Microbiology & Nutrition MCQ Quiz - Objective Question with Answer for Microbiology & Nutrition - Download Free PDF

• Pasteurization is a process of heat treatment used to kill or inactivate harmful microorganisms in food and beverages, particularly milk, without compromising their nutritional quality or flavor.
• The primary goal of pasteurization is to destroy pathogenic microorganisms that can cause diseases. Mycobacterium tuberculosis is a significant pathogen specifically targeted by pasteurization, as it can be transmitted through contaminated milk and cause tuberculosis in humans.
• The standard pasteurization method, such as high-temperature short-time (HTST) pasteurization (heating milk to 72°C for 15 seconds), is effective in killing Mycobacterium tuberculosis along with other pathogens like Brucella and Salmonella.
• The destruction of Mycobacterium tuberculosis during pasteurization is critical for public health, especially in regions where bovine tuberculosis is prevalent.

• Rationale: Clostridium botulinum is a bacterium that produces botulinum toxin, which causes botulism. It forms heat-resistant spores that are not effectively destroyed by standard pasteurization methods. High-temperature sterilization (above 121°C) is required to inactivate these spores.

• Rationale: Bacillus cereus is a bacterium that can cause foodborne illness. Its spores are also heat-resistant and can survive pasteurization. While pasteurization may reduce the number of vegetative cells, it does not entirely eliminate Bacillus cereus spores.

• Rationale: Lactic acid bacteria are generally non-pathogenic and are often beneficial in food production, such as in the fermentation of yogurt and cheese. Pasteurization may reduce their numbers, but they are not the primary target of this process.

• Pasteurization is specifically designed to destroy pathogenic microorganisms like Mycobacterium tuberculosis, which pose significant health risks when consumed via raw milk or other unpasteurized products. While the process may have some impact on other microorganisms, it is not effective against heat-resistant spores like those of Clostridium botulinum or Bacillus cereus. Lactic acid bacteria are not targeted as they are generally harmless or beneficial.

• Sharp instruments should not be sterilized by boiling because boiling water only reaches a temperature of 100°C (212°F), which is not sufficient to eliminate all types of microorganisms, including bacterial spores.
• Boiling is not reliable for sterilization of sharp medical instruments, as it does not ensure complete destruction of all pathogens.
• Sharp instruments require methods that can achieve higher temperatures and more effective sterilization to ensure patient safety and prevent infections.

• Rationale: Autoclaving uses pressurized steam at temperatures of 121°C (250°F) or higher, which is effective in killing all forms of microbial life, including spores. It is a highly effective method for sterilizing sharp instruments.

• Rationale: A hot air oven sterilizes by using dry heat at temperatures typically ranging from 160-180°C (320-356°F). This method is effective for sterilizing sharp instruments as it ensures thorough destruction of microorganisms.

• Rationale: Antiseptic solutions are used for disinfection, not sterilization. They can reduce the number of microorganisms but are not sufficient to eliminate all pathogens, making them less reliable for sterilizing sharp instruments.

• Among the given options, boiling is the least reliable method for sterilizing sharp instruments. Methods like autoclaving and hot air ovens provide higher temperatures necessary for effective sterilization, ensuring the safety and hygiene of medical tools.

• Pathogens are microorganisms such as bacteria, viruses, fungi, and parasites that cause diseases. For these pathogens to multiply and cause infection, they typically need a host organism to provide the necessary conditions and nutrients.
• A host offers an environment that supports the growth and reproduction of pathogens. This environment includes the necessary nutrients, appropriate temperature, and other conditions required for the pathogens' survival and multiplication.

• Rationale: While moisture is important for the survival and growth of many pathogens, it is not universally required by all pathogens. Some pathogens can thrive in dry environments or even in the absence of moisture.

• Rationale: Light is not necessary for the multiplication of most pathogens. In fact, many pathogens, especially bacteria and viruses, can be killed or inhibited by ultraviolet (UV) light.

• Rationale: Not all pathogens require oxygen to multiply. There are many anaerobic pathogens that can grow and multiply in the absence of oxygen. Examples include certain bacteria that cause tetanus and botulism.

• Among the given options, a host is the most critical and universally needed requirement for the multiplication of all pathogens. While other factors like moisture, light, and oxygen can influence the growth of specific pathogens, they are not required by all pathogens. The host provides the essential environment for the survival and proliferation of pathogenic organisms.

Key Points

• Body Mass Index (BMI) is a simple calculation using a person's height and weight.
• The formula is BMI = kg/m² where kg is a person's weight in kilograms and m² is their height in meters squared.
• BMI is used as an indicator of whether a person has a healthy body weight for a given height.
• It is a useful tool to identify whether an individual is underweight, normal weight, overweight, or obese.

