CBSE Class 11 Biology Digestion and Absorption Assignments

Solve the MCQ questions below

Question. Assertion :- Food is one of the basic requirement of all living organisms.
Reason :- Food provides energy and organic materials for growth and repair of tissue.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- The digestion is an essential events before absorption of food substances.
Reason :- This is process of conversion of complex food substance into simple absorbable form.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Human has thecodont teeth.
Reason :- All teeth are embedded in the socket of jaw bone.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Enamel is the hardest subtance of human body.
Reason :- Enamel is originated from ectodermal ameloblast cells.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- Most part of pharynx is lined by non-keratinised squamous stratified epithelium.
Reason :- The pharynx serves as a common passage for food and air.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- A cartilaginous flap called epiglottis prevents the entery of food in to gullet.
Reason :- It's movement controlled by hormonal reflex.
(a) A
(b) B
(c) C
(d) D
Answer: D

Question. Assertion :- The sub-lingual salivary gland situated just outside the buccal cavity.
Reason :- These glands secrete salivary juice into the buccal cavity.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- The hepatic cells are the structural and functional unit of liver.
Reason :- The bile secreted by the hepatic cells and collected by hepatic duct.
(a) A
(b) B
(c) C
(d) D
Answer: D

Question. Assertion :- Buccal cavity performs two major functions, mastication and fascilitation of swallowing.
Reason :- Mucus in saliva helps in lubricating and adhering the masticaticated food particles in a bolus.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Saliva also contains antibacterial properties.
Reason :- It contains electrolytes (\( \text{Na}^+ \), \( \text{K}^+ \) \( \text{Cl}^– \), \( \text{HCO}_3^– \), thiocynate (\( \text{SCN}^– \)), Lysozyme.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- About 70% of starch is hydrolysed in buccal cavity
Reason :- Salivary amylase is a strongest \( \alpha \)-amylase at which acts on pH 1.8.
(a) A
(b) B
(c) C
(d) D
Answer: D

Question. Assertion :- The stomach stores food for 4-5 hours.
Reason :- The food mixed thoroughly with acidic gastric juice of the stomach by the churing movement.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- A small amount of lipid can digest in stomach.
Reason :- Small amounts of lipase are also secreted by gastric glands.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- HCl provides the acidic pH(pH 1.8) optimal for pepsin.
Reason :- Oxyntic cells of gastric glands secrets highly concentrated hydrochloric acid.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Bile juice play a very important role in digestion of lipid.
Reason :- Bile contains strongest lipase whcih is activated by bile salts.
(a) A
(b) B
(c) C
(d) D
Answer: C

Question. Assertion :- Proteoses and peptones are partially hydrolysed proteins which are formed by action of pepsin upon protein.
Reason :- Pepsin is an endopeptidase, which acts on specific internal peptide bond of denatured protein.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- The faeces enters into the caecum of the large intestine through ileo-caecal valve.
Reason :- Ileo-caecal valve prevents the back flow of the faecal matter.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- The sight, smell and for the presence of food in the oral cavity can stimulate the secretion of saliva as well as gastric juice.
Reason :- The secretion of saliva and gastric juice is controlled by reflex action.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Small amount of monosaccharide like glucose, amino acids and some of electrolytes like chloride ions are generally absorbed by simple diffusion.
Reason :- The passage of these substances into the blood depends upon the concentration gradients.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Various nutrients like amino acids, monosaccharides like glucose, electrolytes like \( \text{Na}^+ \) are absorbed in to blood by active transport.
Reason :- Active transport occurs against the concentration gradient
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Maximum absorption occurs in the small intestine.
Reason :- Small intestine is the longest part of gut, here complex biomolecule’s are changed in absorbable forms.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Rugae appears in mucosa of stomach.
Reason :- Mucosa in empty stomach shows small rough appearance.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Parietal cells secrete Hydrogen ions (\( \text{H}^+ \)) and chloride ions (\( \text{Cl}^– \)) separately into the stomach lumen the net effect is secretion of hydrochloric acid (HCl).
Reason :- Proton pumps powered by \( \text{H}^+/\text{K}^+ \) ATPase actively transport \( \text{H}^+ \) into the lumen while bringing potassium ions (\( \text{K}^+ \)) into the cell.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- Excess intake of saturated fats, often leads to cardiac disorder.
Reason :- Butter, Ghee, vegetable oils, red meat, eggs, etc. often leads to hypercholesterolemia.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Very high intakes of minerals and fat soluble vitamins (obtained from food sources alone) can be toxic.
Reason :- They are stored in the body.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Rate of absorption of galactose is highest.
Reason :- Galactose is actively consumed during glycolysis.
(a) A
(b) B
(c) C
(d) D
Answer: C

