Secrets to Exam Success | "Introduction to Nutrition and Digestion" class 9 level Board Exams and Tests preparation guide

Are you struggling to prepare for your Class 9 level Biology exams? Look no further than our comprehensive Biology Notes on short and conceptual answers to "Introduction to Nutrition and Digestion." In this article, we will cover some of the most important exam short and conceptual questions that are crucial for exam success.

We'll start with the basics, including definitions of nutrition and nutrients, types of nutrients in plants and animals, and the importance of nutrients for living organisms. Next, we'll dive into specific topics like the role of nitrogen and magnesium in plants, the importance of fertilizers for plant growth, and the environmental hazards related to their use.

Moving on to the human body, we'll explore essential vitamins such as Vitamin-A, Vitamin-C, and Vitamin D, as well as important minerals like Calcium and Iron and their roles in maintaining good health. We'll also cover dietary fibers, their types, and their critical functions in the human body.

Other important topics we'll cover include the importance of water, balanced diets, and energy requirements based on age, gender, and activities. We'll also delve into the causes of malnutrition and provide definitions of important terms related to the human digestive system.

Our notes are simple and easy to understand, but they are also comprehensive enough to guarantee high scores on a variety of exams including BISE, Federal Boards examinations, NEET, MDCAT, ETEA, NTS, and many others. With these Biology Notes on short answers to "Introduction to Nutrition and Digestion," you'll be fully prepared to excel on your Class 9 level Biology exams.

Biology Notes for Class 9 level board exams, ETEA, NEET, MDCAT, NTS, on chapter 8 "Introduction to Nutrition and Digestion"

Biology short and conceptual answers Notes on Nutrition and Digestion
From the Notes Library of H.E.S (Health, Education, and Skills)

Define Nutrition and Nutrients.

Nutrition

The process of synthesis of food, its breakdown, and utilization for various functions in the body is called nutrition. (OR)

The process by which an organism gets its food and energy is called nutrition.

Nutrients

The substances which provide nutrition are called nutrients. (OR)

Any substance that can be metabolized by living organisms to give energy and build tissue is called a nutrient.

What are the types of nutrients? Give examples

Types of nutrients

Nutrients are of the following two types

i. Macronutrients

The type of nutrients which are required in large amounts for living bodies is called macronutrients.

For example, C, O, H, N, K, Ca, P, Mg, S, etc. are some of the macronutrients.

ii. Micronutrients

The type of nutrients which are required in a small amount for living bodies is called micronutrients.

For example, Fe, Zn, Mn, B, Mo, Na, etc. are some of the micronutrients.

Shortly State the importance of nutrients.

Importance of nutrients

They provide materials for the repair and growth of cells, tissues, and organs, etc.
They initiate and facilitate life processes, such as locomotion, respiration, reproduction, growth, etc.
They provide different forms of energy such as ATP, heat energy, chemical energy, mechanical energy, etc.
Eating the right foods can help us avoid certain diseases or recover faster when illnesses occur.

Explain the role of nitrogen and magnesium and the symptoms of their deficiency in plants.

i. Role of Nitrogen

Nitrogen is an essential component of proteins, chlorophyll, nucleic acids, enzymes, hormones, and vitamins. Nitrogen metabolism is a major factor in stem and leaf growth. Plants obtain Nitrogen in the form of nitrates and ammonia from the decay of dead animals. Nitrogen also helps in protein synthesis.

Deficiency symptoms of Nitrogen (in plants)

Too much low nitrogen supply can delay flowering and fruiting.
Deficiency of nitrogen in soil cause the yellowing of leaves and stunt growth.

ii. Role of Magnesium

Magnesium is absorbed as Mg⁺² ions from the soil. It is found in chlorophyll molecules as a coordinating ion. It activates plant enzymes to produce carbohydrates and fats. It also affects the process of protein synthesis and photosynthesis.

Deficiency symptoms of Magnesium (in plants)

Its deficiency causes chlorosis, which may lead to cell necrosis.
Yellowing between veins of older leaves.

