The cardiac pacemaker in a patient fails to function normally. The doctors find that an artificial pacemaker is to be grafted in him. It is likely that it will be grafted at the site of
1
atrioventricular bundle
2
Purkinje system
3
sinuatrial node
4
atrioventricular node.
Official Solution
Correct Option: (3)
SA node is a specialised bundle of neurons located in the upper part of the right atrium of the heart. SA node is the natural cardiac pacemaker from which the heart beat originates. If this system is damaged, it may send non-coordinated impulses to the heart chambers resulting in symptoms like irregular heart rate, tiredness, dizziness and loss of consciousness. As the pacemaker cells create these rhythmical impulse therefore an artificial pacemaker is implanted at the site of SA node to mimic the actions of the node and conducting system and helps to regulate heart beat.
02
PYQ 1980
medium
biologyID: neet-ug-
In the ABO system of blood groups, if both antigens are present but no antibody, the blood group of the individual would be
1
B
2
O
3
AB
4
A.
Official Solution
Correct Option: (3)
Human blood groups are special characteristics of blood in human and related primates due to presence of genetically controlled antigens and antibodies. ABO blood groups were the first to be discovered and are the most important in assuring safe blood transfusion. This system reflect the presence or absence of A and B agglutinogens (antigen) which are carried on the surface of plasma membrane of red blood cells. The ABO blood groups are determined by the gene I having three alleles - IA,IB,I0. In human being, there are present two antigens A and B produced by IA and IB alleles respectively. These antigens are always present on the surface of RBCs. Also are present two antibodies in the plasma-anti A and anti B. Blood group AB has both antigens A and B but no antibodies.
03
PYQ 1988
medium
biologyID: neet-ug-
Breakdown product of haemoglobin is
1
bilirubin
2
iron
3
biliverdin
4
calcium.
Official Solution
Correct Option: (1)
The haemoglobin is broken down into haem i.e. iron and globin protein which is then converted into yellowish substance bilirubin which is extracted by the liver cells from the blood and stored in the form of bile in gall bladder.
04
PYQ 1989
medium
biologyID: neet-ug-
Arteries carry oxygenated blood except
1
pulmonary
2
cardiac
3
hepatic
4
systemic.
Official Solution
Correct Option: (1)
Pulmonary artery carries the blood from the right ventricle of the heart to the lungs for oxygenation so it carries deoxygenated blood.
05
PYQ 1989
medium
biologyID: neet-ug-
Lymph differs from blood in possessing
1
only WBC
2
more RBC and WBC
3
more RBC and few WBC
4
more WBC and few RBC.
Official Solution
Correct Option: (1)
Lymph (called tissue fluid in the intercellular spaces) is a vascular tissue consisting of two parts-a clear, colourless fluid matrix, the plasma and floating amoeboid cells, the white blood cells, mostly lymphocytes. It differs from the blood in lacking red blood cells and some blood proteins. The lymph eventually enters the bloods near the heart.
06
PYQ 1991
medium
biologyID: neet-ug-
Blood group AB has
1
no antigen
2
no antibody
3
neither antigen nor antibody
4
both antigen and antibody.
Official Solution
Correct Option: (2)
Human blood groups are special characteristics of blood in human and related primates due to presence of genetically controlled antigens and antibodies. ABO blood groups were the first to be discovered and are the most important in assuring safe blood transfusion. This system reflect the presence or absence of A and B agglutinogens (antigen) which are carried on the surface of plasma membrane of red blood cells. The ABO blood groups are determined by the gene I having three alleles - IA,IB,I0. In human being, there are present two antigens A and B produced by IA and IB alleles respectively. These antigens are always present on the surface of RBCs. Also are present two antibodies in the plasma-anti A and anti B. Blood group AB has both antigens A and B but no antibodies.
07
PYQ 1992
medium
biologyID: neet-ug-
Cells formed in bone marrow include
1
RBC
2
RBC and leucocytes
3
leucocytes
4
lymphocytes.
Official Solution
Correct Option: (2)
In the embryo and foetal stage of vertebrates, RBCs and leucocytes are formed in the bone marrow, lymph nodes, yolk sac, liver, spleen and thymus but after birth they are formed in red bone marrow only.
08
PYQ 1992
medium
biologyID: neet-ug-
Component of blood responsible for producing antibodies is
1
thrombocytes
2
monocytes
3
erythrocytes
4
lympocytes.
Official Solution
Correct Option: (4)
Lymphocytes have a very large, rounded nucleus and scanty cytoplasm. They are nonmotile and nonphagocytic. They secrete antibodies to destory microbes and their toxins, reject grafts and kill tumour cells. They also help in healing of injuries. Thrombocytes aid in clotting of blood. Monocytes are phagocytic in nature. RBCs transport gases in the body.
