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Table of Contents
Nutrition is the biochemical and physiological method by which an organism uses food to help its life. It includes ingestion, absorption, assimilation, biosynthesis, catabolism, and leaving. The science that studies the physiological process of nutrition is called nutritional science.
Q.1) What are the effects of the lack of nitrate and magnesium ions on plant growth?
Answer: Role of nitrogen in plant growth: Plants get nitrogen in the form of nitrates. Nitrogen is a major component of proteins, hormones, chlorophyll, vitamins, and enzymes essential for plant life. Nitrogen metabolism is a major factor in stem and leaf growth. An adverse effect of nitrates: Deficiencies of nitrogen can reduce yields and cause yellowing of leaves and stunt growth. Too much nitrogen can delay flowering and fruiting. Role of magnesium in plant growth: Magnesium is a structural component of chlorophyll. It is also necessary for the functioning of plant enzymes to produce carbohydrates, sugars, and fats. It is used for fruit and nut formation and is essential for seed germination. Deficiency of nitrogen: The deficiency of magnesium causes yellowing and wilting of leaves.
Q.2) How are inorganic and organic fertilizers important in agriculture?
Answer: Fertilizers: Fertilizers are natural or artificial substances containing chemical elements that improve the growth and productiveness of plants. Fertilizers enhance the natural fertility of the soil or replace the chemical elements taken from the soil by previous crops. Classification of fertilizers: Fertilizer is broadly classified as organic or inorganic. 1- Organic fertilizers: Organic fertilizers are derived from plant and animal materials. They are more complex and take time to be broken down into forms usable by plants. Manure and compost are used as organic fertilizers. Agricultural benefits of organic fertilizers:
Organic fertilizers improve the structure of a soil
Organic fertilizers help to retain soil moisture and increase aeration
They release nutrients slowly and consistently
There is less risk of leaching
Increase the ability of the soil to hold nutrients
2- Inorganic fertilizers: Naturally occurring inorganic fertilizers include rock phosphate, elemental sulfur, and gypsum. These are not chemically modified. If nitrogen is the main element, they are called nitrogen fertilizers. Agricultural importance of inorganic fertilizers:
Higher and accurate amount of nitrogen promotes protein and chlorophyll synthesis and encourages the growth of stem and leaves
Most inorganic fertilizers dissolve readily in water and are immediately available to plants for uptake.
Higher amounts of phosphorous results in more flowers, larger fruits, and healthier roots.
Proteins play an important role in building cellular protoplasm, muscles, and connective tissues. Proteins are also required for making enzymes, hormones, and antibodies.
Milk Butter Cheese Eggs Fish Coconut Dry fruits
Lipids are used to form membranes, the sheaths surrounding neurons, and certain hormones. Lipids are extremely useful energy resources.
Q.4) How are vitamins A, C and D important in our diets?
Answer: 1- Vitamin A: Vitamin A was the first fat-soluble vitamin identified (in 1913). It combines with a protein called opsin to form rhodopsin in rod cells of the retina of the eye. Sources of vitamin A: Humans get vitamin A from leafy vegetables (spinach, carrots), yellow/orange fruits (mango). liver, fish, egg, milk, butter etc. The function of vitamin A:
When vitamin A is inadequate, the lack of rhodopsin makes it difficult to see in dim light.
It is also involved in cell differentiation, a process through which embryonic cells transform into mature cells with specific functions.
Vitamin A also supports bone growth and immune functions.
One of the symptoms of vitamin-A deficiency is night blindness. It is a temporary condition, but if left untreated it can cause permanent blindness.
Vitamin-A deficiency can also cause a condition in which hair follicles become clogged with keratin, giving dry texture to the skin.
2- Vitamin C: (Ascorbic Acid): Source of Vitamin C: Minute quantities of vitamin C are present in muscles since meat consists of muscles so it is not a good source of vitamin C. Main source of vitamin C is citrus fruits (e.g. oranges, lemons, and grapefruit), leafy green vegetables, beef liver etc. Function of vitamin C: Vitamin C participates in many reactions.
It is needed to form collagen (a fibrous protein) that gives strength to connective tissues.
Collagen is also needed for the healing of wounds.
Vitamin C in white blood cells enables the immune system to function properly.
