Blood and Blood Group Questions in English

(D) Antibodies are specialized proteins known as immunoglobulins that are produced by the immune system to identify and neutralize foreign objects like bacteria and viruses.
Specifically,$B$-lymphocytes (a type of white blood cell) differentiate into plasma cells upon activation,which then secrete large quantities of antibodies into the blood and lymph.
Therefore,the correct answer is $D$ (Lymphocytes).

(A) Erythroblastosis foetalis is a condition caused by $Rh$ incompatibility between an $Rh$-negative mother and an $Rh$-positive foetus.
During the first pregnancy,the mother's blood is exposed to the foetus's $Rh$ antigens,leading to the production of anti-$Rh$ antibodies.
In subsequent pregnancies,these antibodies can cross the placenta and destroy the foetal red blood cells,leading to severe anaemia and jaundice.

(A) The disease caused by the deficiency of plasma thromboplastin component $(PTC)$,also known as Factor $IX$,is called Christmas disease or Haemophilia $B$.
This condition leads to a prolonged blood clotting time because $PTC$ is essential for the formation of the thromboplastin complex in the intrinsic pathway of the coagulation cascade.
While Haemophilia $A$ is caused by a deficiency of Factor $VIII$,Christmas disease is specifically associated with the lack of $PTC$ (Factor $IX$).

(B) Erythroblastosis foetalis is a hemolytic disease of the newborn.
It occurs when an $Rh$-negative mother carries an $Rh$-positive fetus.
During the first pregnancy,the mother's blood is exposed to the $Rh$ antigens of the fetus,leading to the formation of anti-$Rh$ antibodies in her blood.
In subsequent pregnancies with an $Rh$-positive fetus,these antibodies can cross the placenta and destroy the fetal red blood cells,causing severe anemia and jaundice.
Therefore,it is caused by the incompatibility or disadjustment of the $Rh$ factor.

(D) Leukemia is a type of cancer that affects the blood and bone marrow. It is characterized by the uncontrolled proliferation of abnormal white blood cells (leukocytes) in the body. Therefore,it is commonly referred to as 'blood cancer'.

(C) Dextran is a complex branched polysaccharide composed of glucose units.
It is clinically used as a plasma volume expander.
Therefore,it plays an important role in blood transfusion and managing hypovolemic shock.

(A) Mature mammalian red blood cells $(RBCs)$ lack mitochondria and other organelles.
Because aerobic respiration (the Krebs cycle and electron transport chain) occurs within the mitochondria,these cells cannot perform aerobic respiration.
Instead,they rely exclusively on anaerobic glycolysis to produce $ATP$ for their energy requirements.

(C) Hemoglobin is a respiratory pigment found in red blood cells.
Its key characteristics include:
$1$. It contains iron $(Fe^{2+})$ in its heme group,not copper $(Cu)$.
$2$. It has a red color due to the presence of heme.
$3$. It binds reversibly with oxygen to form oxyhemoglobin.
$4$. It consists of a globin protein part (four polypeptide chains).
Therefore,the presence of $Cu$ is not a characteristic property of hemoglobin.

(A) Antibodies are specialized proteins produced by the immune system in response to antigens.
These proteins belong to a class of plasma proteins known as immunoglobulins or globulins.
Therefore,antibodies are essentially globulin proteins.

(D) The extracellular fluid $(ECF)$ includes interstitial fluid and blood plasma. In the $ECF$,the primary cation is sodium $(Na^+)$,which maintains osmotic balance and membrane potential. In contrast,potassium $(K^+)$ is the primary cation found in the intracellular fluid $(ICF)$. Therefore,the concentration of $Na^+$ is significantly higher in the $ECF$ compared to other ions like $K^+$,$Mg^{+2}$,or $Ca^{+2}$.