09
PYQ 1993
medium
biologyID: neet-ug-
Blood capillaries are made of
1
endothelium, connective tissue and muscle fibres
2
endothelium and muscle fibres
3
endothelium and connective tissue
4
endothelium only.
Official Solution
Correct Option: (4)
The wall of capillaries is very thin (usually less than one micron) and have numerous minute pores and made up of only endothelium. Exchange of material takes place between blood and tissue fluid across the endothelial membrane of capillaries through active diffusion. The wall of blood vessels (arteries and veins) is made up of mainly 3 layers - the outer most tunica externa has connective tissue, collagen fibres, lymph vessels and the middle tunica media has circular smooth muscle fibres some elastic fibres and the inner most tunica interna in a single layered endothelium of polyhedral squamous cells. If the arteries reach organs they form arterioles which are thinner and mainly consist smooth muscles and when they subdivide in the tissues they make capillaries..
10
PYQ 1994
medium
biologyID: neet-ug-
The heart sound 'dup' is produced when
1
mitral valve is closed
2
semi-lunarval ves at the base of aorta get closed
3
tricuspid valve is opened
4
mitral valve-is opened.
Official Solution
Correct Option: (2)
The kdup sound is produced by the closure of the semilunar valves at the start of ventricular relaxation. It lasts for 0.1 seconds and its principle frequency is 50 cycles/sec. It is higher pitched, louder, sharper and of short duration as compared to 'lub'. The semilunar valves close to prevent any back flow of blood from aorta to the ventricles.
11
PYQ 1995
medium
biologyID: neet-ug-
In veins, valves are present to check backward flow of blood flowing at
1
atmospheric pressure
2
high pressure
3
low pressure
4
all of these.
Official Solution
Correct Option: (3)
Veins carry blood at low pressure as compared to blood carried by arteries. Arteries carry blood from the heart whose function is to pump blood at high pressure so that blood can reach each and every part of the body. Veins carry blood from tissues to the heart, so they carry blood at low pressure. Valves are present in the veins to prevent backflow of flood due to force of gravity.
12
PYQ 1996
medium
biologyID: neet-ug-
Which vertebrate organ receives only oxygenated blood?
1
spleen
2
liver
3
gill
4
lung.
Official Solution
Correct Option: (1)
Spleen receives only oxygenated blood from the heart through splenic artery. The liver receives a blood supply from two sources. The first is the hepatic artery which delivers oxygenated blood from the general circulation. The second is the hepatic portal vein delivering deoxygenated blood from the small intestine containing nutrients. The blood flows through the liver tissue to the hepatic cells where many metabolic functions take place. The blood drains out of the liver via the hepatic vein. Gill and Lung receive deoxygenated blood as these are the organs where oxygenation of blood takes place.
13
PYQ 1998
medium
biologyID: neet-ug-
Which of the following is not the main function of lymph glands?
1
forming RBCs
2
destroying bacteria
3
forming WBCs
4
forming antibodies.
Official Solution
Correct Option: (1)
The correct answer is A:Forming RBCs Formation of WBCs, antibodies and destruction of bacteria occur in lymph glands while formation of RBCs occur in bone marrow. Lymph gland is a rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Lymph glands filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells). They are located along lymphatic vessels. They are also called a lymph node.
14
PYQ 1998
medium
biologyID: neet-ug-
An adult human with average health has systolic and diastolic pressures as
1
120 mm Hg and 80 mm Hg
2
50 mm Hg and 80 mm Hg
3
80 mm Hg and 80 mm Hg
4
70 mm Hg and 120 mm Hg.
Official Solution
Correct Option: (1)
The temporary rise in blood pressure during the contraction of the heart is called systolic pressure and the temporary fall in blood pressure during relaxation of the heart is called diastolic pressure. Blood pressure is expressed as the ratio of the systolic pressure over the diastolic pressure. For a healthy resting adult person, the average systolic/diastolic pressures are 120/ 80 mm Hg.
15
PYQ 1999
medium
biologyID: neet-ug-
Which is the principal cation in the plasma of the blood?
1
potassium
2
magnesium
3
calcium
4
sodium.
Official Solution
Correct Option: (4)
Blood consists of a watery fluid called plasma. Plasma is a faint yellow, slightly alkaline, viscous fluid. It consists of 90% water, 1% inorganic salts, 7% or 8% proteins and 1% of other substances. The inorganic salts in plasma occur as ions. Sodium is the main cation of plasma and chloride, the main anion. Potassium, calcium and magnesium occur in small amount.
16
PYQ 2000
medium
biologyID: neet-ug-
Which statement is true for WBC:
1
Non nucleated
2
In deficiency cancer is caused
3
Manufactured in thymus
4
Can squeeze through blood capillaries
Official Solution
Correct Option: (4)
The statement that is true for white blood cells (WBC) is that they can squeeze through blood capillaries. This ability is essential for WBCs to reach sites of infection or inflammation within tissues where they can perform their immune functions. They can deform and pass through the narrowest capillaries to access affected areas.
