Biology 3 Marks Question

Earthworm exhibits a closed type of blood vascular system. It consists of blood vessels, capillaries and heart. Due to a closed circulatory system, blood is confined to the heart and blood vessels. Contractions keep blood circulating in one direction. Smaller blood vessels supply the gut, nerve cord and body wall. Blood glands are present on the 4th, 5th and 6th segments. They produce blood cells and hemoglobin which is dissolved in blood plasma. Blood cells are phagocytic in nature.

	Cardiac muscles		Striated muscles
1.	They are involuntary in function.	1.	They are voluntary in function.
2.	They are multi-nucleated and branched.	2.	They are multi-nucleated and un branched.
3.	They are found only in the heart.	3.	They are found in triceps, biceps, and limbs.

	Simple epithelium		Compound epithelium
1.	It is composed of only one layer of cells.	1.	It is composed of many layers of cells.
2.	It is mainly involved in the function of absorption and secretion.	2.	It is mainly involved in the function of protection.
3.	It is present in the lining of the stomach, intestine.	3.	It is present in the lining of the pharynx and buccal cavity.

1. All the musical instruments play in perfect harmony and thus the wonderful music is created.

Every organ system is related to each other and malfunctioning of a particular system can affect another system. The digestive system is the system through which we get the fuel which is utilized by the whole body for energy. If the digestive system malfunctions, it results in reduced supply of fuel to other organ systems. In such a situation, other organ system may start malfunctioning and finally the whole body can become out of tune. So, taking care of the digestive system is important for maintaining a healthy body.

The three types of cell junctions are:

1. Tight junctions.
2. Gap junctions.
3. Adhering junctions.

Functions of cell junctions are:

1. Tight junctions prevent the leaking of substances across a tissue.
2. Gap junctions facilitate the cells to communicate with each other by connecting their cytoplasm.
3. Adhering junctions perform cementing of the adjacent cells to keep them together.

Differences between Blatta orientalis and Periplanata americana are:

S. No.	Blatta orientalis	Periplanata americana
1.	Brownish-black to black coloured.	Shining brown-coloured.
2.	20-25 mm, smaller in size.	35-40 mm, larger in size.
3.	Less capable of flying.	Good capacity of flying.
4.	Forewings are vestigial. Hindwings are absent.	In both sexes, both pairs of wings are well-developed.
5.	Ootheca is black-coloured.	Ootheca is grey-coloured.

Differences between keratinised and non-keratinised stratified squamous epithelia are:

S. No.	Keratinised Stratified Squamous Epithelium	Non-keratinised Stratified Squamous Epithelium
1.	It is found over the surfaces exposed to drying.	It occurs over the surfaces which are not subjected to drying.
2.	The outer cells are dead.	The outer cells are living.
3.	The outer cells are filled with keratin.	Keratin is absent.
4.	It has adhesive lipid layer.	Lipid layer is absent.
5.	The epithelium is impervious to water.	Impermeability to water is low.

1. Neuroglial cells: These are supporting cells which form a packing around the neurons in the brain, spinal cord and ganglia.
2. Ependymal cells: They forms the epithelium that lines the cavities in the brain and spinal cord.
3. Spindle cells: These are biconvex nucleated cells found in the blood of vertebrates other than mammals.

1. Development in cockroach is paurometabolous, since it involves nymphal stages.
2.  

• Gizzard helps in grinding the food materials.
• Malpighian tubules help in removing the excretory products from the haemolymph.

3. Periplaneta americana.

Nervous System of Cockroach:

• The nervous system of cockroach consists of a series of fused, segmentally arranged ganglia joined by paired longitudinal connectives on the ventral side.
• Three ganglia lie in the thorax, and six in the abdomen. The nervous system of cockroach is spread throughout the body.
• The head holds a bit of a nervous system while the rest is situated along the ventral (belly-side) part of its body.

1. Nictitating membrane Protect the eyes while the frog is in water.
2. Tympanum Receives sound signals.
3. Copulatory pad Helps the male in grasping the female during amplexus.

Adipose tissue is a fat storing connective tissue. Its matrix is packed with the large, spherical or oval fat cells or adipocytes. The fibres are few in number and form a loose network for supporting fat laden cells. This tissue is found in the subcutaneous parts, in the mesenteries, covering of the heart and around the blood vessels and kidneys. The adipose tissue mainly stores reserve food. It acts as shock absorbing cushions around the heart, kidneys, eyeball, etc.

S.No.	Striated Muscles	Smooth Muscles
1	Cells are cylindrical and unbranched.	Cells are spindle-shaped with a broad centre.
2	Striations are prominent.	Striations are absent.
3	They are voluntary in function.	They are involuntary in function.
4	The cells are multinucleate.	The cells are uninucleate.
5	They are found in the walls of visceral organs.	They are attached to the skeletal system.

All cells are held together with intercellular material. These materials form junctions between cells. There are three types of cell junctions found in epithelial tissue:

1. Tight Junctions: These junctions help in stopping leakage of substances across a tissue.
2. Adhering Junctions: These junctions keep neighbouring cells together.
3. Gap Junctions: These junctions connect cytoplasm of adhering cells, and facilitate exchange of materials.

Functions of Connective Tissue The connective tissue performs following main functions:

1. The connective tissue mainly joins one tissue to another in the organs.
2. The adipose tissue stores fat.
3. The cartilage and bones form a supporting framework for the body.
4. Blood and lymph carry materials from one part to another in the body.
5. The cells of connective tissues like macrophages, monocytes, neutrophils ingest bacteria, cell debris and foreign materials. Thus, they protect and clean the body.
6. The adipose tissue acts as shock absorber around some organs, such as eyeballs and kidneys. It also acts as packing material in various organs.
7. Bone marrow is the source of blood corpuscles.
8. The collagen fibres help in the repair of injured tissues.

S. No.	Blood Plasma	Blood Serum
1.	It is the fluid minus blood corpuscles.	it is liquid minus clotting elements and corpuscles
2.	It is faint yellow in colour.	It is pale yellow in colour.
3.	It contains fibrinogen and other clotting factors.	It lacks fibrinogen and other clotting factors.
4.	It takes part in blood clotting.	It does not take part in blood clotting.

Functions of Neural Tissue d be Neural tissue performs the following functions:

1. The neural tissue coordinates and controls the functioning of different parts of the body.
2. The sensation of smell, vision, taste, hearing, pain, pleasure, etc., are performed through the nervous tissue.
3. The neural tissue helps in meditating conscious activities.
4. The information about the changes in various internal structures is provided by nerves.
5. It makes us aware about the environment around us.
6. The nervous tissue brings about an appropriate response to each and every stimulus.
7. The tissue is also a seat of experiences, memories, etc.

1. Grinding of food particles.
2. Cockroach.
3. Cardiac muscle.

On the basis of texture, bones may be compact or spongy.

1. Compact bone: It has lamellae arranged in regular Haversian systems without gap between them. It is comparatively hard and compact. Compact bones are found in the shaft of long bone. Its cavity contains yellow bone marrow.
2. Spongy bone: It has lamellae, called trabeculae that forms interlacing network with small spaces between them. These spaces contain red bone marrow. The spongy bones are without Haversian systems. This bone form expanded ends of long bones, vertebrae, ribs, skull bones.

Digestion in Frog:

• In the stomach digestion of food takes place by the action of HCl and gastric juices secreted from the walls of the stomach.
• Partially digested food called chyme is passed from stomach to the first part of the intestine, the duodenum. The duodenum receives bile from gall bladder and pancreatic juices from the pancreas through a common bile duct.
• Bile emulsifies fat and pancreatic juices digest carbohydrates and proteins. Final digestion takes place in the intestine.
• Digested food is absorbed by the numerous finger-like folds in the inner wall of intestine called villi and microvilli.

1. Similarities between cardiac and skeletal muscles The cardiac and skeletal muscles both are made up of elongated fibres, which have numerous myofibrils. The myofibrils of the cardiac muscles have the same structure as those of skeletal muscle and are made up of actin and myosin filaments. The cardiac and skeletal muscles fibres have dark and light bands.
2. Similarities between cardiac and smooth muscles Cardiac and smooth muscles both are uninucleate, contain nucleus at the centre and are involuntary in function.

Earthworm is called the friend of farmer because it helps in making the soil loose and porous by burrowing, which in turn causes aeration and absorption of water by soil and thus, helps in respiration and penetration of the developing plant roots. Earthworms are also used in vermin composting as worm castings are used as manure and increases soil fertility. Nitrogenous wastes of earthworms are used as plant food and they help in creating optimum conditions for plant growth by reducing acidity and alkalinity of soil.

The excretory organs occur as segmentally arranged coiled tubules called nephridia (sing. nephridium). They are of following three types:

1. Septal Nephridia: These are present on both the sides of inter segmental septa of segment 15 to the last that opens into intestine. They discharge the waste matter into the gut via septal excretory ducts and supraintestinal ducts.
2. Integumentary Nephridia: These are attached to the lining of the body wall of segment 3 to the last that open on the body surface.
3. Pharyngeal Nephridia: These are present as three paired tufts in the 4th, 5th and 6th segments. These different types of nephridia are basically similar in the structure.

