Important Questions for CBSE Class 11 Biology Chapter 7 Structural Organisation in Animals 2024-25

Very Short Answer Questions: (1 Marks)
1. Name the tissue which contains Haversian canals.

Ans: Haversian canals are also known as haver and these are part of Mammalian bone.

2. Mention two special properties of nervous tissues.

Ans. Nervous tissues are the part of the brain, spinal cord, and nerves. The notable properties of nervous tissues are conductivity and irritability.

3. Name the large cells present in adipose tissue.

Ans: Adipose tissue is a special connective tissue consisting of lipid-rich cells known as adipocytes and the important function is to store energy in the form of lipids

4. Name the cells responsible for clotting of blood.

Ans: Platelets are the cells that form a blood clot. Platelets form clumps in the hole of a vessel to stop bleeding.

5. What are exocrine glands?

Ans: Exocrine glands are the glands that secrete substances into an epithelial surface through the duct. Examples include sweat, salivary, etc.

6. Differentiate between tendon and ligament.

Ans: A tendon is a connective tissue that attaches muscle to bone.  A ligament is also a connective tissue that attaches bone to bone and holds structures together and keeps them stable

7. Where are RBC s formed?

Ans: RBCs are present within the bones known as bone marrow. Red blood cells are formed in the red bone marrow of bones.

8. Name the kind of tissue that forms the lining of blood vessels? 

Ans: The kind of epithelium that forms the lining of blood vessels is the squamous epithelium. Squamous epithelium is also found in the alveoli of the lung for the exchange of gases.

9. Name the chemical which helps in transmitting nerve impulses at the synapse?

Ans: Acetylcholine is the chemical that helps in transmitting nerve impulses at the synapse. Acetylcholine is an abundant neurotransmitter in the human body. It is found in both the central nervous system and the peripheral nervous system.

10. What is the main function of WBCs?

Ans: The main function of WBC is to defend the body against infections. They are also called immunity cells.

11. What are the organs of excretion in insects?

Ans: Malpighian tubules are the organs of excretion in insects such as Ant.

12. Which tissue has fat globules?

Ans: Adipose tissue has fat globules. Adipose tissue is a specialized connective tissue consisting of lipid-rich cells called adipocytes.

13. Name two anticoagulants of the blood of man? 

Ans: Anticoagulants are medicines that help prevent blood clots. Heparin and antiprothrombin are the anticoagulants of the blood of man

14. Name the type of epithelium that lines the inner surface of the stomach?

Ans: The gastric epithelium is the simple columnar, non-ciliated epithelial tissue that lines the inner surface of the stomach. These are the cells found in the digestive tract of the human body.

15. What causes fatigue of the muscle fibers?

Ans: There are two main causes of muscle fatigue: 

Firstly the limitations of a nerve's ability to generate a sustained signal 

Secondly, the reduced ability of the muscle fiber to contract (metabolic fatigue).

16. Name the type of epithelium lining the buccal cavity?

Ans: Stratified squamous epithelium. It consists of a single basal layer containing stem cells, 2–3 layers of proliferative basaloid cells in the suprabasal region, and larger keratinized cells toward the surface.

17. Why are muscle cells usually called muscle fibers?

Ans: Muscle cells are usually called muscle fibers because muscle cells are thin & elongated into thread-like structures. Also, the muscle cells are long and tubular.

18. Define glands.

Ans: Glands are secretory structures formed of epithelial tissues. A gland is an organ that produces and releases substances that perform a specific function in the body

19. How many spermathecae are present in earthworms.

Ans: Four pairs of spermathecae are found in each of 6 to 9 segments of an earthworm. They help in receiving and storing the spermatozoa during copulation.

20. Name the proteins which constitute muscle fibers.

Ans: The muscle proteins can be divided into contractile, regulatory, sarcoplasmic, and extracellular forms. The most important are the contractile proteins namely Actin & myosin.

21. Which type of epithelium is found in the urinary bladder.

Ans: Transitional epithelium. Transitional epithelium is a type of tissue that consists of multiple layers of epithelial cells that can contract and expand. This tissue structure type is found in the urinary bladder and gland ducts of the prostate.

22. From which germ layers do the following organs originate.

Ans:

(a) Mesoderm: The mesoderm is the middle layer. In the embryo, it differentiates to give rise to a number of tissues and structures including bone, muscle, connective tissue, and the middle layer of the skin. 

(b) Endoderm is the innermost of the three primary germ layers in the very early embryo. The endoderm consists at first of flattened cells, which subsequently become columnar.

Short Answer Questions (2 Marks)

1.What are the two types of fibers of connective (issues? Distinguish between the two.

