CBSE Board Paper 2022 (Marking Scheme and Solutions) | Biology Class 12 - NEET PDF Download

 Page 1


XII_115_044_57/1/1_Biology # Page-1 
 
Strictly Confidential: (For Internal and Restricted use only) 
Senior Secondary School Term II Examination, 2022 
Marking Scheme – BIOLOGY (SUBJECT CODE — 044) 
(PAPER CODE — 57/1/1) 
General Instructions: - 
 
1. You are aware that evaluation is the most important process in the actual and correct 
assessment of the candidates. A small mistake in evaluation may lead to serious problems 
which may affect the future of the candidates, education system and teaching profession. 
To avoid mistakes, it is requested that before starting evaluation, you must read and 
understand the spot evaluation guidelines carefully. 
2. “Evaluation policy is a confidential policy as it is related to the confidentiality of the 
examinations conducted, Evaluation done and several other aspects. Its’ leakage to 
public in any manner could lead to derailment of the examination system and affect 
the life and future of millions of candidates. Sharing this policy/document to anyone, 
publishing in any magazine and printing in News Paper/Website etc may invite action 
under IPC.” 
3. Evaluation is to be done as per instructions provided in the Marking Scheme. It should not 
be done according to one’s own interpretation or any other consideration. Marking Scheme 
should be strictly adhered to and religiously followed. However, while evaluating, 
answers which are based on latest information or knowledge and/or are innovative, 
they may be assessed for their correctness otherwise and marks be awarded to them. 
In class-X, while evaluating two competency based questions, please try to 
understand given answer and even if reply is not from marking scheme but correct 
competency is enumerated by the candidate, marks should be awarded.   
4. The Head-Examiner must go through the first five answer books evaluated by each 
evaluator on the first day, to ensure that evaluation has been carried out as per the 
instructions given in the Marking Scheme. The remaining answer books meant for 
evaluation shall be given only after ensuring that there is no significant variation in the 
marking of individual evaluators. 
5. Evaluators will mark( v ) wherever answer is correct.  For wrong answer ‘X’ be marked.  
Evaluators will not put right kind of mark while evaluating which gives an impression that 
answer is correct and no marks are awarded.  This is most common mistake which 
evaluators are committing. 
6. If a question has parts, please award marks on the right-hand side for each part. Marks 
awarded for different parts of the question should then be totalled up and written in the left-
hand margin and encircled.  This may be followed strictly. 
7. If a question does not have any parts, marks must be awarded in the left-hand margin and 
encircled. This may also be followed strictly. 
8. If a student has attempted an extra question, answer of the question deserving more marks 
should be retained and the other answer scored out. 
9. No marks to be deducted for the cumulative effect of an error. It should be penalized only 
once. 
Page 2


XII_115_044_57/1/1_Biology # Page-1 
 
Strictly Confidential: (For Internal and Restricted use only) 
Senior Secondary School Term II Examination, 2022 
Marking Scheme – BIOLOGY (SUBJECT CODE — 044) 
(PAPER CODE — 57/1/1) 
General Instructions: - 
 
