BiologyQ51–83 of 121 questions
Page 2 of 2 · English
51
BiologyMediumMCQAIPMT · 1989
Sieve tubes are associated with the translocation of food because they possess:
A
Bordered pits
B
End walls without pores
C
Peripheral cytoplasm and perforated cell walls
D
Lack of cytoplasm
Solution
(C) Sieve tubes are the main conducting elements of phloem in angiosperms.
They are long,tube-like structures arranged longitudinally and are associated with companion cells.
Their end walls are perforated in a sieve-like manner to form 'sieve plates'.
Mature sieve tube elements possess a peripheral layer of cytoplasm and a large central vacuole,but they lack a nucleus.
The presence of peripheral cytoplasm and perforated end walls (sieve plates) facilitates the efficient translocation of food materials.
They are long,tube-like structures arranged longitudinally and are associated with companion cells.
Their end walls are perforated in a sieve-like manner to form 'sieve plates'.
Mature sieve tube elements possess a peripheral layer of cytoplasm and a large central vacuole,but they lack a nucleus.
The presence of peripheral cytoplasm and perforated end walls (sieve plates) facilitates the efficient translocation of food materials.
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52
BiologyMediumMCQAIPMT · 1989
The organization of the shoot apex into $Corpus$ and $Tunica$ is determined by:
A
Plane of cell division
B
Region of meristematic activity
C
Rate of cell growth
D
Rate of shoot apex growth
Solution
(A) The $Tunica-Corpus$ theory,proposed by $Schmidt$ $(1924)$,explains the organization of the shoot apical meristem in angiosperms.
According to this theory,the shoot apex is divided into two distinct zones based on the plane of cell division:
$1$. $Tunica$: The peripheral layer$(s)$ where cells divide primarily by anticlinal divisions,leading to surface growth.
$2$. $Corpus$: The central mass of cells where divisions occur in various planes,contributing to the increase in volume.
Therefore,the differentiation between $Tunica$ and $Corpus$ is determined by the plane of cell division.
According to this theory,the shoot apex is divided into two distinct zones based on the plane of cell division:
$1$. $Tunica$: The peripheral layer$(s)$ where cells divide primarily by anticlinal divisions,leading to surface growth.
$2$. $Corpus$: The central mass of cells where divisions occur in various planes,contributing to the increase in volume.
Therefore,the differentiation between $Tunica$ and $Corpus$ is determined by the plane of cell division.
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53
BiologyMediumMCQAIPMT · 1989
The mineral element found in the blood of vertebrates is . . . . . . .
A
Magnesium
B
Iron
C
Calcium
D
Copper
Solution
(B) The blood of vertebrates contains hemoglobin,which is a respiratory pigment present in red blood cells $(RBCs)$.
Hemoglobin is a conjugated protein consisting of a protein part called globin and a non-protein prosthetic group called heme.
The heme group contains an iron $(Fe^{2+})$ ion at its center,which is responsible for binding with oxygen molecules.
Therefore,iron is the essential mineral element found in the blood of vertebrates.
Hemoglobin is a conjugated protein consisting of a protein part called globin and a non-protein prosthetic group called heme.
The heme group contains an iron $(Fe^{2+})$ ion at its center,which is responsible for binding with oxygen molecules.
Therefore,iron is the essential mineral element found in the blood of vertebrates.
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54
BiologyMediumMCQAIPMT · 1989
Haversian canals are found in .............
A
Humerus
B
Femur
C
Scapula
D
Clavicle
Solution
(A) Haversian canals are characteristic features of the compact bone (osteon) found in mammals.
These canals contain blood vessels,nerves,and lymphatic vessels.
Among the given options,the $Humerus$ (the bone of the upper arm) is a long bone composed of compact bone tissue,which contains Haversian systems.
While the $Femur$ also contains Haversian canals,in many standard biological contexts,the $Humerus$ is frequently cited as the primary example of long bones containing these structures.
However,since both $A$ and $B$ are long bones,the question typically refers to the structure of long bones in general. Given the standard curriculum,$Humerus$ is the most common representative.
These canals contain blood vessels,nerves,and lymphatic vessels.
Among the given options,the $Humerus$ (the bone of the upper arm) is a long bone composed of compact bone tissue,which contains Haversian systems.
