Human nutrition Answer Key (21/02/2026)
14. Human Nutrition
ANSWER KEY
SECTION A – MCQs (1 Mark Each)
1. Acinar cells are present in pancreas.
• Acinar cells are exocrine cells of the pancreas.
• These cells secrete digestive enzymes into the pancreatic duct.
2. Molars are maximum in number in human buccal cavity.
• An adult human has twelve molars in total.
• Molars are more in number compared to incisors, canines, and premolars.
3. Talking is not a digestive function of the tongue.
• Talking is related to speech and communication.
• Taste, swallowing, and mixing food with saliva are digestive functions.
4. Pepsin is a protease enzyme.
• Pepsin helps in the digestion of proteins.
• Protease is an enzyme that breaks down proteins into simpler substances.
5. Pepsin works best in acidic medium.
• Pepsin functions effectively at a pH of about 1.5 to 2.
• The acidic environment of the stomach activates pepsin.
SECTION B – Short Answer (3 Marks Each)
1. Why was Shiv advised to consume Glucon-D or fruit juice but not sugarcane juice?
• Glucon-D and fruit juices contain simple sugars like glucose.
• Glucose does not require digestion before absorption.
• It is directly absorbed into the bloodstream.
• It provides immediate energy during physical activity.
• Sugarcane juice contains more complex sugars.
• Complex sugars take more time to digest and absorb.
2. Alcoholic people may suffer from liver disorders due to excessive alcohol intake.
• The liver is responsible for detoxifying alcohol from the body.
• Continuous alcohol consumption damages liver cells.
• Fat begins to accumulate in liver cells.
• This condition may lead to fatty liver disease.
• Long-term damage can cause cirrhosis of the liver.
• Liver functions such as metabolism and digestion get affected.
3. The digestive action of pepsin stops in the small intestine.
• Pepsin functions only in an acidic environment.
• The small intestine has an alkaline medium.
• Bile juice neutralises the acidic chyme from the stomach.
• Pancreatic juice is also alkaline in nature.
• The change in pH makes pepsin inactive.
• Trypsin continues protein digestion in the small intestine.
4. The small intestine does not twist normally because of mesentery.
• The small intestine is attached to the abdominal wall by a membrane called mesentery.
• The mesentery holds the intestine in proper position.
• It contains blood vessels and nerves.
• The intestine shows controlled peristaltic movements.
• Twisting of intestine is called volvulus.
• Volvulus may block blood supply and cause tissue damage.
5. Salivary glands and pancreas perform important digestive functions.
• There are three pairs of salivary glands in humans.
• Salivary glands secrete saliva containing amylase enzyme.
• Saliva begins the digestion of starch in the mouth.
• The pancreas is a heterocrine gland.
• It has an exocrine part that secretes digestive enzymes.
• It also has an endocrine part that secretes insulin and glucagon.
SECTION C – Long Answer (4 Marks Each)
1. Digestive enzymes are secreted at the appropriate time through regulation mechanisms.
• The nervous system controls the secretion of digestive juices.
• Hormones also regulate digestive secretions.
• The hormone gastrin stimulates the secretion of gastric juice.
• The hormone secretin stimulates the secretion of pancreatic juice.
• The presence of food in the stomach triggers enzyme secretion.
• The sight and smell of food also stimulate secretion.
• Feedback mechanisms regulate the quantity of enzymes released.
• Proper regulation prevents damage to digestive organs.
2. The human tooth has a specific structure and dentition pattern.
• Each tooth has three parts: crown, neck, and root.
• The outermost layer of the crown is enamel.
• Enamel is the hardest substance in the human body.
• Dentine lies below the enamel.
• The pulp cavity contains blood vessels and nerves.
• Human dentition is called thecodont because teeth are fixed in sockets.
• It is diphyodont because two sets of teeth develop during lifetime.
• It is heterodont because different types of teeth perform different functions.
3. The stomach has different histological layers with specific functions.
• The muscular layer consists of three sub-layers.
• These layers help in churning and mixing food.
• The mixing action converts food into chyme.
• The mucosa layer contains gastric glands.
• Gastric glands secrete hydrochloric acid.
• They also secrete pepsinogen.
• Hydrochloric acid activates pepsinogen into pepsin.
• Mucus protects the inner lining of the stomach.
4. Each digestive enzyme has a specific optimum pH.
• Salivary amylase works best at a pH of about 6.8 to 7.
• Trypsin works best at a pH of around 8.
• Nucleotidase also functions in an alkaline medium.
• Pepsin works best at a pH of about 1.5 to 2.
• Every enzyme has a specific optimum pH range.
• Changes in pH affect the shape of the enzyme.
• Extreme pH can denature enzymes permanently.
• Different organs maintain different pH levels for specific enzymes.
SECTION D – Diagram (5 + 5 Marks)
Labels the following diagram.
• A represents the liver.
• B represents the stomach.
• C represents the pancreas.
• D represents the duodenum.
• E represents the gall bladder.
Function of Liver:
• The liver produces bile juice.
• Bile helps in emulsification of fats.
• The liver stores glycogen.
• It detoxifies harmful substances.
• It stores vitamins and minerals.
• The liver produces plasma proteins.
• It regulates carbohydrate metabolism.
• It converts ammonia into urea.
• It helps maintain blood glucose level.
• It supports digestion indirectly.
Function of Pancreas:
• The pancreas secretes trypsin for protein digestion.
• It secretes amylase for carbohydrate digestion.
• It secretes lipase for fat digestion.
• Pancreatic juice is alkaline in nature.
• It neutralises acidic chyme from the stomach.
• The pancreas also has endocrine function.
• It secretes insulin to reduce blood sugar.
• It secretes glucagon to increase blood sugar.
• It helps maintain glucose balance.
• It plays an important role in digestion.
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