Biology · Science General

Human Digestive System

1,953 Questions

The human digestive system explores the breakdown of biomacromolecules, covering organs from the stomach to the small intestine. It involves physiological processes like chyme movement, pH levels, and nutrient absorption in the gut. These fundamental biology concepts are regularly featured in medical and general science competitive exams.

Small intestine functionsBiomacromolecule breakdownStomach and digestionIntestinal bacteria

Human Digestive System Questions

Multiple choice evs nutritious food minerals and vitamins nutrition and diet role of various nutrients

The part of food that is not digested in the body is

  1. Starch

  2. Cellulose

  3. Proteins

  4. Fat
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The digestive system of Humans has many enzymes, and acids to break down and digest all kinds of different foods (carbohydrates. proteins and fats), but do not have the enzymes needed to break down cellulose. Cows, Goats, Sheep and other animals that graze on many organic foods(For example, grass) do have the enzymes needed to break down cellulose. Hence The part of food that is not digested in the body is Cellulose because the cellulose-digesting enzyme is absent.

So, the correct answer is 'cellulose'.

Multiple choice biology food for health fats fats and their test different nutrients in food

Bile salts take part in

  1. Digestion of carbohydrates

  2. Breakdown of proteins

  3. Emulsification of fat

  4. Absorption of glycerol
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Bile salts are essential for the emulsification of fats, which breaks large fat globules into smaller droplets to increase the surface area for lipase enzymes to act upon.

Multiple choice biology food for health fats fats and their test different nutrients in food

Lacteals take part in.

  1. Secretion of lactic acid

  2. Formation of milk

  3. Absorption of milk

  4. Absorption of fat
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Lacteals are specialized lymphatic capillaries located in the villi of the small intestine that absorb dietary fats (chylomicrons) that are too large to enter the blood capillaries directly.

Multiple choice biology food for health fats fats and their test different nutrients in food

Emulsified fats are digested by

  1. Gastric juice and pancreatic juice

  2. Pancreatic and intestinal juices

  3. Pancreatic and bile juices

  4. Bile and intestinal juices
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Emulsified fats are primarily digested in the small intestine by pancreatic lipase and intestinal lipase, which break them down into absorbable components.

Multiple choice biology food for health fats fats and their test different nutrients in food

Which of the following plays a key role in absorption and distribution of fats?

  1. Lacteals

  2. Villi

  3. Secretin

  4. Segmentation movements
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Meats, dairy products, seeds, nuts and oils contain dietary fat which needs to be broken down to be absorbed by the system. While the bile contains bile salts that emulsifies and pancreatic lipase acts to break lipids, to be absorbed in the blood stream this goes through further breakdown process in the small intestine where lacteals found in the villi of the intestinal wall help the lipids to pass through the  lymphatic system.

Therefore, the correct answer is option A.

Multiple choice biology food for health fats fats and their test different nutrients in food

Which of the following plays a key role in absorption and distribution of fats?

  1. Lacteals

  2. Villi

  3. Secretin

  4. Liver
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Lipids are fat-like molecule that cannot dissolve in water. When these reach the small intestine, the enzymes present there responsible for fat digestion acts on it. The pancreatic lipase breaks lipids down, resulting in free fatty acids and monoglycerides. Further, these are resynthesized into triglycerides which enter the lymphatic capillaries and lacteals present as the finger-like projections of the villi these acts on the lipids so as to be absorbed before they enter the bloodstream. 

Multiple choice biology coordination generation and conduction of nerve impulse generation of nerve impulse neurons and synapses

Which one of the following nerve stimulates gastric glands of secrete gastric juice and promote contractions of smooth muscles of stomach wall?

  1. Sacral spinal nerve

  2. Vagus nerve

  3. Glassopharyngeal

  4. Lumbar spinal nerve
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The vagus nerve (cranial nerve X) is the primary parasympathetic nerve that innervates visceral organs in the thoracic and abdominal cavities, stimulating gastric juice secretion and stomach wall contractions.

Multiple choice properties of enzyme enzyme properties enzymes biomolecules: chemical constituents of living cells biology

What is common among amylase, renin and trypsin?

