Explore topic-wise InterviewSolutions in Current Affairs.

 Modification of Leaves

Tendrils: In some plants, leaves are modified into tendrils to assist in climbing, e.g. pea.

Spines: In some plants, leaves are modified into spines for defence, e.g. cactus. The leaf spine in cacti and in some other xerophytes also helps in reducing water loss by preventing transpiration. 

Bulb: In some plants, the leaves are modified into bulb for food storage, e.g. garlic and onion.

(i) By the local people for the fulfillment of their daily needs.

(ii) By industrialists deforestation for industrial needs.

(iii) Deforestation for developmental projects building, roads, dams etc.

(iv) By tourists or in making arrangements for tourists.

(i) Disturbance in natural habitat. Waste disposal, restriction,in movement, poaching/ hunting. 

(ii) Ecological imbalance less food for herbivores, overgrazing might result in loss of habitat.

(i) Sometimes, the crystalline lens of people at old age becomes milky and cloudy. This condition is called a cataract. This causes partial or complete loss of vision. 

It is possible to restore vision through a cataract sursery.

(ii) Focal length for lens for distance vision

=-1/1= -1 m

Focal length for a lens for near vision

= + 1/2 = +0.5 m

(iii)The focal length of the eye lens, cannot be decreased below a certain minimum limit.If we try to read a printed page by, holding it very.close  to our, eyes we may see the image being blurred or feel the strain in the eye. To see an object comfortably and distinctly  we must hold it at about 25 cm from the eyes.

Correct answer is (b) 4600 ml

The maximum amount of air that the lungs can hold after a maximum forceful inspiration (5200 to 5900 ml).

This difference is due to the location of hemoglobin as. In earthworm, it is present in dissolved form in plasma whereas in humans, in it is present in R.B.Cs.

The maximum amount of air that can be breathed out after of maximum inspiration. It is the sum total of TV, IRV and ERV and is 4100 to 4600 ml.

An artificial pace-maker is an electronic device which regularly sends small amount of electrical charges that stimulate the heart. 

The artificial pacemaker consists of -

(i) a pulse generator containing cell (solid state lithium cell) to produce electrical impulse, 

(ii) the lead in the form of a wire which transmits the impulse and 

(iii) an electrode, which is connected to the portion of the heart where impulse is to be transmitted.

The right atrium receives the opening of coronary sinus which is known as the basian valve.

It is two layered sac consisting of outer parietal pericardium and inner visceral pericardium. in between the two layers, a space called the pericardial cavity is present which is filled with a pericardial fluid.

Significance: The pericardium protects the heart from shocks and mechanical injuries and also allows free movement of the heart.

The pericardium protects the heart from shocks and mechanical injuries and also allows free movement of the heart.

The lymphatic capillaries of intestine absorbs the digested fats. They are milky in appearance a are called as lacteals.

It is the wave of distention that passes along the arteries immediately following the ventricular systole.

The constituents of lymphatic system are lymphatic capillaries, lymphatic vessels, lymphatic nodes and lymphatic ducts.

Conducting system of Human heart: 

(i) Human heart acts as a pumping station. The heart beat is initiated by the Sino-atrial node (SAN) which lies near the opening of the superior vena cava.

(ii) The SAN acts as a pacemaker. When it is warmed or cooled the frequency of the heart beat is increased or decreased respectively. 

(iii) The excitation originated at the SA is picked up by another specialized muscle fibres, the AV node in the auricular septum. 

(iv) From the AV node the excitation travels through the special muscle fibres present in the septum dividing in the two ventricles. 

(v) This conducting bundle divides into two-right and left bundle. Each branch enters the ventricles through a fine network of the Purkinje fibres. 

(vi) All the conducting fibres are very specialized type of muscle fibres.

It is because lymphatic circulation occurs due to squeezing action of surrounding muscles and not by the heart.

(i) The heart is composed of two types of chambers. The upper two, small, thin walled chamber are the auricles or atria and receives blood from various parts of the body and lower two large, thick walled muscular ventricles that supply blood to various body organs. 

(ii) The two auricles are separated by inter-auricular septum. 

(iii) The right atrium receives the openings of superior vena cava, inferior vena cava and coronary sinus. 