Deficiency of vitamin C: Deficiency of vitamin C causes connective tissue changes throughout the body. The disease is known as scurvy results from lack of vitamin C. In this condition the synthesized collagen is unstable. Symptoms of scurvy include muscle and joint pain, swollen and bleeding gums, slow-wounds healing, and dry skin. 3- Vitamin D: The best-known function of vitamin D is to help regulate blood levels of calcium and phosphorous. Function of Vitamin D: Vitamin D increases the absorption of these minerals from the intestine and their deposition in bones. Sources of vitamin D:
Vitamin D is mainly found in fish liver oil, milk, ghee, and butter etc.
It is also synthesized by the skin when ultraviolet (UV) radiations from the Sun are used to convert a compound into vitamin D.
Deficiency of vitamin D:
Long-term deficiency of vitamin D affects bones. In children, vitamin-D deficiency leads to rickets, a condition in which bones weaken and bow under pressure.
In adults, vitamin-D deficiency causes osteomalacia or softening of bones, increasing the risk of fractures in bones.
Q.5) Which foods contain calcium and iron and what role these minerals play in our bodies?
Answer: 1- Calcium: Sources of calcium: Humans get calcium from milk, cheese, egg yolk, beans, nuts, cabbage, etc. Role of calcium:
Calcium is essential for the development and maintenance of bones and teeth.
It is also needed for maintaining cell membranes and connective tissues and for the activation of several enzymes.
Calcium also aids in blood clotting.
Deficiency of calcium: Deficiency of calcium causes the spontaneous discharge of nerve impulses which may result in tetany. Bones also become soft, blood clots slowly and wounds heal slowly.
2- Iron: Sources of iron: Humans get iron from red meat, egg yolk, whole wheat, fish, spinach, mustard, etc. Role of iron:
Iron plays a major role in oxygen transport and storage. It is a component of haemoglobin in red blood cells and myoglobin in muscle cells.
Cellular energy production also requires iron.
It acts as a cofactor for many enzymes of cellular respiration.
Iron also supports immune function.
Deficiency of iron: Its deficiency is the most common nutrient deficiency worldwide. Iron deficiency causes anemia.
Q.6) Why are water and dietary fibers considered important in our diets?
Answer: Water: Approximately 60% of the adult human body is composed of water. Importance of water: Nearly all life-sustaining chemical reactions require an aqueous (watery) environment. Water also functions as the environment in which water-soluble foodstuff is absorbed in the intestines and the waste products are eliminated in urine. Another essential role of water is to maintain body temperature through evaporation, as in sweating. Severe dehydration may result in cardiovascular problems. The estimated water requirement of an average adult is two liters per day. Source of water: Important sources of daily water intake are natural water, milk, juicy fruits, and vegetables. 2- Dietary fiber: Dietary fiber (roughage) is the part of human food that is indigestible. It is found only in plant foods and it moves undigested through the stomach and small intestine and into the colon. i- Insoluble dietary fibre: The insoluble dietary fibre travels quickly through the small intestines. Its sources are wheat bran, cereals, and skins of many fruits and vegetables. ii- Soluble dietary fibre: The soluble dietary fibre breaks down as it passes through the alimentary canal. Its sources are oats, beans, barley, and many fruits and vegetables. Importance of dietary fibres: Fibre prevents and relieves constipation by stimulating the contraction of intestinal muscles. Avoiding constipation reduces the risk of many other diseases. Soluble fibre helps in lowering blood cholesterol and sugar levels. Insoluble fibre speeds up the movement of carcinogens (cancer-causing agents) from the intestine.
Q.7) Define balanced diet. How would you relate it with age, gender and activity?
Answer: Balanced diet: “A diet consisting of a variety of different types of food and providing adequate amounts of the nutrients necessary for good health is termed as a balanced diet.” “Or” “The food which contains all the essential nutrients in the correct proportion for the normal growth and development of the body.” Humans require various types of nutrients in order to keep themselves healthy and fit. These nutrients should be taken appropriately in a diet. A balanced diet is related to one’s age, gender, and activity. It should include different types of nutrients and should be according to the energy requirements. The following chart shows some of the common foods, taken in Pakistan, and the percentage of carbohydrates, lipids, and proteins in each of them.
