Biology · Science General

Human Digestive System

2,002 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 biology coordination and response control of blood glucose endocrine system and hormone hormones in human reproduction

The activities of the gastrointestinal tract are under the control of 

  1. Nervous system

  2. Hormones

  3. Both A and B

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The activities of the gastrointestinal tract are under the control of the nervous system and hormones. The sight, smell and/or the presence of food in the oral cavity can stimulate the secretion of saliva. Similarly, gastric and intestinal secretions are also stimulated by neural signals. The muscular activities of different parts of the alimentary canal can also be moderated by neural mechanisms (both local and through CNS). Hormonal control of the secretion of digestive juices is carried out by local hormones produced by the gastric and intestinal mucosa.

So, the correct option is 'Both'.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Enzyme amylase belongs to class 

  1. Transferases

  2. Hydrolases

  3. Isomerases

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

Hydrolases are the enzymes which break large molecules into smaller ones with the help of hydrogen and hydroxyl groups of water molecules, this phenomenon is known as hydrolysis. Amylase is the enzyme produced by the salivary gland and is found in saliva. It breaks starch into glucose. Thus, the correct answer is B.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Hydrolytic enzymes which act on low pH are called as : -

  1. Protease

  2. -Amylase

  3. Hydrolases

  4. Peroxidase
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The stomach has low pH due to the secretion of HCl. Protease, an enzyme for digesting protein acts in low pH i.e. in the stomach. Amylase is a starch (carbohydrate) digesting enzyme and carbohydrate digestion does not occur in the stomach. All digestive enzymes are hydrolases. Peroxidase is an iron-containing enzyme, found mainly in plants but also present in leucocytes and milk, that catalyses the dehydrogenation (oxidation) of various substances in the presence of hydrogen peroxide.

So, the correct answer is 'Hydrolases'.
Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

The fastest acting enzyme, in the biological kingdom, is 

  1. Lipase

  2. Amylase

  3. Peptidase

  4. Carbonic anhydrase
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Enzymes are biological catalysts which catalyze biological reactions. They do not modify the chemical equilibria in any manner but simply make the attainment of equilibrium faster. Carbonic anhydrase catalyzes reversible reaction between carbon dioxide and water to form carbonic acid. This enzyme is one of the fastest enzyme. It is especially abundant in human erythrocytes.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Most of the digestive enzymes belong to the class of

  1. Lyases

  2. Hydrolases

  3. Oxidoreductases

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

Hydrolase enzymes break large molecules into small molecules with the help of hydrogen and hydroxyl group of water molecules. The phenomenon is known as hydrolysis. Digestive enzymes in our body help to break down macromolecules of food into smaller molecules by the process of hydrolysis. So, digestive enzymes belong to the class Hydrolases. Thus, the correct option is B.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Hydrolysis of starch occurs with the help of

  1. Sucrase

  2. Amylase

  3. Peptidase

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

Starch is used as food reserves in plants. It is a polymer of glucose. It is formed by the attachment of glucose unit by glycosidic bonds. The basic formula of starch is (C$ _6$H$ _{10}$O$ _5$)n. 

Amylase is an enzyme which helps in the digestion of the starch. It acts on the glycosidic bonds of the starch and converts into simpler compounds. It helps in the hydrolysis of this bond. It is present in the saliva and the pancreas secretion in humans and helps in intracellular digestion of starch.
So, the correct answer is option B.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

The fastest acting enzyme in the biological kingdom is

  1. Lipase

  2. Amylase

  3. Carboxypeptidase

  4. Carbonic anhydrase
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In enzymology, turnover number is the number of substrate molecules converted to products in a given unit of time on a single enzyme molecule when the enzyme is saturated with substrate. The enzyme catalase has highest turnover number value of 40,000,000 (per second per molecule of enzyme), followed by Carbonic anhydrase 400,000 (per second per molecule of enzyme), followed by acetylcholinesterase 140,000 (per second per molecule of enzyme), followed by $\beta$-lactamase 2000 (per second per molecule of enzyme).

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

In recent years, pre-soaked laundry agent (detergent) contains an enzyme

  1. Pepsin

  2. Flavin

  3. Amylase

  4. Subtilin
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Natural source of subtilin is bacteria Bacillus subtilis. Subtilisins are proteolytic enzymes mainly used in detergents and house hold cleaning products to remove proteinaceous deposits and stains.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Name the hormone that stimulate the secretion of gastric juice.

  1. Renin

  2. Enterokinase

  3. Enterogastrone

  4. Gastrin
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Gastrin is a peptide hormone, which is secreted by the gastric glands in the stomach wall. The gastrin stimulates secretion of gastric juice rich in pepsin and hydrochloric acid. The stimulation for secretion of gastrin is presence of peptides derived from dietary proteins.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Enzyme amylase belongs to category 

  1. Oxidoreductases

  2. Transferases

  3. Hydrolases

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

An amylase is an enzyme that catalyses the hydrolysis of starch into sugars. A hydrolase or hydrolytic enzyme is an enzyme that catalyzes the hydrolysis of a chemical bond. So, the correct answer is option C.

Multiple choice enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Which is not a hydrolase?

  1. Protease

  2. Dehydrogenase

  3. Sucrase

  4. Amylase

  5. Esterase
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation


A dehydrogenase is an enzyme that oxidizes a substrate by reducing an electron acceptor, usually a flavin coenzyme known as FMN.
While all other are hydrolases because they take part in the hydrolysis. 
So the correct answer is C.

Multiple choice enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Digestive enzymes are found in

  1. Lysosomes

  2. Mitochondria

  3. Chloroplast

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Lysosomes are membrane-bound vesicles that contain digestive enzymes, such as glycosidases, proteases and sulfatases. Lysosomal enzymes are synthesized in the endoplasmic reticulum (ER), are transported to the Golgi apparatus, and are tagged for lysosomes by the addition of mannose-6-phosphate label. Digestive enzymes are not found in chloroplast and mitochondria. 

Therefore, the correct answer is option A.

Multiple choice enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Endopeptidase of plant kingdom is

  1. Trypsin

  2. Pepsin

  3. Papain

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

Endopeptidase are the proteolytic enzymes which cleave the peptide chain at internal locations. They break peptide bonds of non terminal amino acids (i.e. within the molecule), in contrast to exopeptidases, which break peptide bonds from their end-pieces. One example is papain obtained from unripe papaya.

Multiple choice biology biotechnology and genetic engineering stds and infertility gm crops biotechnology

An enzyme used in cheese making is

  1. Protease

  2. Rennet

  3. Glucoamylase

  4. Lactase
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Animal rennet (bovine chymosin) is conventionally used as a milk-clotting agent in dairy industry for the manufacture of quality cheeses with good flavour and texture. Owing to an increase in demand for cheese production world wide, i.e., 4% per annum over the past 20 years, approximating 13.533 million tons – coupled with reduced supply of calf rennet, has therefore led to a search for rennet substitutes, such as microbial rennets. At present, microbial rennet is used for one-third of all the cheese produced world wide.
Thus, the correct answer is option B.