While the $Femur$ also contains Haversian canals,in many standard biological contexts,the $Humerus$ is frequently cited as the primary example of long bones containing these structures.
However,since both $A$ and $B$ are long bones,the question typically refers to the structure of long bones in general. Given the standard curriculum,$Humerus$ is the most common representative.
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55
BiologyEasyMCQAIPMT · 1989
Histamine-secreting cells are found in:
A
Connective tissue
B
Lungs
C
Muscular tissue
D
Nervous tissue
Solution
(A) Histamine is a chemical mediator involved in inflammatory responses and allergic reactions.
It is primarily secreted by mast cells,which are a type of white blood cell found in connective tissues throughout the body.
These cells are particularly abundant in the skin,respiratory tract,and digestive tract,where they play a crucial role in the immune system's defense mechanism.
Therefore,the correct option is $A$.
It is primarily secreted by mast cells,which are a type of white blood cell found in connective tissues throughout the body.
These cells are particularly abundant in the skin,respiratory tract,and digestive tract,where they play a crucial role in the immune system's defense mechanism.
Therefore,the correct option is $A$.
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56
BiologyMediumMCQAIPMT · 1989
Where are nucleoproteins synthesized?
A
Nucleoplasm
B
Nuclear envelope
C
Nucleolus
D
Cytoplasm
Solution
(C) The nucleolus is a spherical structure present inside the nucleus. It is the site of active ribosomal $RNA$ $(rRNA)$ synthesis and processing. Since ribosomes are composed of $rRNA$ and ribosomal proteins (nucleoproteins),the nucleolus serves as the primary site for the synthesis and assembly of nucleoproteins and ribosomal subunits.
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57
BiologyEasyMCQAIPMT · 1989
Cell organelles can be isolated independently by which of the following methods?
A
Chromatography
B
$X$-ray diffraction
C
Differential centrifugation
D
Autoradiography
Solution
(C) Differential centrifugation is a technique used to separate cell organelles based on their size,shape,and density.
In this process,cell homogenate is subjected to increasing speeds of centrifugation.
As the speed increases,organelles with higher sedimentation coefficients (like nuclei) settle down first,followed by mitochondria,lysosomes,and microsomes.
Therefore,it is the standard method for isolating cell organelles independently.
In this process,cell homogenate is subjected to increasing speeds of centrifugation.
As the speed increases,organelles with higher sedimentation coefficients (like nuclei) settle down first,followed by mitochondria,lysosomes,and microsomes.
Therefore,it is the standard method for isolating cell organelles independently.
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58
BiologyEasyMCQAIPMT · 1989
$A$ polyribosome is formed by the arrangement of which of the following?
A
Ribosomes and $r-RNA$
B
Only $r-RNA$
C
Peroxisomes
D
Several ribosomes attached to a single $m-RNA$
Solution
(D) polyribosome (or polysome) is a structure consisting of multiple ribosomes attached to a single $m-RNA$ molecule.
These ribosomes translate the $m-RNA$ simultaneously,which allows for the rapid synthesis of multiple copies of the same polypeptide chain.
This process is highly efficient for protein synthesis in both prokaryotic and eukaryotic cells.
These ribosomes translate the $m-RNA$ simultaneously,which allows for the rapid synthesis of multiple copies of the same polypeptide chain.
This process is highly efficient for protein synthesis in both prokaryotic and eukaryotic cells.
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59
BiologyEasyMCQAIPMT · 1989
What is the cell membrane composed of?
A
Proteins and carbohydrates
B
Proteins and lipids
C
Proteins,lipids,and carbohydrates
D
Proteins,lipids,and some nucleic acids
Solution
(C) The cell membrane (plasma membrane) is primarily composed of lipids and proteins. The lipid bilayer forms the structural framework,while proteins are embedded within it. Additionally,carbohydrates are present on the outer surface of the membrane,attached to proteins (glycoproteins) or lipids (glycolipids). Therefore,the cell membrane is composed of proteins,lipids,and carbohydrates.
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60
BiologyMediumMCQAIPMT · 1989
Reabsorption of useful substances from the glomerular filtrate occurs in the:
A
Collecting duct
B
Loop of Henle
C
Proximal convoluted tubule
D
Distal convoluted tubule
Solution
(C) The $Proximal \text{ Convoluted Tubule} (PCT)$ is the primary site for the reabsorption of useful substances from the glomerular filtrate.
