Q: What are essential and non-essential amino acids? Give two examples of each type.

\$\text {Essential Amino Acids}:\$ Amino acids which can't be created in our body but can only be received from proper food or diet are called \$\text {Essential Amino Acids}\$. Examples- Histidine, Isoleucine, Lysine.\$\text {Non- essential amino acids}:\$ Amino acids which can be created in our body itself are \$\text {Non- essential amino acids}\$. Examples-alanine, arginine, asparagine, aspartic acid. Examples- Histidine, Isoleucine, Lysine.

Question 1

Explain the process of digestion in human beings.

Accepted Answer

Humans have holozoic nutrition, that means the food is consumed as a whole and the digestion occurs internally. It can be described as:1. Ingestion of food- The food is taken in the oral cavity in the process called the ingestion. The teeth help in grinding of the food, salivary amylase helps in partial breakdown of the starch and the tongue helps in mixing the food with saliva and helps in swallowing it. The food is now called bolus.2. Digestion- The process of break-down of complex substances into simpler substances is called digestion and it starts with the mouth where physical break-down occurs along with some chemical digestion. The bolus is swallowed in and it arrives in stomach where the digestion of proteins occurs due to presence of the enzyme pepsin. Bolus is now called the chyme. This chyme now moves into the small intestine where rest of the process of digestion will be completed. The pancreatic juice, the intestinal juice and the bile will result in breakdown of carbohydrates, fats and the rest of the proteins. The chyme is now called the chyle and it moves to the large intestine where the water is absorbed.3. Absorption- The digested food is absorbed via the finger-like projections present on the inner surface of the small-intestine and the reach the blood stream.4. Assimilation- The absorbed food is then used by different tissues for the energy generation. The excess food is stored as glycogen in the liver and s fats in adipose tissue.5. Excretion- The undigested material passes from the small-intestine to the rectum of the large-intestine, from where it is removed from the body through anus.

Question 2

Bile juice contains no digestive enzymes, yet it is important for digestion. Why?

Accepted Answer

Bile is a digestive juice secreted by the liver. Although it does not contain any digestive enzymes, it plays an important role in the digestion of fats. Bile juice has bile salts such as bilirubin and biliverdin. These break down large fat globules into smaller globules so that the pancreatic enzymes can easily act on them. This process is known as emulsification of fats. Bile juice also makes the medium alkaline and activates lipase.

Question 3

What are essential and non-essential amino acids? Give two examples of each type.

Accepted Answer

$\text {Essential Amino Acids}:$  Amino acids which can't be created in our body but can only be received from proper food or diet are called $\text {Essential Amino Acids}$. Examples- Histidine, Isoleucine, Lysine.$\text {Non- essential amino acids}:$ Amino acids which can be created in our body itself are $\text {Non- essential amino acids}$. Examples-alanine, arginine, asparagine, aspartic acid. Examples- Histidine, Isoleucine, Lysine.

Question 4

Explain giving reasons(a) Balanced diet is necessary for maintaining healthy body.(b) Health of an organism depends upon the surrounding environmental conditions.(c) Our surrounding area should be free of stagnant water.(d) Social harmony and good economic conditions are necessary for good health.

Accepted Answer

(a) Food is necessary for the growth and development of the body. A balanced diet provides all the required raw materials and energy in appropriate amount likes proteins, carbohydrates, fats, minerals, etc.(b) Health is a state of being well enough to function well physically, mentally and socially and these conditions depend on the surrounding environmental conditions. For example, if there are unhygienic conditions in surrounding area, it is likely we might get infected or diseased.(c) Our surrounding area should be free of stagnant water. This is so because many waterborne diseases and insect vectors flourish in stagnant water which causes diseases in human beings.(d) Human beings live in societies and different localities like villages or cities, which determines the social and physical environment and hence both are to be kept in harmony. Public cleanliness is important for individual health. For better living conditions lot of money is required. We need good food for healthy body and for this we have to earn more. For the treatment of diseases also, one has to be in good economic condition.

Question 5

What are the functions of gastric glands present in the wall of the stomach?

Accepted Answer

Gastric glands are present in the wall of the stomach which secrete gastric juice containing the digestive enzyme like pepsin, renin, mucus and HCl. The function of these enzymes are as follows:(a) Production of pepsin enzyme that digests proteins.(b) Secretion of mucus for the protection of inner lining of the stomach.(c) Secretion of HCl, which kills the bacteria and foreign harmful organisms in the food. Thus, the correct answer is option D.

Question 6

Give the dental formula of human beings.

Accepted Answer

The dental formula represents the arrangement of teeth in each half of the upper and the lower jaw. The entire formula is multiplied by two to represent the total number of teeth.The dental formula for milk teeth in humans is:Each half of the upper jaw and the lower jaw has 2 incisors, 1 canine, and 2 molars. Premolars are absent in milk teeth  hence the zero.The dental formula for permanent teeth in humans is: Each half of the upper jaw and the lower jaw has 2 incisors, 1 canine, 2 premolars, and 3 molars. An adult human has 32 permanent teeth.

Question 7

Name the following :(a) The nutrients which mainly give energy to our body.(b) The nutrients that are needed for growth and maintenance of our body.(c) A vitamin required for maintaining good eyesight.(d) A mineral that is required for keeping our bones healthy.

Accepted Answer

(a) Carbohydrates are one of the main types of nutrients found in food. They are the most important source of energy for the body of many organisms, including humans. Carbohydrate provides about 4 kcal per gram and is the energy that is used first to fuel muscles and the brain. Fat is also one of the three main macronutrients, along with carbohydrates and protein. Compared to carbohydrates and protein, each gram of fat provides more than twice the amount of calories (9 kcal per gram).  So, the answer is carbohydates and fats.(b) Protein is the major structural component of cells and is responsible for the building and repair of body tissues. Proteins are organic molecules made up of amino acids &#8211; the building blocks of life. These amino acids are joined together by chemical bonds. They do most of the work in cells and are required for the structure, function, and regulation of the body's tissues and organs.So, the answer is proteins.(c) Vitamin A is a fat soluble vitamin that is also a powerful antioxidant. Vitamin A plays a critical role in maintaining healthy vision, neurological function, healthy skin, healthy immune system, and cell growth.So, the answer is vitamin A.(d) Minerals are components of foods that are involved in many body functions. For example, Calcium helps to maintain and build strong bones and teeth So, the answer is calcium.

Question 8

Write two differences between autotrophic and heterotrophic nutrition.

Accepted Answer

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Question 9

Which one of the following is not a characteristic of minerals?

Accepted Answer

An inexhaustible resource is one that is replaceable, while an exhaustible resource is not replaceable.Minerals are natural resources and they cannot be replaced by man.Therefore, the constant use of minerals at this rate will lead to their exhaustion. Thus, they are considered as exhaustible natural resources.

Question 10

What is the role of acid in our stomach?

Accepted Answer

The gastric juice is made up of hydrochloric acid, pepsinogen and other digestive enzymes, gastrin, mucus, and bicarbonates. It has a pH ranging from 1 to 2. Its low pH is essential in activating digestive enzyme such as pepsinogen and convert it into the active pepsin, a Proteolytic activity of pepsin and in destroying various pathogens. Thus, the correct answer is option D.