So, the correct option is (D): Can squeeze through blood capillaries
17
PYQ 2000
medium
biologyID: neet-ug-
Erythroblastosis foetalis is caused when:
1
Rh– female & Rh+ male
2
Rh+ female & Rh– male
3
Rh+ female & Rh+ male
4
Rh– female & Rh– male
Official Solution
Correct Option: (1)
Erythroblastosis fetalis is caused when an Rh- negative female (with Rh- negative blood type) is pregnant with an Rh- positive fetus (with Rh- positive blood type). If fetal Rh- positive blood enters the mother's bloodstream during pregnancy or childbirth, the mother's immune system may produce antibodies against Rh- positive blood cells, potentially causing hemolytic disease in the newborn.
So, the correct option is (A): Rh– female & Rh+male
18
PYQ 2000
medium
biologyID: neet-ug-
In which point, pulmonary artery is different from pulmonary vein?
1
its lumen is broad
2
its wall is thick
3
it has valves
4
it does not possess endothelium.
Official Solution
Correct Option: (2)
its wall is thick
19
PYQ 2001
medium
biologyID: neet-ug-
What is correct for Blood group 'O'
1
No antegens but both a and b antibodies are present
2
A antegen and b antibody
3
Antigen and Antibody both absent
4
A and B antigens and a, b, antibodies
Official Solution
Correct Option: (1)
Blood group 'O' individuals have no A or B antigens on the surface of their red blood cells (RBCs), but they have both anti-A and anti-B antibodies in their plasma.
So, the correct option is (A): No antegens but both a and b antibodies are present
20
PYQ 2002
medium
biologyID: neet-ug-
Impulse of heart beat originates from :-
1
S.A. Node
2
A.V. Node
3
Vagus Nerve
4
Cardiac Nerve.
Official Solution
Correct Option: (1)
SA node is a specialised bundle of neurons located in the upper part of the right atrium of the heart. SA node is the natural cardiac pacemaker from which the heart beat originates. If this system is damaged, it may send non-coordinated impulses to the heart chambers resulting in symptoms like irregular heart rate, tiredness, dizziness and loss of consciousness. As the pacemaker cells create these rhythmical impulse therefore an artificial pacemaker is implanted at the site of SA node to mimic the actions of the node and conducting system and helps to regulate heart beat.
21
PYQ 2002
medium
biologyID: neet-ug-
Which of the following statement is true for Lymph
1
WBC and serum
2
All components of blood except RBCs and some proteins
3
RBCs, WBCs and Plasma
4
RBCs, Proteins and Platelets
Official Solution
Correct Option: (2)
The correct option is (B) : All components of blood except RBCs and some proteins
Due to the lack of RBCs and platelets, lymph has a pale yellow tint. However, it is rich in WBCs, lymphocytes, carbohydrates, proteins, lipids, and nitrogenous waste.
22
PYQ 2003
medium
biologyID: neet-ug-
Bundle of His is a network of
1
Muscle fibres distributed throughout the heart walls
2
Muscle fibres found only in the ventricle wall
3
Nerve fibres distributed in ventricles
4
Nerve fibres found throughout the heart
Official Solution
Correct Option: (2)
Bundle of His is a network of cardiac muscle fibres found only in the ventricle wall. The bundle of His in continuation of the AV node gives off a left bundle branch at the top of the interventricular septum and continues as the right bundle branch. It is a part of conducting system along with other parts like SA node, intemodal atrial pathways, atrioventricular node, Purkinje system. SA node '>> Impulse '> Atrial pathways '>> AV node -> Bundle of His Purkinje system '> Ventricular muscle.
23
PYQ 2006
medium
biologyID: neet-ug-
Examination of blood of a person suspected of having anaemia, shows large, immature, nucleated erythrocytes without haemoglobin. Supplementing his diet with which of the following, is likely to alleviate his symptoms ?
1
Thiamine
2
Folic acid and cobalamine
3
Riboflavin
4
Iron compounds
Official Solution
Correct Option: (2)
Large, immature, nucleated erythrocytes without hemoglobin are characteristic of megaloblastic anemia, which can be caused by deficiencies in folic acid (vitamin B9) and cobalamin (vitamin B12). Supplementation with these vitamins can help improve the production of normal red blood cells and alleviate the symptoms of megaloblastic anemia. Iron compounds (option D) are typically used to treat other forms of anemia, such as iron-deficiency anemia.
So, the correct option is (B): Folic acid and cobalamine
24
PYQ 2006
medium
biologyID: neet-ug-
Which one of the following has an open circulatory system?
1
Octopus
2
Pheretima
3
Periplaneta
4
Hirudinaria
Official Solution
Correct Option: (3)
Periplaneta has open circulatory system i.e. the blood does not flow in blood vessels but flows in a haemocoel (body cavity). The circulatory systems of all vertebrates, as well as of annelids (for example, earthworms) and cephalopods (squid and octopus) are closed, in which the blood never leaves the system of blood vessels consisting of arteries, capillaries and veins.
