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Chapter test · Zoology · Class 12 · Human Health and Disease

Human Health and Disease — 80-Question Chapter Test

Aamirah Fathima · NEET 2027 · every question lost on this paper, rebuilt in full

278marks / 320
71correct
6attempted, wrong
3left blank
42marks lost (incl. −6)
Target was 290+, danger line 260: this lands between them, 12 marks short. Cancer was 12 / 12 and common diseases 19 / 20. Everything lost sits in two places — immunity (21 / 27) and statement-count questions.

Weak areas from this paper

Antibodies — three questions, three losses 3rd repeat

Q40, Q47 (and Q36 alongside). H₂L₂ read as 'two chains' has now been chosen on all three papers that asked it (45Q Q17, 60Q Q35, and Q47 here).

Fix to drill. One card, read aloud daily: “Antibody = H₂L₂ = two heavy + two light = FOUR chains. Made by B-cells. IgE → allergy, IgA → colostrum.”

Assertion–Reason in a full paper recurring

Q36 wrong, Q37 blank, Q38 wrong — all three A–R items she met went badly, although the 10-question A–R drill scored 10 / 10. Q36 denied a real link; Q38 accepted a false assertion because the reason sounded right.

Fix to drill. Write the three margin lines in the paper itself, not only in the drill: A: T/F — reason, R: T/F — reason, then 'A because R' aloud. Judge A before reading R.

Statement-count questions watch

Q14 (counted two instead of three — a true line rejected) and Q78 (counted three instead of one — three altered lines accepted). The same format failed in both directions on one paper.

Fix to drill. T/F plus a two-word reason beside every line before counting; underline the single swappable word (lungs, depressant, methylation, heart).

Three blanks, all one-liners attempt rate

Q37 (memory cells), Q40 (antibody statements) and Q57 (HIV factory cell) are 12 marks, and each is straight recall. Q57 repeats the macrophage-versus-helper-T question missed on both earlier papers.

The nine at a glance

QStatusMarkedKeyTopicError family
Q14wrongBCCommon DiseasesA true statement marked false
Q25wrongCDImmunity — Primary and Secondary ResponsePrimary vs secondary response
Q36wrongBAImmunity — Active, Passive and VaccinationAssertion–Reason link denied
Q37blank—AImmunity — Active, Passive and VaccinationBlank — vaccination and memory cells
Q38wrongADImmunity — Active, Passive and VaccinationSingle-word substitution (yeast → bacteria)
Q40blank—CAntibodiesBlank — antibody statements
Q47wrongDCAntibodiesH₂L₂ read as two chains
Q57blank—AAIDSBlank — which cell is the HIV factory
Q78wrongCADrugs and Alcohol AbuseThree false statements accepted

Question by question

Common Diseases

Q14
Q14Attempted · wrong A true statement marked false
How many of the following statements are correct?
A. Plague and diphtheria are bacterial diseases.
B. Rhinoviruses of the common cold infect the lungs.
C. Amoebiasis is caused by a protozoan parasite in the large intestine.
D. Filariasis is caused by the helminth Wuchereria.
  1. Only one
  2. Only two her answer
  3. Only three ✓ key
  4. All four
Concept
Three of the four are NCERT lines. Plague and diphtheria are listed among the bacterial diseases; amoebiasis is caused by the protozoan Entamoeba histolytica in the large intestine; filariasis is caused by the helminths Wuchereria bancrofti and W. malayi. Only B is altered: rhinoviruses infect the nose and respiratory passage but not the lungs — that is the exact NCERT wording, and it is what separates the common cold from pneumonia.
Diagram
RHINOVIRUS: nose and respiratory passage ✓… but NOT the lungs ✗Pneumonia (S. pneumoniae, H. influenzae) → alveoliupper airway
Animated · the still frame carries the full message.
Answer
(C) Only three
Why (one line)
Only B is false: rhinoviruses infect the nose and respiratory passage but not the lungs.
Why not the others
A · rule outThree are true, not one.
B · rule outOnly B is false.
C · keepA, C and D are NCERT; B changes 'not the lungs' into 'the lungs'.
D · rule outB is false, so 'all four' fails.
Shortcut
In a 'how many' question, mark T/F beside each line with a two-word reason, then add up. Do not stop at the first suspicious line.
NCERT line
§7.1 — Rhino viruses infect the nose and respiratory passage but not the lungs.
Trap (as built)
Lungs vs upper airway
Where it went wrong
Marked (B): Only two.
Two were counted instead of three, so one true statement was rejected as well as the false one spotted. The likely casualty is A (plague and diphtheria), which is easy to doubt because those two diseases are named only in passing.

