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BBCET-141: Nutritional Biochemistry

BBCET-141: Nutritional Biochemistry

IGNOU Solved Assignment Solution for 2023

If you are looking for BBCET-141 IGNOU Solved Assignment solution for the subject Nutritional Biochemistry, you have come to the right place. BBCET-141 solution on this page applies to 2023 session students studying in BSCBCH courses of IGNOU.

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Assignment Code: BBCET-141/TMA/2023

Course Code: BBCET-141

Assignment Name: Metabolism of Carbohydrates and Lipids

Year: 2023

Verification Status: Verified by Professor


Marks: 50

Q1) Explain the following terms in 2-4 lines:


(a) Macronutrients.

Ans) Macronutrients are nutrients like carbohydrates, proteins, and fats that our bodies need in large amounts (many grammes per day). Water is also a macronutrient because it makes up between 50 and 65% of the human body.


(b) Estimated average requirements.

Ans) Estimated Average Requirement (EAR) is the level of daily nutrient intake that meets the needs of 50% of healthy people in a certain age and gender group. It is set in the middle of a normal distribution curve.


(c) Dietary guidelines.

Ans) Dietary Guidelines are sets of statements that give advice about what people should eat to improve their overall nutritional health and deal with all conditions that are related to diet. These rules are about making healthy food choices and eating in a healthy way. They are meant to improve your nutritional status and help you change the way you act around food.


(d) Respiratory quotient.

Ans) A certain parameter can give you an idea of the mix of nutrients being used as an energy source. This parameter is found by measuring the amount of oxygen and the amount of carbon dioxide. When each nutrient is broken down, it gives off a set amount of energy and uses a set amount of O2. Along with energy, it also gives off CO2 and H2O in the same amounts. The respiratory quotient of a nutrient is the ratio of how much VCO2 is released to how much VO2 is used when a nutrient is completely broken down in a cell.


Q1) (e) Glucose tolerance test.

Ans) Glucose is the carbohydrate that moves through the blood and is one of the main ways that cells get energy. Glucose levels reach a steady state 8 to 12 hours after the last meal. When you are fasting, a normal glucose level is below 110 mg/dL.


If your blood sugar level when you're fasting is >110mg/dL, this is called impaired fasting glucose. Impaired glucose tolerance is when your blood sugar is normal when you wake up, but it goes up after 2 hours of eating a lot of sugar. Oral glucose tolerance test is done in the morning after about 10 hours of not eating or drinking.


Q2) (a) Explain total energy expenditure of a non- growing individual and its different components.

Ans) The rate at which a living thing uses up energy is called its "metabolic rate." The amount of food a person needs is based on their metabolic rate. The amount of food an adult need depends on their metabolic rate. An individual's energy requirement is the level of energy intake from food that will balance energy expenditure when the person's body size, composition, and level of physical activity are all in line with long-term good health and will allow the person to keep up economic and socially desirable physical activity. In children, women who are pregnant or nursing, and women who are making milk, the energy needs include the energy needed to build up tissues during growth or to make milk at a healthy rate.


Q2) (b) Which different methods are used to measure the energy expenditure of an individual? Explain any one.

Ans) Total energy expenditure can be broken down into three parts: Basal Metabolic Rate or Resting Metabolic Rate, Thermic Effect of Feeding, and Physical Activity Energy Expenditure.


Basal and Resting Metabolism

Basal metabolic rate is the amount of energy a person uses when they are in the thermoneutral zone, fasting, and at rest. The thermo neutral zone is the temperature range where the metabolic rate is the slowest. For fasting to have no effect on SDA in studies of basal metabolic rate, the post-absorptive phase should be long. To measure BMR, a person should be fasting, lying down, and not thinking about anything.


The person should be in a place that is comfortable in terms of temperature and not too brightly lit. During the measurement, the person should be still and calm, and nothing else should be going on. BMR should be measured in the morning, after the person has spent the night at the place where they are being measured.


Q3) (a) Define Z-score. What information does it give about the nutritional status of an individual?

Ans) A graph between a parameter and the number of people for an age or age group, like weight for age, can be used to study a region's human population. A weight's median or mean value shows how many people of that age or age group weigh that much. People in a population have weights that range from the average to the lowest and highest. This difference on either side of the median value shows the range's low and high points. If the graph has a sharp peak, the maximum number of people can be covered with a small deviation from the median. If the graph has a broad peak, the deviation can be large.


A statistical value called standard deviation is used to measure this difference. About 68 percent of the population falls into the median SD range, while about 94 percent fall into the median 2SD range. A person in a group can have a value that is far from or close to the median value. Z-score works out, in multiples of SD, how close an individual value is to the median. Using this score, a person in a group can be put inside or outside of the normal range.


Q3) (b) Write significance of pentose phosphate pathway and uronic acid pathway.


Pentose Phosphate Pathway

Ribose-5-Phosphate is used to make the building blocks of RNA and DNA, called nucleotides. NADPH is a molecule that helps cells make fatty acids and cholesterol. It does this by taking part in a number of reduction reactions.


