Please refer to Structural Organisation in Animals Class 11 Biology Exam Questions provided below. These questions and answers for Class 11 Biology have been designed based on the past trend of questions and important topics in your class 11 Biology books. You should go through all Class 11 Biology Important Questions provided by our teachers which will help you to get more marks in upcoming exams.
Class 11 Biology Exam Questions Structural Organisation in Animals
Class 11 Biology students should read and understand the important questions and answers provided below for Structural Organisation in Animals which will help them to understand all important and difficult topics.
Question. The ciliated columnar epithelial cells in humans occur in
(a) Eustachian tube and stomach lining
(b) bronchioles and fallopian tubes
(c) bile duct and oesophagus
(d) fallopian tubes and urethra
Question. Epithelial tissue is distinguished from connective tissue, muscular, or nervous tissue by its
(a) large extracellular matrix.
(c) ability to carry action potentials.
(d) basement membrane.
Question. General function of gland is to
(a) protect the body.
(b) control the function of epithelial tissues.
(c) produce and secrete specialized compounds to control and maintain different body functions.
(d) help to maintain blood pressure and nerve actions.
Question. The only type of cell seen in a tendon is
(a) muscle fibres
(b) reticular cells
(c) collagenous cells
Question. The shape of a person’s ear is mainly due to
(a) dense regular connective tissue
(b) dense irregular connective tissue
(c) elastic cartilage
Question. Muscle tissue cells are contractile, which means they
(a) are responsible for the production and secretion of enzymes.
(b) are specialized in contraction and relaxation.
(c) help in the movement of involuntary organs only.
(d) all of the above
Question. Three essential components of most neurons are
(a) simple epithelium, extracellular matrix and nerves.
(b) axon, dendrites and cell body.
(c) nerve cells, synapse and neuroglia.
(d) mylein sheeth, node of Ranvier and Schwann cells.
Question. The fibres of which of the following muscles are fusiform and do not show striations
(a) Skeletal muscles
(b) Cardiac muscles
(c) Both (a) and (b)
(d) Smooth muscles
Question. Smooth muscles are______.
(a) voluntary, branched, uninucleate
(b) voluntary, multinucleate, cylindrical
(c) involuntary, cylindrical, multinucleate
(d) involuntary, spindle shaped, uninucleated, tapering
Question. Which one of the following pairs of structures distinguished a nerve cell from other types of cell ?
(a) Vacuoles and Fibres
(b) Flagellum and Medullary sheath
(c) Nucleus and Mitochondria
(d) Cell body and Dendrites
Question. In earthworms setae are present in all segments except
(a) first and the last segments
(b) first segment and the clitellum
(c) first segment
(d) clitellum and last segments
Question. Cockroaches are brown or black bodied animals that are included in class _______ of phylum _______.
(a) reptilia; annelida
(b) insecta; arthropoda
(c) insecta; annelida
(d) reptilia; arthropoda
Question. In cockroach, the testes are present in
(a) 3, 4, 5 abdominal segments
(b) 4, 5, 6 abdominal segments
(c) 5, 6, 7 abdominal segments
(d) 6, 7, 8 abdominal segments
Question. Phallic organs in cockroach are related to
(a) male excretory system.
(b) male reproductive system.
(c) female excretory system.
(d) female reproductive system.
Question. A frog never drinks water but absorbs it through one of its respiratory organ. Identify the organ.
(c) Buccal cavity
(d) None of the above.
Very Short Answer Type Questions:
Question. How many times do nymphs moult to reach the adult form of cockroach?
Ans. The nymph grows by moulting about 13 times to reach. In cockroach, the development is indirect and paurometabous adult form and has three stages. i.e., egg, nymph and adult.
The nymph resembles adult except for undeveloped wings and genitalia.
Question. Special venous connection between liver and intestine and between kidney and intestine is found in frog, what are they called?
Ans. Special venous connection between liver and intestine is called hepatic portal system and venus connection between the kidney and the lower parts of the frog is called renal portal system.
Question. What is the scientific term given to earthworm’s body segments?
Ans. Metamers is the scientific term given to earthworm’s body segments.
Question. Which mouth part of cockroach is comparable to our tongue?
Ans. Hypopharynx acts as a tongue in cockroach and lies within cavity enclosed by the mouth parts.