25
PYQ 2006
medium
biologyID: neet-ug-
People living at sea level have around 5 million RBC per cubic millimeter of their blood whereas those living at an altitude of 5400 metres have around 8 million. This is because at high altitude:
1
people get pollution-free air to breathe and more oxygen is available
2
atmospheric O2 level is less and hence more RBCs are needed to absorb the required amount of O2 to survive
3
there is more UV radiation which enhances RBC production
4
people eat more nutritive food, therefore more RBCs are formed
Official Solution
Correct Option: (2)
At high altitudes, the partial pressure of oxygen in the atmosphere decreases. This means that there is less oxygen available in each breath, and as a result, the body needs to adapt to efficiently transport oxygen to its tissues. One way the body adapts is by producing more red blood cells (erythropoiesis). More RBCs are needed to capture and transport the reduced oxygen available at high altitudes. This adaptation helps individuals living at high altitudes ensure their tissues receive an adequate oxygen supply. Therefore, the increase in RBC count is a physiological response to the lower atmospheric oxygen levels, not due to pollution-free air, UV radiation, or dietary factors.
So, the correct option is (B): atmospheric O2 level is less and hence more RBCs are needed to absorb the required amount of O2 to survive
26
PYQ 2008
medium
biologyID: neet-ug-
Which type of white blood cells are concerned with the release of histamine and the natural anticoagulant heparin ?
1
Eosinophils
2
Basophils
3
Monocytes
4
Neutrophils
Official Solution
Correct Option: (2)
Basophils are a type of white blood cell (leucocyte) that has a lobed nucleus surrounded by granular cytoplasm. They move about in an amoeboid fashion, are capable of ingesting foreign particles and they produce histamine and heparin as part of the body's defences at the site of infection or injury.
27
PYQ 2008
medium
biologyID: neet-ug-
In humans blood passes from post caval to the diastolic right atrium of heart due to
1
Stimulation of the sino-auricular node
2
Pressure difference between the post caval and atrium
3
Pushing open of the venous valves
4
Suction pull
Official Solution
Correct Option: (2)
Blood passes from the superior and inferior vana cava into the right atrium. During the start of diastole, the pressure drops in the right atrium, thereby forcing the blood from vena cava to enter the right atrium. During diastole as the atrium relaxes and enlarges in size, the pressure falls.
28
PYQ 2009
medium
biologyID: neet-ug-
Globulins contained in human blood plasma are primarily involved in
1
Clotting of blood
2
Osmotic balance of body fluids
3
Defence mechanism of body
4
Oxygen transport in the blood
Official Solution
Correct Option: (3)
Globulins in human blood plasma are primarily 1 involved in defence mechanisms of body. Globulins like ; immunoglobulins act as antibodies that destroy bacteria, ; viruses and toxic substances that may enter into the blood from outside.
29
PYQ 2009
medium
biologyID: neet-ug-
Compared to blood our lymph has
1
Plasma without proteins
2
No plasma
3
More WBCs and no RBCs
4
More RBCs and less WBCs
Official Solution
Correct Option: (3)
Lymph is a mobile connective tissue comprising lymph plasma and lymph corpuscles (type of WBCs). Its composition is just like plasma except that it lacks RBCs and large plasma proteins.
30
PYQ 2010
medium
biologyID: neet-ug-
Chordae tendineae are found in
1
atria of heart
2
ventricles of heart
3
ventricles of brain
4
arch of aorta
Official Solution
Correct Option: (2)
Chordae tendineae are found in ventricles of heart. They are commonly called as heart strings. Chordae tendineae are fibrous cords of connective tissue which connects the tricuspid valve and the mitral valve to the papillary muscles of the heart. These fibrous cords resembles tendon in appearance and are made up of about 80% collagen.
They prevent the cusps of the valves to swing back into the atrial chamber when they close with pressure. When the ventricles of the heart contract, blood pressure is increased in both the chambers that results in closing of AV valves. The closure of the valves prevent blood from flowing back into the atria. But the pressure in atria at this time is lower than the ventricles, so the flaps of the valves tends to turn into the low-pressure region. The chordae tendineae prevents this turning by holding them in the position.
31
PYQ 2010
medium
biologyID: neet-ug-
If due to some injury the chordae tendinae of the tricuspid valve of the human heart is partially non-functional, what will be the immediate effect ?