Ans: The two types of fibers of connective tissues are: White and yellow fibers.

2. To which tissue do the following belongs to

(a) Osteocytes  (b) Chondrocytes

(c) Neuroglia     (d) Intercalated discs Ans.

Ans: 

(a) Bone tissue

(b) Cartilage

(c) Neural tissue

(d) Cardiac muscle

3. Name the locomotory appendages of cockroaches on the basis of external morphology.

Ans: Three pairs of legs and 2 pairs of wings. The body of a cockroach is segmented and divided into three distinct segments- head, thorax, and abdomen. The three pairs of legs in a cockroach help them in locomotion. These are attached to the thorax part of the body.

4. Give the characteristic of epithelial tissues?

Ans: The characteristics features of epithelial tissue are:

1. It is made up of thin, irregular-shaped cells which fit to form a compact tissue.

2. It forms the lining of blood vessels, mouth, alveoli, nose, esophagus, and skin.

3. It protects the parts of the body from mechanical injury, entry of germs, chemicals, and drying. 

4. They are cube-shaped cells found in kidney tubules and ducts of salivary glands.

5.  How many types of nephridia are found in earthworms based on their location?

Ans: On the  basis of location, there are three types of nephridia;

• Septal

• Integumentary

• Pharyngeal

(i) Septal Nephridia: Those present on both the sides of intersegmental septa & open into the intestine

(ii) Integumental Nephridia: Those found attached to the lining of the body wall & open on the body surface.

(iii) Pharyngeal Nephridia: Those found on the 4th, 5th, & 6th segment in the form of three paired tufts are pharyngeal nephridia.

6. What do you mean by hemopoiesis?

Ans: Hemopoiesis is the formation of new erythrocytes from the Hematopoietic tissue. The hematopoietic tissue is the young fetus in the liver and spleen whereas, in adults, it is the bone marrow of the long bone. The hematopoietic tissue synthesizes millions of RBCs every minute and its excess lot is stored in the spleen.

7. Differentiate between blood & lymph?

Ans: The difference between blood and lymph are as following:

8. What are nissl’s granules? Where are they found? 

Ans: 

• Nissl granules occur in the neurons and are the site for protein synthesis. 

• Nissl's granules are present in the cytoplasm of the cell body of the neurons along with other cell organelles like Golgi apparatus, endoplasmic reticulum, mitochondria, nucleus, etc. 

• These granules give a slight colored appearance to the cytoplasm of the cell body. They help in protein synthesis in the neurons.

9. Discuss the structure of the Haversian system in the histology of bone?

Ans: Bone consists of connective tissue having matrix surrounded by periosteum. In mammalian bone, the Haversian canal which carries blood vessels and nerves of the bone is surrounded by a number of concentric lamellae of intercellular matrix and bone.

10. Distinguish between myosin & actin filament?

Ans: The difference between myosin and actin filament are given below:

11. What are chondrocytes? Where are they found?

Ans: Chondrocytes: They are cells of cartilages and are present in small cavities within the matrix secreted by them. 

Chondrocytes occur in clusters of 2 or 3 cells in small spaces called the lacunae.

12. Name the major class of plasma protein & mention their functions. 

Ans: Three major classes of plasma proteins are:-

(a) Serum (b) Serum globulin (c) Fibrinogen

The following are the main functions of Plasma Proteins:- 

(i) It provides body immunity

(ii) It helps in the prevention of blood loss. 

(iii) It helps in the retention of fluids in the blood. 

(iv) It helps in the transport of material

(v) It helps in maintaining the PH of blood.

(vi) It helps in conducting heat to skin for dissipation

13. What is the function of nephridia?

Ans: The nephridium or nephridia) is an invertebrate organ that is found in pairs and performs a function similar to the vertebrate kidney. Nephridia help in removing metabolic wastes from an animal's body.

14. Distinguish between smooth & striated muscles.

Ans: The difference between smooth and striated muscles are given below:

15. What are the functions of mast cells?

Ans: Mast cells are long-lived tissue-resident cells with an important role in many inflammatory settings including host defense to parasitic infection and in allergic reactions.

(i)  They store inflammation-producing substance histamine. 

(ii)  They also release heparin which prevents activation of prothrombin.

16. How can a male frog be distinguished from a female frog?

Ans: The male frogs may be distinguished by the presence of sound-producing vocal sacs. They also have a copulatory pad on the first digit of the forelimbs. Vocal sacs and copulatory pads are absent in female frogs. 

Also, a small round disc called the tympanum covers the ears of both male and female frogs. On males of most frog species, the circumference of this small disc is larger than the eye of the frog. On females of most frog species, the disc's circumference is equal to the size of the frog's eye.