Immunity — Primary and Secondary Response

Q25
Q25Attempted · wrong Primary vs secondary response
A person is exposed to antigen Y on day 1 and again on day 24. On day 24 he is also exposed to antigen X for the first time. After day 24, which is expected?
  1. The anti-X and anti-Y responses are equal in size
  2. There is no anti-Y response because Y was already met
  3. The anti-X response is larger because X is new her answer
  4. The anti-Y response is faster and much larger than the anti-X response ✓ key
Concept
The first meeting with an antigen gives a primary response: slow and of low intensity. Because memory B and T cells are left behind, a later meeting with the same antigen gives a secondary (anamnestic) response that is faster and far larger. Antigen Y is met twice (day 1 and day 24), so on day 24 it gets the secondary response; antigen X is met for the first time on day 24, so it gets only a primary response.
Diagram
days →antibody levelday 1day 24Y: primary (small, slow)Y again: SECONDARY (fast, much larger)X first time: primary (small)Memory B and T cells make the SECOND meeting with the same antigen fast and large
Animated · the still frame carries the full message.
Answer
(D) The anti-Y response is faster and much larger than the anti-X response
Why (one line)
Y gives a secondary (anamnestic) response; X gives only a primary response.
Why not the others
A · rule outEqual responses would mean memory does not exist.
B · rule outX is new — novelty gives a small first response, not a large one.
C · rule outBeing new makes the X response smaller, not larger.
D · keepY has memory cells behind it → fast and much larger.
Shortcut
Ask one question: which antigen has been seen before? That one gets the tall curve.
NCERT line
§7.2.2 — Subsequent encounters with the same pathogen elicit a highly intensified secondary or anamnestic response.
Trap (as built)
Equal peaks chosen (B1 ILTS-08 Q143)
Where it went wrong
Marked (C): The anti-X response is larger because X is new.
'X is larger because it is new' reverses the rule — the response to a new antigen is the weak one. This is the same question she left blank in B1 ILTS-08 (Q143), so it is a gap rather than a slip.