(D) Vitamin-$K$ (phylloquinone) is a fat-soluble vitamin that plays a crucial role in the process of blood coagulation.
It acts as a cofactor for the enzyme carboxylase,which is responsible for the carboxylation of glutamic acid residues in certain proteins.
Specifically,it is essential for the hepatic synthesis of prothrombin (Factor $II$) and other clotting factors (Factors $VII, IX,$ and $X$).
Without adequate Vitamin-$K$,the liver cannot produce these functional clotting factors,leading to impaired blood clotting.

(B) The liver contains specialized macrophages known as $Kupffer$ cells.
These cells are located in the lining of the hepatic sinusoids.
Their primary function is to act as phagocytes,which means they engulf and destroy foreign particles,bacteria,and aged red blood cells,thereby playing a crucial role in the body's immune defense system.

(D) The spleen acts as a primary lymphoid organ in adults,filtering blood and removing old red blood cells. However,during fetal development,the spleen serves as a site for hematopoiesis (the production of blood cells). Therefore,it acts as a hematopoietic tissue in the fetus.

(D) The spleen acts as a primary lymphoid organ and is involved in various functions in mammals.
In the developing fetus (embryo),the spleen serves as a site for hematopoiesis,which is the production of blood cells.
After birth,it primarily functions as a reservoir for blood and a site for the destruction of old red blood cells (erythrocytes).
Therefore,the correct role mentioned among the options is that it acts as a blood-forming tissue in the embryo.

(D) The $Spleen$ is known as the 'graveyard of red blood cells' because it filters out old and damaged $RBCs$ from the circulation. The $Liver$ also plays a significant role in the breakdown of hemoglobin from destroyed $RBCs$ and the recycling of iron. Therefore,both the $Liver$ and $Spleen$ are primarily responsible for the removal and processing of destroyed red blood cells.

(D) Blood plasma contains various electrolytes that maintain osmotic pressure and pH balance.
Among the given ions, $Na^+$ (sodium) is the primary extracellular cation.
The concentration of $Na^+$ in human blood plasma is approximately $135-145 \, mEq/L$.
In contrast, the concentrations of $K^+$ $(\approx 3.5-5.0 \, mEq/L)$, $Ca^{+2}$ $(\approx 4.5-5.5 \, mEq/L)$, and $Mg^{+2}$ $(\approx 1.5-2.5 \, mEq/L)$ are significantly lower.
Therefore, $Na^+$ is found in the highest concentration.

(B) Folic acid is essential for $DNA$ synthesis and cell division. $A$ deficiency of folic acid leads to a reduction in the production of white blood cells,particularly lymphocytes. The condition characterized by a significant decrease in the number of white blood cells (leukocytes) is known as $Leukopenia$.
$Leukemia$ is a type of blood cancer characterized by an abnormal increase in white blood cells.
$Polycythemia$ is an increase in the number of red blood cells.
$Tay-Sachs$ disease is a genetic disorder that results in the destruction of nerve cells in the brain and spinal cord.

(C) The most active phagocytic cells in the human blood are $Neutrophils$ and $Monocytes$.
$Neutrophils$ are the most abundant type of white blood cells and act as the first line of defense by engulfing pathogens.
$Monocytes$ migrate into tissues and differentiate into $Macrophages$,which are highly efficient at phagocytosis to clear cellular debris and pathogens.

(D) The concentration of organic acids in the blood is regulated by the acid-base balance mechanism. $K^+$ ions play a crucial role in maintaining the intracellular and extracellular pH balance. When there is an excess of $K^+$ ions in the blood (hyperkalemia),the body attempts to exchange $K^+$ with $H^+$ ions across cell membranes to maintain electrical neutrality. This exchange helps in preventing the accumulation of $H^+$ ions,thereby preventing the increase in the concentration of organic acids and maintaining the blood pH within the normal range.