Common foods and the percentage of nutrients
Relation of a balanced diet with age, gender, and activity: During the growth period of the body, there is a higher metabolic rate in body cells and so the body needs a balanced diet that contains more energy. Adults need fewer proteins per kilogram body weight, but a growing boy or girl needs more proteins per kilogram weight. Similarly, children need more calcium and iron for their growing bones and red blood cells respectively. Gender has an impact on the requirements of a balanced diet. Women have comparatively less metabolic rates than men of the same age and weight. So men need a balanced diet that provides comparatively more energy. Different people have different lifestyles and varied nature of work. A man with sedentary habits does not require as much energy as a man who is on his feet for most of the day.
Estimated Calorie Requirements (in kilocalories) for Each Gender and Age Group at Three Levels of Physical Activity.
1,000 – 1,400
1,000 – 1,400
4 – 8
1,400 – 1,600
1,400 – 1,800
1,600 – 2,000
1,800 – 2,000
2,000 – 2,200
2,000 – 2,200
1,400 – 1,600
1,600 – 2,000
1,800 – 2,200
2,000 – 2,600
2,400 – 2,800
2,800 – 3,200
2,600 – 2,800
2,400 – 2,600
2,800 – 3,000
2,200 – 2,400
2,400 – 2,800
Q.8) Describe how protein-energy malnutrition, mineral deficiency disease and over intake of nutrients are the major forms of malnutrition?
Answer: Malnutrition: “Malnutrition is a condition that results from eating a diet in which one or more nutrients are either not enough or are too much such that the diet causes health problems.” Malnutrition often refers to undernutrition resulting from inadequate consumption, poor absorption, or excessive loss of nutrients. Malnutrition also includes over-nutrition, resulting from overeating or excessive intake of specific nutrients. Most commonly, malnourished people either do not have enough calories in their diet, or eat a diet that lacks protein, vitamins, or trace minerals. Malnutrition weakens the immune system, impairs physical and mental health, slows thinking, stunts growth and affects fetal development.
Types of malnutrition:
Common forms of malnutrition include:
1- Protein-energy malnutrition (PEM) 2- Mineral deficiency disease (MDD) 3- Over-intake of nutrients (OIN).
1- Protein-energy malnutrition: Protein-energy malnutrition means inadequate availability or absorption of energy and proteins in the body. It is the leading cause of death in children in developing countries. It may lead to diseases such as Kwashiorkor and marasmus. i- Kwashiorkor: Kwashiorkor is due to protein deficiency at the age of about 12 months when breastfeeding is discontinued. It can also develop at any time during a child’s growing years. Children may grow to normal height but are abnormally thin. ii- Marasmus: Marasmus usually develops between the ages of six months and one year. Patients lose all their body fat and muscle strength and acquire a skeletal appearance. Children with marasmus show poor growth and look small for their age. 2-Mineral deficiency diseases: i- Goiter: Goiter is a condition caused by an insufficient amount of iodine in the diet. Iodine is used by thyroid gland to produce hormones that control the body’s normal functioning and growth. If sufficient iodine is not available in a person’s diet, thyroid gland becomes enlarged and it results in swelling in the neck. This condition is known as goiter. ii. Anemia: Anemia is the most common of all mineral deficiency diseases. The term anemia literally means a lack of blood. It is caused when the number of red blood cells is reduced than the normal. Haemoglobin molecule contains a single atom of iron at its center. If the body fails to receive sufficient amounts of iron, adequate number of haemoglobin molecules are not formed. In this case, there are not enough functioning of red blood cells. The patient is weak and there is a shortage of oxygen supply to the body’s cells. 3- Over-Intake of Nutrients Over-intake of nutrients (OIN) is a form of malnutrition in which more nutrients are taken than the amounts required for normal growth, development, and metabolism. The effects of over-intake of nutrients are usually intensified when there is a reduction in daily physical activity (decline in energy expenditure). Health problems related to over-intake of nutrients: Over-intake of nutrients causes a number of health problems. For example, a high intake of carbohydrates and fats leads to obesity, diabetes, and cardiovascular problems. Similarly, a high dose of vitamin A causes loss of appetite and liver problems. Excess intake of vitamin D can lead to deposition of calcium in various tissues. Effects of malnutrition: An extended period of malnutrition can lead to problems like starvation, heart diseases, constipation, and obesity. a- Starvation: Starvation is a severe reduction in nutrient and energy intake and is the most horrible effect of malnutrition. In humans, prolonged starvation causes permanent organ damage and eventually results in death. b- Heart disease: Heart diseases are also increasing on the global level. One of the causes of heart diseases is malnutrition. People who take unbalanced diet (high in fats) are more exposed to heart problems. c- Constipation: Malnutrition often leads to situations where people cannot schedule their meals. This irregularity results in many health problems including constipation. d- Obesity: Obesity means becoming over-weight and it may also be due to malnutrition. People who take food that contains energy more than their requirement and do very little physical work can become obese. Obesity is known as the mother-disease and may lead to heart problems, hypertension, diabetes etc
Q.9) How would you advocate the unequal distribution of food as the major factor that contributes to famine?