Question. A muscle fibre tapers at both ends and does not show striations. Name the muscle fibre.
Ans. Smooth muscle fibres taper at both the ends (fusiform) and do not show striations.
They are also called involuntary muscles.
Question. Name the different cell junctions found in tissues
Ans. The different cell junctions found in tissues are
(i) Tight junctions are regions where plasma membrane of adjacent epithelial cells are held close together. They check the movement of material between then.
(ii) Gap junctions are meant for chemical exchange between adjacent cells.
(iii) Adhering junctions perform connecting function to keep neighbouring cells together.
Question. Name the process by which a tadpole develops into an adult frog.
Ans. Tadpole undergoes metamorphosis to form adult.
Question. State the number of segments in earthworm which are covered by a prominent dark band or clitellum.
Ans. Segments 14-16 are covered by a prominent dark band of glandular tissue called clitellum in a mature earthworm.
Which secretes mucus and albumen that help in formation of cocoon and is used for fertilisation of eyes and sperms.
Question. The digestive system of frog is made of the following parts. Arrange them in an order beginning from mouth.
Mouth, oesophagus, buccal cavity, stomach, intestine, cloaca, rectum, cloacal aperture.
Ans. The correct arrangement of the parts of digestive system in frog is as follows
Mouth → Buccal cavity → Oesophagus → Stomach → Intestine → Rectum → Cloaca →Cloacal aperture.
Question. What is the difference between cutaneous and pulmonary respiration?
Ans. In frog respiration takes place via two means, i.e., skin and lungs.
Cutaneous respiration occrrs through highly vascular moist skin. It takes place in water as well as land.
Pulmonary respiration through lungs. It takes place outside the water.
Question. Identify the sex of a frog in which sound producing vocal sacs are present.
Ans. In amphibians, sex of frogs can be distinguished with the presence of sound producing vocal sacs. These organs are present in males which make them crock lauder, than females, so as to attract females for mating.
Question. Where are sclerites present in cockroach?
Ans. Sclerites are present in all the body segments of cockroach. These are of two types Dorsal sclerites often known as tergites, and Ventral sclerites which are referred to as sternites.
Question. Give two identifying features of an adult male frog.
Ans. The two identifying features of an adult male frog are as follows
(a) Vocal Sacs These are loose skin folds on throat of male frogs for producing louder croak.
(b) Nuptial Pad This copulatory pad present on the first digit of the forelimb of male frog and helps in closing female during amphelexus.
Short Answer Type Questions:
Question. The body of sponges does not possess tissue level of organisation though it is made of thousands of cells. Comment.
Ans. The level of organisation in sponges is of cellular level. The cells in sponges do not organise to form tissue, although they possess thousands of independently associated cells.
The cells may be solitary or colonial and function more or less independently. The cells show division of labour for performing specialised functions.
Question. What is special about tissue present in the heart?
Ans. Special tissue present in heart is cardiac muscle, these have the following features
(i) Cardiac muscle fibres are supplied with both central and autonomic nervous system and are not under the control of animal will.
(ii) These muscles are immune to fatigue and show rhythmicity.
(iii) They have rich blood supply.
(iv) They possess the property of contraction even if isolated from the body completely, i.e., they are myogenic
Question. Frogs are beneficial for mankind, justify the statement.
Ans. Frogs are beneficial for mankind because they eat insects and thus, protect our crops.
They serve as an important link of food chains and hence food web in the ecosystem, thus maintaining the ecological balance. Some countries use the muscular legs of frog as a food source.
Question. How do you distinguish between dorsal and ventral surface of the body of earthworm?
Ans. The body of earthworm can be distinguished into dorsal and ventral sides due to the presence of certain peculiar feature in it like.
(i) The dorsal surface is darker then ventral surface because it is marked by a dark median mid dorsal line along the longitudinal axis of body. This is due to dorsal blood vessel, seen through integument.
(ii) The ventral surface genital openings (pores), both male and female.
(iii) Genital papilla is located on ventral surface and help in copulation.
Question. Mention special features of eye in cockroach. Discuss compound eye in arthropods and mention its structural features.
Ans. The eyes in cockroach are large, sessile, paired, bean-shaped and present on either side of head. These are compound in nature. Each compound eye consists of a large number of visual elements called ommatidia.