(D) The $RBCs$ (Red Blood Cells) have an average lifespan of approximately $120$ days. After this period, they become fragile and are removed from the circulation. The primary sites for the destruction and filtration of these worn-out $RBCs$ are the $Spleen$ and the $Liver$. The $Spleen$ is often referred to as the 'graveyard of $RBCs$' because it is the main site where old $RBCs$ are broken down by macrophages. The $Liver$ also plays a significant role in phagocytosing old $RBCs$ and recycling their components, such as iron.

(B) Arterial blood carries oxygenated blood,which has a higher concentration of $O_2$ and a lower concentration of $CO_2$.
Venous blood carries deoxygenated blood,which has a higher concentration of $CO_2$.
$CO_2$ reacts with water to form carbonic acid $(H_2CO_3)$,which dissociates into $H^+$ and $HCO_3^-$.
The increase in $H^+$ concentration leads to a decrease in $pH$.
Therefore,the $pH$ of arterial blood is slightly higher (more alkaline,approximately $7.40$) compared to venous blood (slightly more acidic,approximately $7.35$).

(B) The spleen acts as a reservoir for blood and is involved in the destruction of old red blood cells. It also plays a role in the storage and regulation of blood platelets. When the spleen is removed (a procedure known as splenectomy),the body loses a significant storage site for platelets,which often leads to an increase in the number of circulating blood platelets in the bloodstream,a condition known as thrombocytosis.

(B) The spleen is a secondary lymphoid organ that acts as a filter for the blood.
It removes old,damaged,or abnormal red blood cells $(RBCs)$ from the circulation.
Because of this function,the spleen is commonly referred to as the 'graveyard of $RBCs$'.
Therefore,the correct option is $B$.

(B) Diapedesis is the process by which white blood cells (leukocytes),particularly neutrophils and monocytes,migrate out of the blood capillaries into the surrounding tissues. This occurs by squeezing through the endothelial cells of the capillary walls. This mechanism is crucial for the immune response,as it allows white blood cells to reach the site of infection or injury to destroy pathogens and clear cellular debris.

(B) Megakaryocytes are large bone marrow cells with a lobulated nucleus responsible for the production of blood platelets,also known as thrombocytes.
These cells undergo fragmentation to release platelets into the blood circulation.
Therefore,megakaryocytes are the precursors or producers of thrombocytes.

(C) Blood coagulation (clotting) is a complex process involving various clotting factors.
$1$. $Fibrinogen$ is a plasma protein that is converted into $Fibrin$ during the clotting process.
$2$. $Fibrin$ forms a network of threads that trap blood cells to form a clot.
$3$. $Calcium$ ions $(Ca^{2+})$ play a crucial role in the activation of various clotting factors.
$4$. $Bilirubin$ is a bile pigment formed from the breakdown of hemoglobin in the liver and is excreted in bile; it has no role in the blood coagulation process.
Therefore,$Bilirubin$ is the correct answer.

(D) The color of human blood plasma is typically pale yellow. This yellowish color is primarily due to the presence of a pigment called $Urochrome$. $Urochrome$ is a breakdown product of hemoglobin metabolism that is excreted by the kidneys,but it is also present in small amounts in the plasma. Therefore,the correct option is $D$.

(A) The $RBCs$ (Red Blood Cells) have a lifespan of approximately $120$ days. After this period,they become fragile and are destroyed primarily in the spleen,which is often called the 'graveyard of $RBCs$'. Within the spleen and liver,specialized macrophages known as Kupffer cells (in the liver) and splenic macrophages engulf and break down the aged $RBCs$ through phagocytosis. Among the given options,Kupffer cells are the phagocytic cells involved in the breakdown of cellular debris,including old $RBCs$.

(B) person with blood group '$A$' has '$A$' antigens on the surface of their red blood cells and '$anti-B$' antibodies in their plasma.
Therefore,they can receive blood from individuals with blood group '$A$' (same antigen) or blood group '$O$' (universal donor,no antigens).
They cannot receive blood from '$B$' or '$AB$' because these contain '$B$' antigens,which would trigger an immune reaction with the '$anti-B$' antibodies present in the recipient's plasma.