Question. Assertion :- The product of fat digestion - monoglyceride, fatty acids and glycerols are first absorbed by enterocyte and reconstructed to triglycerides.
Reason :- These products are water solube can be easily transported through blood and lymphatic circulation.
(a) A
(b) B
(c) C
(d) D
Answer: C

Question. Assertion :- Chylomicrons are water soluble, and protein coated droplets.
Reason :- Chylomicrons are synthesised in the lymph capillaries.
(a) A
(b) B
(c) C
(d) D
Answer: D

Question. Assertion :- In the large intestine mainly water is absorbed.
Reason :- It is lined with simple squamous epithelium.
(a) A
(b) B
(c) C
(d) D
Answer: C

Question. Assertion :- Absorption of vitamin \( \text{B}_{12} \) (Cobalamine) in human required a glycoprotein, called Castles lntrinsic factor.
Reason :- Vitamin \( \text{B}_{12} \) can not be absorbed directly.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Failure of absorption of cobalamine can causes pernicious anaemia
Reason :- It is essential for RBC maturation.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Water, minerals and vitamins can be absorbed directly.
Reason :- These can be assimilated as such.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Starch, present in plants, needs its digestion.
Reason :- It is a complex substances that can not be absorbed as such.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- The structural simplification of vitamins and minerals is brought by the action of hydrolytic enzyme vitaminase.
Reason :- Vitamins can not be assimilated by all cells.
(a) A
(b) B
(c) C
(d) D
Answer: D

Question. Assertion :- The various part of alimentary canal can produces various hydrolytic enzymes.
Reason :- Alimentary canal is associated with digestion and absorption of nutrients.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- Salivary gland and pancreas can be considered as accessory digestive glands.
Reason :- These glands are presence outside the alimentary canal and help in digestion by pouring their secretions into the alimentary canal.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- The digestive organs are concerned in the mastication, deglutition, digestion and absorption of food and elimination of unabsorbed constituents of food.
Reason :- Digestive organs are resistant to action of digestive enzymes.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- Food is one of the basic requirements of all living organism.
Reason :- The major component of our food are vitamines and minerals.
(a) A
(b) B
(c) C
(d) D
Answer: C

Question. Assertion :- Biomacromolecules in food can be utilised by out body in their original form
Reason :- Our alimentany canal absorbed these molecules in as such form.
(a) A
(b) B
(c) C
(d) D
Answer: D

Question. Assertion :- Human have heterodont dentition
Reason :- In human four different types of teeth are present.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- The upper surface of the tongue has small projections called papillae.
Reason :- All papillae bear taste buds.
(a) A
(b) B
(c) C
(d) D
Answer: C

Question. Assertion :- The opening of the stomach into the duodenum is guarded by the pyloric sphincter.
Reason :- Pyloric sphincter is a weak sphincter than gastro-oesophageal sphincter.
(a) A
(b) B
(c) C
(d) D
Answer: C

Question. Assertion :- Caecum is a small blind sac which is a vestigial organ.
Reason :- Ileum open into small intestine.
(a) A
(b) B
(c) C
(d) D
Answer: D