Immunity — Active, Passive and Vaccination

Q36Q37Q38
Q36Attempted · wrong Assertion–Reason link denied
Assertion (A): The immunity a foetus receives from its mother through the placenta is passive immunity.
Reason (R): Ready-made antibodies are transferred to the foetus; its own immune system does not make them.
  1. Both A and R are true and R is the correct explanation of A ✓ key
  2. Both A and R are true but R is NOT the correct explanation of A her answer
  3. A is true but R is false
  4. A is false but R is true
Concept
Passive immunity is defined by where the antibodies come from: if they are ready-made and given to the body, the immunity is passive. Antibodies crossing the placenta from the mother are ready-made — the foetus makes none of them. So R is not a separate fact; it is the definition that makes A true.
Diagram
PASSIVE — ready-made antibodiesmother → foetusthrough the placentacolostrum (IgA)first days of lactationanti-tetanus / antivenompreformed antibodies injectedACTIVE — the body makes themnatural infectionhost makes its own antibodiesvaccinationmemory B and T cells formslowtakes time for a full responseIf the antibodies arrive ready-made, it is passive — that IS the explanation, not a separate fact
Animated · the still frame carries the full message.
Answer
(A) Both A and R are true and R is the correct explanation of A
Why (one line)
R is the definition of passive immunity applied to A.
Why not the others
A · keepR is the definition that makes A true.
B · rule outDenies a real link.
C · rule outR is correct as stated.
D · rule outA is an NCERT example of passive immunity.
Shortcut
Say 'A because R' aloud. If R is the definition or mechanism behind A, the answer is (A).
NCERT line
§7.2.3 — The foetus also receives some antibodies from their mother, through the placenta during pregnancy — passive immunity.
Trap (as built)
Link denied (45Q Q20: marked A false)
Where it went wrong
Marked (B): Both A and R are true but R is NOT the correct explanation of A.
Option B was chosen — the same denial pattern as the Evolution Q63 pair and the Physics Q23 pair. In Biology her drill score is 10/10, so the habit works when she uses it; here the margin line was not written.
Q37Left blank Blank — vaccination and memory cells
Assertion (A): Vaccination protects a person from subsequent infection by the same pathogen.
Reason (R): Vaccination generates memory B and T cells that recognise the pathogen quickly on later exposure.
  1. Both A and R are true and R is the correct explanation of A ✓ key
  2. Both A and R are true but R is NOT the correct explanation of A
  3. A is true but R is false
  4. A is false but R is true
Concept
A vaccine contains inactivated or weakened pathogens, or their antigenic proteins. The body responds by producing antibodies AND by generating memory B and T cells. On a later, real infection those memory cells recognise the pathogen quickly and mount a massive response. R is therefore the mechanism behind A.
Diagram
vaccineinactivated pathogen orantigenic proteinsantibodiesneutralise the pathogenMEMORY B and T cellsremain in the bodylater infectionfast, massive responseThe memory cells ARE the reason vaccination protects later — the link is real
Animated · the still frame carries the full message.
Answer
(A) Both A and R are true and R is the correct explanation of A
Why (one line)
The memory cells in R are exactly why vaccination protects.
Why not the others
A · keepMemory cells are exactly why the protection lasts.
B · rule outThe link is real, not incidental.
C · rule outR is an NCERT line.
D · rule outA is true — that is the purpose of vaccination.
Shortcut
Vaccination questions almost always turn on the words 'memory B and T cells'. If R names them, the link is genuine.
NCERT line
§7.2.4 — The antibodies produced would neutralise the pathogenic agents; vaccines also generate memory B and T-cells.
Trap (as built)
Link denied (60Q Q53 pattern)
Q38Attempted · wrong Single-word substitution (yeast → bacteria)
Assertion (A): Hepatitis B vaccine is produced using bacteria by recombinant DNA technology.
Reason (R): Recombinant DNA technology allows antigenic polypeptides of a pathogen to be produced in bacteria or yeast.
  1. Both A and R are true and R is the correct explanation of A her answer
  2. Both A and R are true but R is NOT the correct explanation of A
  3. A is true but R is false
  4. A is false but R is true ✓ key
Concept
Recombinant DNA technology allows the antigenic polypeptides of a pathogen to be produced in bacteria or yeast — that part is true, so R stands. But NCERT names the hepatitis B vaccine specifically as one produced from yeast. The assertion swaps that one word, so A is false while R is true.
Diagram
antigenic geneof the pathogenYEASThepatitis B vaccine ✓bacteria(possible in general)large-scaleproductionNCERT names YEAST for the hepatitis B vaccine — one word decides the assertion
Animated · the still frame carries the full message.
Answer
(D) A is false but R is true
Why (one line)
R is true, but NCERT says hepatitis B vaccine is produced from yeast.
Why not the others
A · rule outA is false — the hepatitis B vaccine comes from yeast.
B · rule outA is false.
C · rule outR is a correct NCERT statement.
D · keepA false, R true.
Shortcut
When R is a broad true statement and A is a specific example, check the example's one identifying word (here: yeast).
NCERT line
§7.2.4 — e.g., hepatitis B vaccine produced from yeast.
Trap (as built)
Single-word substitution
Where it went wrong
Marked (A): Both A and R are true and R is the correct explanation of A.
Option A accepted the assertion because R sounded right and the two seemed to agree. They do agree in general — the error is in the specific organism. Judge A on its own first.