Answer: Famine: “A famine is a widespread scarcity of food, caused by several factors including war, inflation, crop failure, and population imbalance.” “Or” “Famine means the lack of enough food to feed all people living in an area.” Major causes of famine: The major causes of famine are an unequal distribution of food, drought, flooding or increasing population. 1- Unequal distribution of food: The achievements in science have enabled human beings to produce better food in terms of quality and quantity. Today the agricultural practices produce more than enough food that can be supplied to everyone on the Earth. But due to political and administrative problems, food is not equally distributed to different regions of the world. The result is that there is always surplus food in countries like America, UK, and Canada etc. and at the same time people have nothing to eat in countries like Ethiopia, Somalia etc. 2- Drought: A drought is a period of time when there is not enough water to support agricultural and human needs. Drought is usually due to a long period of below-normal rainfall. Droughts decrease or even stop the crop yields and it results in famine. 3- Flooding: Flooding occurs due to more than normal rainfall or due to weak water distribution system. Rivers and canals overflow their banks and destroy the soil quality of agricultural lands. It becomes impossible to grow crops immediately after flooding. In this way, flooding may be a reason for short-term famine. 4- Increasing population: In spite of the global increase in food production, millions of human beings are undernourished. In the over-populated regions of the world, large populations overuse natural resources to grow maximum food in order to meet the problems of food shortage. It leads to dry and infertile lands and depletion of resources. In such situations, crops can no longer be grown and famines result.
Q.10) Describe the structures and functions of the main regions of the alimentary canal.
Answer: Alimentary canal: “Alimentary canal is the whole passageway along which food passes through the body from mouth to anus during digestion.” It is part of the digestive system. The digestive system also includes the liver and the pancreas.
Regions of the alimentary canal: The main regions of the alimentary canal and associated organs are:
1- Mouth, salivary glands
5- Small intestine (duodenum + ileum)
6- Large intestine (colon +rectum)
1- Oral cavity (Selection, grinding, partial digestion): The oral cavity is the space behind the mouth and has many important functions in the whole process of digestion. Function of oral cavity: i- Food selection: Food selection is one of them. When food enters the oral cavity, it is tasted and felt. The senses of smell and vision also help the oral cavity in the selection of food. ii- Grinding of food: The second function of the oral cavity is the grinding of food by teeth. It is known as chewing or mastication. This is useful because the esophagus can pass only small pieces. Enzymes also cannot act on large pieces of food. They require small pieces with large surface areas to attack.
iii- Lubrication and chemical digestion: The third and fourth functions of the oral cavity are lubrication and the chemical digestion of food. The chewing process stimulates the three pairs of salivary glands (under the tongue, behind jaws, and in front of ears) to release a juice called saliva in an oral cavity. Saliva adds water and mucous to food which acts as a lubricant to ease the passage of food through the esophagus. Saliva also contains the enzyme salivary amylase, which helps in the semi-digestion of starch. During the processes of chewing, lubrication, and semi-digestion, the pieces of food are rolled up by the tongue into a small, slippery, spherical mass called a bolus. The bolus is swallowed and push it in the esophagus through the pharynx.
2- Pharynx: During swallowing, bolus is pushed to the back of the mouth by the tongue. When the tongue pushes the bolus, the soft palate also moves upward and to rear. In this way, the opening of nasal cavity is closed. When swallowed, the bolus passes pharynx to enter oesophagus. Pharynx has adaptations to prevent the entry of bolus particles in trachea (wind pipe to lungs). During swallowing, larynx (the top of the trachea) moves upward and forces the epiglottis (a flap of cartilage) into horizontal position. Thus glottis i.e. the opening of the trachea is closed. The beginning of swallowing action is voluntary, but once food reaches the back of mouth, swallowing becomes automatic. 3- Oesophagus: After being swallowed, food enters the tube called oesophagus, which connects pharynx to the stomach. Neither pharynx nor oesophagus contributes to digestion and the previous digestive actions of saliva continue.