1. You are aware that evaluation is the most important process in the actual and correct 
assessment of the candidates. A small mistake in evaluation may lead to serious problems 
which may affect the future of the candidates, education system and teaching profession. 
To avoid mistakes, it is requested that before starting evaluation, you must read and 
understand the spot evaluation guidelines carefully. 
2. “Evaluation policy is a confidential policy as it is related to the confidentiality of the 
examinations conducted, Evaluation done and several other aspects. Its’ leakage to 
public in any manner could lead to derailment of the examination system and affect 
the life and future of millions of candidates. Sharing this policy/document to anyone, 
publishing in any magazine and printing in News Paper/Website etc may invite action 
under IPC.” 
3. Evaluation is to be done as per instructions provided in the Marking Scheme. It should not 
be done according to one’s own interpretation or any other consideration. Marking Scheme 
should be strictly adhered to and religiously followed. However, while evaluating, 
answers which are based on latest information or knowledge and/or are innovative, 
they may be assessed for their correctness otherwise and marks be awarded to them. 
In class-X, while evaluating two competency based questions, please try to 
understand given answer and even if reply is not from marking scheme but correct 
competency is enumerated by the candidate, marks should be awarded.   
4. The Head-Examiner must go through the first five answer books evaluated by each 
evaluator on the first day, to ensure that evaluation has been carried out as per the 
instructions given in the Marking Scheme. The remaining answer books meant for 
evaluation shall be given only after ensuring that there is no significant variation in the 
marking of individual evaluators. 
5. Evaluators will mark( v ) wherever answer is correct.  For wrong answer ‘X’ be marked.  
Evaluators will not put right kind of mark while evaluating which gives an impression that 
answer is correct and no marks are awarded.  This is most common mistake which 
evaluators are committing. 
6. If a question has parts, please award marks on the right-hand side for each part. Marks 
awarded for different parts of the question should then be totalled up and written in the left-
hand margin and encircled.  This may be followed strictly. 
7. If a question does not have any parts, marks must be awarded in the left-hand margin and 
encircled. This may also be followed strictly. 
8. If a student has attempted an extra question, answer of the question deserving more marks 
should be retained and the other answer scored out. 
9. No marks to be deducted for the cumulative effect of an error. It should be penalized only 
once. 
XII_115_044_57/1/1_Biology # Page-2 
 
10. A full scale of marks 0-35 has to be used. Please do not hesitate to award full marks if the 
answer deserves it. 
11. Every examiner has to necessarily do evaluation work for full working hours i.e., 8 hours 
every day and evaluate 30 answer books per day in main subjects and 35 answer books 
per day in other subjects (Details are given in Spot Guidelines). This is in view of the 
reduced syllabus and number of questions in question paper. 
12. Ensure that you do not make the following common types of errors committed by the 
Examiner in the past: - 
• Leaving answer or part thereof unassessed in an answer book. 
• Giving more marks for an answer than assigned to it. 
• Wrong totalling of marks awarded on a reply. 
• Wrong transfer of marks from the inside pages of the answer book to the title page. 
• Wrong question wise totalling on the title page. 
• Wrong totalling of marks of the two columns on the title page. 
• Wrong grand total. 
• Marks in words and figures not tallying. 
• Wrong transfer of marks from the answer book to online award list. 
• Answers marked as correct, but marks not awarded. (Ensure that the right tick mark is 
correctly and clearly indicated. It should merely be a line. Same is with the X for incorrect 
answer.) 
• Half or a part of answer marked correct and the rest as wrong, but no marks awarded.  
 
13. While evaluating the answer books if the answer is found to be totally incorrect, it should be 
marked as cross (X) and awarded zero (0) Marks. 
  
14. Any unassessed portion, non-carrying over of marks to the title page, or totalling error 
detected by the candidate shall damage the prestige of all the personnel engaged in the 
evaluation work as also of the Board. Hence, in order to uphold the prestige of all 
concerned, it is again reiterated that the instructions be followed meticulously and 
judiciously. 
 
15. The Examiners should acquaint themselves with the guidelines given in the Guidelines for 
spot Evaluation before starting the actual evaluation. 
 
16. Every Examiner shall also ensure that all the answers are evaluated, marks carried over to 
the title page, correctly totalled and written in figures and words. 
 
17. The Board permits candidates to obtain photocopy of the Answer Book on request in an 
RTI application and also separately as a part of the re-evaluation process on payment of 
the processing charges.  
  