Each ommatidium is composed of a diopteric region and reticular (receptor) region. It is capable of producing a separate image of a small part of object seen.
Thus, the image of the object viewed consists of several pieces and hence known as mosaic image. From the inner end of each ommatidium, fine nerve fibres arise, all of which combine to form one optic nerve connected to the brain.
Question. Give the location of hepatic caeca in a cockroach. What is their function?
Ans. Hepatic or gastric caecae are 6-8 narrow and hollow blind tubules called is present at the junction of foregut and midgut. The hepatic caecae are similar to vertebrate liver, secretes digestive juices and help in the digestion.
Question. Why are blood, bone and cartilage called connective tissue?
Ans. Connective tissue provides the structural framework and support to different organ forming tissue. Blood is a fluid or vascular connective tissue, which connects various organs and transports substances from one place to another.
Bone is a solid, rigid and strong skeletal connective tissue, which support the body and help in locomotion. Cartilage is also a skeletal connective tissue, not as rigid bone but piable and
resist comparission. It plays a role in support and protection and present in tip of nose, outer ear joints etc.
Question. Correct the wrong statements among the following.
(a) In earthworm, a single male genital pore is present.
(b) Setae help in locomotion of earthworm.
(c) Muscular layer in the body wall of earthworm is made up of only circular muscles.
(d) Typhlosole is the part of intestine of earthworm.
Ans. Among the given statements (b) and (d) are correct statement, correct statement for (a) would be in earthworm there are a pair of male genital pore lying on the ventro-lateral side of the 18th segment.
Male reproductive fluid containing sperms is discharged by these pores. However, a single female genital pore is present in the mid ventral line of 14th segment. Correct statement for (c) Muscular layer in earthworm is consist of an outer layer of circular muscles and the inner layer of longitudinal muscles.
Question. Write the appropriate type of tissues in column II according to the functions mentioned in column I.
Ans. (a) Simple Columnar Epithelium This epithelium lines the stomach, intestine, gall bladder etc. It forms goustric and intestinal glands, where it has a secretory role and is called as glandular epithelium. In intestinal mucosa, this epithelium has microvilli which increase the absorptive surface area and is called brush bordered columnar epithelium.
(b) Stratified Epithelium These are made up of more than one layer of epithelial cells ( also called compound epithelium). They are the only cells of the deepest layer and rest on the basement membrane they cover the surface where constant wear and tear take place. They mainly function as a protective epithelium.
(c) Connective Tissue It is the tissue which connects different tissues or organs and provides support to various structures of animal body. These tissues are mesodermal in origin and consist of living cells and extra cellular matrix, e.g., blood is a fluid or vascular connective tissue.
Question. Structural organisation in animals attains different levels as cell-organ-organ system. What is missing in this chain? Mention the significance of such an organisation.
Ans. Tissue is the missing in the chain. Structural organisation can be shown as cell-tissueorgan- organ system.
Number of cells together form tissue, number of tissue together form organ which on when unit with several organ form organ-system.
In organisms like Hydra, the body is comprised of thousands of cells in which each cell works independently whereas in a complex body system as that in humans billions of cells
perform various functions together via connecting each other through connecting tissue
Question. Write the functions in brief in column II, appropriate to the structures given in column I.
Ans. (a) Nictitating Membrane It protects the eye from water and any other damaging matter by covering the eye ball of forg.
(b) Tympanum It is a present on each side of frog head and is involved in the hearing process.
(c) Copulatory Pad These pads are present in the limbs of the male frog and helps in copulation by holding the female during its sexual activity.
Question. Using appropriate examples, differentiate between false and true body segmentation.
Ans. Segmentation is the serial repetition of similar body parts along with the length of an animal. The body of animals can be truely segmented or pseudo/false segmented.
True segmentation is found in annelids, arthropods and some chordates. In this, there is a linear repetition of body parts and each repeated unit is called somite (metamere).
In earthworms, the successive somites are essentially similar but they are dissimilar in different body regions of a crayfish or insect. Metamerism is conspicuous both externally and internally in annelids.
Pseudosegmentation is seen when body is divided into number of pseudosegments which are independent of each other. Each segment is able to perform all the vital function of body. Body grows by the addition of new segments from the anterior end, e.g., tapeworm.
