NCERT Solutions for Class 11 Biology Chapter 16 Excretory Products and Their Elimination

NCERT Solutions For Class 11 Biology Chapter 16 - PDF Download

Students can download the PDF for Chapter Excretory Products and Their Elimination from the link given below. This PDF can be accessed offline for easy and quick revision anytime. The NCERT Solutions for Class 11 are prepared in simple language to help students understand all concepts clearly. Download PDF

Access to Class 11 Biology Chapter 16 Solutions (Exercise Questions)

The complete exercise and in-text answers are given below. These solutions are based on the latest syllabus and help in quick revision before exams. Studying through Excretory Products and their Elimination questions and answers helps students revise important concepts.

Q1. Define Glomerular Filtration Rate (GFR)

Answer: The Glomerular Filtration Rate (GFR) is a measure of how well the kidneys filter the blood.

• GFR is the rate of fluid filtered by all of the nephrons in both kidneys per minute.
• Normal GFR in healthy adults is roughly 125 mL/min (180 litres per day).

Q2. Explain the autoregulatory mechanism of GFR.

Answer: The kidneys contain a systematic mechanism to control GFR through the Juxtaglomerular apparatus (JGA).

• The JGA senses reduced GFR and releases renin, activating the renin-angiotensin system to cause vasoconstriction and increase blood pressure.
• This action restores glomerular filtration pressure, bringing GFR back to normal.

Q3. Indicate whether the following statements are true or false:

(a) Micturition is carried out by a reflex.
(b) ADH helps in water elimination, making the urine hypotonic.
(c) Protein-free fluid is filtered from blood plasma into the Bowman’s capsule.
(d) Henle’s loop plays an important role in concentrating the urine.
(e) Glucose is actively reabsorbed in the proximal convoluted tubule.

Answer: The true and false statements are mentioned below:

Q4. Give a brief account of the counter-current mechanism.

Answer: The countercurrent mechanism plays a crucial role in the concentration of urine and water conservation.

• It supports a medullary osmotic gradient (300 → 1200 mOsm/L).
• The Loop of Henle removes NaCl (ascending limb) and urea (collecting duct), while the vasa recta keep this gradient maintained by the countercurrent exchange.

Q5. Describe the role of the liver, lungs and skin in excretion

Answer: Various organs contribute to the excretion processes of the body, each with distinct functions.

Q6. Explain micturition

Answer: Passing urine out of the bladder is called Micturition

• As the urine builds up, bladder stretch initiates a spinal reflex, the urethral sphincters relax, and the muscles of the bladder contract.
• Adults typically urinate approximately 1–1.5 litres per day.

Q7. Match the items of column I with those of column II

Column I Column II

(a) Ammonotelism (i) Birds
(b) Bowman’s capsule (ii) Water reabsorption
(c) Micturition (iii) Bony fish
(d) Uricotelism (iv) Urinary bladder
(e) ADH (v) Renal tubule

Answer: The correct matching is a-iii, b-v, c-iv, d-i, e-ii

Q8. What is meant by the term osmoregulation?

Answer: Osmoregulation is important for the balance of water and salts in body fluids.

• It controls water and ionic content to maintain the internal environment constant.

Q9. Terrestrial animals are generally either ureotelic or uricotelic, not ammonotelic. Why?

Answer: Terrestrial animals primarily excrete urea or uric acid due to ammonia's toxicity and water requirements.

Q10. What is the significance of the juxta-glomerular apparatus (JGA) in kidney function?

Answer: The JGA has an important function in the control of kidney function through the monitoring of blood pressure.

• It secretes renin when GFR is low, which stimulates angiotensin II to constrict blood vessels and stimulate the secretion of aldosterone.
• This increases blood pressure and glomerular filtration rate.

Q11. Name the following:

(a) A chordate animal having flame cells as excretory structures

Answer: A chordate animal having flame cells as excretory structures is an Amphioxus.

Q11. Name the following:

(b) Cortical portions projecting between the medullary pyramids in the human kidney

Answer: Cortical portions projecting between the medullary pyramids in the human kidney are called columns of Bertini.

Q11. Name the following:

(c) A loop of capillary running parallel to Henle's loop.

Answer: A loop of capillary running parallel to Henle’s loop is the vasa recta.

Q12. Fill in the gaps :

(a) The ascending limb of Henle’s loop is _______ to water, whereas the descending limb is _______ to it.
(b) Reabsorption of water from the distal parts of the tubules is facilitated by hormone _______.
(c) Dialysis fluid contains all the constituents as in plasma except _______.
(d) A healthy adult human excretes (on average) _______ gm of urea/day.

Answer:

(a) The ascending limb of Henle’s loop is impermeable to water, whereas the descending limb is permeable to it.
(b) Reabsorption of water from the distal parts of the tubules is facilitated by the hormone ADH.
(c) Dialysis fluid contains all the constituents as in plasma except nitrogenous wastes.
(d) A healthy adult human excretes (on average) 20-30 gm of urea/day.

NCERT Solutions for Class 11: Subject-wise

• NCERT Solutions for Class 11 Maths
• NCERT Solutions for Class 11 Chemistry
• NCERT Solutions for Class 11 Physics

Approach to Solve Questions of Class 11 Biology Chapter 16 Solutions

To answer questions from this chapter correctly, Students can follow the simple steps which are given below:

• Start by understanding the different types of nitrogenous wastes. It includes ammonia, urea, and uric acid, and knows which organisms excrete which type.

• Learn the structure and function of the human excretory system, especially the kidneys and nephrons. These are well-explained in the NCERT Solutions for Class 11 Biology Chapter 16 Excretory Products and their Elimination.
  
  

• Understand the process of urine formation, and the steps, like filtration, reabsorption, and tubular secretion. Practice diagram-based questions, especially of the nephron and excretory system.

• Study from the Excretory Products and their Elimination NCERT PDF. Focus on how kidneys regulate water and salts in the body (osmoregulation).

• Revise disorders related to the excretory system, such as kidney stones, uremia, dialysis, and kidney transplantation.

• Solve the different questions given in the NCERT Solutions for Class 11 Biology to improve the conceptual clarity.

Important Question from Class 11 Biology Chapter 16 Solutions

Take a look at this important question that can help in increasing the understanding of the concept. To score well in the exam, it is very important to practice many questions of different types. For this purpose, students can depend on the Excretory Products and their Elimination Class 11 Solutions.

Question: Which of the following is not a component of the human excretory system?

i. Kidneys

ii. Ureters

iii. Lungs

iv. Urethra

Options:

1. i and ii

2. ii and iii

3. i and iii

4. iii and iv

Answer: Option 4

Explanation: Lungs are not included in the excretory system and are responsible for expelling nitrogenous wastes such as urea. The urinary system includes the kidneys, ureters, urinary bladder, and urethra responsible for excretion. Lungs are respiratory organs that eliminate carbon dioxide but not nitrogenous wastes.

Also, check the NCERT Books and NCERT Syllabus here :

• NCERT Books Class 11 Biology

• NCERT Syllabus Class 11 Biology

• NCERT Books Class 11

• NCERT Syllabus Class 11

What Extra Should Students Study Beyond the NCERT for NEET?

Here is a table for all the important topics from the chapter. Students should also focus on diagrams, MCQs, and conceptual questions from books. For more understanding, they can refer to Excretory Products and their Elimination Class 11 Solution, which are explained in easy language.

NCERT Solutions for Class 11 Biology - Chapter Wise

Below are the Chapterwise solutions for quick and easy access: