BIOLOGY 3 Marks Question

1. Septal nephridia: These are present on both sides of the inter-segmental septa behind the 15^th segment and they open into the intestine.
   
2. Integumentary nephridia: These lie attached to the body wall from the third segment to the last segment, which opens on the body surface.
   
3. Pharyngeal nephridia: These are present as three paired tufts in fourth, fifth, and sixth segments.
   

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.

• 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. 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.

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. 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.

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.

• 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. 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:

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.

• 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.

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. 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.

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.

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.

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.

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.

1. Nervous System of Cockroach to- Nervous system consists of a brain in the head and segmentally arranged ganglia joined by paired longitudinal connectives along the ventral side and the nerves arising from each of the ganglia.
2. The nervous system is spread throughout body.
3. Brain is represented by the supraoesophageal ganglion in the head; it supplies nerves to the antennae and compound eyes.
4. There are three ganglia in the thorax- one in prothorax, one in mesothorax and one in metathorax and six in the abdomen.

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.

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.

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

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.

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.

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.

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.

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