Write down the importance of fertilizers.

Importance of fertilizers

Most of the soil lacks many nutrients required for the optimum growth of plants. Similarly, once the soil is fertile, then after some time it again requires nutrients because the previous nutrients are now absorbed by plants. Therefore, in order to nourish plants and for normal healthier growth, fertilizers are widely used.

Enlist some of the environmental hazards related to the use of fertilizers.

Environmental hazards related to the use of fertilizers

Increased salinity and soil compaction.
The major risk of groundwater quality from the nutrient application is NO₃ leaching into groundwater sources, this has potential human and animal health concerns.
Its use can cause eutrophication (the addition of more nutrients to water bodies).
Manure pathogens may be transmitted to surface water, which is risky for human and other animal health if consumed.
The odor from manure application can affect air quality.

Write a note on vitamins. What are its two types?

Vitamins

Vitamins are organic compounds that do not produce energy but are required for the growth and normal functioning of our body. They are also essential for general body health and for the prevention and cure of many diseases. All natural vitamins are organic substances found only in plants and animals. With few exceptions, our body cannot synthesize vitamins (called essential vitamins). These essential vitamins must be supplied in the diet.

Types of vitamins

Following are the two types of vitamins on the basis of their solubility i.e.

A. Fat-soluble vitamins

Vitamins A, D, E, and K are fat-soluble vitamins. They stay and store in our body i.e. some for a few days, some for up to six (6) months. They are then used when the body needs them. They are stored in fat tissues and the liver.

B. Water soluble vitamins

Vitamins B and C are water-soluble vitamins. They do not store as much in the body. When they are not used by the body, they are then removed with urine.

Discuss the metabolic functions and deficiency symptoms of Vitamin-A.

Vitamin-A (Chemical name= Retinol)

Vitamin-A is also known as “retinol” because it participates in the functions of the retina of the eye.

Metabolic functions of vitamin-A/ Importance of Vitamin-A

It has a vital role in human immunity.
It also enhances the function of white blood cells (WBC) by increasing the response of antibodies to antigens.
Vitamin-A is best known for its vital role in vision.
It also helps in the maintenance of epithelial and mucosal tissues, growth, reproduction, and bone development.

Sources of Vitamin-A

Plant sources: Mangoes, apricots, oranges, grapefruit, carrot, spinach, pumpkin, sweet potatoes, etc.
Animal sources: Eggs, fish, butter, fish, fish oil, cheese, milk, chicken liver, etc.

Deficiency symptoms of Vitamin-A

Vitamin-A deficiency primarily affects the health of the skin, hair, eyes, and immune system, loss of appetite, bone abnormalities, and growth retardation.
Vitamin-A deficiency also leads to measles, chicken pox, pneumonia, and night blindness, etc.

Explain the metabolic functions, sources, and deficiency symptoms of Vitamin-C.

Vitamin-C (Chemical name= Ascorbic acid)

Vitamin C is a water-soluble vitamin and is known as ascorbic acid.

Metabolic functions/ importance of Vitamin-C

It is needed for the growth and repair of tissues in all parts of the body.
It also helps the body in making collagen, an important protein in skin, cartilage, tendon, ligament, and blood vessels.
It is essential for healing wounds and for repairing and maintaining bones and teeth.
Vitamin C act as an antioxidant along with Vitamin E.

Sources of Vitamin-C

Citrus fruits like oranges, tomatoes, strawberries, grapefruit, guava, lychee, cabbage, etc. are some of the main sources of Vitamin-C.

Deficiency symptoms of Vitamin-C

The deficiency symptoms of Vitamin-C lead to Scurvy disease (a severe deficiency of Vitamin-C).
It also causes dry and splitting hairs, dry and scaly skin, nose bleeding, and a decrease in wound healing rate.
It also causes low blood pressure (hypotension), gall bladder disease, stroke, some cancers, and atherosclerosis.