  1. These are all proteins

  2. These are proteolytic enzymes

  3. These are produced in stomach

  4. These act at a pH lower than 7
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Amylase is a protein-based enzyme that is secreted by the salivary glands of mouth and is involved in the breakdown of starch. It functions in a neutral pH (pH 7). Renin is also a protein enzyme secreted in the stomach and involved in the coagulation of milk. It functions in a acidic pH. Trypsin is also a protein enzyme that is produced in the small intestine and is a proteolytic enzyme. It also functions in acidic pH. So, the correct answer is 'These are all proteins'.

Multiple choice properties of enzyme enzyme properties enzymes biomolecules: chemical constituents of living cells biology

Many enzymes are secreted in inactive form to protect

  1. Cell proteins

  2. Mitochondria

  3. Cell membrane

  4. Cell DNA
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The enzymes are protein in nature and they are generally produced in inactive form so to protect the intracellular damage of protein. For example,  digestive enzymes are secreted in form of zymogens which remains inactive in the cells in which it is produced. The active sites are blocked by the peptide which keeps the enzyme in the inactive stage so the other proteins do not get harmed by the reaction. Cleavage of this peptide cleaves activates the enzyme.

So, the correct answer is option A. 

Multiple choice properties of enzyme enzyme properties enzymes biomolecules: chemical constituents of living cells biology

Mark the INCORRECT statement about the enzyme carboxypeptidase.

  1. Zinc is the co-factor for this proteolytic enzyme

  2. It is exopeptidase

  3. It cleaves the peptide bond at N-terminal end of the polypeptide chain

  4. It is an enzyme of pancreatic juice
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Carboxypeptidase is a pancreatic exopeptidase that cleaves peptide bonds at the C-terminal end of a polypeptide chain, not the N-terminal end. Thus, statement C is incorrect.

Multiple choice properties of enzyme enzyme properties enzymes biomolecules: chemical constituents of living cells biology

Read the following statement
(i) The enzymes acts on 'N' terminal of a polypeptide chain is present in A
(ii) The enzymes in 'C' terminal of a polypeptide chain is present in BChoose the option which correctly fills up the blanks
A and B

  1. Gastric juice Pancreatic juice

  2. Pancreatic juice Gastric juice

  3. Pancreatic juice Succus entericus

  4. Intestine juice Pancreatic Juice
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The Pancreatic juice containing carboxypeptidases cleave the amino acid from the peptides from the carboxyl-terminal or C terminal.
The aminopeptidases present in the succus entericus cleave the amino acid from the amino-terminal or the N-terminal.

So, the correct answer is 'Pancreatic juice Succus entericus'

Multiple choice properties of enzyme enzyme properties enzymes biomolecules: chemical constituents of living cells biology

The hydrolytic enzymes acting at low pH are

  1. $\alpha$-amylases

  2. Hydrolases

  3. Proteases

  4. Pyrimidases
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A protease (also called peptidase or proteinase) is any enzyme that performs proteolysis, that is, begins protein catabolism by hydrolysis of the peptide bonds that link amino acids together in the polypeptide chain forming the protein. Proteases may be classified by the optimal pH in which they are active: acid proteases or neutral proteases or basic proteases.

Multiple choice biology blood circulatory system of human blood clotting platelets and their function defence against infectious disease

How many of the following nutrients, follow fol-lowing route of absorption
Blood capillaries $\rightarrow$ Mesentric vein $\rightarrow$ Hepatic portal vein $\rightarrow$ Liver $\rightarrow$ Hepatic vein $\rightarrow$ IVC $\rightarrow$ Heart $\rightarrow$ Body
(i) Glucose
(ii) Galactose
(iii) Fructose
(iv) L-amino acids
(v) D-amino acids
(vi) Long chain fatty acids.

  1. Six

  2. Five

  3. Only one

  4. Three.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Nutrients absorbed via blood capillaries follow the hepatic portal system route to the liver before reaching the heart. Glucose, galactose, L-amino acids, D-amino acids, and fructose all take this route, whereas long-chain fatty acids are absorbed into lacteals and enter the lymphatic system first. Thus, five of the listed nutrients follow this specific venous pathway.