17. Give a reason why earthworms are known as friends of farmers.

Ans: Earthworms are known as “friends of farmers” as they make burrows in the soil which makes that porous.

It facilitates respiration as well as penetration for the developing roots of the plants. The earthworms eat decaying vegetation and in the burrows, it enriches the soil.

18. Write a short note on adipose tissues.

Ans: Adipose tissue is a specialized connective tissue consisting of lipid-rich cells known as adipocytes. It comprises about 20-25% of total body weight in healthy individuals. Its main function is to store energy in the form of lipids.

19. What are neuroglial cells?

Ans: Neuroglial cells are cells that hold the neurons together. Neuroglia is non-neuronal cells in the central nervous system (brain and spinal cord) and the peripheral nervous system that do not produce electrical impulses. 

They maintain homeostasis, form myelin in the peripheral nervous system, and provide support and protection for neurons.

20. How does saltatory conduction take place along a nerve fiber?

Ans. Saltatory conduction describes the way an electrical impulse skips from node to node down the full length of an axon, speeding the arrival of the impulse at the nerve terminal in comparison with the slower continuous progression of depolarization spreading down an unmyelinated axon. Along with a myelinated nerve fiber, the conduction of impulse is called saltatory conduction. This is so because the ionic changes and consequent depolarization are taking place only.

21. Write a short note on gaseous exchange in cockroaches.

Ans: Cockroaches are insects that have a system of the trachea. Tracheal respiration occurs in such animals. It is a complicated system of air tubes. They divide and form tracheoles.

Tracheoles are connected to the spiracles located in the segments of the thorax and abdomen. The body cells or fluid come in direct communication with air.

22. Draw a well-labeled diagram of a nerve cell.

23. Distinguish between tendon & ligament.

Ans: The difference between tendon and ligament is given below:

24. What is mucosa?

Ans: Mucosa is a moist tissue that lines certain parts of the inside of the body. The mucosa is the mucous secreting epithelial tissue along with the supporting connective tissue beneath it. It lines some hollow organs or cavities of the body e.g. alimentary canal, nose, trachea, and lungs, etc.

Short Answer Question (3 Marks)

1.

(a) Give the common name of Periplaneta Americana.

(b) How many spermathecae are found in cockroaches?

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

(d) How many segments are present in the abdomen of the cockroach?

(e) Where do you find malpighian tubules?

(f) What is the mosaic vision?

Ans:

(a) It is a large reddish-brown free-flying cockroach and the common name for Periplaneta Americana is American Cockroach.

(b) There are four pairs of spermatheca is a cockroach.

(c) The female cockroach consists of two large ovaries. The ovaries are present in the 12th and 13th segments in anatomy. The exact position of the ovaries is the 2nd and 6th abdominal terga.

(d) The anatomy of cockroaches comprises three segments: head, thorax, and abdomen. The abdomen part has 10 segments.

(e) Malpighian tubules are found in phylum Arthropoda and these are the excretory part of the insect and positioned in the abdominal cavity.

(f) It is the type of vision found in insects that can see the small part of the object seen and not the entire object.

2. 

(i) Give three differences between frogs & toads?

(ii) What do you understand about the open type of circulatory system?

Ans: (i) The difference between frogs and toads are given below:

(ii) Insects, spiders, prawns, and most mollusks have an open type of circulatory system which defines these systems to transmit blood into a hemocoel with the blood diffusing back to the circulatory system between cells.

3. What are the cellular components of blood?

Ans: The main components of blood are plasma, red blood cells, white blood cells, and platelets.

• Red blood cells or erythrocytes function to transmit oxygen from the lungs to the rest of the body.

• White blood cells or leukocytes help to fight infection and build the immune system.

• Platelets or thrombocytes support blood clotting

4. How do erythrocytes transport oxygen & carbon dioxide in the blood?

Ans: RBCs help in the transportation of oxygen in the blood. During inhalation, oxygen is taken into the lungs, and from the lungs, oxygen diffuses into the blood. As soon as it enters the blood, it also enters the RBC where it binds to the hemoglobin. 3% of oxygen is dissolved in the blood where 97% of transported oxygen is bound to hemoglobin. This oxygen then diffuses into the tissues.

Carbon dioxide is produced as a result of transpiration inside the body cells. From the cell, the carbon dioxide diffuses into the blood where it is carried as:

1. Carbaminohemoglobin, when it is bound to hemoglobin.

2. Dissolved into the plasma.

3. Bicarbonate Ions.

Carbon dioxide is maximally transported as bicarbonates and it is taken back to the lungs with the help of blood where it is released back into the atmosphere. The diffusion of these gases takes place according to their partial pressures.

