Q.Which of the following cells does not exhibit phagocytotic activity
Concept understanding — Types Of Leucocytes
Types of Leucocytes (White Blood Cells)
Imagine your blood as a busy city. Red blood cells are the delivery trucks, carrying oxygen. Platelets are the road repair crews, patching up leaks. But the white blood cells — the leucocytes — are the police and army. Their only job is to find, fight, and destroy anything that doesn't belong: bacteria, viruses, parasites, even your own cells if they turn cancerous.
There are about 4,000 to 11,000 white blood cells in every microliter of your blood. But they are not all the same. They come in two broad families, and the difference is visible under a microscope.
The Two Families: Granulocytes vs Agranulocytes
The name tells you the story. Granulocytes have visible little sacs (granules) inside their cytoplasm when you stain them. These granules are like ammunition pouches — they contain enzymes and chemicals to kill invaders. Agranulocytes look smooth inside; they have no such visible granules. Their weapons are different.
The "granules" in granulocytes are not just decoration. They are lysosomes and secretory vesicles packed with digestive enzymes, histamine, and other attack chemicals.
Granulocytes (The "Granular" Fighters)
These cells have a nucleus that is lobed — it looks like it has 2–5 separate blobs connected by thin threads. They are also called polymorphonuclear leukocytes (many-shaped nucleus). There are three types, and they are distinguished by how their granules take up dye.
1. Neutrophils (The Frontline Soldiers)
Intuition: If a bacterial infection starts, neutrophils are the first responders. They rush to the site, swallow bacteria whole (phagocytosis), and then die. Pus is mostly dead neutrophils.
Precise statement: Neutrophils make up 60–70% of all white blood cells. Their granules stain with both acidic and basic dyes, appearing a pale pink or lilac. They have a nucleus with 3–5 lobes. They are the most abundant and the fastest to arrive at an infection.
A high neutrophil count usually means a bacterial infection. A low count (neutropenia) makes you very vulnerable to infection.
2. Eosinophils (The Parasite Hunters & Allergy Responders)
Intuition: Think of a tapeworm or a hookworm — too big for a neutrophil to swallow. Eosinophils attach to the parasite's surface and release their granules to kill it. They also show up in allergic reactions.
Precise statement: Eosinophils make up only 2–4% of WBCs. Their granules stain bright red-orange with acidic dyes like eosin. The nucleus is typically bilobed (two lobes, like a pair of glasses). They are especially active against parasitic worms and modulate allergic inflammation.
3. Basophils (The Alarm System)
Intuition: Basophils are rare. When they encounter an allergen, they explode, releasing histamine and heparin. Histamine causes inflammation and itching; heparin prevents blood clotting at the site. They are the "fire alarm" that calls other immune cells to the area.
Precise statement: Basophils are the least common granulocyte, less than 1% of WBCs. Their large granules stain dark blue-purple with basic dyes, often obscuring the nucleus. They release histamine (vasodilation, inflammation) and heparin (anticoagulant). They are central to immediate hypersensitivity (allergic) reactions.
Granulocyte Summary
| Type | % of WBCs | Granule Color | Nucleus Shape | Main Role |
|---|---|---|---|---|
| Neutrophil | 60–70% | Pale pink/lilac | 3–5 lobes | Phagocytosis of bacteria |
| Eosinophil | 2–4% | Bright red-orange | Bilobed | Kill parasites, allergy |
| Basophil | <1% | Dark blue-purple | Often hidden | Release histamine, heparin |
Agranulocytes (The "Smooth" Fighters)
These cells have no visible granules in the cytoplasm. Their nucleus is not lobed — it is round, kidney-shaped, or indented. They are also called mononuclear leukocytes (single nucleus).
1. Lymphocytes (The Special Forces & Memory)
Intuition: Lymphocytes are not just soldiers; they are also intelligence officers. They learn to recognise a specific invader, then either kill it directly or produce antibodies that tag it for destruction. And they remember it for years — that is why you only get chickenpox once.
Precise statement: Lymphocytes make up 20–30% of WBCs. They have a large, round nucleus that fills most of the cell, with only a thin rim of pale blue cytoplasm. There are two main types:
- B lymphocytes (B cells): Produce antibodies (humoral immunity).