Question. Assertion :- The wall of alimentary canal from oesophagus to rectum possesses four layers.
Reason :- Muscularis layer is formed by smooth muscles.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- The sub mucosal layer is formed by loose connective tissue
Reason :- Sub mucosal layer is without nerves, blood and lymph vessels.
(a) A
(b) B
(c) C
(d) D
Answer: C

Question. Assertion :- Liver is largest exocrine gland in human body.
Reason :- It is located in abdominal cavity.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- Saliva is mainly produced by three salivary gland.
Reason :- Saliva help in digestion of proteins.
(a) A
(b) B
(c) C
(d) D
Answer: D

Question. Assertion :- The hapatic lobules are structural and functional unit of liver.
Reason :- Bile juice secreted by hepatocytes.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- The chemical process of digestion is initiated in the oral cavity.
Reason :- Salivary amylase present in saliva.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- The exocrine portion of pancreas secretes an alkaline juice.
Reason :- Endocrine portion of pancreas secretes hormones.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- In buccal cavity bacteria can be killed.
Reason :- Lysozyme present in saliva.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- HCl in stomach help in digestion of proteins.
Reason :- At acidic pH proten denatured and HCl causes conversion of pepsinogen into pepsin.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Damage of oryntic cells results into pernicious anaemia.
Reason :- Castle intrinsic fuctor not secreted.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- No siginficant digestive activity occurs in the large intestine.
Reason :- In mucosa layes of large intestine digestive enzyme secreating cells are absent.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- The activities of gastro-intestinal tract are under neural control only.
Reason :- Hormonal control activities of gastrointestinal tract is ineffective.
(a) A
(b) B
(c) C
(d) D
Answer: D

Question. Assertion :- Secretion of Brunner's glands help is protection of intestinal mucosa.
Reason :- Its secretion is alkaline in nature so neutralise the acidic chyme and provid alkaline medium.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- The abnormal frequency of bowel movement and decrease liquidity of faecal discharge is known as diarrhoea.
Reason :- It is the ejection of stomach contents through anus.
(a) A
(b) B
(c) C
(d) D
Answer: D

Question. Assertion :- Hormonal control of secretion of digestive juices is carried out by local hormones produced by mucosa of oesophagus and large intestine.
Reason :- Gastric juice is complete digestive juice.
(a) A
(b) B
(c) C
(d) D
Answer: D

DIGESTION AND ABSORPTION

POINTS TO REMEMBER

Digestion: The process in alimentary canal by which the complex food is converted mechanically and biochemically into simple substances suitable for absorption and assimilation.

Food: A substance which on taken and digested in the body provides materials for growth, repair, energy, resistance from disease or regulation of body processes.

Thecodont: The teeth embedded in the sockets of the jaw bone, e.g., in mammals.

Diphyodont: The teeth formed twice in life time e.g., in mammals.

Peristalsis: The involuntary movement of the gut by which the food bolus is pushed forward.

Deglutition: The process of swallowing of food bolus. It is partly voluntary and partly involuntary.

Ruminants: The herbivores animals (e.g., cow, buffalo etc.) which have symbiotic bacteria in the rumen of their stomach which synthesize enzymes to hydrolyse cellulose into short chains fatty acids.

Diarrhoea: The abnormal frequent discharge of semisolid or fluid faecal matter from the bowel.

Vomiting: The ejection of stomach contents through the mouth, caused by antiperistalsis.

Dysentry: Frequent watery stools often with blood and mucus and with pain, fever and causes dehydration.

Chyme: The semifluid mass into which food is converted by gastric secretions.

Hepatic: Anything associated with liver is given a prefix 'hepatic'.

Gastric: Anything associated with stomach is given a prefix 'gastric'.

Proenzyme: The inactive forms of enzymes.

Sphincter: A flap like structure at various junctions of the alimentary canal which facilitates one way traffic in the alimentary canal.