(D) Granular $WBCs$ (leukocytes) include neutrophils,eosinophils,and basophils.
These cells are characterized by the presence of granules in the cytoplasm and a multi-lobed or lobulated nucleus.
For example,neutrophils have a multi-lobed nucleus ($3-5$ lobes),while eosinophils typically have a bilobed nucleus.
Therefore,the nucleus of granular $WBC$ is mainly lobulated.

(A) Blood clotting (coagulation) requires calcium ions $(Ca^{2+})$ as a cofactor for the activation of clotting factors. Sodium oxalate acts as an anticoagulant by chelating or precipitating the calcium ions present in the blood. By removing free calcium ions,the coagulation cascade is inhibited,thus preventing the blood from clotting in the test tube.

(A) The $haematocrit$ (also known as packed cell volume or $PCV$) is the volume percentage of red blood cells in blood. It is measured as part of a blood test and is typically expressed as a percentage. For example,a $haematocrit$ of $40\%$ means there are $40$ milliliters of red blood cells in $100$ milliliters of blood.

(B) Monocytes are the largest of the white blood cells (leukocytes).
They are characterized by a large,kidney-shaped or bean-shaped nucleus.
These cells are phagocytic in nature and play a crucial role in the immune response by engulfing pathogens and cellular debris.

(B) Anticoagulants are substances that prevent blood from clotting.
Sodium oxalate $(Na_2C_2O_4)$ is commonly used as an anticoagulant in laboratory settings because it precipitates calcium ions $(Ca^{2+})$ from the blood.
Since calcium ions are essential for the blood coagulation cascade,their removal prevents the formation of fibrin clots.
Therefore,sodium oxalate is added to blood samples during storage to keep them in a liquid state.

(C) Monocytes are the largest type of white blood cells and are known as the 'macropolice' of the blood.
They differentiate into macrophages in tissues,which perform phagocytosis to engulf and destroy pathogens,cellular debris,and foreign particles,acting as a primary defense mechanism.

(B) Vitamin $K$ is essential for the synthesis of several clotting factors in the liver,most notably prothrombin (Factor $II$),as well as factors $VII$,$IX$,and $X$.
During the blood coagulation cascade,the liver requires Vitamin $K$ to produce these inactive clotting factors.
Specifically,Vitamin $K$ acts as a cofactor for the enzyme carboxylase,which adds a carboxyl group to glutamic acid residues on these proteins,allowing them to bind calcium ions and function in the clotting process.
Therefore,Vitamin $K$ is primarily involved in the formation of prothrombin.

(C) Macrophages are specialized cells involved in the detection,phagocytosis,and destruction of bacteria and other harmful organisms.
In the spleen,the macrophages are known as reticular cells (or splenic macrophages).
Microglial cells are found in the central nervous system.
Dust cells are found in the lungs.
Monocytes are precursors that circulate in the blood before differentiating into macrophages in tissues.

(C) In a healthy adult human,the average number of Red Blood Cells $(RBCs)$ or erythrocytes is approximately $5.0-5.5$ million per $mm^3$ of blood in males and $4.5-5.0$ million per $mm^3$ of blood in females. Therefore,the correct range for a healthy woman is $4.5-5.0$ million per $mm^3$.

(B) Hemoglobin $(Hb)$ is the iron-containing oxygen-transport metalloprotein in the red blood cells $(RBCs)$ of all vertebrates.
In a healthy human adult,hemoglobin constitutes approximately $33-34\%$ of the total weight of the red blood cell.
This high concentration of hemoglobin allows $RBCs$ to efficiently carry oxygen from the lungs to the tissues and carbon dioxide from the tissues back to the lungs.