Question. Frog is a poikilotherm, exhibits camouflage and undergoes aestivation and hibernation, how are all these beneficial to it?
Ans. Frog is a poikilotherm (cold blooded animal), i.e., it regulates its body temperature according to its environment.
For withstanding very cold temperatures, it undergoes winter sleep (hibernation) and summer sleep in hot temperatures (aestivation). During this period, it lives in a dormant stage with very minimal vital body activities.
Also, frog is capable of changing its body colour, though gradually, with the change in its surrounding and climatic conditions. This capability in frog is called as comouflage and lets it escape from the predators, an essential survival parameter for living.
Question. Stratified epithelial cells have limited role in secretion. Justify their role in our skin.
Ans. Stratified epithelium consists of epithelial cells in which the deepest layer is made up of columnar or cuboidal cells. It is a type of compound epithelium and outer few layers, a water proof protein called keratin is present.
These layers of dead cells is called horny layer which is shed at intervals due to frictions hence, has a limited role in secretion and absorption. The main function of stratified epithelium is to provide protection to the body against mechanical and chemical stresses.
Question. Why nephridia in earthworm that are basically similar in structure classified into three types? Mention the names of each.
Ans. Nephridia are the main excretory organs in earthworms. They are associated with excretory and osmoregulatory functions. The nephridia occur in all segments of earthworm except the first two segments. The three types of nephridia are found in earthworm according to their location.
They are distinguished on the basis of being enteronephric (nitrogen waste expelled input) and exonephric (nitrogen waste discharged outside directly).
Septal Nephridia These are present on both sides of inter segmental septa of the segment starting from 15th to the last that open into intestine. They are enteronephric.
Integumenatry Nephridia These are attached to lining of the body wall of segment 3 to the last that open on the body surface. They are exonephric.
Pharyngeal Nephridia These are present as a three paired tufts in the 4th, 5th and 6th segments. They are also enteronephric.
Question. How does a gap junctions facilitate intercellular communication?
Ans. Gap junctions facilitate intercellular communication by allowing small signaling molecules to pass from cell to cell. These are fine hydrophilic channels between two adjacent animal cells that are formed with the help of two protein cylinders called connexus.
Each connexus consists of six proteins subunits that surround a hydrophilic channel. pH and Ca2+ ion concentration controls, opening or closing of channels.
Question. Why are neurons called excitable cells? Mention special features of the membrane of the neuron.
Ans. Neurons are called excitable cells because these membranes are in a polarised state.
Different types of ion channels are present in the neural membrane, i.e., are selectively permeable to different ions.
When a neuron is suitably stimulated an electric disturbance is generated, which swiftly travels along its plasma membrane.
Arrival of the disturbance at the neuron’s ending or output zone, triggers events that may cause stimulation of adjacent neuron. These are excitable cells due to differential concentration gradient of ions (specially natural K+) across the membrane.
The special features of membrane of neuron are
(i) Excitability Neurons are able to percieve stimulus and enter a state activity caused by change in electrial potential difference across its covering membrane.
(ii) Conductivity Change in potential difference, spreads through the membrane to the whole neuron.
(iii) Connectivity Neurons are connected to several others, receiving and transmitting impulses to various directions.
(iv) Response The processed message may elicit a response in the form of a sensation.
Question. Complete the following statement.
(a) In cockroach grinding of food particle is performed by ……… .
(b) Malpighian tubules help in removal of ……… .
(c) Hind gut of cockroach is differentiated into ……… .
(d) In cockroach blood vessels open into spaces called ……… .
Ans. (a) Gizzard It is a muscular and greatly folded structure which marks the end of foregut and bears six plates with teeth for crushing and grinding the food.
(b) Malpighian tubules They help in the removal of nitrogenous wastes in arthropods, hence are excretory in function.
(c) IIeum, colon and rectum and rectum opens and through anus.
(d) Haemocoel It is the body cavity of cockroach divided into sinuses and contains visceral organs of cockroach floating in haemolymph.
Question. Why earthworm is called the friend of farmer?
Ans. Earthworms are called ‘friends of farmer’ because they make burrows in the soil and make it porous which helps plants in respiration and penetration within the soil.
The worm casting is rich in urea and ammonia which improves fertility of soil. Thus, they are of much importance to mankind and used as vermicompart.