Write down the metabolic role, sources, and deficiency symptoms of Vitamin D.

Vitamin-D

Vitamin D is a fat-soluble vitamin. It is naturally present in a few food items. Chiefly it is obtained by ultraviolet rays from sunlight.

Metabolic functions/ importance of Vitamin-D

It helps in the absorption of Calcium (Ca). Calcium keeps the bones strong.
It also maintains normal blood levels of Calcium and Phosphorous (P). Phosphorous (a mineral) maintains good teeth and bones.
It also keeps nerves and muscles working properly

Sources of Vitamin-D

Egg yolk, cod liver oil, fortified bread with Vitamin D, fortified cheese, fortified margarine. Striking of ultraviolet rays also produces Vitamin D.

Deficiency symptoms of Vitamin-D

Bones can become thin, brittle, and soft.
Its deficiency causes rickets (a condition in which bones become weak and bow under pressure)in children and osteomalacia (a condition in which bones become soft) in adults.

What are minerals and their sources? Also, define major minerals and trace minerals.

Minerals

Those inorganic substances that originate in the earth and cannot be made in the body of plants and animals are called minerals.

Sources of minerals

We get minerals in organic form from plants and in metallic form from the soil. So our mineral intake is dependent on the mineral contents of the soil. Over the years, there has been a gradual depletion of minerals in the soil due to over-farming. Some key minerals we need are boron (B), calcium (Ca), chloride (Cl), chromium (Cr), copper (Cu), iron (Fe), fluoride (F), iodine (I), selenium (Se), magnesium (Mg), molybdenum (Mo), manganese (Mn) sodium (Na) and zinc (Zn), etc.

Major minerals: Those which are required 100 mg or more per day are called major minerals. Such as Na, F, Cl, Ca, Mg, P, and S.
Trace or minor minerals: Those which are required less than 100 mg per day are called trace or minor minerals. Such as Fe, Zn, Cu, Cr, I, Se, Mn, and Mo.

Discuss the role of calcium. Also, describe its sources and deficiency symptoms.

Role of Calcium (Ca)

Calcium is one of the most important and abundant mineral in the human body.

Functions of Calcium

Calcium plays an important role in the development and maintenance of bones.
Calcium is also needed in tooth formation.
It also plays an important role in blood clotting, the transmission of nerve impulses, muscle contraction, and other metabolic activities.

Sources of Calcium

Dairy products are the major source of calcium, eggs, green leafy vegetables, broccoli, legumes nut, and whole grains. About 99% of the body's calcium is stored in bone tissues. The remaining 1% of the body's calcium circulates in the blood.

Deficiency symptoms

Due to calcium deficiency, the nails become brittle and the skin becomes dry.
Muscle cramping and eye twitching are two other symptoms of calcium deficiency.
Its deficiency also causes osteoporosis.
Its deficiency can also lead to rickets.
In children, deficiency symptoms include bowed legs, sunken or extended chest, and protruding foreheads.

Discuss the role of Iron. Also, describe its sources and deficiency symptoms.

Role of Iron (Fe)

Iron is an important mineral and is found in the hemoglobin of red blood cells. Hemoglobin is a protein that transports oxygen in the form of oxyhemoglobin. Vitamin C helps the body to absorb iron. Women have a higher daily requirement for iron than men.

Functions of Iron

Iron helps in the transport and storage of oxygen.
It also helps the immune system and central nervous system.

Sources of iron

Red meat is the main source of iron. Other sources are meats, fish, beans, spinach, dried fruit, etc.

Deficiency of iron

Low iron intake can cause iron deficiency anemia. Anemia is a disease characterized by a low level of iron in the blood.
Other symptoms are fatigue, weakness, rapid heartbeat, fainting, and swelling of the tongue.

What are dietary fibers? Also, discuss their types and importance.

Dietary fibers

Dietary fibers are also known as roughage or bulk. They are part of the food that cannot be digested and absorbed to produce energy. it is found only in plant food. It moves unchanged through the digestive tract into the colon i.e. it is indigestible.