4- Stomach:- Stomach is a dilated part of alimentary canal. It is J-shaped, located in the left of abdomen, just beneath the diaphragm. Parts of stomach: Stomach has two main portions. The cardiac portion of the stomach is present immediately after oesophagus and pyloric portion is located beneath cardiac portion.
Stomach muscles: Stomach has two sphincters (openings which are guarded by muscles). Cardiac sphincter is between stomach and oesophagus while pyloric sphincter is between stomach and small intestine. Bolus enters stomach from oesophagus through cardiac sphincter.
Function of stomach: Gastric juice in stomach: When food enters stomach, the gastric glands found in the stomach wall are stimulated to secrete gastric juice. Gastric juice is composed chiefly of mucous, hydrochloric acid, and a protein-digesting enzyme pepsinogen. Hydrochloric acid converts the inactive enzyme pepsinogen into its active form i.e. pepsin. HCl also kills microorganisms present in food. Pepsin partially digests the protein portion of food (a bulk of mutton) into polypeptides and shorter peptide chains.
Churning: In the stomach, food is further broken apart through a process of churning. The walls of stomach contract and relax and these movements help in thorough mixing of gastric juice and food. The churning action also produces heat which helps to melt the lipid content of food. Chyme: Chyme is the pulpy acidic fluid which passes from the stomach to the small intestine, consisting of gastric juices and partly digested food. After it, the pyloric sphincter allows a little mass of chyme to enter duodenum. 5- Small Intestine: i- Duodenum: Duodenum comprises of the first 10 inches (25 cm) of small intestine and it is the part of alimentary canal where most of the digestive process occurs. Process of complete digestion in small intestine: In small intestine, food is further mixed with 3 different secretions:
Bile from liver helps in the digestion of lipids through emulsification i.e. by keeping the lipid droplets separate from one another.
Pancreatic juice from pancreas contains enzymes trypsin, pancreatic amylase, and lipase which digest proteins, carbohydrates and lipids respectively.
Intestinal juice from intestine walls contains many enzymes for the complete digestion of all kinds of food.
ii- Jejunum: Next to the duodenum is 2.4 meters long jejunum. It is concerned with the rest of the digestion of proteins, carbohydrates, and lipids of food. iii- Ileum: Last 3.5 meters long part of small intestine is ileum. It is concerned with the absorption of digested food.
Function of small intestine (Absorption of food): There are circular folds in the inner wall of the ileum. These folds have numerous finger-like projections called villi (singular: villus). Villi increase the surface area of the inner walls and it helps a lot in the absorption of digested food. Each villus is richly supplied with blood capillaries and a vessel of the lymphatic system, called lacteal.
The walls of villus are only single-cell thick. The digested molecules i.e. simple sugars and amino acids are absorbed from the intestine into the blood capillaries present in villi. Blood carries them away from small intestine via the hepatic portal vein and goes to the liver for filtering. Here, toxins are removed and extra food is stored. From the liver, the required food molecules go towards heart via the hepatic vein. Fatty acids and glycerol, present in the small intestine, are absorbed into the lacteal of villus. Lacteal carries them to the main lymphatic duct, from where they enter in the bloodstream.
6- Large intestine: After the digested products of food have been absorbed in blood, the remaining mass enters large intestine. Parts of small intestine and its functions: It has 3 parts; caecum (or pouch that forms the T-junction with small intestine), colon and rectum. i- Colon: From the colon, water is absorbed into the blood. As water is absorbed, the solid remains of food are called faeces. Faeces mainly consist of the undigested material. A large number of bacteria, sloughed off cells of alimentary canal, bile pigments and water are also part of faeces. ii- Rectum: Faeces are temporarily stored in the rectum, which opens out through the anus. Under normal conditions when the rectum is filled up with faeces, it gives rise to a reflex and anus is opened for defecation. This reflex is consciously inhibited in adults but in infants, it is controlled involuntarily. During growth, the child learns to bring this reflex under voluntary control.