Approximately $70-80\%$ of electrolytes and water, and $100\%$ of glucose and amino acids are reabsorbed in the $PCT$.
This process is essential for maintaining the internal environment and $pH$ balance of the body fluids.
Approximately $70-80\%$ of electrolytes and water, and $100\%$ of glucose and amino acids are reabsorbed in the $PCT$.
This process is essential for maintaining the internal environment and $pH$ balance of the body fluids.
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61
BiologyEasyMCQAIPMT · 1989
The ends of long bones are covered with .......... cartilage.
A
Calcified
B
Fibrous
C
Elastic
D
Hyaline
Solution
(D) The ends of long bones at joints are covered with hyaline cartilage,which is also known as articular cartilage.
This type of cartilage provides a smooth,low-friction surface that facilitates the movement of joints.
Hyaline cartilage is the most abundant type of cartilage in the body and is characterized by a glassy,translucent appearance.
This type of cartilage provides a smooth,low-friction surface that facilitates the movement of joints.
Hyaline cartilage is the most abundant type of cartilage in the body and is characterized by a glassy,translucent appearance.
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62
BiologyEasyMCQAIPMT · 1989
The sensory pigmented layer of the eye is known as:
A
Sclera
B
Retina
C
Choroid
D
Pupil
Solution
(B) The wall of the human eye is composed of three layers:
$1$. The external layer is the sclera,which is composed of dense connective tissue.
$2$. The middle layer is the choroid,which contains many blood vessels and looks bluish in color. It is the pigmented layer.
$3$. The inner layer is the retina,which contains three layers of cells: ganglion cells,bipolar cells,and photoreceptor cells (rods and cones). The retina is the sensory layer of the eye.
Therefore,the sensory layer of the eye is the retina.
$1$. The external layer is the sclera,which is composed of dense connective tissue.
$2$. The middle layer is the choroid,which contains many blood vessels and looks bluish in color. It is the pigmented layer.
$3$. The inner layer is the retina,which contains three layers of cells: ganglion cells,bipolar cells,and photoreceptor cells (rods and cones). The retina is the sensory layer of the eye.
Therefore,the sensory layer of the eye is the retina.
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63
BiologyEasyMCQAIPMT · 1989
Which of the following cranial nerves controls the heart rate?
A
$X$
B
$IX$
C
$VIII$
D
$VI$
Solution
(A) The $X$ cranial nerve is known as the Vagus nerve. It is a major component of the parasympathetic nervous system and plays a crucial role in regulating the heart rate by slowing it down. The Vagus nerve provides parasympathetic innervation to the heart,specifically targeting the sinoatrial $(SA)$ node and the atrioventricular $(AV)$ node.
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64
BiologyMediumMCQAIPMT · 1989
In the developing embryo, cells undergo changes in shape and function. This process is known as:
A
Differentiation
B
Transformation
C
Morphogenesis
D
Rearrangement
Solution
(A) During embryonic development, cells become specialized to perform specific functions and acquire distinct shapes. This process of cellular specialization is known as $Differentiation$. Through differentiation, cells derived from the zygote develop into various tissues and organs of the body.
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65
BiologyMediumMCQAIPMT · 1989
What is the number of diploid chromosomes in humans?
A
$46$
B
$4$
C
$18$
D
$12$
Solution
(A) In humans,the somatic cells are diploid $(2n)$,meaning they contain two sets of chromosomes,one inherited from each parent.
Each set consists of $23$ chromosomes.
Therefore,the total number of diploid chromosomes in a human cell is $23 \times 2 = 46$.
This includes $22$ pairs of autosomes and $1$ pair of sex chromosomes.
Each set consists of $23$ chromosomes.
Therefore,the total number of diploid chromosomes in a human cell is $23 \times 2 = 46$.
This includes $22$ pairs of autosomes and $1$ pair of sex chromosomes.
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66
BiologyMediumMCQAIPMT · 1989
$A$ normal green male maize plant is crossed with a colorless female plant. The offspring are albino (colorless). This is because:
A
The trait for albinism is dominant.