Types of dietary fibers

Following are the two types of dietary fibers i.e.

Insoluble dietary fibers: It does not dissolve in water and moves quickly through the small intestine e.g. wheat, grain bread, cereals, and the skin of many fruits and vegetables.
Soluble dietary fibers: It breaks down as it passes through the digestive tract and forms a gel that traps some substances that are beneficial in lowering cholesterol, stabilizing blood sugar, and affecting nutrient absorption e.g. oat, barley, many fruits, and vegetables.

Importance of dietary fibers

It prevents and relieves constipation by stimulating the movement of intestinal muscles, increasing stool bulk, and making stools softer and easier to pass.
It also controls weight by creating a feeling of fullness without adding many calories to the diet.

Write down the importance of water in living bodies.

Importance of water

Water is the most abundant substance in our body i.e. 70% by weight (while 25% is protein and 5% is minerals). It is a component of everything except tooth enamel and bone. Water performs many functions such as
Most of the reactions in our body will not take place unless the reactants are dissolved. For example, the water component of blood dissolves oxygen from the lungs and in this form, it is then transported to cells.
CO₂ is also get dissolved in water, then reaches the lungs for expiration.
Almost every cell of the body is surrounded by interstitial fluid which is almost water.
Most of the molecules of the body are suspended in water and are thus able to react with other molecules.
Water regulates body temperature.
The digestive tract uses about 10 liters of water per day. Much of this is reabsorbed, however, a certain amount is replenished.
It also acts as a lubricating medium. It is the main part of mucus, saliva, and other lubricating fluids.
Water also helps to remove nitrogenous wastes and other toxic substances from the blood in the kidney.
Water keeps the body tissues moist.

What is a balanced diet? Also, describe the importance of a balanced diet.

Balanced diet

A diet that contains the necessary components of food i.e. carbohydrates, proteins, fats, vitamins, mineral salts, water, and fibers, in correct proportion is called a balanced diet.

A balanced diet ensures normal and optimum health i.e. less illness and more energy. Food lacking enough energy results in a tired body and too much energy-containing food results in being overweight. This diet should be a balanced, so-called balanced diet.

Importance of a balanced diet

We must have all the basic food components in the correct proportion. For example, if there are not enough proteins, we will not be able to grow properly. Similarly, if we don’t have enough energy containing food, we will become weak.

Discuss energy requirements with age, gender, and activities.

Energy requirements

The energy requirement of an individual depends on his/her lifestyle, age, sex, height, weight, occupation and state of health, etc. A young boy of about 15 years requires more calories (a measuring unit for energy requirement) of energy than an adult man who does not do any work.

I. Relationship of energy requirement with age

During growth, new cells are formed at a greater rate and cells expend more energy. so the body needs food that contains more energy. Children of age 13-15 years need more energy per kilogram of body weight than adults. Similarly, children need more calcium and iron for their growing bones and red blood cells respectively.

II. Relationship of energy requirement with gender

Women have a comparatively lower metabolic rate than men of the same age and weight. So, men need food that provides more energy.

III. Relationship of energy requirement with activity

A man with sedentary habits does not require much energy as a man who remains physically active for most of the day.

What are the causes of malnutrition?

Causes of malnutrition

Malnutrition has many causes, some of which are given as

Malnutrition occurs due to a lack of knowledge regarding the right food.
The poor absorption power of the body can also lead to malnutrition.
Poverty is among the most common cause of malnutrition.
Famine is also another leading cause.
Unequal distribution of food.
Drought and flooding also cause malnutrition.

Define digestion and what is its importance? Also, define some of the basic terms used in the description of the human digestive system.

Digestion

The conversion of large, complex, non-diffusible, and insoluble food into small, simple, diffusible, and soluble forms by the action of enzymes is called digestion.

Importance of digestion

Life processes need energy and this energy is provided by the digestion of food. The food we eat is a raw material that is processed by our digestive system so that the necessary energy-containing compounds needed by the body are extracted from it and made available to the body.