- T lymphocytes (T cells): Kill infected cells directly (cell-mediated immunity).
A high lymphocyte count often suggests a viral infection (like flu, measles, or COVID-19). A very low count is seen in HIV/AIDS.
2. Monocytes (The Cleanup Crew & Macrophages)
Intuition: Monocytes are the largest white blood cells. They leave the bloodstream, enter tissues, and transform into macrophages ("big eaters"). They are like the garbage trucks — they clean up dead cells, debris, and leftover pathogens after the battle is over. They also "present" pieces of the invader to lymphocytes to start a smarter immune response.
Precise statement: Monocytes make up 2–8% of WBCs. They are the largest WBC, with a kidney-shaped or horseshoe-shaped nucleus and abundant grey-blue cytoplasm. Once in tissue, they differentiate into macrophages or dendritic cells, performing phagocytosis and antigen presentation.
To remember the order of abundance: Never Let Monkeys Eat Bananas — Neutrophils (most), Lymphocytes, Monocytes, Eosinophils, Basophils (least).
The Big Picture
| Feature | Granulocytes | Agranulocytes |
|---|---|---|
| Visible granules? | Yes | No |
| Nucleus shape | Lobed (polymorphonuclear) | Round or kidney-shaped (mononuclear) |
| Types | Neutrophil, Eosinophil, Basophil | Lymphocyte, Monocyte |
| Main function | Immediate, non-specific attack (innate immunity) | Targeted, long-term defence (adaptive immunity) |
Final takeaway: Your blood has a layered defence. Granulocytes are the rapid, blunt-force responders. Agranulocytes are the precise, intelligent, and memory-equipped specialists. Together, they keep you alive against a world full of microbes.
This concept is aligned with the Body Fluids and Circulation chapter of the NCERT/CBSE Class 11 Biology curriculum, which is why searches like "Types Of Leucocytes notes class 11" and "Types Of Leucocytes NCERT" are common among board-exam candidates. It is equally relevant for NEET preparation, where Body Fluids and Circulation questions appear almost every year.
Among white blood cells, neutrophils and monocytes are specifically identified as phagocytic, engulfing and destroying foreign organisms that enter the body. Basophils, by contrast, are not described as phagocytic — instead they secrete substances such as histamine, serotonin and heparin and take part in inflammatory reactions, a different kind of defensive role altogether.
Basophils do not exhibit phagocytic activity — option (C).
Neutrophils and monocytes are the phagocytic white blood cells; basophils instead secrete inflammatory mediators and do not engulf foreign organisms.
White blood cells (leucocytes) fall into different types with distinct jobs. Neutrophils are the most abundant WBCs, making up about 60 to 65 per cent of the total, and together with monocytes (about 6 to 8 per cent) they are phagocytic — they engulf and destroy foreign organisms that enter the body.
Basophils, the least common of the WBCs (about 0.5 to 1 per cent), have a different role. They secrete substances such as histamine, serotonin and heparin, and take part in inflammatory reactions rather than directly engulfing pathogens.
Monocytes are known to give rise to macrophages, which are themselves strongly phagocytic — so among the four options, it is specifically basophils that stand apart as the non-phagocytic cell type.
Basophils do not show phagocytic activity — option (C).
Method: Solving an "Odd One Out" / Exception MCQ
Use this approach for any MCQ asking which option does NOT share a property that the others do.
Steps
Step 1: Identify the shared property being tested
Here it is phagocytosis — recall which broad category of cells is typically associated with it (certain white blood cells).
Step 2: Classify each option as YES or NO for that property, using its specific defining function
Monocyte → YES (phagocytic); Neutrophil → YES (phagocytic); Basophil → NO (secretes histamine/serotonin/heparin, drives inflammation, does not engulf); Macrophage → YES (phagocytic, and derived from monocytes).
Step 3: Watch for options from the same broad family
All four options here are white blood cells — the odd one out is differentiated by its specific job, not by belonging to a different category altogether.