B
The albino plant contains a chemical that destroys the pigments coming from the green male.
C
Plastids are inherited from the female parent.
D
The green pigments of the male have mutated.
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67
BiologyMediumMCQAIPMT · 1989
Which of the following is not a part of an enzyme but activates the enzyme?
A
$K^+$
B
$C$
C
$N$
D
$Si$
Solution
(A) Many enzymes require non-protein components for their activity. These are called cofactors. Cofactors can be prosthetic groups,co-enzymes,or metal ions. Metal ions form coordination bonds with side chains at the active site and at the same time form one or more coordination bonds with the substrate. $K^+$ (potassium ion) is a well-known metal ion cofactor that activates several enzymes,such as pyruvate kinase,which is involved in glycolysis. Therefore,$K^+$ is not a part of the enzyme structure itself but is essential for its catalytic activity.
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68
BiologyMediumMCQAIPMT · 1989
What does a dyad represent?
A
Two chromatids and one centromere
B
Two chromatids and two centromeres
C
Four chromatids and two centromeres
D
Four chromatids and four centromeres
Solution
(A) dyad refers to a chromosome that has replicated during the $S$-phase of the cell cycle,consisting of two sister chromatids joined at a single centromere.
During meiosis $I$,these dyads pair up to form bivalents or tetrads.
Therefore,a dyad is composed of two chromatids and one centromere.
During meiosis $I$,these dyads pair up to form bivalents or tetrads.
Therefore,a dyad is composed of two chromatids and one centromere.
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69
BiologyMediumMCQAIPMT · 1989
In terrestrial habitats,how are temperature and rainfall conditions primarily influenced?
A
Water transformation
B
Transpiration
C
Thermal periodicity
D
Migration
Solution
(B) In terrestrial habitats,plants play a significant role in influencing the local climate,specifically temperature and rainfall patterns.
Transpiration is the process by which water evaporates from the aerial parts of plants,such as leaves.
This process releases water vapor into the atmosphere,which contributes to local humidity and can influence cloud formation and rainfall.
Additionally,the cooling effect of transpiration helps regulate the temperature of the surrounding environment.
Therefore,transpiration is a key biological process that affects the microclimate of terrestrial ecosystems.
Transpiration is the process by which water evaporates from the aerial parts of plants,such as leaves.
This process releases water vapor into the atmosphere,which contributes to local humidity and can influence cloud formation and rainfall.
Additionally,the cooling effect of transpiration helps regulate the temperature of the surrounding environment.
Therefore,transpiration is a key biological process that affects the microclimate of terrestrial ecosystems.
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70
BiologyMediumMCQAIPMT · 1989
Phosphorus and nitrogen ions are generally leached from the soil because they are usually in the form of:
A
Natural ions
B
Anions
C
Cations
D
Both cations and anions but polar mixtures
Solution
(B) Soil particles are generally negatively charged.
Because of this negative charge,they tend to attract and hold positively charged ions (cations) like $K^+$,$Ca^{2+}$,and $Mg^{2+}$.
Conversely,negatively charged ions (anions) like $NO_3^-$ (nitrate) and $PO_4^{3-}$ (phosphate) are repelled by the negatively charged soil particles.
Due to this repulsion,these anions do not bind to the soil and are easily washed away or leached out by water,especially during heavy rainfall or irrigation.
Because of this negative charge,they tend to attract and hold positively charged ions (cations) like $K^+$,$Ca^{2+}$,and $Mg^{2+}$.
Conversely,negatively charged ions (anions) like $NO_3^-$ (nitrate) and $PO_4^{3-}$ (phosphate) are repelled by the negatively charged soil particles.
Due to this repulsion,these anions do not bind to the soil and are easily washed away or leached out by water,especially during heavy rainfall or irrigation.
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71
BiologyMediumMCQAIPMT · 1989
Which crop provides the highest net primary productivity of $2-4 \ kg/m^2$ from solar energy?
A
Wheat
B
Sugarcane
C
Rice
D
Millet
Solution
(B) Sugarcane $(Saccharum \ officinarum)$ is a $C_4$ plant that exhibits high photosynthetic efficiency.
It is known for having one of the highest net primary productivity rates among agricultural crops,often reaching $2-4 \ kg/m^2$ per year.