Antibodies

Q40Q47
Q40Left blank Blank — antibody statements
How many of the following statements are correct?
A. Each antibody molecule has two heavy and two light chains.
B. Antibody-mediated response is called humoral immune response because antibodies are found in blood.
C. IgE antibodies are produced in allergic reactions.
D. Antibodies are produced by T-lymphocytes.
  1. Only one
  2. Only two
  3. Only three ✓ key
  4. All four
Concept
Three of the four are NCERT: each antibody has two heavy and two light chains (H₂L₂); the response is called humoral because antibodies circulate in the blood; IgE is the allergy antibody. The false one is D — antibodies are produced by B-lymphocytes; T-lymphocytes help the B-cells but make no antibodies.
Diagram
PQRthin bars = S–S bonds2 HEAVY chains (long, inner)2 LIGHT chains (short, outer)H₂L₂2 + 2 = FOUR polypeptide chainssubscripts count chains of each kind, not the total
Animated · the still frame carries the full message.
Answer
(C) Only three
Why (one line)
B-lymphocytes produce antibodies; T-cells help them.
Why not the others
A · rule outThree are true.
B · rule outOnly D is false.
C · keepA, B and C are NCERT lines; D swaps B for T.
D · rule outD is false.
Shortcut
B for B-cells makes antibodies; T-cells are the helpers and the graft-rejecters.
NCERT line
§7.2.2 — The B-lymphocytes produce an army of proteins in response to pathogens called antibodies.
Trap (as built)
B/T swap; H2L2 (45Q Q17)
Q47Attempted · wrong H₂L₂ read as two chains
The antibody molecule shown is represented as (Use the antibody figure given in Q46.)
  1. HL — two polypeptide chains
  2. H4L4 — eight polypeptide chains
  3. H2L2 — four polypeptide chains ✓ key
  4. H2L2 — two polypeptide chains her answer
Concept
An antibody has four peptide chains: two small light chains and two longer heavy chains, written H₂L₂. The subscript counts how many of each kind there are — two heavy plus two light — so the molecule has four chains in total.
Diagram
PQRthin bars = S–S bonds2 HEAVY chains (long, inner)2 LIGHT chains (short, outer)H₂L₂2 + 2 = FOUR polypeptide chainssubscripts count chains of each kind, not the total
Animated · the still frame carries the full message.
Answer
(C) H2L2 — four polypeptide chains
Why (one line)
Add the subscripts: 2 heavy + 2 light = 4 chains.
Why not the others
A · rule outHL would be one of each.
B · rule outH₄L₄ would be eight chains.
C · keepH₂L₂ = 2 + 2 = four chains.
D · rule out'Two chains' reads the formula as a total.
Shortcut
Read H₂L₂ aloud as 'two heavy, two light' and then add. Keep it on a flashcard: antibody = 4 chains.
NCERT line
§7.2.2 — Hence, an antibody is represented as H2L2.
Trap (as built)
Missed on BOTH papers (45Q Q17, 60Q Q35: answered 'two')
Where it went wrong
Marked (D): H2L2 — two polypeptide chains.
'H₂L₂ — two polypeptide chains' has now been chosen on all three papers (45Q Q17, 60Q Q35 and here). The formula was recognised; only the counting step failed.

