. 

When two drops of copper sulphate and ten drops of caustic soda or NaOH is added to egg, it turns violet. This indicates the presence of proteins.
This is Biuret's test and the principle is simple as follows:
In the presence of alkaline medium (caustic soda or NaOH), the Cu2+ ions get reduced to Cu+ and binds to the egg proteins, thereby giving a violet color.
Therefore, the correct answer is option B.

Shake or crush the food to make it dissolve. Filter or dilute the food and ethanol mix so that you get a clear liquid (a solution of fat in ethanol). Add this to a test tube of water. A white (milk-like) emulsion indicates the presence of fats or oils.

Oils are complex mixtures of various hydrocarbons, primarily triglycerides derived from fatty acids, which are long-chain hydrocarbons.

The iodine test is used to test for the presence of starch. Iodine dissolved in an aqueous solution of potassium iodide reacts with the starch, producing a purple-black colour. The intensity of the colour decreases with increasing temperature and with the presence of water-soluble organic solvents, such as ethanol.

Fats and oils are esters formed by the condensation reaction between glycerol (an alcohol) and three fatty acid molecules (carboxylic acids).

A chemical test for starch is to add iodine solution (red) and see if it turns blue/black in colour. It is possible to distinguish starch from other carbohydrates using this iodine solution test. For example, if iodine is added to an peeled potato then it will turn black. 

The Biuret test is a chemical test used for detecting the presence of peptide bonds. In the presence of peptides, a copper (II) ion forms violet-coloured coordination complexes in an alkaline solution. The Biuret reaction can be used to assess the concentration of proteins because peptide bonds occur with the same frequency per amino acid in the peptide. 

If an animal needed to store energy for long-term use, but not be encumbered with the weight of extra tissue, then high-calorie fat molecules are the best molecules for storage. So, the correct answer is "high-calorie fat molecules".

A.Leaching - the loss of water-soluble plant nutrients from the soil. It does not help in nutrient conservation.

B.Mineralisation – The process of formation of minerals from the organic compounds is called mineralisation. It helps in nutrient conservation.

C.Nitrification – Formation of nitrites or nitrates from ammonia or nitrogenous compounds is called Nitrification. It also helps in nutrient conservation.

D. Immobilisation – elements, cannot be transported from one place to another place in the body is called Immobilisation and the elements are called Immobilised elements.

So, the correct option is ‘Mineralisation or Nitrification’. 

Amylase is a protein enzyme, a polymer of amino acids. Glycogen is homopolysaccharide of D-glucose with highly branched structure (every 8-12 residues as compared to presence of branches in starch for every 24-30 residues). Phopholipids have phosphate and lipids (carbon and hydrogen atoms) while polysaccharides are polymer of simple sugars. RNA is polymer of ribonucleotides. 

Proteins are the building blocks, which takes part in several metabolic reaction. They have four different levels of structure primary, secondary, tertiary and quaternary. There are 20 different standard L-α-amino acids used by cells for protein construction. Amino acids contain both a basic amino group and an acidic carboxyl group. This difunctionality allows the individual amino acids to join together in long chains by forming peptide bonds: amide bonds between the -NH2 of one amino acid and the -COOH of another. Sequences with fewer than 50 amino acids are generally referred to as peptides, while the terms protein or polypeptide are used for longer sequences. A protein can be made up of one or more polypeptide molecules. The end of the peptide or protein sequence with a free carboxyl group is called the carboxy-terminus or C-terminus. The terms amino-terminus or N-terminus describe the end of the sequence with a free α-amino group. The amino acids differ in structure by the substituent on their side chains. These side chains confer different chemical, physical and structural properties to the final peptide or protein.
So, the correct answer is option B.

Amino acids are the building blocks of polypeptide chain or proteins. These are encoded by the triplet codons of mRNA. Each codon synthesizes a specific amino acid. Example: AUG for methionine, UUU for phenylalanine and so on. Amino acids are connected via the peptide bonds to form the proteins.

Proteins are the polymers of amino acids linked with peptide bonds and perform various functions like carrier, enzyme or hormone. It is considered the most diverse molecule and differs from animal to animal. The diversity in proteins occurs due to the R group present which changes with the change in the amino acid.

a) Glycerol has chemical formula of  C$ _3$H$ _8$O$ _3$. 3 OH groups act as binding site. The carboxyl end of the fatty acid combines with the three -OH groups of the glycerol to form ester. The statement is true.

Proteins are large biomolecules, or macromolecules, consisting of one or more long chains of amino acid residues. Amino acids are Linked by peptide bonds to form polypeptide chains. Proteins are linear polymers formed by linking the α-carboxyl group of one amino acid to the α-amino group of another amino acid with a peptide bond (also called an amide bond).

An amino acid is the structural and functional unit of protein and are made up of carbon, hydrogen, oxygen, nitrogen and sometimes sulphur. These are organic acids with a carboxyl group and one amino group.  Amino acid acts as a buffer. 

A green leaf is partially covered and placed in the light for several days. If it is then boiled and tested for starch with iodine starch will be found only in the part of the leaf exposed to light. This is because starch is the end product of photosynthesis. The process of photosynthesis will take place only in the location of leaves where light is present. 

Starch is an important food reserve present in the leaf of the plant. The Iodine test is used to test for the presence of starch. Iodine solution where the iodine dissolved in an aqueous solution of potassium iodide reacts with the starch, producing a purple-black color.