Uronic Acid Pathway

UDP-Glucuronate is a source of Glucuronate for making Glycosaminoglycans and for reactions that get rid of toxic chemicals that come from outside the body.


Q4) (a) What are the beneficial effects of taking diet rich in fibers?

Ans) Keeping glucose from getting close to intestinal epithelial cells, which slows its absorption. Also, fibres can't be digested, don't give energy, and can hold a lot of water. A diet high in fibre makes you feel full even if you only ate a small amount of food and reduces your hunger. In short, a diet high in fibre keeps you from eating too much, lowers the amount of calories in food, and slows down the digestion of starch and absorption of glucose. All of these help a person with diabetes control their weight and lower their blood sugar after a meal.


Q4) (b) What are essential fatty acids? Explain their metabolic functions.

Ans) Fatty acids are mostly needed by the body to make triacyglycerols, phospholipids, and glycolipids, to connect proteins to the plasma membrane, to get energy, to control gene expression, and to act as local mediators. Most of the time, the body can make most of the fatty acids it needs. But our body can't make linoleic acid or linolenic acid, which come from the w6 and w3 families of fatty acids, respectively.


Since neither of the two fatty acids is saturated, when they are added to phospholipids, they keep the plasma membrane fluid. Second, Linoleic and Linolenic acids' most important job is to make Eicosanoids, which are chemicals that help cells communicate with each other. Linoleic acid from food is changed into arachidonic acid, which is a fatty acid with 20 carbons, 6 bonds, and 4 double bonds.


Q5) (a) Illustrate the role of proteins in transportation of biological molecules with the help of suitable examples.

Ans) Proteins are spread all over the plasma membrane of a cell. These membrane proteins are very important because they move things across the plasma membrane, hold cells together and to the extracellular matrix, and receive signalling molecules.

Biological membranes do not let all substances pass through freely. Large polar molecules and ions can't get through the plasma membrane without help from membrane proteins. Ion channels and membrane transporters are some of the names for these proteins. Transporters bind things on one side of the membrane and let them out on the other. Also, only molecules that are very similar can use the same transporter or channel.



Q5) (b) Explain the digestion and absorption of proteins with the help of a suitable diagram.




Marks: 50


Q6) (a) Explain the biochemical functions of vitamin A.


Biochemical Functions

  1. Retinoic acid works like steroid hormone to control how genes are turned on and off and how tissues change. All-trans retinoic acid and 9-cis retinoic acid are the two biologically active isomers. They are taken to the nucleus of the cell and bind to nuclear receptors, which then bind to response elements in the DNA. This causes that gene to be turned on and mRNA to be made. This will lead to the production of a certain protein that is needed for growth.

  2. Vitamin A is needed for reproduction to go well. All-trans retinoic acid helps both men and women have babies and helps embryos grow and develop. When female rats don't get enough vitamin A, they have miscarriages.

  3. Vitamin A is important for keeping the epithelium and skin healthy. Retinoyl phosphate helps move oligosaccharides across the cell membrane. The oligosaccharides are then used to make glycoproteins, which are needed for mucus production. Mucin is a glycoprotein that is found in mucus. So, when you don't get enough vitamin A, you make less mucus, which causes the epithelial tissues of your eyes, lungs, digestive tract, and genitourinary tract to harden into keratin.


Q6) (b) How is vitamin D important in calcium absorption?

Ans) Calcitriol helps calcium and phosphorus get into the body through the intestine. Calcium is taken in passively through the surface of the brush-border. Energy is needed to move calcium from cells in the gut into the blood. Calcitriol is a hormone called a steroid. Calbindin is made by turning on the genes that make it. Calcium is absorbed better because there are more calcium-binding proteins in the body.


Calcitriol in blood>Enters intestinal cell and binds receptor to form calcitriol receptor complex>Complex binds DNA in nucleus>Induces synthesis of calbindin protein>Calbindin binds calcium from lumen.


Q7) (a) Explain the deficiency diseases of vitamin B3?

Ans) Niacin deficiency in the diet leads to Pellagra disease. Pellagra affects the skin, the digestive system, and the brain and spinal cord. It can cause dermatitis, diarrhoea, and dementia, and if it's not treated, it can kill you. The role of NAD+ in fixing DNA could be linked to skin infections that get worse when exposed to light. Digestive problems can also be caused by a lack of niacin or tryptophan, like in Hartnup disease, which is a genetic disorder of amino acid transport. In this disease, tryptophan is not absorbed in the intestines and is not reabsorbed by the kidneys, which leads to a lack of this amino acid. In India, where jowar (sorghum) is used as a staple, the symptoms are common.


Q7) (b) Give two examples each of NAD and FAD dependent enzymes. Also name the vitamins from which these cofactors are derived.