This high productivity is due to the $C_4$ pathway,which minimizes photorespiration and allows the plant to maintain high rates of carbon fixation even under high light intensity and temperature conditions.
It is known for having one of the highest net primary productivity rates among agricultural crops,often reaching $2-4 \ kg/m^2$ per year.
This high productivity is due to the $C_4$ pathway,which minimizes photorespiration and allows the plant to maintain high rates of carbon fixation even under high light intensity and temperature conditions.
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72
BiologyMediumMCQAIPMT · 1989
Which of the following is the substrate for photorespiration?
A
Phosphoglyceric acid
B
Glycolate
C
Serine
D
Glycine
Solution
(B) Photorespiration is a process that occurs in $C_3$ plants when the enzyme $RuBisCO$ acts as an oxygenase instead of a carboxylase.
In this process,$RuBP$ $(Ribulose-1,5-bisphosphate)$ reacts with $O_2$ to form one molecule of $3-phosphoglycerate$ and one molecule of $2-phosphoglycolate$.
$2-phosphoglycolate$ is then dephosphorylated to form $Glycolate$.
$Glycolate$ serves as the primary substrate that enters the photorespiratory pathway (also known as the $C_2$ cycle) in the peroxisomes.
Therefore,$Glycolate$ is the correct substrate for photorespiration.
In this process,$RuBP$ $(Ribulose-1,5-bisphosphate)$ reacts with $O_2$ to form one molecule of $3-phosphoglycerate$ and one molecule of $2-phosphoglycolate$.
$2-phosphoglycolate$ is then dephosphorylated to form $Glycolate$.
$Glycolate$ serves as the primary substrate that enters the photorespiratory pathway (also known as the $C_2$ cycle) in the peroxisomes.
Therefore,$Glycolate$ is the correct substrate for photorespiration.
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73
BiologyMediumMCQAIPMT · 1989
In $C_4$ plants,where does the $Calvin$ cycle take place?
A
In the bundle sheath chloroplasts located in the stroma
B
In the bundle sheath chloroplasts of the grana
C
In the mesophyll chloroplasts of the grana
D
In the mesophyll chloroplasts of the stroma
Solution
(A) In $C_4$ plants,the $Calvin$ cycle occurs exclusively in the bundle sheath cells.
These cells contain chloroplasts that are specialized for the $Calvin$ cycle,as they lack grana (agranal chloroplasts) and are rich in $RuBisCO$ enzyme.
The initial $CO_2$ fixation occurs in the mesophyll cells,forming a $4$-carbon compound $(OAA)$,which is then transported to the bundle sheath cells for the $Calvin$ cycle.
These cells contain chloroplasts that are specialized for the $Calvin$ cycle,as they lack grana (agranal chloroplasts) and are rich in $RuBisCO$ enzyme.
The initial $CO_2$ fixation occurs in the mesophyll cells,forming a $4$-carbon compound $(OAA)$,which is then transported to the bundle sheath cells for the $Calvin$ cycle.
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74
BiologyMediumMCQAIPMT · 1989
Many types of grass leaves have the ability to roll or unroll because they contain ........
A
are very thin.
B
are isobilateral.
C
contain specialized bulliform cells.
D
have parallel vascular bundles.
Solution
(C) In grasses,certain epidermal cells along the veins modify themselves into large,empty,colorless cells known as $ \text{bulliform cells} $.
When these cells are turgid due to water absorption,the leaf surface is exposed.
When there is water stress,these cells lose water and become flaccid,causing the leaf to roll inwards to minimize water loss through transpiration.
When these cells are turgid due to water absorption,the leaf surface is exposed.
When there is water stress,these cells lose water and become flaccid,causing the leaf to roll inwards to minimize water loss through transpiration.
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75
BiologyMediumMCQAIPMT · 1989
Which of the following increases in the absence of light?
A
Upward movement of mineral elements
B
Absorption of water
C
Elongation of internodes
D
Ascent of sap
Solution
(C) In the absence of light,plants exhibit a phenomenon known as etiolation.
Etiolation is a process in flowering plants grown in partial or complete absence of light.
It is characterized by long,weak stems,smaller leaves due to longer internodes,and a pale yellow color.
Therefore,the elongation of internodes increases significantly in the absence of light as the plant attempts to reach a light source.