Page 3


XII_115_044_57/1/1_Biology # Page-1 
 
Strictly Confidential: (For Internal and Restricted use only) 
Senior Secondary School Term II Examination, 2022 
Marking Scheme – BIOLOGY (SUBJECT CODE — 044) 
(PAPER CODE — 57/1/1) 
General Instructions: - 
 
1. You are aware that evaluation is the most important process in the actual and correct 
assessment of the candidates. A small mistake in evaluation may lead to serious problems 
which may affect the future of the candidates, education system and teaching profession. 
To avoid mistakes, it is requested that before starting evaluation, you must read and 
understand the spot evaluation guidelines carefully. 
2. “Evaluation policy is a confidential policy as it is related to the confidentiality of the 
examinations conducted, Evaluation done and several other aspects. Its’ leakage to 
public in any manner could lead to derailment of the examination system and affect 
the life and future of millions of candidates. Sharing this policy/document to anyone, 
publishing in any magazine and printing in News Paper/Website etc may invite action 
under IPC.” 
3. Evaluation is to be done as per instructions provided in the Marking Scheme. It should not 
be done according to one’s own interpretation or any other consideration. Marking Scheme 
should be strictly adhered to and religiously followed. However, while evaluating, 
answers which are based on latest information or knowledge and/or are innovative, 
they may be assessed for their correctness otherwise and marks be awarded to them. 
In class-X, while evaluating two competency based questions, please try to 
understand given answer and even if reply is not from marking scheme but correct 
competency is enumerated by the candidate, marks should be awarded.   
4. The Head-Examiner must go through the first five answer books evaluated by each 
evaluator on the first day, to ensure that evaluation has been carried out as per the 
instructions given in the Marking Scheme. The remaining answer books meant for 
evaluation shall be given only after ensuring that there is no significant variation in the 
marking of individual evaluators. 
5. Evaluators will mark( v ) wherever answer is correct.  For wrong answer ‘X’ be marked.  
Evaluators will not put right kind of mark while evaluating which gives an impression that 
answer is correct and no marks are awarded.  This is most common mistake which 
evaluators are committing. 
6. If a question has parts, please award marks on the right-hand side for each part. Marks 
awarded for different parts of the question should then be totalled up and written in the left-
hand margin and encircled.  This may be followed strictly. 
7. If a question does not have any parts, marks must be awarded in the left-hand margin and 
encircled. This may also be followed strictly. 
8. If a student has attempted an extra question, answer of the question deserving more marks 
should be retained and the other answer scored out. 
9. No marks to be deducted for the cumulative effect of an error. It should be penalized only 
once. 
XII_115_044_57/1/1_Biology # Page-2 
 
10. A full scale of marks 0-35 has to be used. Please do not hesitate to award full marks if the 
answer deserves it. 
11. Every examiner has to necessarily do evaluation work for full working hours i.e., 8 hours 
every day and evaluate 30 answer books per day in main subjects and 35 answer books 
per day in other subjects (Details are given in Spot Guidelines). This is in view of the 
reduced syllabus and number of questions in question paper. 
12. Ensure that you do not make the following common types of errors committed by the 
Examiner in the past: - 
• Leaving answer or part thereof unassessed in an answer book. 
• Giving more marks for an answer than assigned to it. 
• Wrong totalling of marks awarded on a reply. 
• Wrong transfer of marks from the inside pages of the answer book to the title page. 
• Wrong question wise totalling on the title page. 
• Wrong totalling of marks of the two columns on the title page. 
• Wrong grand total. 
• Marks in words and figures not tallying. 
• Wrong transfer of marks from the answer book to online award list. 
• Answers marked as correct, but marks not awarded. (Ensure that the right tick mark is 
correctly and clearly indicated. It should merely be a line. Same is with the X for incorrect 
answer.) 
• Half or a part of answer marked correct and the rest as wrong, but no marks awarded.  
 
13. While evaluating the answer books if the answer is found to be totally incorrect, it should be 
marked as cross (X) and awarded zero (0) Marks. 
  
14. Any unassessed portion, non-carrying over of marks to the title page, or totalling error 
detected by the candidate shall damage the prestige of all the personnel engaged in the 
evaluation work as also of the Board. Hence, in order to uphold the prestige of all 
concerned, it is again reiterated that the instructions be followed meticulously and 
judiciously. 
 
15. The Examiners should acquaint themselves with the guidelines given in the Guidelines for 
spot Evaluation before starting the actual evaluation. 
 