1
The 'Pacemaker' will stop working
2
The blood will tend to flow back into the left atrium
3
The flow of blood into the pulmonary artery will be reduced
4
The flow of blood into the aorta will be slowed down
Official Solution
Correct Option: (3)
Tricuspid valve is the valve in the heart between the right atrium and right ventricle. It consists of three cusps that channel the flow of blood from the atrium to the ventricle. When the right ventricle contracts, forcing blood into the pulmonary artery, the tricuspid valve closes the aperture to the atrium, thereby preventing any backflow of blood. The valve reopens to allow blood to flow from the atrium into the ventricle. Thus, if tricuspid valve is partially non-functional the flow of blood into the pulmonary artery will be reduced.
32
PYQ 2011
medium
biologyID: neet-ug-
The given figure is the of a normal human. Which one of its components is correctly interpreted below?
1
Complex - one complete pulse
2
Peak - initiation of total cardiac contraction
3
Peak and peak together - systolic and diastolic blood pressures
4
Peak - initiation of left atrial contraction only
Official Solution
Correct Option: (1)
The complex represents the depolarisation of the ventricles, which initiates the ventricular contraction. By counting the number of complexes that occur in a given time period, one can determine the rate of heart beat of an individual.
33
PYQ 2011
medium
biologyID: neet-ug-
Arteries are best defined as vessels which
1
Break up into capillaries which reunite to form a vein
2
Carry blood from one visceral organ to another visceral organ
3
Supply oxygenated blood to different organs
4
Carry blood away from the heart to different organs
Official Solution
Correct Option: (4)
Arteries and veins are main blood vessels. Arteries carry blood from the heart to different body parts. Veins bring blood from different body parts to the heart.
34
PYQ 2012
medium
biologyID: neet-ug-
Which one of the following human organs is often called the 'graveyard' of RBCs?
1
Gall bladder
2
Kidney
3
Spleen
4
Liver.
Official Solution
Correct Option: (3)
Spleen is a vertebrate organ, lying behind the stomach, that is basically a collection of lymphoid tissue. Its functions include producing lymphocytes and destroying foreign particles. It acts as a reservoir for RBCs and can regulate the number in circulation. It is also the site for the breakdown of worn out RBCs and thus is known as graveyard of RBCs. The life of an RBC is about 120 days. Liver cells degrade the haemoglobin of worn out RBCs into bile pigments (bilirubin and biliverdin).
35
PYQ 2012
medium
biologyID: neet-ug-
Compared to those of humans, the erythrocytes in frog are
1
Without nucleus but with haemoglobin
2
Nucleated and with haemoglobin
3
Very much smaller and fewer
4
Nucleated and without haemoglobin
Official Solution
Correct Option: (2)
Human erythrocytes are enucleated, discoidal while in frogs erythrocytes are large, oval and biconvex nucleated cells. Erythrocytes are the carriers of haemoglobin.
36
PYQ 2012
medium
biologyID: neet-ug-
The given figure is the representation of a certain event at a particular stage of a type of cell division. Which is this stage?
1
Prophase-I during meiosis
2
Prophase-II during meiosis
3
Prophase of mitosis
4
Both prophase and metaphase of mitosis
Official Solution
Correct Option: (1)
The given figure shows crossing over i.e., exchange of segments between two homologous chromosomes. Crossing over is characteristic of meiosis and occurs during pachytene stage of prophase -1.
37
PYQ 2014
medium
biologyID: neet-ug-
Person with blood group AB is considered as universal recipient because he has
1
both A and B antigens on RBC but no antibodies in the plasma
2
both A and B antibodies in the plasma
3
no antigen on RBC and no antibody in the plasma
4
both A and B antigens in the plasma but no antibodies.
Official Solution
Correct Option: (1)
ABO blood groups are determined by the gene I (isoagglutinin). There are three alleles, IA, IB and 1� of this gene. IA allele is responsible for formation of A antigen, while IB allele is responsible for formation of B antigen. People with blood group A have the A antigen on the surface of their RBCs, and antibodies to antigen B in their plasma. Persons with blood group B have B antigen on their RBCs, and antibodies against A antigen in their plasma. Individuals with AB blood group have both antigen A and B on their RBCs, and no antibodies for either of the antigen in their plasma. Type O individuals are without A and B antigens on their RBCs, but have antibodies for both these antigens in their plasma. Individuals with blood group AB can receive blood of A, B or O group, while those with blood group O can donate blood to anyone.
Which one of the following animals has two separate circulatory pathways?
1
Whale
2
Shark
3
Frog
4
Lizard
Official Solution
Correct Option: (1)
Whale is a mammal and in mammals, two separate circulatory pathways are found systemic circulation and pulmonary circulation. Oxygenated and deoxygenated bloods received by the left and right atria I respectively pass on to the left and right ventricles. Thus, oxygenated and deoxygenated bloods are not mixed. This is referred to as double circulation. In shark (fish), the heart pumps out deoxygenated blood which is oxygenated by the gills and sent to the body j parts from where deoxygenated blood is carried to the heart. It is called single circulation. In frog (amphibian)and lizard (reptile), the left atrium get oxygenated blood from the gills/ lungs/skin/ buccopharyngeal cavity and the right atrium receives the deoxygenated blood from other body parts. The oxygenated and deoxygenated bloods get mixed up in single ventricle which pumps out mixed blood. This is called incomplete double circulation.