NAD+ Dependent Enzymes

Carbohydrate Metabolism

  1. Glyceraldehyde-3-phosphate dehydrogenase

  2. Lactate dehydrogenase

  3. Pyruvate dehydrogenase complex

  4. a-ketoglutarate dehydrogenase complex

  5. Malate dehydrogenase

Lipid Metabolism

  1. B (3)-Hydroxybutyrate dehydrogenase

  2. B (3)-Hydroxy acyl CoA dehydrogenase

  3. Alcohol dehydrogenase


FAD Dependent Enzymes

D- amino acid oxidase, Pyruvate dehydrogenase complex, a- ketoglutarate dehydrogenase complex and succinate dehydrogenase. Complex-II of the electron transport chain, Acyl CoA dehydrogenase, xanthine oxidase, and a part of the microsomal hydroxylase system are some of the others. Glutathione reductase needs FAD as a cofactor, so it is an important part of antioxidant activity in cells. Vitamin B6, niacin, and vitamin K can't be broken down without riboflavin.


Q8) (a) Write the biochemical functions of vitamin C and B12.


Biochemical Functions of Vitamin C

Ascorbic acid is made up of the same kind of molecules as hexose sugars. It can be in both the L- and D- forms. However, only L-Ascorbate has vitamin activity and is involved in the following biochemical processes:

  1. It works as an antioxidant to get rid of free radicals that are harmful.

  2. It helps make collagen by making the hydroxylation of proline and lysine happen.


Biochemical Functions of Vitamin B12

Coenzyme B12 is involved in biochemical processes like the transfer of methyl groups and the movement of hydrogen atoms from one group to another. It takes part in the breakdown of fatty acids and the making of DNA. There are two enzymes that can't work without vitamin B12.

  1. Methionine synthase:

  2. L-methylmalonyl CoA mutase: It speeds up the change of methylmalonyl-CoA into succinyl-CoA when vitamin B12 is present. Methylmalonic acid is found in the urine of people who don't get enough vitamin B12 (methylmalonic aciduria).


Q8) (b) How is alcohol consumption associated with nutritional deficiencies?

Ans) Alcohol is not a drug, but it is a popular drink that can affect nutrition in a number of ways if you drink too much of it. It gives 7 calories per gramme but none of the vitamins and minerals. It's a drug that can get you hooked, so you shouldn't use it. If you drink too much alcohol, you might feel sick and lose your appetite. Alcohol makes it harder for the body to absorb sodium and water, which makes it more likely for alcoholics to get diarrhoea. When you drink a lot of alcoholic drinks, your body doesn't absorb nutrients as well as it should. This can happen with vitamins like thiamine, folate, vitamin B6, vitamin A, and zinc. Many metabolic disorders are caused by not getting enough of these nutrients.


Q9) (a) What is metabolic syndrome?

Ans) Metabolic syndrome is a group of five conditions that can cause heart disease, diabetes, stroke, and other health problems. Metabolic syndrome is diagnosed when someone has three or more of these risk factors:

  1. High blood glucose

  2. Low levels of HDL cholesterol in the blood

  3. High levels of triglycerides in the blood

  4. Large waist circumference or “apple-shaped” body

  5. High blood pressure


Even though each of these is a risk factor for heart disease, the chances of getting a serious heart condition go up when a person has three or more and is diagnosed with metabolic syndrome. For example, high blood pressure is a major risk factor for heart disease. However, when high fasting blood sugar levels and abdominal obesity (a big waistline) are also present, the risk of heart disease is even higher.


Q9) (b) Explain three risk factors of cardiovascular diseases.


Risk Factors of Cardiovascular Diseases

  1. Genetics:

  2. Age: Age is one of the most important risk factors for heart disease that can't be changed, and the risk triples for every decade you live. Since puberty, fatty streaks start to show up on the walls of the arteries. 82 percent of people who live to be 65 or older die at that age or later.

  3. Sex: Men have a greater chance of getting cardiovascular diseases than women before menopause. Coronary heart disease affects middle-aged men 2 to 5 times more often than it does middle-aged women. The results of a study showed that differences between men and women explain almost half of the risk of cardiovascular diseases.


Q10) Write short notes on:


(a) Food additives and adulterants.

Ans) According to the Food Safety and Standards Authority of India, a food additive is "any substance not normally consumed as a food by itself and not normally used as a typical ingredient of the food, whether or not it has nutritive value, the intentional addition of which to food for a technological purpose in the manufacture, processing, preparation, treatment, packing, packaging, transport, or holding of such food results, or may result, in a change in the organoleptic. This term does not include contaminants or substances that are added to food to keep it safe or make it healthier.” Food additives are added to give foods a certain texture, colour, or taste, or to make them last longer.


(b) Food allergy and intolerance.

Ans) Food allergies and intolerances are not the same as getting sick from food. In food poisoning, there is something in the food that makes the body sick because it is toxic. On the other hand, a food allergy is an immune response to something in food. The body responds to a food as if it were a dangerous invader. Food intolerance is when the body can't break down certain parts of food, usually because it doesn't have enough of certain enzymes. It has nothing to do with the immune system. Food allergens are usually proteins found in foods. Egg, soy, shellfish, fish, tree nuts, peanuts, milk, wheat, and other foods are common allergens.

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