Etiolation is a process in flowering plants grown in partial or complete absence of light.
It is characterized by long,weak stems,smaller leaves due to longer internodes,and a pale yellow color.
Therefore,the elongation of internodes increases significantly in the absence of light as the plant attempts to reach a light source.
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76
BiologyMediumMCQAIPMT · 1989
Which of the following helps in delaying leaf senescence?
A
Abscisic acid
B
Auxin
C
Florigen
D
Cytokinin
Solution
(D) Cytokinins are plant hormones that promote cell division and delay the process of leaf senescence (aging).
They help in maintaining the chlorophyll content and protein synthesis in leaves for a longer duration,thereby preventing premature yellowing and shedding.
Abscisic acid,on the other hand,promotes senescence and abscission.
Therefore,the correct option is $D$.
They help in maintaining the chlorophyll content and protein synthesis in leaves for a longer duration,thereby preventing premature yellowing and shedding.
Abscisic acid,on the other hand,promotes senescence and abscission.
Therefore,the correct option is $D$.
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77
BiologyMediumMCQAIPMT · 1989
Lawn grass is managed more effectively because
A
it regenerates with the stimulation of the sheath.
B
apical dominance is removed and intercalary meristems are stimulated.
C
apical dominance is removed.
D
apical dominance is removed and lateral meristem growth is induced.
Solution
(B) Lawn grass is managed by regular mowing. When the top of the grass is cut,the apical bud (which is the source of apical dominance due to auxin production) is removed. This removal of apical dominance allows the intercalary meristems,which are located at the base of the nodes or internodes,to become active and stimulate the growth of the grass,leading to a thicker and more uniform lawn.
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78
BiologyMediumMCQAIPMT · 1989
The secretion of pancreatic juice is stimulated by:
A
Enterokinase
B
Cholecystokinin
C
Trypsinogen
D
Secretin
Solution
(D) The secretion of pancreatic juice is primarily regulated by gastrointestinal hormones.
$1$. $Secretin$ acts on the exocrine pancreas to stimulate the secretion of water and bicarbonate ions.
$2$. $Cholecystokinin$ $(CCK)$ stimulates the pancreas to secrete digestive enzymes.
Since both hormones are involved,and $Secretin$ is the primary hormone known for stimulating the watery component of pancreatic juice,in many contexts,both are considered correct. However,$Secretin$ is the classic answer for the stimulation of pancreatic juice secretion (specifically the bicarbonate-rich fluid).
Therefore,the most appropriate answer is $Secretin$.
$1$. $Secretin$ acts on the exocrine pancreas to stimulate the secretion of water and bicarbonate ions.
$2$. $Cholecystokinin$ $(CCK)$ stimulates the pancreas to secrete digestive enzymes.
Since both hormones are involved,and $Secretin$ is the primary hormone known for stimulating the watery component of pancreatic juice,in many contexts,both are considered correct. However,$Secretin$ is the classic answer for the stimulation of pancreatic juice secretion (specifically the bicarbonate-rich fluid).
Therefore,the most appropriate answer is $Secretin$.
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79
BiologyMediumMCQAIPMT · 1989
The tricuspid valve is found between ...............
A
Sinus venosus and right atrium
B
Right atrium and right ventricle
C
Left ventricle and left atrium
D
Ventricle and aorta
Solution
(B) The human heart has four chambers: two atria and two ventricles.
$1$. The tricuspid valve is a three-flap valve located between the right atrium and the right ventricle.
$2$. Its primary function is to prevent the backflow of blood from the right ventricle into the right atrium during ventricular systole.
$3$. The bicuspid or mitral valve is located between the left atrium and the left ventricle.
$4$. Therefore,the correct option is $B$.
$1$. The tricuspid valve is a three-flap valve located between the right atrium and the right ventricle.
$2$. Its primary function is to prevent the backflow of blood from the right ventricle into the right atrium during ventricular systole.
$3$. The bicuspid or mitral valve is located between the left atrium and the left ventricle.
$4$. Therefore,the correct option is $B$.
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80
BiologyMediumMCQAIPMT · 1989
Which of the following cells phagocytose microorganisms rapidly?
