Punjab State Board PSEB 11th Class Biology Important Questions Chapter 16 Digestion and Absorption Important Questions and Answers.
PSEB 11th Class Biology Important Questions Chapter 16 Digestion and Absorption
Very short answer type questions
What do we call the type of teeth attachment in which each tooth, is embedded in a socket of jaws bones? [NCERT Exemplar]
Out of the three types of salivary glands, which is situated in the upper palate on either side of cheek.
Parotid gland (type of salivary gland) is situated in the upper palate on the either side of the cheek.
If a person is suffering from reflux oesophagitis, which part of his alimentary canal is not functioning properly?
In reflux oesophagitis, the oesophagus does not function properly.
HCl is secreted in stomach. Give the name of the cells that secrete it.
Oxyntic cells (parietal cells) are the stomach epithelial cells, that secretes gastric acid, i.e., HCl.
Crypts of Lieberkuhn are found in which part of the alimentary canal.
These are found in small intestine portion of alimentary canal.
Give the name of the enzymes involved in the breakdown of nucleotides into sugars and bases? [NCERT Exemplar]
Trypsinogen is an inactive enzyme of pancreatic juice. An enzyme, enterokinase activates it. Which tissue/cells secrete this enzyme? How is it activated? [NCERT Exemplar]
The cells of duodenum secrete enzyme enterokinase. It is activated by food in the duodenum.
Mention the function of saliva other than digestion.
Apart from taking part in digestion, saliva also helps to lubricate the food for swallowing.
State the source of trypsin and the food constituent which this enzyme hydrolyses.
Pancreatic juice is the source of trypsin which hydrolyses proteins into peptides.
If the bile duct is completely blocked. How would it affect the digestion of food?
If the bile duct is blocked completely, the bile will fail to reach the small intestine and the digestion of fats gets affected.
By which type of mechanism, amino acids are absorbed in our body?
Small amounts of amino acids are absorbed by active transport and some are absorbed by the facilitated transport.
As fatty acids and glycerol are not absorbed directly. Name the form in which fatty acids are converted to get absorbed?
Fatty acids and glycerols are not absorbed directly into the bloodstream. Thus, they are absorbed in the form of small droplets called micelles.
Which type of absorption takes place in large intestine?
Absorption of water, some minerals and drugs takes place in the large intestine.
What happens in the condition when bile from the liver crystalises?.
When bile from the liver get crystallised, person form stones in the body.
Short answer type questions
What is the role of tongue indigestion?
Tongue helps in mixing the food properly with salivary enzymes. Moreover, tongue has tastebuds which give the sense of different tastes. Eating is a complex process which needs involvement of olfactory and visual senses as well. Alongwith tongue all these senses help in picking the right food.
What is the function of large intestine?
Functions of large intestine are as follows:
- Absorption of some water, minerals and certain drugs.
- Secretion of mucus. Mucus helps in adhering the waste particles together and lubricates it for easy passage.
What is digestive waste and how is it removed from the body?
After digestion and absorption of food is over the residue left makes the digestive waste. The digestive wastes, solidified into coherent faeces in the rectum initiate a neural reflex causing an urge or desire for its removal. The egestion of faeces to the outside through the anal opening (defaecation) is a voluntary process and is carried out by a mass peristaltic movement.
How does the nervous system control the activities of gastrointestinal tract?
The sight, smell and/or presence of food in the oral cavity can stimulate the secretion of saliva. Gastric and intestinal secretions are also stimulated by similar neural signals. Muscular activities of alimentary canal is coordinated by both local and CNS neural mechanisms. Hormonal control of secretion of digestive enzymes is carried out by local hormones.
Write a short note on-Disorders of digestive system.
Disorders of Digestive System
(i) Inflammation of intestinal tract
This is the most common disorder of the digestive system.
It is caused by infections by bacteria or viruses and also by parasites like roundworm, hookworm, pinworm, etc.
It is the infection and inflammation of the liver.
Bile pigments are present in the blood and cause yellowing Of eyes, skin, etc.
It is the egestion of contents of the stomach through the mouth.
The abnormal frequency of bowel movement and increased liquidity of the faecal discharge is known as diarrhoea.
It reduces the absorption of food.
In constipation, the faeces are retained within the rectum as the bowel movements occur irregularly.
In indigestion, the food is not properly digested leading to a feeling of fullness.
The causes of indigestion are inadequate enzyme secretion, anxiety, food poisoning, overeating, spicy food, etc.
Long answer type questions
As a result of intestinal disease, parts of the alimentary canal are sometimes surgically removed. Discuss the effect of this removal on lifestyle and digestive function:
(i) the stomach
(ii) the colon.
(i) Removal of the stomach, which is the main organ for digestion of protein, leads to a change in the patient’s diet. It is the stomach where proteins are first broken down into polypeptides by pepsin in gastric juice before they can be acted on by pancreatic enzymes and intestinal enzymes. The patient must lower down the amount of protein in his diet. Animal meat especially red meat, which is rich in proteins must be avoided.
(ii) Removal of the colon, which is responsible for absorption of water from undigested food, result in loss of water (dehydration) inpatient. The patient needs to drink plenty of fluids to replace water loss. In most cases, where the whole colon is removed, a surgical procedure.is done to attach the small intestine to the rectum to allow for recta elimination of liquid stools. A small pouch is created in the lower abdomen to collect the stool. The patient has to learn to regulate his bowel movements.
A person had roti and dal for his lunch. Trace the changes that will take place during its complete passage through the alimentary canal. [NCERT Exemplar]
Changes that will take place in food (roti and dal) through the passage of alimentary canal are given below:
- The food substances are first masticated by the teeth in the mouth, where carbohydrate part of the food is digested by the action of salivary amylase enzyme secreted by the salivary glands.
- This partially digested food reaches the stomach, where it receives acidic HCl and mainly the protein part of the food is digested by the action of proteolytic enzymes.
- The lipid part of the food is digested by the bile secreted by the gall bladder.
- In the small intestine, particularly in the duodenum, this semi-digested food is finally digested by the digestive enzymes present in the intestinal and pancreatic juices.
- After digestion, the broken down products of food, i.e., amino acids, glycerol, starch, etc., are observed mainly in the small intestine.
- The undigested remains of food will finally pass through the anus.