Functions of Nephridia:
Nephridia regulates the volume and composition of the body fluids. A nephridium starts open up as a funnel that collects excess fluid from the coelomic chamber. The funnel connects with a tubular part of the nephridium, delivers the wastes through a pore to the surface in the body wall into the digestive tube.

Frogs are beneficial for mankind in the following way:

1. Frogs maintain the ecological balance as they occupy and serve an important link in the food chain.
2. They eat insects and protect the crops.
3. They are used as food in some countries. The muscular legs of the frog are used as food.

1. Saliva.
2. Earwax.
3. Milk.
4. Mucus.
5. Oil.
6. Enzymes.

Hepatic caecae are arise from the anterior end of midgut. They are present at junction of midgut and gizzard and are 6-8 in number. They are lined by the glandular cells which secrete digestive secretion containing amylolytic, proteolytic and lipolytic types of enzymes, which help in the digestion of carbohydrates, proteins and fats.

S. No.	column I	S. No.	column II
A.	Compound epithelium	3.	canal Skin
B.	Compound eye	4.	Mosaic vision
C.	Septal nephridia	5.	Earthworm
D.	Open circulatory system	2.	Cockroach
E.	Typhlosole	1.	Alimentary canal
F.	Osteocytes	7.	Bone
G.	Genitalia	6.	Phallomere

Central Nervous System of Frog:

• Brain is enclosed in a bony structure called brain box or skull (cranium).
• The brain is divided into fore-brain, mid-brain and hind-brain.
• Forebrain includes olfactory lobes, paired cerebral hemispheres and unpaired diencephalon.
• The midbrain is characterised by a pair of optic lobes.
• Hind-brain consists of cerebellum and medulla oblongata.
• The medulla oblongata passes out through the foramen magnum and continues into spinal cord, which is enclosed in the vertebral column.
• There are ten pairs of cranial nerves arising from the brain.

S.No.	Smooth Muscle	Skeletal Muscle	Cardiac Muscle
1.	Spindle shaped cells.	Striated unbranched cells.	Striated branched cells.
2.	Found in muscles of internal organs.	Found in musculo-skeletal system.	Found in the heart.
3.	Control involuntary actions.	Control involuntary actions.	Control heart's pumping which is involuntary.

The body wall of earthworm has four layers, i.e., cuticle, epidermis, musculature and coelomic epithelium or parietal peritoneum.

1. Cuticle: It is a thin, transparent, non-cellular outermost layer. The cuticle is secreted by the epidermis and is perforated by numerous minute pores.
2. Epidermis: It is the next layer after cuticle, made up of a single layer of columnar epithelium which contain secretory gland cells, i.e., basal cells, sensor or receptor cells, setigerous cells (seta forming cells), etc.
3. Muscle layers: It is composed of an outer thin layer of circular muscle fibres and an inner thick layer of longitudinal muscle fibres. Contraction of circular muscles makes the body long and thin whereas, the contraction of longitudinal muscle fibres makes the body thick and short.
4. Coelomic epithelium: It is a thin, membrane-like coelomic epithelium consisting of flattened squamous cells.

Malphighian tubules are the main excretory organs of cockroach.

1. Adipose tissue:

• It is located beneath the skin.
• The cells of this tissue store fats.

2. Intercalated disc:

• It is present in the cardiac muscle, at certain fusion points of the fibres.
• It allows the cells to contract as a unit.

3. Malpighian tubules:

• They are present at the junction of midgut and hindgut of cockroaches (insects).
• They absorb the nitrogenous excretory products from the haemolymph and convert them into uric acid and send into the hindgut.

Differences between male and female frog:

S. No.	Male Frog	Female Frog
1.	Vocal cords are present on ventrolateral side of throat.	Vocal sacs are absent.
2.	Croaking is more louder.	Croaking is less louder.
3.	Forelimbs are stouter and more muscular.	Forelimbs are less muscular.
4.	Amplexusory pads are present on ventral side of index fingers.	Amplexusory pads are absent.
5.	During breeding season, abdomen does not change much.	Abdomen gets swollen during breeding season as it is full of ova released from mature ovaries.

Differences between eyes of cockroach and eyes of frog:

S.No.	Eyes of Cockroach	Eyes of Frog
1.	Compound eyes made of multiple. units.	Simple eyes made of single unit.
2.	Ommatidia comprise eyes.	Lens comprise eyes.
3.	Project mosaic vision with less resolution.	Stereoscopic vision with high resolution.

Functions of Muscular Tissues:

1. These are involved in the movement of body parts and locomotion of the organism to maintain the positions of the various parts of the body.
2. Muscles are responsible for heart beat, production of sound and peristalsis in tubular viscera.
3. The muscles support the bones and other structures.
4. Muscles are essential during parturition.