The following processes take place in digestion

Mechanical digestion: The breakdown of food by the action of teeth and mouth muscles is called mechanical digestion.
Chemical digestion: The breakdown of food by the action of enzymes (like amylase, pepsin, lipase, etc.) is called chemical digestion.
Ingestion: The taking of food into the body through the mouth is called ingestion.
Absorption: The uptake of soluble and diffusible food from the digestive tract into the cell or blood is called absorption.
Assimilation: The utilization of digested food material for a new mass of protoplasm is called assimilation.
Egestion: The removal of undigested food from the body is called egestion.

Discuss some disorders of the gut.

Disorders of gut

Any defect that occurs in the digestive system is called a disorder of the gut. Some common digestive system disorders are

i. Constipation

The condition in which the feces become dry hard, and defecation occurs irregularly and difficult is known as constipation.

Constipation reduces the frequency of bowel movement to less than three stools a week, but the frequency may vary from person to person.

Symptoms of constipation

Passing hard stool three times a week or less.
Unusual straining at stool.
Abdominal bloating or discomfort.
May also cause depression, headache, and inflammation of blood vessels in the anus.

Causes of constipation

Frequent use of spicy food.
Insufficient fluid intake.
Excessive use of foodstuff tends to create dryness of mucus membranes.

Prevention and treatment

Increase your intake of liquid.
Eating fibrous food like cereals, vegetables, and fruits.
Avoid junk food.
Don’t postpone using the toilet just because you are busy, otherwise, the stool will start becoming hard.
Use of laxative medicines.

ii. Diarrhea

The passage of watery stools (containing water, half-digested food, and having a specific smell) with abnormal frequency is called diarrhea.

It can lead to a severe deficiency of water and salts in the body, called dehydration. Dehydration is dangerous in children and older persons.

Symptoms of diarrhea

Diarrhea cause dehydration, and loss of minerals, which lead to kidney failure.
It causes weakness and disturbs the contraction of muscles (heart muscles) due to an imbalance of salt in the blood.
Abdominal pain, bloating nausea, or urgent need for the toilet are other common causes.

Causes of diarrhea

Diarrhea is usually related to a bacterial, viral or parasitic infection e.g. bacteria include salmonella and Escherichia coli. Parasites like Entamoeba and histolytic (histo= tissue, lytic = breakdown) like rotavirus.

Prevention, control and treatment of diarrhea

Water should be boiled before use.
Unhygienic food and water should not be consumed.
ORS (oral rehydration solution) is most commonly prescribed in order to balance water, salts, and electrolyte imbalance.
Electrolytes and salts can also be replaced naturally by taking fruit juices, soups, and vegetables.
Antibiotics (such as ciprofloxacin) should be used.

iii. Ulcers

An ulcer is a small erosion (hole) in the gastrointestinal tract. The inner wall of the digestive tract (stomach + duodenum) is covered with mucous to protect it from enzymes; when the mucus breakdown, the digestive enzyme eats away the wall of the stomach or duodenum. The most common types are

Duodenal ulcer: The ulcer that occurs in the first part of the small intestine beyond the stomach is called a duodenal ulcer.
Gastric ulcer: Ulcers that form in the stomach is called a gastric ulcer.

Symptoms

Burn feeling in the stomach that lasts between 30 minutes and 3 hours. This condition is commonly known as heartburn, indigestion, or hunger.
The patient feels stomach pain, abdominal pain, and blood in feces.
Appetite and weight loss are other symptoms.

Causes and prevention/ control

The main cause of the breakdown of the mucosa layer are bacteria, drugs (such as NSAIDs), cigarette smoking, and prolonged tension.
Coffee, tea, soft drinks, and acidic food should be minimized.
Take green vegetables instead of fast and spicy food.

Treatment of ulcer

Use of alkaline medicines (such as ENO).
Drugs used for stomach wall protection (such as omeprazole).
Use of antibiotics.

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