40
PYQ 2015
medium
biologyID: neet-ug-
Erythropoiesis starts in
1
spleen
2
red bone marrow
3
kidney
4
liver.
Official Solution
Correct Option: (2)
Erythropoiesis is the formation of red blood cells (erythrocytes) which occurs in the red bone marrow. Proerythroblast is the earliest precursor which gives rise successively to the early erythroblast, intermediate erythroblast and late erythroblast. Then, the nucleus is forced out and a biconcave, enucleated cell called | reticulocyte is formed, which is released into blood. In blood, it develops into mature erythrocytes.
41
PYQ 2015
medium
biologyID: neet-ug-
Blood pressure in the mammalian aorta is maximum during
1
systole of the left ventricle
2
diastole of the right atrium
3
systole of the left atrium
4
diastole of the right ventricle.
Official Solution
Correct Option: (1)
The temporary rise in blood pressure during the I contraction of the heart is called systolic pressure and | the temporary fall in blood pressure during relaxation of the heart is called diastolic pressure. Blood pressure is expressed as the ratio of the systolic pressure over the , diastolic pressure. For a healthy resting adult person, the ; average systolic/diastolic pressures are 120/80 mm Hg. Aorta is directly supplied by left ventricle thus, the blood pressure in aorta is highest during systole of left ventricle. During it, left ventricle contracts and pushes blood into aorta.
42
PYQ 2016
medium
biologyID: neet-ug-
In mammals, which blood vessel would normally carry largest amount of urea?
1
Dorsal Aorta
2
Hepatic Vein
3
Hepatic Portal Vein
4
Renal Vein
Official Solution
Correct Option: (2)
Answer:
Explanation:
Urea is produced in the liver as a result of the breakdown of amino acids through the urea cycle (also known as the ornithine cycle).
The hepatic vein carries blood away from the liver to the inferior vena cava. Since the liver is the site of urea production, the blood in the hepatic vein has a high concentration of urea.
Other vessels like:
Dorsal Aorta: Carries oxygenated blood from the heart to various body parts, not directly related to urea transport.
Hepatic Portal Vein: Brings blood from the intestines to the liver, containing nutrients but not high in urea.
Renal Vein: Carries blood after urea filtration by kidneys, hence has lower urea content.
43
PYQ 2016
medium
biologyID: neet-ug-
Blood pressure in the pulmonary artery is
1
More than that in the carotid
2
More than that in the pulmonary vein
3
Less than that in the venae cavae
4
Same as that in the aorta
Official Solution
Correct Option: (2)
Why Arteries Have Higher Blood Pressure Than Veins
Arteries have higher blood pressure than veins due to the following reasons:
1. Blood is Forced into Arteries from the Heart:
Arteries carry oxygenated blood away from the heart and towards various parts of the body. The heart pumps blood with significant force into the arteries during each contraction (systole), leading to high pressure inside the arteries.
2. Narrow Lumen of Arteries:
The lumen (the inner diameter of the blood vessel) of arteries is narrower compared to veins. This narrower lumen creates resistance to the blood flow, further contributing to higher pressure within the arteries.
Conclusion:
Thus, arteries experience higher blood pressure than veins due to the combined effect of blood being forcefully pumped from the heart and the narrower lumen of the arteries.
44
PYQ 2017
easy
biologyID: neet-ug-
Adult human RBCs are enucleated. Which of the following statement(s) is/are most appropriate explanation for this feature ? (a) They do not need to reproduce (b) They are somatic cells (c) They do not metabolize (d) All their internal space is available for oxygen
1
only (a)
2
(a), (c) and (d)
3
(b) and (c)
4
only (d)
Official Solution
Correct Option: (2)
The circular mammalian erythrocyte is synthesized in the bone marrow. After synthesis, it undergoes a process called enucleation in which the nucleus is removed. The absence of a nucleus allows the red blood cells to contain more hemoglobin and hence all their internal space is available for oxygen transport in order to the body tissues. As they do not have any organelle, it does not show any metabolic activity and multiplication.
45
PYQ 2017
easy
biologyID: neet-ug-
The hepatic portal vein drains blood to liver from :
1
Stomach
2
Kidneys
3
Intestine
4
Heart
Official Solution
Correct Option: (3)
Blood enters the liver from two sources. From the hepatic artery, it gets oxygenated blood and from the hepatic portal vein, it receives deoxygenated blood. Blood in the hepatic artery comes from the aorta. Blood in the hepatic portal vein comes directly from the intestine (containing newly absorbed nutrients), stomach, etc
46
PYQ 2017
medium
biologyID: neet-ug-
Adult human RBCs are enucleate. Which of the following statement(s) is/are most appropriate explanation for this feature? (a) They do not need to reproduce (b) They are somatic cells (c) They do not metabolize (d) All their internal space is available for oxygen transport
1
Only (d)
2
Only (a)
3
(a), (c) and (d)
4
(b) and (c)
Official Solution
Correct Option: (1)
The correct option is (A): Only (d).