Bolus: The masticated food mixed with saliva.

Goblet cells: The cells of intestinal mucosal epithelium which secrete mucus.

Glisson's capsule: The connective tissue sheath which covers the hepatic lobules of liver.

Hepatic lobules: The structural and functional units of liver containing hepatic cells which are arranged in the form of cords.

Sphincter of Oddi: The sphincter which guard the opening of common hepato-pancreatic duct.

Villi: The small finger-like folding in the innermost layer of the alimentary canal which increase the absorption surface area.

PEM: Protein Energy Malnutrition.

Types of Nutrition: Autotrophic (Photoautotrophic e.g., green plants & Euglena etc., Chemoautotrophic e.g., Nitrosomonas & Nitrobacter), Heterotrophic (1. Saprotorphic e.g., yeast, 2. Holotrophic e.g., man, lion, 3. Parasitic e.g., Ascaris), Symbiotic (e.g., Rhizobium).

Basic steps of Holozoic Nutrition:
(1) Ingestion: Intake of food.
(2) Digestion: Breaking down of complex organic food materials into simpler, smaller soluble molecules.
(3) Absorption and assimilation: Absorption of digested food into blood or lymph and its use in the body cells for synthesis of complex components.
(4) Egestion: Elimination of undigested food as faeces.

Digestive glands:
(A) Salivary glands (found in mouth). Three types are: (i) Parotid, (Cheek) (ii) (Below the tongue) Sublingual, (iii) Submaxillary or sub-mandibular (lower jaw). Secrete saliva which contains ptyalin (Salivary Amylase)
(B) Pancreas: Secretes pancreatic juice.
(C) Liver: Secretes bile.
(D) Gastric glands: Secretes gastric juice.
(E) Intestinal glands: Secretes intestinal juice or succus entericus.

Digestion in mouth: Saliva contains enzyme Ptyalin (Salivary Amylase)
Starch \(\xrightarrow[\text{pH 6.8}]{\text{Salivary amylase}}\) Maltose

Digestion in stomach: Gastric juice contains HCl and enzymes pepsin, rennin and gastric lipase.
Pepsinogen \(\xrightarrow[\text{pH 1.8}]{\text{HCl}}\) Pepsin + Protein
Protein \(\xrightarrow{\text{Pepsin}}\) Proteoses + Peptones
Milk caseisinogen \(\xrightarrow{\text{Rennin}}\) solid casein (curd)
Curd \(\xrightarrow{\text{Pepsin}}\) Peptone
Fat \(\xrightarrow{\text{Lipase}}\) Fatty acids

Digestion in small intestine: Liver secretes bile.
Fat \(\xrightarrow{\text{Bile}}\) Emulsification
Pancreatic juice contains trypsin.
Proteoses & peptones \(\xrightarrow{\text{Trypsin}}\) Tri and dipeptides
Starch & glycogen \(\xrightarrow{\text{Amylase}}\) Maltose
Emulsified fats \(\xrightarrow{\text{Steapsin}}\) Fatty acids & glycerols
Maltose \(\xrightarrow{\text{Maltase}}\) Glucose
Polypeptides \(\xrightarrow{\text{Carboxypeptidase}}\) Tri and dipeptides
Nucleic acids \(\xrightarrow{\text{Nuclease}}\) Nucleotides + Nucleosides

Functions of succus entericus:
Dipeptides \(\xrightarrow{\text{Dipeptidases}}\) Amino acids
Maltose \(\xrightarrow{\text{Maltase}}\) Glucose + Glucose
Lactose \(\xrightarrow{\text{Lactase}}\) Glucose + Galactose
Sucrose \(\xrightarrow{\text{Sucrase}}\) Glucose + Fructose
Nucleotides \(\xrightarrow{\text{Nucleotidase}}\) Nucleosides \(\xrightarrow{\text{Nucleosidases}}\) Sugars + Bases
Di and monoglycerides \(\xrightarrow{\text{Lipases}}\) Fatty acids + Glycerol

QUESTIONS

Very Short Answer Questions (1 mark each)

Question 1. What do you mean by the term malnutrition?
Answer: The state of health due to improper intake of food or nutrients. It covers both undernutrition as well as overnutrition.
In simple words: Malnutrition happens when a person does not get the right amount of nutrients, either too little or too much.