(iv) The opening of inferior vena cava is guarded by eustachian valve. 

(v) The opening of the coronary sinus has Thebasian valve. 

(vi) The left auriculo-ventricular valve consists of two flaps and is termed bicuspid or mitral valve. 

(vii) The right auriculo-ventricular valve consists of three triangular flaps and is called tricuspid valve. 

(viii) The right and left ventricles are separated by interventricular septum. 

(ix) The ventricles function as pumping chambers, thus they have thick muscles walls. 

(x) Attached to the flaps of the bicuspid and tricuspid valves are special fibrous cords, the chordae tendineae, which are joined to the other ends with the special muscles of the ventricular wall, the papillary muscles. 

(xi) The openings of the right and the left ventricles into the pulmonary atery and the aorla respectively are provided with the semilunar valves.

The flow of oxygenated blood from the ascending aorta to the heart muscles and the return of deoxygenated blood from the heart muscles to the right atrium is called coronary circulation.

It is a condition in which impulses are interrupted at any point along the conducting system of the heart. Thus, impulses do not follow the normal conduction pathway.

The movement of blood once through the heart during each circulation cycle is called single circulation.

The relationship between HbO₂ saturation and oxygen tension (PPO₂ ) is called oxygen dissociation curve.

Cyclosis is the streaming movement of the cytoplasm shown by almost all living organisms. E.g. Paramoecium, Amoeba, etc.

The process that involves trapping the heat energy in the form of high energy bond of ATP molecule is called phosphorylation.

Plasma is the fluid portion of the blood.

A ventilator is a machine that supports breathing and is used during surgery, treatment for serious lung diseases or other conditions when normal breathing fails.

The process of circulation helps in the supply of digested food and oxygen to all parts of the body (cells) and also to bring back the waste material.

It is the method of inducing breathing in a person when natural respiration has ceased or is faltering.

(a) Neutrophils

Stethoscope is the instrument used to feel and measure the heart beat.

Correct answer is (c) coronary sulcus

(1) Artificial ventilation is the artificial respiration. It is the method of inducing breathing in a person when natural respiration has ceased or is faltering. If used properly and quickly, it can prevent death due to drowning, choking, suffocation, electric shock, etc. 

(2) The process involves two main steps: 

a. Establishing and maintaining an open air passage from the upper respiratory tract to the lungs.

b. Force inspiration and expiration as in mouth to mouth respiration or by mechanical means like ventilator. 

(3) A ventilator is a machine that supports breathing and is used during surgery, treatment for serious lung diseases or other conditions when normal breathing fails.

The rhythmic contraction followed by its relaxation of heart is called heartbeat.

1. When the blood gushes through the blood vessels, the walls of blood vessels -can expand a little due to their elasticity. 

2. But as the age advances, the elasticity is reduced and then the blood vessels do not expand. 

3. Hence the flowing blood gets more resistance and the blood pressure can rise. 

4. Lesser the elasticity more will be the blood pressure, whereas more the elasticity of the vessel wall, then the pressure will not rise.

5. In this way, the blood pressure is inversely related to the elasticity of the blood vessels.

1. Blood pressure is the pressure exerted by the flowing blood on the walls of arteries. 

2. Blood pressure described in two terms viz. systolic blood pressure and diastolic blood pressure. Systolic blood pressure is the maximum pressure of blood when heart undergoes ventricular systole. It is responsible for flow of blood in the arteries. Normal systolic pressure is 120 mm Hg. 

3. Diastolic blood pressure is the minimum pressure of blood when heart undergoes diastole. Normal diastolic pressure is 80 mm Hg.

4. Blood pressure is represented as 120/80 mm Hg for a normal human being.

1. Erythrocytes or red blood corpuscles. They are circular, biconcave, enucleated cells. 

2. The RBC size : 7 pm in diameter and 2.5 pm in thickness. 

3. The RBC count : 5.1 to 5.8 million RBCs/ cu mm of blood in an adult male and 4.3 to 5.2 million/cu mm in an adult female. 

4. The average life span of RBC : 120 days.

5. RBCs are formed by the process of erythropoiesis. In foetus, RBC formation takes place in liver and spleen whereas in adults it occurs in red bone marrow. 