Step 4 (Applying to this problem): Select the lone "NO." If more than one option seems to qualify, re-check the most specific defining fact for each — for instance, remembering that monocytes give rise to macrophages helps confirm both belong with the phagocytic group.
- TG EAPCET 2022Set ap-2022-07-31-FN1 markMCQQ.Match the following : Leucocyte Number A) Eosinophils I) 5.3 % B) Monocytes II) 30% C) Basophils III) 2.3% D) Lymphocytes IV) 62% V) 0.4% The correct match is (A) A B C D III I IV II (B) A B C D II V III I (C) A B C D IV I III III (D) A B C D III I V II
›Reveal solutionSolution
This question tests the typical differential leukocyte count (DLC) percentages in human blood. The correct match is A–III, B–I, C–V, D–II, which corresponds to option (D).
The concept here is the differential white blood cell count — the relative percentages of each type of leukocyte in normal adult blood. These values are standard in physiology and are often memorized, but understanding the relative abundance helps avoid confusion. Eosinophils and basophils are rare, monocytes are intermediate, and lymphocytes are the second most abundant after neutrophils (which are not listed here). The trick is to pair the rarest cells with the smallest percentages.
Let’s match step by step:
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Eosinophils (A) — These are moderately rare, typically around 2–4%. The closest value in the list is 2.3% (III). So A → III.
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Monocytes (B) — They make up about 3–8% of leukocytes. The value 5.3% (I) fits perfectly. So B → I.
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Basophils (C) — These are the rarest white blood cells, usually less than 1%. The only value that small is 0.4% (V). So C → V.
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Lymphocytes (D) — They are the second most common, normally 20–40%. The largest remaining percentage is 30% (II). So D → II.
Now check the options:
- (A) A–III, B–I, C–IV, D–II → C is wrong (IV is 62%, far too high).
- (B) A–II, B–V, C–III, D–I → all mismatched.
- (C) A–IV, B–I, C–III, D–III → repeats III and uses IV incorrectly.
- (D) A–III, B–I, C–V, D–II → matches our reasoning exactly.
Watch outA common mistake is confusing eosinophils (2.3%) with basophils (0.4%) or thinking lymphocytes are the most abundant (they are second; neutrophils are first, but not listed here). Always remember: basophils are the rarest.
TipIf you forget exact numbers, remember the mnemonic: "Never Let Monkeys Eat Bananas" — Neutrophils (60–70%), Lymphocytes (20–40%), Monocytes (3–8%), Eosinophils (2–4%), Basophils (0–1%). Here, since neutrophils are absent, lymphocytes take the largest listed value (30%), and basophils take the smallest (0.4%).
✓Final answerThe correct option is (D).
ANSWER: D
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- TG EAPCET 2021Set ap-2021-08-10-AN1 markMCQQ.Pick up the mismatched pair (A) Basophils - 6% (B) Esinophils - 2.3% (C) Neutrophils - 62% (D) Monocytes - 5.3%
›Reveal solutionSolution
This question tests knowledge of the normal percentage distribution of different types of white blood cells (leukocytes) in human blood. The pair with Basophils at 6% is mismatched because their normal percentage is much lower.
Concept and Intuition
White blood cells, also known as leukocytes, are crucial components of the immune system, defending the body against infections and foreign substances. There are five main types of leukocytes, each with specific roles: Neutrophils, Lymphocytes, Monocytes, Eosinophils, and Basophils.
The relative proportion of these different types of white blood cells in the blood is typically stable in a healthy individual. This distribution is often referred to as a "differential leukocyte count." Deviations from these normal percentages can indicate various physiological conditions, infections, or diseases. For example, an increase in neutrophils might suggest a bacterial infection, while an increase in eosinophils could point to an allergic reaction or parasitic infection. Therefore, knowing the normal ranges is fundamental for diagnostic purposes.
The question asks to identify the mismatched pair, meaning one of the options presents a percentage that is significantly outside the normal, healthy range for that specific type of white blood cell.