47
PYQ 2017
medium
biologyID: neet-ug-
The hepatic portal vein drains blood to liver from
1
Heart
2
Stomach
3
Kidneys
4
Intestine
Official Solution
Correct Option: (4)
The correct option is (D): Intestine.
48
PYQ 2019
medium
biologyID: neet-ug-
Match the Column -I with Column-II:
COLUMN I
COLUMN II
a
P-wave
i
Depolarisation of ventricles
b
QRS complex
ii
Repolarisation of ventricles
c
T-wave
iii
Coronary ischemia
d
Reduction in the of size of T-wave
iv
Depolarisation of atria
v
Repolarisation of atria
Select the correct option.
1
(a)-(iv) (b)- (i) (c)-(ii) (d)-(iii)
2
(a)-(iv) (b)-(i )(c)-(ii) (d)-(v)
3
(a)-(ii) (b)-(i) (c)-(v) d-(iii)
4
(a)-(ii) (b)- (iii) (c)-(v) (d)-(iv)
Official Solution
Correct Option: (1)
The correct option is (A) :(a)-(iv) (b)- (i) (c)-(ii) (d)-(iii)
49
PYQ 2019
medium
biologyID: neet-ug-
What would be the heart rate of a person if the cardiac output is 5 L, blood volume in the ventricles at the end of diastole is 100 mL and at the end of ventricular systole is 50 mL ?
1
100 beats per minute
2
125 beats per minute
3
50 beats per minute
4
75 beats per minute
Official Solution
Correct Option: (1)
Cardiac output = stroke volume Heart rate Cardiac output = 5L or 5000 ml Blood volume in ventricles at the end of diastole = 100 ml Blood volume in ventricles at the end of systole = 50 ml Stroke volume = 100 - 50 = 50 ml. So, 5000 ml = 50 ml Heart rate So, Heart rate = 100 beats per minute.
50
PYQ 2019
medium
biologyID: neet-ug-
Match the Column-1 with Column-II: Select the correct option from the following:
1
a ? ii, b ? i, c ? v, d ? iii
2
a ? ii, b ? iii, c ? v, d ? iv
3
a ? iv, b ? i, c ? ii, d ? iii
4
a ? iv, b ? i, c ? ii, d ? v
Official Solution
Correct Option: (3)
In ECG P-wave represents depolarisation of atria. QRS complex represents depolarisation of ventricles. T-wave represents repolarisation of ventricle i.e. return from excited to normal state. Reduction in the size of T-wave i.e. if the T-wave represents insufficient supply of oxygen i.e. coronary ischaemia.
51
PYQ 2020
medium
biologyID: neet-ug-
Select the correct statement.
1
Glucocorticoids stimulate gluconeogenesis.
2
Glucagon is associated with hypoglycemia.
3
Insulin acts on pancreatic cells and adipocytes.
4
Insulin is associated with hyperglycemia.
Official Solution
Correct Option: (1)
The correct option is (A) : Glucocorticoids stimulate gluconeogenesis.
52
PYQ 2021
medium
biologyID: neet-ug-
Persons with ‘AB’ blood group are called as “Universal recipients”. This is due to
1
Absence of antibodies, anti-A and anti-B, in plasma
2
Absence of antigens A and B on the surface of RBCs
3
Absence of antigens A and B in plasma
4
Presence of antibodies, anti-A and anti-B, on RBCs
Official Solution
Correct Option: (1)
To determine why individuals with 'AB' blood group are referred to as "Universal recipients," we need to understand the basic principles of blood group compatibility and the role of antigens and antibodies.
Blood groups are categorized based on the presence or absence of specific antigens on the surface of red blood cells (RBCs) and antibodies in the plasma. The main blood group system is the ABO system, which includes four main types: A, B, AB, and O.
Individuals with blood group A have A antigens on their RBCs and anti-B antibodies in their plasma.
Individuals with blood group B have B antigens on their RBCs and anti-A antibodies in their plasma.
Individuals with blood group O have neither A nor B antigens on their RBCs but have both anti-A and anti-B antibodies in their plasma.
Individuals with blood group AB have both A and B antigens on their RBCs but do not have anti-A or anti-B antibodies in their plasma.
The absence of anti-A and anti-B antibodies in the plasma of individuals with AB blood group means there are no antibodies to react against incoming A, B, AB, or O blood types, making them "universal recipients." They can safely receive blood from any ABO blood group because the transfused blood's antigens won't face any antibody-mediated rejection.