6. The old and worn out RBCs are destroyed in liver and spleen. 

7. Polycythemia is an increase in number of RBCs while erythrocytopenia is decrease in their (RBCs) number.

Functions of RBCs:

1. Transport of oxygen from lungs to tissues and carbon dioxide from tissues to lungs with the help of haemoglobin. 

2. Maintenance of blood pH as haemoglobin acts as a buffer. 

3. Maintenance of the viscosity of blood.

Correct answer is (b) right atrium

Correct answer is (b) ventricular contraction

1. The rhythmic contraction and relaxation of the heart is called heartbeat. 

2. Each heartbeat includes one systole and one diastole. During systole the heart contracts and during diastole it relaxes. 

3. The rate with which the heart beats is called heart rate. The normal heart rate is 72 beats per minute. 

4. Tachycardia means faster heart rate of about more than 100 beats per minute. 

5. Bradycardia means slower heart rate that is below 60 beats per minute.

1. Pacemaker is the region in tile heart which initiates the beating. 

2. The natural pacemaker of the heart is sinoatrial node (SA node). 

3. The pacemaker is autorhythmic, it is able to repeatedly and rhythmically generate impulses.

4. SA node is responsible for initiation of cardiac excitation. Therefore, it is called a pacemaker.

Correct answer is (d) Radial artery

1. A pressure wave that travels through the arteries after each ventricular systole is called a pulse.

2. The pulse can be felt in any artery that lies near the surface of the body. 

3. The radial artery at the wrist is most commonly used to feel the pulse. 

4. The pulse rate per minute indicates the heart rate. Since each heartbeat generates one pulse in the arteries, the pulse rate is same as that of heart rate, 

i.e. 72 times per minute.

(B) 8

The single homozygous plants are YYRr (2), YyRR (2), Yyrr (2) and yyRr (2).

(C) Ttrr

Phenotype of TtRr, TTRR and TtRR is Tall Round, but phenotype of Ttrr is tall wrinkled.

(C) Tt Rr

The ratio given is \(\rightarrow\) 9: 3: 3: 1 (56.25 : 18.75 : 18.75 : 6.25)

This ratio occurs due to the F1 hybrid which is heterozygous for both the genes, i.e. TtRr.

(B) 192

The dihybrid phenotypic ratio is 9 : 3 : 3 : 1.

9 - Tall yellow

3 - Tall green

3 - Dwarf yellow

1 - Dwarf green

∴ If there are 36 tall and green plants there will be 36 dwarf yellow, 12 dwarf green and 108 tall yellow plants. Thus the total number of progeny will be 192.

Imamura and M. Fujino (1959) found a direct correlation between stomatal movement and K⁺ ion concentration of guard cells. Fujino proposed that stomatal opening and closing are a result of an active transport of K+ ion into the guard cells. They showed the accumulation of K+ in the guard cells during stomatal opening. By using the electron probe micro analyzer, it has been found that opening of stomata in light is accompanied by the transport of K⁺ into the guard cells from the adjacent cells.  It has been found that anions which balance the positive charge of K⁺ are those of organic acid especially malic acid. The influx of K⁺ into the guard cells is accompanied by the synthesis of malic acid.

Opening of stomata in light:  Stomata open in light due to following reactions.

1. In light starch in the guard cells is metabolised into Phospho Enol Pyruvate (PEP). It is later converted into organic acids, particularly malic acid. The reaction takes place in the presence of an enzyme phospho enol pyruvic carboxylase.
2. Malic acid dissociates into malate and hydrogen ions in the guard cells.
3. Hydrogen ions from guard cells are transported to epidermal cells and K⁺ ions from epidermal cells are absorbed into the guard cells.
4. In the guard cells, K⁺ ions are balanced by malate anions. Besides, small amount of Cl^-ions are also absorbed which neutralize a small percentage of K+ ions.
5. The process of K+ ions exchange requires ATP and thus, it is an active process.
6. Increased K⁺ ions and anion concentration in the guard cells increases their osmotic concentration. Hence, water enters the guard cells by endosmosis.
7. Turgor pressure of the guard cells increases due to endosmosis and the stoma opens.