AIDS

Q57
Q57Left blank Blank — which cell is the HIV factory
In the figure, if host cell H is the first human cell HIV infects and it keeps surviving while releasing new virus particles, cell H is the (Use the retrovirus replication figure given in Q56.)
  1. macrophage ✓ key
  2. helper T-lymphocyte
  3. mast cell
  4. B-lymphocyte
Concept
After entering the body, HIV enters macrophages. Inside them the RNA genome is copied into viral DNA by reverse transcriptase, that DNA joins the host genome, and the macrophage then keeps making virus particles while surviving — NCERT calls it an HIV factory. Helper T-lymphocytes are attacked afterwards and are progressively destroyed, which is what causes the symptoms.
Diagram
Host cell HVretrovirus (RNA genome)1. Viral RNA coreenters the cell2. X3. Viral DNA joinsthe host genome4. New viral RNAis produced5. New virusesare assembled6. New viruses leaveto infect other cellsMACROPHAGEsurvives and keepsreleasing virus → HIV factoryHELPER T-LYMPHOCYTEattacked later andDESTROYED — its number falls→ symptoms of AIDSFactory = the cell that survives (macrophage); the helper T-cell is the victim
Animated · the still frame carries the full message.
Answer
(A) macrophage
Why (one line)
The surviving 'factory' cell is the macrophage.
Why not the others
A · keepThe macrophage survives and keeps producing virus.
B · rule outHelper T-cells are killed, so they cannot be the factory.
C · rule outB-lymphocytes are not the entry cell.
D · rule outMast cells belong to allergy.
Shortcut
Factory = the cell that survives and keeps producing. Victim = the helper T-cell whose numbers fall.
NCERT line
§7.3 — After getting into the body of the person, the virus enters into macrophages.
Trap (as built)
Missed TWICE (45Q Q31, 60Q Q44)

Drugs and Alcohol Abuse

Q78
Q78Attempted · wrong Three false statements accepted
How many of the following statements are correct?
A. Opioids bind to specific opioid receptors in the CNS and gastrointestinal tract.
B. Cocaine is a depressant.
C. Heroin is obtained by methylation of morphine.
D. Cannabinoid receptors are present principally in the heart.
  1. Only one ✓ key
  2. Only two
  3. Only three her answer
  4. All four
Concept
Only A is true: opioids bind to specific opioid receptors in the central nervous system and the gastrointestinal tract. B is false — cocaine has a potent stimulating action on the CNS. C is false — heroin is obtained by acetylation of morphine. D is false — cannabinoid receptors are present principally in the brain.
Diagram
A. Opioids bind receptors in CNS and gutTRUEB. Cocaine is a depressantFALSEcocaine is a CNS STIMULANTC. Heroin is obtained by methylation of morphineFALSEheroin = ACETYLATIOND. Cannabinoid receptors are principally in the heartFALSEreceptors are in the BRAINOnly ONE statement survives — each false one swaps a single word
Animated · the still frame carries the full message.
Answer
(A) Only one
Why (one line)
Only A is true: cocaine is a stimulant, heroin comes from acetylation, and the receptors are mainly in the brain.
Why not the others
A · keepOnly statement A survives.
B · rule outTwo would need one more true line.
C · rule outThree of the four are altered.
D · rule outOnly one is correct.
Shortcut
Each false line here swaps a single word: depressant/stimulant, methylation/acetylation, heart/brain. Underline that word before deciding.
NCERT line
§7.5 — Opioids are the drugs which bind to specific opioid receptors present in our CNS and gastrointestinal tract.
Trap (as built)
Single-word substitutions
Where it went wrong
Marked (C): Only three.
'Only three' means three lines were accepted without checking. Since the words are close to the NCERT wording, they read as familiar — the check has to be word by word, not sentence by sentence.

What to carry into the next paper

HabitWould have saved
Antibody card: H₂L₂ = four chains, made by B-cells.Q40, Q47 — 9 marks (and two earlier papers)
Three margin lines on every assertion–reason item in the paper itself.Q36, Q37, Q38 — 14 marks
T/F with a two-word reason beside each statement; underline the swappable word.Q14, Q78 — 10 marks
HIV: factory = macrophage (survives), victim = helper T-cell (destroyed).Q57 — 4 marks