16. Every Examiner shall also ensure that all the answers are evaluated, marks carried over to 
the title page, correctly totalled and written in figures and words. 
 
17. The Board permits candidates to obtain photocopy of the Answer Book on request in an 
RTI application and also separately as a part of the re-evaluation process on payment of 
the processing charges.  
  
XII_115_044_57/1/1_Biology # Page-3 
 
MARKING SCHEME 
Senior Secondary School Examination TERM–II, 2022 
BIOLOGY   (Subject Code — 044) 
[ Paper Code — 57/1/1 ] 
Q. No. EXPECTED ANSWER / VALUE POINTS Marks 
 SECTION – ‘A ’  
1. • Common cold–nose / respiratory passage 
         - Pneumonia–(alveoli of) lungs / (air sacs of) lungs 
• causative agents–Streptococcus pneumoniae / Haemophilus influenzae  
(pneumonia)  
   - Rhino virus  (common cold ) 
½ 
½ 
 
½  
½  
  2 
2. Allows vigorous growth of microbes, formation of flocs to form mesh like 
structures, microbes consume major part of organic waste in the sewage, reduces 
BOD of the affluent / reduces polluting potential  
OR 
(a)  
• Biogas / Gobar gas 
• Methane, CO
2
 /?? 2
 / ?? 2
?? 
Note: any one component along with methane to be awarded one mark. 
(b) Anaerobic digestion of cellulose 
 
 
½×4 
 
 
½  
½+½ 
 
½  
  2 
3. (a) Baculoviruses /  Nucleopolyhedrovirus 
(b) Species specific, narrow spectrum insecticidal application, no negative 
impact on plants / mammals / birds / fish / non-target insects, desirable for 
integrated pest management        (any two) 
1 
 
½+½ 
  2 
4. Female Anopheles mosquito takes up gametocytes with blood meal, Fertilization 
and development take place in the mosquito’s gut, Mature infective stage 
(sporozites) escape from the gut and migrate to mosquito salivary gland, Female 
Anopheles bites the humans transmitting the plasmodium to its second host to 
complete its life cycle. 
// 
Completes sexual stages of life cycle in female Anopheles mosquito / female 
Anopheles mosquito acts as primary host, acts as vector to transfer parasites from 
infected person to healthy person to complete its life cycle. 
// 
½×4 
 
 
 
 
 
1+1 
 
 
Page 4


XII_115_044_57/1/1_Biology # Page-1 
 
Strictly Confidential: (For Internal and Restricted use only) 
Senior Secondary School Term II Examination, 2022 
Marking Scheme – BIOLOGY (SUBJECT CODE — 044) 
(PAPER CODE — 57/1/1) 
General Instructions: - 
 
1. You are aware that evaluation is the most important process in the actual and correct 
assessment of the candidates. A small mistake in evaluation may lead to serious problems 
which may affect the future of the candidates, education system and teaching profession. 
To avoid mistakes, it is requested that before starting evaluation, you must read and 
understand the spot evaluation guidelines carefully. 
2. “Evaluation policy is a confidential policy as it is related to the confidentiality of the 
examinations conducted, Evaluation done and several other aspects. Its’ leakage to 
public in any manner could lead to derailment of the examination system and affect 
the life and future of millions of candidates. Sharing this policy/document to anyone, 
publishing in any magazine and printing in News Paper/Website etc may invite action 
under IPC.” 
3. Evaluation is to be done as per instructions provided in the Marking Scheme. It should not 
be done according to one’s own interpretation or any other consideration. Marking Scheme 
should be strictly adhered to and religiously followed. However, while evaluating, 
answers which are based on latest information or knowledge and/or are innovative, 
they may be assessed for their correctness otherwise and marks be awarded to them. 
In class-X, while evaluating two competency based questions, please try to 
understand given answer and even if reply is not from marking scheme but correct 
competency is enumerated by the candidate, marks should be awarded.   
4. The Head-Examiner must go through the first five answer books evaluated by each 
evaluator on the first day, to ensure that evaluation has been carried out as per the 
instructions given in the Marking Scheme. The remaining answer books meant for 
evaluation shall be given only after ensuring that there is no significant variation in the 
marking of individual evaluators. 
5. Evaluators will mark( v ) wherever answer is correct.  For wrong answer ‘X’ be marked.  
Evaluators will not put right kind of mark while evaluating which gives an impression that 
answer is correct and no marks are awarded.  This is most common mistake which 
evaluators are committing. 
6. If a question has parts, please award marks on the right-hand side for each part. Marks 
awarded for different parts of the question should then be totalled up and written in the left-
hand margin and encircled.  This may be followed strictly. 
7. If a question does not have any parts, marks must be awarded in the left-hand margin and 
encircled. This may also be followed strictly. 
8. If a student has attempted an extra question, answer of the question deserving more marks 
should be retained and the other answer scored out. 
9. No marks to be deducted for the cumulative effect of an error. It should be penalized only 
once. 
XII_115_044_57/1/1_Biology # Page-2 
 
10. A full scale of marks 0-35 has to be used. Please do not hesitate to award full marks if the 
answer deserves it. 
11. Every examiner has to necessarily do evaluation work for full working hours i.e., 8 hours 
every day and evaluate 30 answer books per day in main subjects and 35 answer books 
per day in other subjects (Details are given in Spot Guidelines). This is in view of the 
reduced syllabus and number of questions in question paper. 
12. Ensure that you do not make the following common types of errors committed by the 
Examiner in the past: - 
• Leaving answer or part thereof unassessed in an answer book. 
• Giving more marks for an answer than assigned to it. 
• Wrong totalling of marks awarded on a reply. 
• Wrong transfer of marks from the inside pages of the answer book to the title page. 
• Wrong question wise totalling on the title page. 
• Wrong totalling of marks of the two columns on the title page. 
• Wrong grand total. 
• Marks in words and figures not tallying. 
• Wrong transfer of marks from the answer book to online award list. 
• Answers marked as correct, but marks not awarded. (Ensure that the right tick mark is 
correctly and clearly indicated. It should merely be a line. Same is with the X for incorrect 
answer.) 
• Half or a part of answer marked correct and the rest as wrong, but no marks awarded.  
 
13. While evaluating the answer books if the answer is found to be totally incorrect, it should be 
marked as cross (X) and awarded zero (0) Marks. 
  
14. Any unassessed portion, non-carrying over of marks to the title page, or totalling error 
detected by the candidate shall damage the prestige of all the personnel engaged in the 
evaluation work as also of the Board. Hence, in order to uphold the prestige of all 
concerned, it is again reiterated that the instructions be followed meticulously and 
judiciously. 
 
15. The Examiners should acquaint themselves with the guidelines given in the Guidelines for 
spot Evaluation before starting the actual evaluation. 
 
16. Every Examiner shall also ensure that all the answers are evaluated, marks carried over to 
the title page, correctly totalled and written in figures and words. 
 
17. The Board permits candidates to obtain photocopy of the Answer Book on request in an 
RTI application and also separately as a part of the re-evaluation process on payment of 
the processing charges.  
  
XII_115_044_57/1/1_Biology # Page-3 
 
MARKING SCHEME 
Senior Secondary School Examination TERM–II, 2022 
BIOLOGY   (Subject Code — 044) 
[ Paper Code — 57/1/1 ] 
Q. No. EXPECTED ANSWER / VALUE POINTS Marks 
 SECTION – ‘A ’  
1. • Common cold–nose / respiratory passage 
         - Pneumonia–(alveoli of) lungs / (air sacs of) lungs 
• causative agents–Streptococcus pneumoniae / Haemophilus influenzae  
(pneumonia)  
   - Rhino virus  (common cold ) 
½ 
½ 
 
