NCERT Solutions for Class 11 Biology Chapter 7 Structural Organisation in Animals

NCERT Solutions for Class 11 Biology Chapter 7 Structural Organisation in Animals included in the CBSE syllabus aims at providing students with complete solutions to all the questions provided in the NCERT Textbook. These NCERT Solutions for Class 11 are created as per the latest update on the CBSE  Syllabus 2023-24. In order to perform exceedingly well, students are required to refer to multiple resources to widen their horizons, which would be extremely helpful for students not only for the examinations but also in their upcoming competitive exams.

These NCERT Solutions for Class 11 are skillfully crafted by a team of experts with the use of an easy-to-understand and simple language, thus enabling a smooth learning experience. Students get acquainted with the NCERT solutions quickly, as information has been extracted from the standard study tool – the NCERT textbook – and can kickstart their board exam preparations.

NCERT Solutions for Class 11 Biology Chapter 7 – Structural Organisation in Animals

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Access Answers to NCERT Class 11 Biology Chapter 7 – Structural Organisation in Animals

1. Answer in one word or one line.

(i) Give the common name of Periplanata americana.

(ii) How many spermathecae are found in earthworms?

(iii) What is the position of ovaries in cockroaches?

(iv) How many segments are present in the abdomen of cockroaches?

(v) Where do you find Malpighian tubules?

Solution:

i) American cockroach

ii) 4 pairs of spermathecae are found in earthworms.

iii) Two ovaries are found lying laterally around the 2^nd to the 6^th abdominal segments.

iv) 10 segments

v) Malpighian tubules are found at the junction of the midgut and the hindgut of the alimentary canals of insects.

2. Answer the following.

(i) What is the function of nephridia?

(ii) How many types of nephridia are found in earthworms based on their location?

Solution:

i) Nephridia perform the function of excretion and osmoregulation in earthworms.

ii) Three types of nephridia are found in the earthworm based on their location, and they are

• Septal nephridia are present on both sides of the intersegmental septa of segment 15 to the last that opens into the intestine.
• Integumentary nephridia are attached to the lining of the body wall of segment 3 to the last that opens on the body surface.
• Pharyngeal nephridia are present as three paired tufts in the 4th, 5th and 6th segments.

3. Draw a labelled diagram of the reproductive organs of an earthworm.

Solution:

The diagram of the reproductive organs of an earthworm is as follows:

4. Draw a labelled diagram of the alimentary canal of a cockroach.

Solution:

The diagram of the alimentary canal of a cockroach is as follows:

5. Distinguish between the following.

(a) Prostomium and peristomium

(b) Septal nephridium and pharyngeal nephridium

Solution:

a) Prostomium and peristomium

The differences are as follows:

b) Septal nephridium and pharyngeal nephridium

6. What are the cellular components of blood?

Solution:

The cellular components of blood are Red blood cells (RBC), white blood cells (WBC) and platelets.

7. What are the following, and where do you find them in an animal body?

(a) Chondrocytes

(b) Axons

(c) Ciliated epithelium

Solution:

a) Chondrocytes are the cells of cartilage. Cartilage is present in the tip of the nose, outer ear joints, and between adjacent bones of the vertebral column, limbs and hands in adults. They are rounded, large and mature cells that are found occurring in clusters in the matrix of the cartilage.

b) An axon is a long slender projection of a neuron or nerve cell. They are present throughout the body. They emerge from the cyton and are responsible for conducting nerve impulses away from the cell body. They terminate in a group of branches known as terminal arborisations.

c) If the columnar or cuboidal cells bear cilia on their free surface, they are called the ciliated epithelium. They are present in the inner surface of hollow organs like bronchioles and fallopian tubes. It comprises fine vibratile cytoplasmic processes that are termed cilia, found on its free surface. This cilium is functional in trapping foreign substances and dust.

8. Describe various types of epithelial tissues with the help of labelled diagrams.

Solution:

Epithelial tissues are found lining the body surface forming a protective surface. These cells are densely packed with a very little intercellular matrix.

Various types of epithelial tissues are

i) Simple epithelium:

It is a single layer of cells which functions as a lining for body cavities, ducts, and tubes.

Based on the structural modifications of the cells, Simple epithelial cells are further divided into 4 types.

• • Squamous epithelium

Simple epithelium is made of a single layer of a flattened cell having irregular boundaries. Since their cells represent tiles of a floor, they are also referred to as pavement epithelium. They are found in the walls of blood vessels and air sacs of the lungs. They are involved in excretion, protection, exchange of gases, secretion of coelomic fluid, etc.

• • Cuboidal epithelium

Cuboidal epithelium is made up of a single layer of cube-like cells. They are commonly found in ducts of glands and tubular parts of nephrons in kidneys, and their primary functions are secretion and absorption of gamete formation.

• • Columnar epithelium

The columnar epithelium is made of a single layer of tall and slender cells. They are found in the lining of the stomach and intestine and help in secretion and absorption. The nuclei of these cells are elongated and found at different positions. It aids in absorption and secretion.