Additional Information

• History of BMI:
  • BMI was invented in the 1830s by a Belgian mathematician named Adolphe Quetelet.
  • It was originally called the Quetelet Index before being renamed as Body Mass Index.
• BMI Categories:
  • Underweight: BMI less than 18.5
  • Normal weight: BMI 18.5–24.9
  • Overweight: BMI 25–29.9
  • Obesity: BMI 30 or greater
• Limitations of BMI:
  • BMI does not account for muscle mass. A person with a high muscle mass may have a high BMI but not have excess body fat.
  • It does not measure the distribution of fat in the body. Abdominal fat can be more harmful than fat in other areas.
  • BMI may not be accurate for all populations. For instance, the relationship between BMI and body fat can vary among different ethnic groups.
• Health Risks Associated with BMI:
  • Higher BMI increases the risk of chronic diseases such as heart disease, type 2 diabetes, and certain cancers.Low BMI may indicate malnutrition, eating disorders, or other health issues.

• Vitamin C, also known as ascorbic acid, is an essential nutrient that plays a crucial role in the growth and repair of tissues in the body. It is also important for the development of the baby's teeth and bones, and it helps the body absorb iron.
• According to the Indian Council of Medical Research (ICMR) 2010 guidelines, the recommended intake of vitamin C for pregnant women is 60 mg/day. This is to ensure that both the mother and the developing fetus have adequate levels of this vital nutrient.
• Vitamin C is an antioxidant that helps protect cells from damage, and it is important for the formation of collagen, which is a key component of connective tissues.

• Rationale: The intake of 45 mg/day is below the recommended level for pregnant women. This amount may not be sufficient to meet the increased needs during pregnancy, which include the development of the fetus and the health of the mother.

• Rationale: While 55 mg/day is close to the recommended intake, it still falls short of the 60 mg/day suggested by the ICMR 2010 guidelines. This slight deficiency might not meet the full nutritional needs during pregnancy.

• Rationale: An intake of 40 mg/day is significantly below the recommended amount for pregnant women. This level is not adequate to ensure the proper development of the fetus and the health of the mother.

• The recommended intake of vitamin C for pregnant women, according to the ICMR 2010 guidelines, is 60 mg/day. This ensures that both the mother and the developing fetus have enough of this vital nutrient for proper growth and development. The other options fall short of this requirement and may not provide adequate nutritional support during pregnancy.

The correct answer is Vitamin C

Additional Information

• Vitamins were first discovered by FG Hopkins.
• The term Vitamin was coined by C Funk.
• There are two types of Vitamins:

1. Fat-Soluble- Vitamin A, D, E, and K.
2. Water-Soluble - Vitamin B and C.

• Natural sources of Vitamin D are - Sunlight, fish, eggs, and mushrooms. 

The correct answer is A.

• Vitamins are organic compounds that are required in small amounts in our diet but their deficiency causes specific diseases.
• Vitamins are designated by alphabets A, B, C, D, etc. Some of them are further named as sub-groups e.g. B1, B2, B6, B12, etc.
• Vitamins that are soluble in fat and oils but insoluble in water are kept in this group. These are vitamins A, D, E, and K. They are stored in liver and adipose (fat-storing) tissues.
• B group vitamins and vitamin C are soluble in water so they are grouped together.

  Key Points

• The deficiency of one or more nutrients can cause diseases or disorders in our bodies. Diseases that occur due to a lack of nutrients over a long period are called deficiency diseases.
  • Deficiency of Vitamin - A causes Night Blindness.
  • Deficiency of Vitamin - B causes Beri - Beri. 
  • Deficiency of Vitamin - C causes Scurvy.
  • Deficiency of Vitamin - D causes Rickets.
  • Deficiency of Vitamin - E causes Less Fertility.
  • Deficiency of Vitamin - K causes Non- clotting of blood.

Concept:

• A medical condition in which there is a shortage of healthy RBCs in the body is called Pernicious anemia
• It is caused due to the deficiency of Vitamin B12.
• Pernicious anemia is a very rare and fatal disease.
•  pernicious anemia is a type of anemia that lack the Intrinsic factor (IF)

​Explanation:

• Deficiency of Vitamins can cause several diseases like scurvy, night blindness, anemia, etc.
• Pernicious Anemia is caused due to the deficiency of Vitamin B12.
• The chemical name of Vitamin B12 is CyanoCobalamin.
• It is used for the production of RBC as we know that RBC contains Hemoglobin which contains Iron and hence the deficiency also results in Anemia.
• It is mostly found in non-vegetarian food like red meat hence it is known as Nonvegetarian Vitamin.
• It also works along with Vitamin B9 and is quite useful for pregnant ladies.

Additional Information

• Vitamin K -> is responsible for blood coagulation. Without vitamin K, blood coagulation is seriously impaired, and uncontrolled bleeding occurs. 
• Vitamin B6 -> forms part of the coenzyme for amino acid synthesis and glycogen synthesis. It helps in nerve function and RBC formation. Its deficiency causes skin lesions, disturbance of CNS, and anemia.
• Vitamin E -> is also known as Tocopherol its deficiency can result in less fertility.
• Vegetable oil, Sprouted wheat, Leafy vegetables, Milk, Butter, etc are the major sources of Vitamin- E.

• Carbohydrates are one of the essential nutrients in the human diet.
• There are two types of carbohydrates that can be digested by the human digestive system: sugar and starch.
• Amylase breaks down starch into oligosaccharides.
• It is present in the saliva.
• The process of digestion starts with amylase.
• Starch is a polymeric carbohydrate made up of multiple units of glucose.
• Salivary glands and the pancreas produce amylase.

Explanation:

• Amylose or starch breaks into maltose.
• Maltose breaks down into glucose that then enters the glycolytic pathway.
• Glucose breaks into pyruvate.
• Erepsin is a mixture of pancreatic juice and intestinal juices.
• It is an enzyme that digests protein into amino acids.
• Pepsin breaks down protein into peptide bonds.

Concept:

• Protein-energy malnutrition refers to the disease caused by a deficiency of protein and calories.
• It has a loss of 10% or more of body weight within six months or albumin levels of less than 3.5g/dl.
• Kwashiorkor is caused due to lack of protein in the diet, this disease occurs in children between the age of 1 to 5 years.
• Marasmus is a severe case of malnutrition characterised by protein and energy deficiency

Explanation:

• There are two types of protein deficiencies:
  • Kwashiorkor
  • Marasmus
• kwashiorkor is a deficiency of protein.
• Marasmus is a deficiency of protein and calories.

The correct answer is Vitamin A.

• Night blindness is one of the first signs of vitamin A deficiency.
• In its more severe forms, vitamin A deficiency contributes to blindness by making the cornea very dry, thus damaging the retina and cornea.

Key Points

• Vitamin A
  • It is an important micronutrient that is obtained from different food sources such as carrots, spinach, milk, egg, liver, and fish.
  • It is required for normal vision, reproduction, growth, and the healthy immune system of an individual.
  • Most children below five years of age suffer from xerophthalmia, a serious eye disorder, in which the child is at risk of becoming blind.
  • Vitamin A deficiency in a pregnant woman can lead to complications during pregnancy and childbirth. 
  • It is fat-soluble.  

Additional Information

Concept-

• Vitamins are nutrients your body needs to develop and function properly.
• There are 13 essential vitamins.
•  A, D, E, and K, which are fat-soluble, and vitamins C and the B-complex group, which are water-soluble.
• Each vitamin has a distinct role in keeping you healthy.
• Some Vitamin deficiency diseases:
  • Vitamins A deficiency causes blindness.
  • Vitamin B1 deficiency causes Beri-Beri.
  • Vitamin C deficiency causes Scurvy.
  • Vitamins D deficiency causes Rickets (Bone abnormalities).
  • Vitamin E deficiency causes Neurological problems.
  • Vitamin K deficiency causes Blood clotting problems.

Trick to remember fat-soluble vitamins- KEDA

• K-Vitamin K 
• E- vitamin E 
• D-vitamin D
• A-vitamin A

The correct answer is Option 1. 

Key Points

• Vitamin C is an antioxidant. It is a water-soluble vitamin that acts as an antioxidant in the body, helping to protect cells from damage caused by free radicals.
• Free radicals are unstable molecules that can cause oxidative stress and damage to cells and DNA.
• By neutralizing free radicals, vitamin C helps maintain the health of various body tissues and supports the immune system.
• It is important for collagen synthesis, wound healing, and the absorption of iron from plant-based sources.

Additional Information

• Antibiotic: Antibiotics are medications used to treat bacterial infections. They work by either killing the bacteria or inhibiting their growth.
• Antigen: An antigen is a substance that triggers an immune response in the body. When the immune system recognizes an antigen as foreign or harmful, it produces antibodies to neutralize or eliminate it.
• Antiviral treatments can be developed for specific viruses or groups of viruses, such as influenza, HIV, hepatitis, herpes, and respiratory syncytial virus (RSV), among others. These treatments are typically prescribed by healthcare professionals and are tailored to the specific viral infection being targeted.

EXPLANATION -

• The food we eat is made up of a number of components like carbohydrates, fats, proteins, vitamins, minerals, and proteins. 
• All these components are in turn made up of smaller units that combine together to form the bigger components of our food.
• Just like cells combine to form tissues and in turn organisms, these small units combine together to form these larger components. 
• When each one of these nutrients undergoes digestion in the human body:

• Digestion turns the food you eat into nutrients that are the components of our food and then, it breaks down and extracts further constituents from these nutrients by dividing them into smaller units (which they are made up of).
• These units are then absorbed by our body and used for growth, cell repair, and energy.

As amino acids are found in the small intestine, it can be said that the food item being consumed is full of proteins (amino acids are the basic unit of proteins, which are released when proteins are digested), so the answer is - PROTEINS,

Concept:

• Polymer is a compound formed with long repeated chains of molecules.
• Proteins are polymers of amino acids.
• Amino acids combine to form a protein.

Explanation:

• Protein is composed of carbon, hydrogen, oxygen, nitrogen, and sulfur atoms.
• Examples of protein-polymer include gelatin and hemoglobin.