1. Cockroach has following important features which enable it to survive in variety of habitats:

1. Flattened body to easily slip into narrow spaces.
2. Shape of legs allows swift running possible in confined places.
3. Nocturnal habit helps in protection from enemies.

2. Cockroaches are eaten by the people of South American countries and Myanmar (Burma). These are part of food chain as many amphibian, birds, lizards and rodent feed on them.
3. Negative impacts of presence of cockroach in our surroundings are:

1. Cockroaches are pests which damage household materials including clothes, paper, shoes, etc.
2. Contaminate our food by their excreta making it unpalatable.

4. Ram is very attentive, curious, inquisitive, and is aware of is surroundings.

1. Crop: The food remains temporarily stored in this.
2. Gizzard: It helps in grinding the food.
3. Hepatic caecae: Secrete digestive enzymes, to digest all types of nutrients.

Nephridia are the main excretory organs in earthworms. They are associated with excretory and osmo regulatory 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 enter one phric (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 is 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 6thsegments. They are also enteronephric.

Bone marrow is the vascular pulpy connective tissue found in the marrow cavity of the bones. It is of two types:

1. Yellow marrow: It is a yellow coloured tissue rich in fat cells called adipocytes. It is richly supplied with the blood vessels and nerve fibres. It is found in the shaft region of the bones.
2. Red marrow: It is red coloured and blood cells are formed in it. It is found at the ends of long bones, ribs, sternum, vertebrae, etc. In a foetus, red marrow occurs in all bones. After birth, the red marrow becomes restricted to the above mentioned locations.

3. Central Processing Unit of a computer.

The way our brain controls all the functions in the body, the CPU controls all the functions in a computer. Artificial intelligence is still the stuff of science fiction, but many scientists are working overtime to develop machines which could be intelligent. It appears quite fascinating and promising to imagine a world full of intelligent robots. But imagine if those robots would actually overpower us and would start taking controls of the whole world. It may jeopardize the existence of human beings. Even other life forms can be in grave danger. Nature has its own way of making a balance among life forms and that ability of nature would be disturbed because of artificial intelligence.

1. Secretion and absorption Simple epithelium.
2. Protective covering Compound epithelium.
3. Linking and supporting framework Connective tissue.

1. The improper functioning of liver is not able to metabolise bilirubin and biliverdin completely so it start getting accurmulated in main bloodstream.
2. The main function of RBCs is to carry red coloured oxygen carrying pigment haemoglobin.
3. Ruchi is caring, attentive and responsible.

S. No.	Male Cockroach	Female Cockroach
1	Genital pouch or chamber lies at the hind end of abdomen, bounded dorsally by 9th and 10th terga and ventrally by the 9th sternum.	7th sternum is boat shaped and along with the 8th and 9th sterna, it forms a brood/ genital pouch.
2	It contains dorsal anus, ventral male genital pore and gonapophyses.	Its anterior part contains female gono pore, spermathecal pores and collaterial glands.
3	There is a pair of anal styles arising from the 9th sternum.	Anal styles are absent.
4	The abdomen is narrow.	The abdomen is broad.

1. Blood is composed of mainly two components, i.e. fluid part called plasma and cells called formed elements. The formed elements are cellular components of the blood, i.e., red blood cells, white blood cells and blood platelets. The formed elements constitute 40-45% of the total blood volume and plasma SO occupies 55-60% of the blood volume.

Sense Organs in Frog: Frog has different types of sense organs which are as follows:

1. Sensory papillae or organs of touch.
2. Taste buds.
3. Nasal epithelium for the sense of smell.
4. Eyes for vision and us.
5. Tympanum with internal ears for hearing.

Out of these, eyes and internal ears are well-organised structures and the rest are cellular aggregations around nerve endings. Eyes in a frog are a pair of spherical structures situated in the orbit in skull. These are simple eyes. External ear is absent in frogs and only tympanum can be seen externally. The ear is an organ of hearing as well as balancing.

Solution is as follow:

Glands are classified into exocrine glands and endocrine glands.

Exocrine Glands	Endocrine Glands
The glands which have a duct to pour out their secretion, are called exocrine glands.	The glands which do not have a duct and pour out their secretion directly into the blood, are called endocrine glands.
They secrete mucus, enzymes, sebum, tear, etc.	They secrete hormones.
Example: salivary glands, tear glands, etc.	Example: thyroid, pituitary, pineal glands, etc.

Cardiac muscle is specialized tissue that is found only in the heart. It has characteristics similar to both smooth and skeletal muscle tissue, as well as specialized properties that allow it to function with fast but sustained contractions, rapid conduction and coordinated movement. There are also differing types of cardiac muscle tissue that allow for both strong and coordinated contractions.