• • Ciliated epithelium

If cuboidal or columnar epithelium has cilia, they are called ciliated epithelium. They are present in the inner surface of hollow organs like fallopian tubes and bronchioles. Their function is to move particles in a specific direction.

ii) Compound epithelium

The compound epithelium is a layer of two or more cells with a protective function, as it does in our skin. They are thick and strong compared to the simple epithelium, as they comprise two or more cell layers; they render protection. They cover the dry skin surface, the moist surface of the buccal cavity, and the inner lining of the ducts of pancreatic ducts and salivary ducts.

9. Distinguish between

(a) Simple epithelium and compound epithelium

(b) Cardiac muscle and striated muscle

(c) Dense regular and dense irregular connective tissues

(d) Adipose and blood tissue

(e) Simple gland and compound gland

Solution:

a. Simple epithelium and compound epithelium

b. Cardiac muscle and striated muscle

c. Dense regular and dense irregular connective tissues

d. Adipose and blood tissue

e. Simple gland and compound gland

10. Mark the odd one in each series.

(a) Areolar tissue; blood; neuron; tendon

(b) RBC; WBC; platelets; cartilage

(c) Exocrine; endocrine; salivary gland; ligament

(d) Maxilla; mandible; labrum; antennae

(e) Protonema; mesothorax; metathorax; coxa

Solution:

1. The answer is neuron because it is not a connective tissue.
2. The answer is cartilage because it is not part of blood.
3. The answer is ligament because it is connective tissue, whereas the rest are glands.
4. The answer is antennae because the rest are the parts of a cockroach’s stomach.
5. The answer is Protenema because it is a thread-like chain of cells found in the life cycle of moss, whereas others are the parts of segments of a cockroach’s leg.

11. Match the terms in column I with those in column II.

Solution:

12. Mention the circulatory system of earthworms briefly.

Solution:

• The earthworm has a closed circular system which comprises blood vessels, capillaries and the heart.
• In earthworms, blood is confined to the heart and blood vessels, as they have a closed circulatory system.
• Contraction keeps blood circulating in one direction.
• Blood glands are present on the 4th, 5th and 6th segments. They produce blood cells, haemoglobin, that are dissolved in the plasma of the blood.
• Blood cells are phagocytic.
• A specialised breathing system is absent; hence, the moist body surface helps in the respiratory exchange with their bloodstream

13. Draw a neat diagram of the digestive system of a frog.

Solution:

The diagram is as below.

14. Mention the function of the following (a) Ureters in frogs (b) Malpighian tubules (c) Body wall in earthworms

Solution:

1. Ureters in frog – Acts as a urinogenital duct which carries urine and sperm in the male frog.
2. Malpighian tubules – Malpighian tubules are excretory organs in cockroaches.
3. Body wall in earthworm – Helps in movement and burrowing

NCERT Solutions for Class 11 Biology Chapter 7 – Structural Organisation in Animals

NCERT Solutions for Class 11 Biology Chapter 7 – Structural Organisation in Animals is categorised under unit 2 – Structural Organization in Plants and Animals. The total marks that unit 2 constitutes are approximately 12 marks as per past trends, which is roughly 17% of the question paper. Therefore, students are required to pay extra attention to this chapter, as a wide range of questions appears from this unit.

Some of the types of questions that appear in the question paper are as follows:

• Remembering: Knowledge-based
• Understanding
• Application type
• Higher-order thinking skills: Analysing and Synthesis

List of subtopics covered in Chapter 7 – Structural Organisation in Animals

NCERT Solutions for Class 11 Biology Chapter 7 – Structural Organisation in Animals

In this chapter, students learn the complex animal tissues, which are arranged in a particular proportion and pattern for the formation of an organ. These organs, in turn, carry out a similar functionality through their physical and chemical interaction, which constitutes the organ system. Cells, tissues, organs and organ systems divide their work in such a way that exhibits division of labour, contributing to the survival of the body.

This chapter provides details about different parts with examples such as cockroaches, earthworms, frogs, etc. Details of the anatomy of different creatures enable students to understand the anatomical features and their morphological features in-depth.

Key Features of NCERT Solutions for Class 11 Biology Chapter 7 – Structural Organization in Animals

• NCERT Solutions are solved and reviewed by a team of experts
• Extensive coverage of fundamental concepts
• Curriculum-inclined solutions
• The best resource for the CBSE exam preparation as well as competitive exam preparation
• Easy to understand and use a simple language

Disclaimer – 

Dropped Topics – 

7.1 Animal Tissues
7.1.1 Epithelial Tissue
7.1.2 Connective Tissue
7.1.3 Muscle Tissue
7.1.4 Neural Tissue
7.3 Earthworm
7.3.1 Morphology
7.3.2 Anatomy
7.4 Cockroach
7.4.1 Morphology
7.4.2 Anatomy
Summary (Para 2, 3, 4)
Question nos 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14 (c)