Exam Tip: Mention both undernutrition and overnutrition to secure full marks.

Question 2. Name the hardest substance in the body.
Answer: Enamel.
In simple words: Enamel is the hard outer covering of human teeth.

Exam Tip: Spell enamel correctly; do not confuse it with dentine or bone.

Question 3. What is a lacteal?
Answer: Lymph vessel found in villi.
In simple words: Lacteals are specialized lymphatic capillaries inside intestinal villi that absorb digested fats.

Exam Tip: Emphasize its role in fat absorption.

Question 4. Name the small projections, found on the upper surface of tongue.
Answer: Papillae.
In simple words: Papillae are tiny bumps on the tongue that contain taste buds.

Exam Tip: Note that papillae bear taste buds, they are not taste buds themselves.

Question 5. Mention the function of epiglottis.
Answer: Prevention the entry of food into the glottis.
In simple words: Epiglottis acts like a lid that covers the windpipe during swallowing so food goes into the foodpipe instead.

Exam Tip: Clearly state the prevention of food entry into the respiratory tract.

Question 6. Write the names of major parts of stomach.
Answer: Cardiac, fundic, pyloric.
In simple words: The human stomach is divided into three main regions: cardiac, fundic, and pyloric parts.

Exam Tip: List all three regions sequentially from the esophagus to the small intestine.

Question 7. Name the enzyme that digest fats. Mention the end products of fat digestion.
Answer: Lipase. The end products are fatty acids and glycerol.
In simple words: Lipase breaks down fats into simpler units called fatty acids and glycerol.

Exam Tip: Always mention both end products (fatty acids and glycerol) together.

Question 8. In which part of alimentary canal does absorption of water, simple sugars and alcohol takes place?
Answer: Stomach.
In simple words: Alcohol, water, and simple sugars are partially absorbed directly through the stomach lining.

Exam Tip: Stomach absorption is specific; do not confuse with small intestine absorption.

Question 9. Why are proteases generally released in inactive form?
Answer: If released in active form, they will start digesting the membranes and muscular walls of the alimentary canal.
In simple words: Inactive forms prevent protein-digesting enzymes from destroying the organs that produce them.

Exam Tip: Mention self-digestion (autolysis) of the tissue to get complete credit.

Question 10. Trypsinogen is an inactive enzyme of pancreatic juice. An enzyme, enterokinase, activates it. Which tissue/cell secrete the enzyme? How is it activated?
Answer: Intestinal mucosa. Trypsinogen \(\xrightarrow{\text{Enterokinase}}\) Trypsin \(\rightarrow\) Proteins \(\rightarrow\) Peptides.
In simple words: Intestinal cells secrete enterokinase, which converts inactive trypsinogen into active trypsin.

Exam Tip: Name the source tissue (intestinal mucosa) clearly.

Question 11. What is the role of insulin?
Answer: Metabolism of sugar.
In simple words: Insulin helps lower blood sugar levels by facilitating glucose uptake into cells.

Exam Tip: Relate insulin directly to glucose uptake and storage as glycogen.

Short Answer Questions-II (2 marks each)

Question 12. What is emulsification? Where and how does it occur?
Answer: The process of breakdown of large fat droplets into smaller ones. It occurs in small intestine. It is brought about by bile salts through reduction of surface tension of large fat droplets.
In simple words: Emulsification is the breaking of big fat globs into tiny droplets by bile salts in the small intestine to help digestion.

Exam Tip: Mention both the site (small intestine) and the agent (bile salts).

Question 13. Name three parts of large intestine. Which vestigial organ arises from the first part of it?
Answer: Caecum, colon and rectum. Vermiform appendix.
In simple words: The large intestine consists of caecum, colon, and rectum, with the vestigial appendix attached to the caecum.

Question 14. Name the gland which perform/acts as exocrine and endocrine. Also name the products which are secreted by it.
Answer: Pancreas. Exocrine secretion is pancreatic juice containing enzymes and endocrine secretions are hormones: insulin and glucagon.
In simple words: The pancreas acts as both exocrine (making digestive enzymes) and endocrine (making hormones like insulin).

Exam Tip: Clearly separate exocrine secretions (enzymes) from endocrine secretions (hormones).

Question 15. The wall of alimentary canal is made up of four layers. Give the names of these four layers.
Answer: Serosa, muscularis, submucosa and mucosa.
In simple words: The gut wall consists of four concentric layers from outside to inside: serosa, muscularis, submucosa, and mucosa.

Exam Tip: List the layers in order from outermost to innermost.

Question 16. In which part of the digestive system the absorption of following substances takes place?
(a) Certain drugs
(b) Glucose, fructose and fatty acids
(c) Water, some minerals and drugs
(d) Simple sugar and alcohol
Answer: (a) Mouth (b) Small intestine (c) Large intestine (d) Stomach
In simple words: Different parts of the digestive tract absorb specific substances like alcohol in the stomach and nutrients in the small intestine.

Exam Tip: Match each letter precisely with the correct anatomical site.

Short Answer Questions-I (3 marks each)

Question 17. In the following diagram of duct system of liver, gall bladder and pancreas, label \(a, b, c, d, e\) and \(f\):
Answer: Refer Fig. 16.6, page no. 261 (NCERT Text Book, Class XI Biology).
In simple words: Consult the standard NCERT diagram for the hepato-pancreatic duct system and associated glands.

Exam Tip: Practice drawing and labeling the biliary and pancreatic duct system clearly.

Question 18. Give a diagrammatic representation of transverse section of gut.
Answer: Refer Fig. 16.4, page no. 260 (NCERT Text Book, Class XI Biology).
In simple words: Refer to the histological cross-section of the alimentary canal showing serosa, muscularis, submucosa, and mucosa.

Exam Tip: Label all four tissue layers with correct spatial orientation.

Question 19. Draw the sketch of anatomical regions of human stomach and label any four parts in it.
Answer: Refer Fig. 16.3, page no. 259 (NCERT Text Book, Class XI Biology).
In simple words: Refer to the NCERT diagram illustrating the cardiac, fundus, body, and pyloric regions of the stomach.

Exam Tip: Clearly show sphincters and anatomical regions in the sketch.

Question 20. How does the nervous system control the activities of gastro-intestinal tract?
Answer: Refer page 264 (NCERT Text Book, Class XI- Biology).
In simple words: Neural signals from the central nervous system and local enteric nervous plexuses coordinate gastrointestinal secretions and motility.

Exam Tip: Mention both central neural control (CNS) and local enteric nervous system.

Long Answer Questions (5 marks each)

Question 21. Draw a labelled figure of digestive system of human.
Answer: Refer Fig. 16.1, Page no. 258 (NCERT Text Book, Class XI Biology).
In simple words: Draw the complete human alimentary canal along with associated digestive glands like liver and pancreas.

Exam Tip: Ensure accurate relative positions of organs and neat labeling.

Question 22. Give a summary of cause and symptoms of following disorders of digestive system:
(a) Jaundice
(b) Vomiting
(c) Diarrhoea
(d) Constipation
(e) Indigestion
Answer: Refer Page no. 265-266 (NCERT Text Book, Class XI Biology).
In simple words: Digestive disorders arise due to infections, improper diet, or physiological malfunctions leading to symptoms like yellow skin, nausea, or altered bowel habits.

Exam Tip: Detail both causes and symptoms for each disorder separately.