Q.11) Describe swallowing and peristaslsis
Answer: Swallowing: “Swallowing is the process in the humans that make something pass from the mouth, to the pharynx, and into the esophagus, while shutting the epiglottis.” During swallowing, the bolus is pushed to the back of mouth by the tongue. When tongue pushes bolus, the soft palate also moves upward and to rear. In this way, the opening of nasal cavity is closed. When swallowed, the bolus passes pharynx to enter oesophagus. Pharynx has adaptations to prevent the entry of bolus particles in the trachea (windpipe to lungs). During swallowing, larynx (the top of the trachea) moves upward and forces the epiglottis (a flap of cartilage) into a horizontal position. Thus glottis i.e. the opening of the trachea is closed. The beginning of swallowing action is voluntary, but once food reaches the back of the mouth, swallowing becomes automatic. ii- Peristalsis: “Peristalsis is a wave of contraction and relaxation in the smooth muscles of alimentary canal walls.” In much of a digestive tract such as the human gastrointestinal tract, smooth muscle tissue contracts in sequence to produce a peristaltic wave, which propels a ball of food (called a bolus while in the esophagus and upper gastrointestinal tract and chyme in the stomach) along the tract. Peristaltic movement comprises relaxation of circular smooth muscles, then their contraction behind the chewed material to keep it from moving backward, then longitudinal contraction to push it forward.
Q.12) Briefly give the signs and symptoms causes, treatments and preventers of diarrhoea, constipation, and ulcer”
Answer: 1- Diarrhoea: “Diarrhoea is a condition in which the sufferer has frequent watery, loose bowel movements, accompanied by abdominal pain, nausea, and vomiting.” Signs and symptoms: The patient suffers from frequent watery, loose bowel movements, accompanied by abdominal pain, nausea, and vomiting Cause of diarrhoea: It occurs when required water is not absorbed in blood from colon. The main causes of diarrhoea include lack of adequate safe water. Diarrhoea is also caused by viral or bacterial infections of large intestine. If sufficient food and water is available, the patient of diarrhoea recovers in a few days. However, for malnourished individuals diarrhoea can lead to severe dehydration and can become life-threatening. Treatment: The treatment for diarrhoea involves consuming adequate amounts of water (to replace the loss), preferably mixed with essential salts and some amount of nutrients. Antibiotics may be required if diarrhoea is due to bacterial infection. Preventive measures: Preventions of diarrhoea include taking clean water and essential salts, eating regularly and taking hygienic measures.
2- Constipation: “Constipation is a condition where a person experiences hard faeces that are difficult to eliminate.” Causes of constipation: The main causes of constipation include excessive absorption of water through the colon, insufficient intake of dietary fiber, dehydration, use of medicines (e.g. those containing iron, calcium, and aluminum) and tumors in rectum or anus. Treatment: Treatment of constipation is with a change in dietary and exercise habits. The medicines called laxatives (e.g. paraffin) are used for treatment. Constipation is usually easier to prevent than to treat. One should take the required quantities of water and dietary fibers.
3- Ulcers: “Ulcer (peptic ulcer) is a sore in the inner wall of the gut (in oesophagus, duodenum or stomach).” In ulcer, the acidic gastric juice gradually breaks down the tissue of the inner wall. Ulcer of the stomach is called gastric ulcer. Causes of ulcer: The causes of an ulcer include excess acid, infection, long-term use of anti-inflammatory medicines (including aspirin), smoking, drinking coffee, colas, and eating spicy foods. Signs and symptoms: The signs and symptoms of ulcer include abdominal burning after meals or at midnight. Severe ulcers may cause abdominal pain, a rush of saliva after an episode of regurgitation, nausea, loss of appetite and weight loss. Treatment: The ulcer is treated with medicines, which neutralize the acidic effects of gastric juice. Spicy, acidic foods and smoking should be avoided as preventive measures
Science , Technology And Society
Q.1) Explain why farmers use chemical fertilizers for better growth of their plants.
Answer: Chemical fertilizers: Chemical fertilizers are artificial fertilizers manufactured in industries. They are prepared from water-soluble salts. Various examples of chemical fertilizers are sulfate, ammonium phosphate, potassium sulfate, etc. They provide various types of nutrients like nitrogen, potassium, etc.
They provide the necessary nutrient for the proper growth of plants.
They are water soluble so the plant can easily absorb them.
They increase the fertility of the soil.
They are cheaper than organic fertilizers.
The population of the world is increasing day by day. For this growing population, plenty of crops should be produced, and to fulfill the needs of the growing population, the farmers use various fertilizers in agriculture for more productive food crops. Due to the constant use of land for the production of crops, the fertility of the soil goes on decreasing. This decrease in fertility of soil results in less production or loss of the plants due to fewer nutrients for the production of crops.