Now, let's evaluate the options provided:
Absence of antibodies, anti-A and anti-B, in plasma: This is the correct reason. Since individuals with AB blood group lack these antibodies, they can safely receive blood from any ABO group.
Absence of antigens A and B on the surface of RBCs: This describes blood group O, not AB.
Absence of antigens A and B in plasma: Antigens are found on RBCs, not in plasma.
Presence of antibodies, anti-A and anti-B, on RBCs: Antibodies are found in plasma, not on RBCs. This statement is also factually incorrect.
Thus, the most accurate explanation for why individuals with AB blood group are called "Universal recipients" is the absence of antibodies, anti-A and anti-B, in plasma.
53
PYQ 2021
medium
biologyID: neet-ug-
Which enzyme is responsible for the conversion of inactive fibrinogens to fibrins
1
Thrombokinase
2
Thrombin
3
bin (3) R
4
Epinephrine
Official Solution
Correct Option: (2)
The correct answer is option (B): Thrombin
54
PYQ 2023
easy
biologyID: neet-ug-
Match List I with List II.
List I
List II
A
P-wave
I
Beginning of systole
B
Q-wave
II
Repolarisation of ventricles
C
QRS complex
III
Depolarisation of atria
D
T-wave
IV
Depolarisation of ventricles
Choose the correct answer from the options given below:
1
A-IV, B-III, C-II, D-I
2
A-II, B-IV, C-I, D-III
3
A-I, B-II, C-III, D-IV
4
A-III, B-I, C-IV, D-II
Official Solution
Correct Option: (4)
To solve the given problem, we need to match the items in List I with their corresponding descriptions in List II based on the characteristics of heart activity represented in an electrocardiogram (ECG).
List I
List II
A
P-wave
I
Beginning of systole
B
Q-wave
II
Repolarisation of ventricles
C
QRS complex
III
Depolarisation of atria
D
T-wave
IV
Depolarisation of ventricles
In an ECG:
P-wave represents the depolarisation of atria, which corresponds to item III.
Q-wave is part of the early ventricular depolarisation process marking the beginning of ventricular systole, but given the options, it is best associated with the beginning of systole (item I).
QRS complex corresponds to the depolarisation of ventricles, which matches item IV.
T-wave represents the repolarisation of ventricles, which matches item II.
From the analysis above, the correct matching is: A-III, B-I, C-IV, D-II.
55
PYQ 2023
easy
biologyID: neet-ug-
Given below are two statements:
Statement I: The coagulum is formed of a network of threads called thrombins. Statement II: Spleen is the graveyard of erythrocytes.
In the light of the above statements, choose the most appropriate answer from the options given below:
1
Both statement I and Statement II are correct
2
Both statement I and Statement II are incorrect
3
Statement I is correct but statement II is incorrect
4
Statement I is incorrect but statement II is correct
Official Solution
Correct Option: (4)
To understand which statements are correct, let's analyze each one:
Statement I: "The coagulum is formed of a network of threads called thrombins." This statement is incorrect. In the coagulation process, thrombins are not threads. Thrombin is an enzyme that converts fibrinogen into fibrin, which forms the network of threads to create the coagulum. Thus, the threads are fibrins, not thrombins.
Statement II: "Spleen is the graveyard of erythrocytes." This statement is correct. The spleen is known as the graveyard of red blood cells (erythrocytes) because it is the organ responsible for removing old and damaged erythrocytes from circulation.
Conclusion: Based on the evaluation, Statement I is incorrect but Statement II is correct. Therefore, the correct answer from the options provided is: Statement I is incorrect but Statement II is correct.
56
PYQ 2024
easy
biologyID: neet-ug-
Match List I with List II:
List I
List II
A
P wave
I
Heart muscles are electrically silent.
B
QRS complex
II
Depolarisation of ventricles.
C
T wave
III
Depolarisation of atria.
D
T-P gap
IV
Repolarisation of ventricles.
Choose the correct answer from the options given below:
1
A-I, B-III, C-IV, D-II
2
A-III, B-II, C-IV, D-I
3
A-II, B-III, C-I, D-IV
4
A-IV, B-II, C-I, D-III
Official Solution
Correct Option: (2)
To solve the matching problem between List I and List II, we need to understand the terms associated with an ECG (Electrocardiogram).
P wave indicates the depolarisation of the atria, which corresponds to option III.
QRS complex corresponds to the depolarisation of the ventricles, matching with option II.
T wave is associated with the repolarisation of the ventricles, linking to option IV.
T-P gap signifies a period when heart muscles are electrically silent, which matches with option I.
Therefore, the correct matching is:
List I
List II
A - P wave
III - Depolarisation of atria
B - QRS complex
II - Depolarisation of ventricles
C - T wave
IV - Repolarisation of ventricles
D - T-P gap
I - Heart muscles are electrically silent
Thus, the correct answer is: A-III, B-II, C-IV, D-I.