A
Acidophils
B
Monocytes
C
Neutrophils
D
Both $(B)$ and $(C)$
Solution
(D) Neutrophils and Monocytes are types of white blood cells $(WBCs)$ that act as the body's defense mechanism.
Neutrophils are the most abundant $WBCs$ $(60-65\%)$ and are phagocytic in nature, meaning they engulf and destroy foreign microorganisms.
Monocytes $(6-8\%)$ are also phagocytic and differentiate into macrophages to engulf bacteria and cellular debris.
Therefore, both Neutrophils and Monocytes are responsible for the rapid phagocytosis of microorganisms.
Neutrophils are the most abundant $WBCs$ $(60-65\%)$ and are phagocytic in nature, meaning they engulf and destroy foreign microorganisms.
Monocytes $(6-8\%)$ are also phagocytic and differentiate into macrophages to engulf bacteria and cellular debris.
Therefore, both Neutrophils and Monocytes are responsible for the rapid phagocytosis of microorganisms.
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81
BiologyMediumMCQAIPMT · 1989
$A$ person with blood group $A$ needs a blood transfusion. Which blood group$(s)$ can be donated to them?
A
$A$ and $B$
B
$A$ and $AB$
C
$A$ and $O$
D
$A, B, AB$ and $O$
Solution
(C) person with blood group $A$ has $A$ antigens on the surface of their red blood cells and anti-$B$ antibodies in their plasma.
To avoid an immune reaction,the donor's blood must not contain $B$ antigens.
Therefore,a person with blood group $A$ can receive blood from individuals with blood group $A$ (same type) or blood group $O$ (universal donor,as it lacks both $A$ and $B$ antigens).
Thus,the correct option is $C$.
To avoid an immune reaction,the donor's blood must not contain $B$ antigens.
Therefore,a person with blood group $A$ can receive blood from individuals with blood group $A$ (same type) or blood group $O$ (universal donor,as it lacks both $A$ and $B$ antigens).
Thus,the correct option is $C$.
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82
BiologyDifficultMCQAIPMT · 1989
What happens when calcium is removed from freshly collected blood?
A
Coagulation is delayed
B
Coagulation is prevented
C
It clots immediately
D
Hemoglobin degradation is stopped
Solution
(B) Calcium ions $(Ca^{2+})$ play a critical role in the blood clotting process. They are essential for the activation of clotting factors,specifically in the conversion of prothrombin to thrombin. When calcium is removed from freshly collected blood (e.g.,by adding chelating agents like $EDTA$ or sodium citrate),the coagulation cascade is interrupted,thereby preventing the blood from clotting.
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83
BiologyEasyMCQAIPMT · 1989
Arteries carry $O_2$-rich blood except for the:
A
Pulmonary artery
B
Cardiac artery
C
Hepatic artery
D
Systemic artery
Solution
(A) In the human circulatory system,arteries are defined as blood vessels that carry blood away from the heart.
Most arteries carry oxygenated ($O_2$-rich) blood to the tissues of the body.
The pulmonary artery is an exception to this rule,as it carries deoxygenated ($CO_2$-rich) blood from the right ventricle of the heart to the lungs for oxygenation.
Therefore,the correct answer is the pulmonary artery.
Most arteries carry oxygenated ($O_2$-rich) blood to the tissues of the body.
The pulmonary artery is an exception to this rule,as it carries deoxygenated ($CO_2$-rich) blood from the right ventricle of the heart to the lungs for oxygenation.
Therefore,the correct answer is the pulmonary artery.
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How many Biology questions are in AIPMT 1989?
There are 121 Biology questions from the AIPMT 1989 paper on Vedclass, each with a detailed step-by-step solution in English.
Are AIPMT 1989 Biology solutions available in English?
Yes. All solutions on this page are in English. You can also switch to English or Hindi using the language buttons above the questions.
Can I practice AIPMT 1989 Biology as a timed test?
Yes. Use the Vedclass Test Series to attempt a full AIPMT mock test covering Biology with time limits and instant score analysis.
Can teachers create Biology papers from AIPMT previous year questions?
Yes. The Vedclass Exam Paper Generator lets teachers mix AIPMT Biology questions and generate Set A/B/C/D papers in minutes.
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Pick AIPMT 1989 Biology questions, set difficulty, and generate Set A/B/C/D in 2 minutes.