Q.2) Describe ways in which research about nutrition has brought about improvements in human health (e.g., development of nutritional supplements, and diets based the needs of the age, gender, and activity).
Answer: A diet consisting of a variety of different types of food and providing adequate amounts of the nutrients necessary for good health is termed a balanced diet. Research in science, especially in food technology and nutritional supplements, has revolutionized food biology. Nutritional supplements are products that are made from medicinal plants, natural extracts, traditional foods, dehydrated or concentrated fruit, and vegetables, with added vitamins and minerals, or not, that can be presented to the drug style and which aim to increase of certain supplements in a diet intake, increase or supplement them in these specific components.
Humans require various types of nutrients in order to keep them healthy and fit. These nutrients should be taken appropriately in a diet. A balanced diet is related to one’s age, gender, and activity. It should include different types of nutrients and should be according to the energy requirements. During growth period of the body, there is a higher metabolic rate in body cells and so the body needs a balanced diet that contains more energy. Adults need fewer proteins per kilogram body weights, but a growing boy or girl needs more proteins per kilogram weight. Similarly, children need more calcium and iron for their growing bones and red blood cells respectively.
Gender has an impact on the requirements of a balanced diet. Women have comparatively less metabolic rate than men of the same age and weight. So men need a balanced diet that provides comparatively more energy. Different people have different lifestyles and varied nature of work. A man with sedentary habits does not require as much energy as the man who is on his feet for most of the day.
If supplements are used with knowledge and responsibility are a good help to our daily diet. They also help us to balance a bad or poor nutrition, in case that our diet has some nutritional deficiencies, helping us to improve our nutrition. Food supplements are the help offered to the suffering of disease, as some act like shields when developing certain diseases. In this case, we find elements such as iron, which helps in pregnancy or prevents anemia, some vitamins with antioxidant properties are other elements used to prevent the spread of disease.
Q.3) Exemplify the societies suffering from famine due to unequal distribution of food and due to over-population.
Answer: A famine is a widespread scarcity of food, caused by several factors including war, inflation, crop failure, and population imbalance. Unequal distribution of food: The achievements in science have enabled human beings to produce better food in terms of quality and quantity. Today the agricultural practices produce more than enough food that can be supplied to everyone on the Earth. But due to political and administrative problems, food is not equally distributed to different regions of the world. The result is that there is always surplus food in countries like America, UK, and Canada etc. and at the same time people have nothing to eat in countries like Ethiopia, Somalia etc.
Effect of over-population: In over-populated continents like Asia, societies suffer from famine due to unequal distribution of food. Lack of food supply leads to deficiency diseases, and starvation and overpopulation lead to the social diseases of unemployment and poverty. In spite of the global increase in food production, millions of human beings are undernourished. In the over-populated regions of the world e.g. Africa, Asia populations overuse natural resources to grow maximum food in order to meet the problems of food shortage. It leads to dry and infertile lands and depletion of resources. In such situations, crops can no longer be grown and famines result.
Q.4) Explain how the customary food habits contribute to digestive tract disorders (e.g diarrhoea, constipation).
Answer: Customary food habits and health risks: Customary food habits may cause various stomach ailments. The main reason behind these problems is the presence of high acidic content in spicy food. Although spices provide a number of vitamins and nutrients that are present in abundance, too much of these nutrients can be harmful too. Following are the ailments caused by our customary food habits. Acid reflux: Spices are basically a combination of acids. When too much of these acids are introduced into the stomach, which already has its own acidic contents, it starts damaging the walls of the stomach. Diarrhoea: Diarrhoea is another digestive disorder caused by unhealthy food consumption. The main cause of diarrhea is taking food and water which is not hygienic and contains microbes that cause diarrhea. In this condition, the sufferer has frequent watery, loose bowel movements. This condition may be accompanied by abdominal pain, nausea, and vomiting. Gastric ulcer: Spicy food can cause ulcers in the sensitive mucosal lining or in the small intestine, called the duodenum (duodenal ulcer), or either in the esophagus (esophageal ulcer). Gastric ulcers are painful causing burning stomach pain, nausea, vomiting, and weight loss. Constipation: Constipation is a condition where a person experiences hard feces that are difficult to eliminate. The main cause of constipation in our eating habits include junk food like burgers, insufficient intake of dietary fiber present in vegetables and fruits which leads to less peristaltic movement of residue food in the large intestine causing constipation.
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