Step-by-Step Solution
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Recall the normal percentage ranges for each type of leukocyte:
The typical normal percentage ranges for the five types of white blood cells in human blood are:
- Neutrophils: 60−65%
- Lymphocytes: 20−25%
- Monocytes: 6−8%
- Eosinophils: 2−3%
- Basophils: 0.5−1%
ImportantThese percentages represent the relative abundance of each leukocyte type among all white blood cells.
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Evaluate each given option against its normal range:
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(A) Basophils - 6%
The normal range for Basophils is 0.5−1%. A value of 6% is significantly higher than this normal range. Basophils are the least numerous type of white blood cell. This pair is a clear mismatch.
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(B) Eosinophils - 2.3%
The normal range for Eosinophils is 2−3%. The value 2.3% falls within this normal range. This pair is correctly matched.
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(C) Neutrophils - 62%
The normal range for Neutrophils is 60−65%. The value 62% falls within this normal range. This pair is correctly matched.
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(D) Monocytes - 5.3%
The normal range for Monocytes is 6−8%. While 5.3% is slightly below the lower limit of 6%, some accepted ranges for monocytes can be broader (e.g., 2−10% or 3−8%). Compared to the drastic deviation seen with Basophils, this value is much closer to the normal range and might be considered within an acceptable variation depending on the specific reference range used. However, the 6% for Basophils is unequivocally outside any normal physiological range.
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Identify the most mismatched pair:
Comparing all options, the percentage given for Basophils (6%) is an extreme deviation from its normal range (0.5−1%). This makes option (A) the most definitively mismatched pair.
✓Final answerThe mismatched pair is (A) Basophils - 6%.
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- TG EAPCET 2021Set ap-2021-08-10-FN1 markMCQQ.Pick up the mismatched pair (A) Basophils − 6% (B) Esinophils − 2.3% (C) Neutrophils − 62% (D) Monocytes − 5.3%
›Reveal solutionSolution
The question tests the normal differential leukocyte count (DLC) percentages. The mismatched pair is (B) Eosinophils – 2.3%, because the normal eosinophil range is 1–4%, and 2.3% falls within it — but the actual mismatch is that the given value is too low for eosinophils? Wait, let’s check: the correct normal values are: Neutrophils 40–80% (typically 60–70%), Eosinophils 1–4%, Basophils 0.5–1%, Monocytes 2–8%. Here, Basophils at 6% is far too high (normal ~0.5–1%), so (A) is the mismatched pair.
The key concept here is the differential leukocyte count (DLC) — the percentage distribution of different white blood cells in a blood smear. In Indian medical entrance exams (NEET, AIIMS, etc.), you are expected to memorize the approximate normal ranges for each type of WBC. The question gives four pairs: cell type and a percentage. One of these percentages does not match the normal range for that cell type. Your job is to spot the odd one out.
Let’s recall the standard normal ranges (as commonly taught):
WBC type Normal percentage range Neutrophils 40–80% (often quoted as 60–70%) Eosinophils 1–4% Basophils 0.5–1% (sometimes up to 2%) Monocytes 2–8% Lymphocytes 20–40% Now examine each option:
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Option (A): Basophils – 6%
Basophils are the rarest granulocytes. Their normal count is typically 0.5–1% of total WBCs. Even in some textbooks, the upper limit is 2%. A value of 6% is far outside this range — it would indicate a pathological condition (e.g., basophilic leukemia or chronic myeloid leukemia). So this is clearly mismatched.
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Option (B): Eosinophils – 2.3%
Eosinophils normally range from 1% to 4%. 2.3% lies comfortably within that range. This is a perfectly normal value. So this pair is correctly matched.
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Option (C): Neutrophils – 62%
Neutrophils are the most abundant WBCs, typically 40–80% (often 60–70%). 62% is well within the normal range. Correct match.
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Option (D): Monocytes – 5.3%
Monocytes normally constitute 2–8% of WBCs. 5.3% is right in the middle. Correct match.
Watch outA common mistake is to think that 2.3% for eosinophils is too low or too precise — but the normal range is broad enough to include it. The real outlier is basophils at 6%, which is about 6–10 times the normal value.
Thus, the only pair that does not match the known normal range is (A).
✓Final answerThe mismatched pair is option (A) Basophils – 6%.
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