(C) Blood clotting (coagulation) is a complex process involving a cascade of enzymatic reactions.
$1$. The process is initiated by the release of thromboplastin from damaged tissues or platelets.
$2$. Calcium ions $(Ca^{2+})$ play a critical role as a cofactor in the conversion of inactive prothrombin into active thrombin.
$3$. Thrombin then converts soluble fibrinogen into insoluble fibrin threads,which form the clot.
$4$. Therefore,$Ca^{2+}$ and thromboplastin are essential components for the initiation and progression of the blood clotting cascade.

(C) The $ABO$ blood grouping system is based on the presence or absence of two surface antigens,namely $A$ and $B$,on the surface of red blood cells $(RBCs)$.
These antigens determine the blood type of an individual.
Therefore,the antigens of blood groups are found on the surface of $RBCs$.

(A) The average lifespan of human red blood cells ($R.B.C.$ or erythrocytes) is approximately $120$ days.
After this period,they are broken down and removed from the circulation by the spleen,which is often referred to as the 'graveyard of $R.B.C.$'.

(C) Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells $(RBCs)$ of all vertebrates.
In a healthy human adult,hemoglobin constitutes approximately $33\%$ to $34\%$ of the total weight of the $RBC$ (or $34$ grams per $100$ ml of packed cells).
Therefore,the correct percentage of hemoglobin in $RBCs$ is $34\%$.

(D) In the early stages of human embryonic development,hematopoiesis (the formation of blood cells) begins in the yolk sac. This is known as the mesoblastic phase. Later,the liver and spleen take over this function (hepatic phase),and finally,the bone marrow becomes the primary site of hematopoiesis (myeloid phase) before birth and throughout adulthood.

(B) Serum is defined as the liquid component of blood that remains after the blood has clotted.
When blood is allowed to clot, the clotting factors, specifically fibrinogen, are consumed in the process of forming the fibrin mesh.
Therefore, serum is essentially plasma from which the clotting factors (like fibrinogen) have been removed.
Mathematically, it can be represented as: $\text{Serum} = \text{Plasma} - \text{Clotting factors (Fibrinogen)}$.
Thus, the correct option is $B$.

(D) Blood plasma is the liquid component of blood.
It contains various electrolytes,among which sodium ions $(Na^+)$ are the most abundant cations.
These ions play a crucial role in maintaining osmotic pressure and the acid-base balance of the blood.
Therefore,the correct answer is $Na^+$.

(B) In human blood,the white blood cells $(WBCs)$ are categorized into granulocytes and agranulocytes.
Among the agranulocytes,monocytes are the largest type of white blood cells.
They are phagocytic in nature and play a crucial role in the immune response by engulfing pathogens and cellular debris.
Therefore,monocytes are the largest corpuscles found in human blood.

(C) $1$. The mother has '$B$' antibodies,which means her blood group is '$A$'. Her genotype can be either $I^A I^A$ or $I^A i$.
$2$. The father has blood group '$O$',so his genotype must be $ii$.
$3$. If the mother is $I^A I^A$,the cross is $I^A I^A \times ii$,resulting in offspring with genotype $I^A i$ (Blood group '$A$').
$4$. If the mother is $I^A i$,the cross is $I^A i \times ii$,resulting in offspring with genotypes $I^A i$ (Blood group '$A$') and $ii$ (Blood group '$O$').
$5$. Therefore,the possible blood groups for the child are '$A$' and '$O$'.

(A) In the historical classification of blood clotting factors,Factor $VI$ was initially proposed as an active form of Factor $V$ (accelerin). However,later research confirmed that it is not a distinct clotting factor. Therefore,Factor $VI$ is considered non-existent or invalid in the current coagulation cascade.

(D) Blood platelets,also known as thrombocytes,are cell fragments derived from megakaryocytes in the bone marrow. These are specifically characteristic of mammalian blood. In other vertebrates like birds,reptiles,and fish,the equivalent cells are nucleated and are called thrombocytes,which are complete cells rather than fragments.