State one role of each of the following in human digestive system: (i) Hydrochloric acid (ii) Villi (iii) Anal Sphincter (iv) Lipase
State one role of each of the following in human digestive system: (i) Hydrochloric acid (ii) Villi (iii) Anal Sphincter (iv) Lipase
Official answer
In the human digestive system, the roles are as follows:
(i) Hydrochloric acid (HCl): It creates an acidic medium in the stomach which is necessary for the activation and action of the enzyme pepsin. It also kills harmful bacteria that may enter with food.
(ii) Villi: These are finger-like projections in the small intestine that increase the surface area for the efficient absorption of digested food into the blood.
(iii) Anal Sphincter: It regulates the exit of undigested waste material (faeces) from the body.
(iv) Lipase: This enzyme is responsible for the chemical breakdown of emulsified fats into fatty acids and glycerol.
Marking scheme
- 1.0.5 mark for the role of Hydrochloric acid (acidic medium/killing bacteria).
- 2.0.5 mark for the role of Villi (increasing surface area for absorption).
- 3.0.5 mark for the role of Anal Sphincter (regulating exit of waste).
- 4.0.5 mark for the role of Lipase (digestion of fats).
Hint
Think about the specific environment needed for enzymes to work and how the body maximizes nutrient uptake.
Quick oral answer
What is the primary function of the acidic medium in the stomach? It activates the protein-digesting enzyme pepsin and kills ingested pathogens.
Common mistakes
- 1.Confusing lipase with pepsin or trypsin.
- 2.Stating that HCl digests food directly rather than creating the environment for enzymes.
Analysis and explanation
The provided text identifies digestion as a chemical change where complex substances are broken down into simpler ones. For instance, carbohydrates are broken down into glucose (). This chemical transformation is facilitated by various biological catalysts (enzymes) and specific environments (like the acidic medium created by ) within the digestive tract. Villi and sphincters provide the mechanical and structural support necessary for the completion of these chemical processes and the subsequent absorption of products.
Interesting facts
The surface area provided by the villi in the human small intestine is approximately equivalent to the size of a tennis court.
Question details
Q22 of 39 questions
- Board
- CBSE
- Class
- Class 10
- Subject
- Science
- Year
- 2024
- Section
- Section B
- Marks
- 2
- Type
- Very Short Answer
- Chapter
- Chemical Reactions and Equations
- Topic
- Chemical Changes in Daily Life
- Bloom's level
- Remembering
- Syllabus topic
- Life Processes: Digestion
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Frequently asked questions
How many marks does this question carry in CBSE Class 10 Science 2024?
This question carries 2 marks in the CBSE Class 10 Science 2024 examination.
Which chapter does this question come from in Science?
This question is from the chapter "Chemical Reactions and Equations" in the CBSE Class 10 Science syllabus.
What topic does this question cover in Science?
This question covers the topic "Chemical Changes in Daily Life" from CBSE Class 10 Science.
What type of question is this in the CBSE Class 10 Science 2024 paper?
This is a Very Short Answer question from Section B in the CBSE Class 10 Science 2024 paper.