Question. Common name of some animals are given in column I, write their scientific name in column II
Ans. A. Tiger – Panthera tigris
B. Peacock – Pavo cristatus
C. Housefly – Musca domestica
Long Answer Type Questions:
Question. Comment upon the gametic exchange in earthworm during mating.
Discuss the physiology in reproduction of earthworm.
Ans. Mating in earthworm is a unique process, earthworm is a hermaphrodite organism.
Breeding in earthworm takes place during rainy season and begins with copulation soon after maturation of the sperms.
The gametic exchange and the physiology reproduction during mating can described as below
(i) Earthworms are protandrous animal (i.e., maturation of sperm takes place much earlier then that of ova).
(ii) Mating process in earthworm occurs through cross-fertilisation.
(iii) The mating process involves exchange of sperms between the two worms.
(iv) Two individuals from adjacent burrows half emerge out and lie in contact with each other, and opposite gonadal opening exchange the packets of sperms called spermatophores.
(v) During the process, the skin encircling male pore, elevates a little to form a temporary papilla that fits like a penis into the opposite spermathecal pore to keep it open.
(vi) After filling of spermathecal, the copulating worm moves a bit to adjust another pair of spermathecae to face the male pores of the other. This is accomplished in about an hour’s copulation.
(vii) Within the spermathecae, the sperms mostly remain in their diverticula and the ampulla is associated with the secretion of nutritive substances for the sperms.
(viii) The sperm and egg are passed into cocoon which is secreted by clitellar gland.
(ix) Fertilisation is therefore external and cross fertilisation.
Question. Explain the digestive system of cockroach with the help of a labelled sketch.
Ans. The alimentary canal present in cockroach is divided into three regions that foregut, midgut and hindgut.
(i) Foregut includes mouth cavity, pharynx, oesophagus, crop and gizzard.
(ii) Mouth cavity is a small space, surrounded by mouth parts. Food is crushed and acted upon by the salivary secretion in mouth.
(iii) The mouth opens into a short tubular pharynx, leading towards the narrow tubular passage called oesophagus into a sac-like structure called crop which acts as a storage organ.
(iv) The crop is further followed by gizzard (proventriculus). Gizzard the structure composed of thick circular muscles and thick inner cuticle forming six highly chitinous plates called as teeth. It associated with the grinding and crushing of food particles.
Entire forgut is lined by a thick cuticle.
(v) Midgut or mesentron is about one-third middle part of alimentry canal. The internal lining of midgut is an endodermal epithelium of columnal cells raised into several small villi like folds.
(vi) Anterior most part of midgut surrounding the stomadaeal valve is called cardia and finger like blind processess are called as enteric or hepatic caeca, present the junction of foregut and midgut.
(vii) A ring of yellow filamentous structures formed between the midgut and hindgut are called Malpighian tubules help in the removal of excretory products from haemolymph.
(viii) Hindgut is the remaining one-third posterior part of alimentary canal. It is relatively thicker than the midgut is lined by cuticle and ectodermal epithelium.
(ix) Hindgut is differentiated into three parts, i.e., anterior ileum, middle colon and posterior rectum. Ileum is short and relatively narrower and its cuticle bears minute spines.
Colon is the longest, relatively thicker and a coiled part of hindgut. Rectum is a small and oval chamber that opens out through anus.
Question. Draw a neat and well labelled diagram of male reproductive system of a frog.
Ans. A well labelled diagram of male reproductive system is shown below
Question. Classify and describe epithelial tissue on the basis of structural modifications of cells.
Ans. The table given below summarises the structure, location and function of the epithelial tissue
Question. Write down the common features of the connective tissue. On the basis of structure and function. Differentiate between bones and cartilages.
Ans. Common features of connective tissue are
(i) Connective tissue is the most abundent and widely distributed tissue of the body. It connect with tissue with organs and also provides support to various body structures in animals.
(ii) Connects tissue is developed from the embroyonic mesoderm.
(iii) Three components are majorly present in the connective tissue matrix, cells and fibres.
(iv) The extracellular matrix has nearly amorphous ground substance made of glycoproteins with associated monopoly saccharides. This ground substance may be liquid, gel or solid.
(v) The tissue has good amount of regenerative ability.
(vi) Functions of connective tissue include storage of energy, protection of organs and body’s structural integrity.