5. Describe the different types of connective tissues & give examples?

Ans: On the Basis of the matrix, connective tissues are of two main types:-

(I) Connective Tissue Proper: It connects and supports many tissues and organs. Its matrix is dense. E.g.

(a) Areolar Tissue: It consists of three types of cells and types of fibers, all distributed in the matrix. Fibroblasts are irregularly shaped flat cells with long protoplasmic processes, they secrete collagen and elastin proteins for the fibers.

(b) Adipose Tissue: It consists of collagen fibers, elastin fibers, fibroblast, macrophages, & adipocytes which store fat. It prevents heat loss by forming one insulating layer beneath the skin.

(II) Supportive Connective Tissues: It consists of the following types of connective tissue:

(a) Cartilage: It is the endoskeletal material of the vertebrates, it is in the form of a solid matrix formed of chondrin with few collagen fibers and chondroblasts cells.

(b) Bone: The matrix consists of bone cells, osteocytes, fibers, and a ground substance impregnated by calcium phosphate, calcium carbonate, magnesium phosphate, and calcium fluoride. Due to these salts, it becomes very hard & forms skeletal support of the body.

6. Describe briefly the structure of voluntary muscles

Ans: 

(i) A voluntary muscle is a bundle of numerous striated muscle fibers.

(ii) Each fiber is long, unbranched, and enclosed in a membrane called sarcolemma and its cytoplasm called sarcoplasm. Just beneath the sarcolemma in each fiber, many nuclei occur, thus these fibers are multinucleated.  

(iii) The sarcoplasm contains many myofibrils that are long, thin, and unbranched.  

(iv) Each myofibril consist of alternating thick 'A' and thin ‘I' band.

(v) The thick filaments lie parallel to each other while thin filaments extend between them.  

(vi) At the center of the I-band is a fine, dense dark band called Z-line. It forms a contractile unit called a sarcomere.

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7. How does blood gets coagulated on coming out from an injured vessel. How coagulation normally prevented uninjured vessels.

Ans. When a blood vessel is injured, the blood starts coming out of it. At that time, the thrombocytes clump together, break and release the coagulation-promoting substances called thromboplastin. 

Thromboplastin helps in the formation of the enzyme thrombokinase. This enzyme thrombokinase hydrolyses prothrombin in the plasma into thrombin. 

Thrombin catalyzes the hydrolysis of soluble fibrinogen in the plasma into insoluble fibrin. The fibrin precipitates as a network of fibers and traps many blood cells to form a red solid mass called a blood clot. The clot seals the wound in the blood vessel to stop bleeding.

However, in uninjured tissues and blood vessels, thromboplastin does not get released. That is why coagulation is prevented in an uninjured vessel.

8. Give an account of the alimentary canal of frogs.

Ans: Alimentary canal of frog: It is a short tube starting from mouth to cloaca. The mouth opens into the buccopharyngeal cavity. It has many maxillary teeth as the margin of the upper jaw. 

Vomerine teeth lie on the floor of this cavity. The tongue is bilobed and muscular. It is used to capture the prey. 

Gullet opens into the esophagus which is distended into the stomach. The stomach follows the small and large intestine. The rectum opens into the cloaca. The liver and pancreas are digestive canals.

Practice Questions For CBSE Class 11 Biology Chapter 7: Structural Organisation in Animals

Very Short Answer Type Questions

1. What are the four basic types of tissues found in animals?

2. Which sugar is found in milk?

3. How are frogs useful for mankind?

Short Answer Type Questions

1. Explain connective tissues.

2. Which organ/s is/are found in both male and female cockroaches?

3. Define adipose tissue.

Long Answer Type Questions

1. What are the different sense organs found in frogs?

2. Explain the process of respiration in frogs.

3. Explain the difference between cutaneous and pulmonary respiration.

Extra Questions for Practice

1. Explain the different types of epithelial tissues with the help of a diagram.

2. Explain the difference between Prostomium and Peristomium.

3. Which is the most common frog found in India?

4. What are the four major types of tissues?

5. Why are earthworms known as the friends of farmers?

Benefits of Solving CBSE Class 11 Biology Chapter 7 Important Questions

Students can get the following benefits when practising Class 11 Biology Chapter 7  important questions:

• Students can develop time management skills while solving questions repeatedly in a given time duration.

• Practising these important questions will give you an overall idea about the important topics of the chapter.

• Solving various types of questions given will ensure enhanced problem-solving skills.

• Students can clear all their doubts with respect to important topics of the chapter by practising these important questions and detailed explanations which are provided by our experts in order to help them prepare better for the exams.

Conclusion

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