½  
½  
  2 
2. Allows vigorous growth of microbes, formation of flocs to form mesh like 
structures, microbes consume major part of organic waste in the sewage, reduces 
BOD of the affluent / reduces polluting potential  
OR 
(a)  
• Biogas / Gobar gas 
• Methane, CO
2
 /?? 2
 / ?? 2
?? 
Note: any one component along with methane to be awarded one mark. 
(b) Anaerobic digestion of cellulose 
 
 
½×4 
 
 
½  
½+½ 
 
½  
  2 
3. (a) Baculoviruses /  Nucleopolyhedrovirus 
(b) Species specific, narrow spectrum insecticidal application, no negative 
impact on plants / mammals / birds / fish / non-target insects, desirable for 
integrated pest management        (any two) 
1 
 
½+½ 
  2 
4. Female Anopheles mosquito takes up gametocytes with blood meal, Fertilization 
and development take place in the mosquito’s gut, Mature infective stage 
(sporozites) escape from the gut and migrate to mosquito salivary gland, Female 
Anopheles bites the humans transmitting the plasmodium to its second host to 
complete its life cycle. 
// 
Completes sexual stages of life cycle in female Anopheles mosquito / female 
Anopheles mosquito acts as primary host, acts as vector to transfer parasites from 
infected person to healthy person to complete its life cycle. 
// 
½×4 
 
 
 
 
 
1+1 
 
 
XII_115_044_57/1/1_Biology # Page-4 
 
 
 
 
 
 
 
 
½ x 4 
 
 
 
  2 
5. 
(a) Carrying capacity is the maximum possible number of organisms (beyond 
which no further growth is possible) in a habitat. 
(b) Limited resources lead to competition, fittest survives and reproduces 
1 
 
½+½ 
  2 
6. (a) Shark harvest increases over the years from 1992 to 2003. 
(b) Biodiversity decreases due to over exploitation/ excessive harvesting 
OR 
Tilman conducted experiments in out door plots, plots with more species shows 
less year to year variation in biomass (more stability). 
 
1+1 
 
 
1+1 
  2 
 SECTION – ‘B ’  
7. (i) Panama—Tropic 
 Canada—Temperate 
 Denmark—Polar                           
(ii) Latitudinal gradient, species diversity decreases as we move away from 
equator toward poles / species diversity vary due to different climatic 
conditions present at different places of world. 
 
½×3 
 
 
½+1 
  3 
8. (a) 
• Five extinctions have already occurred  
• sixth is in progress 
(b) 
• Sixth extinction is much faster / sixth extinction is 100 to 1000 times faster 
• Human activities like industrialisation, loss of habitat, over 
exploitation,land reforms.                                      (Any two) 
 
½+½ 
 
 
1 
½+½ 
  3 
Page 5


XII_115_044_57/1/1_Biology # Page-1 
 
Strictly Confidential: (For Internal and Restricted use only) 
Senior Secondary School Term II Examination, 2022 
Marking Scheme – BIOLOGY (SUBJECT CODE — 044) 
(PAPER CODE — 57/1/1) 
General Instructions: - 
 
1. You are aware that evaluation is the most important process in the actual and correct 
assessment of the candidates. A small mistake in evaluation may lead to serious problems 
which may affect the future of the candidates, education system and teaching profession. 
To avoid mistakes, it is requested that before starting evaluation, you must read and 
understand the spot evaluation guidelines carefully. 
2. “Evaluation policy is a confidential policy as it is related to the confidentiality of the 
examinations conducted, Evaluation done and several other aspects. Its’ leakage to 
public in any manner could lead to derailment of the examination system and affect 
the life and future of millions of candidates. Sharing this policy/document to anyone, 
publishing in any magazine and printing in News Paper/Website etc may invite action 
under IPC.” 
3. Evaluation is to be done as per instructions provided in the Marking Scheme. It should not 
be done according to one’s own interpretation or any other consideration. Marking Scheme 
should be strictly adhered to and religiously followed. However, while evaluating, 
answers which are based on latest information or knowledge and/or are innovative, 
they may be assessed for their correctness otherwise and marks be awarded to them. 
In class-X, while evaluating two competency based questions, please try to 
understand given answer and even if reply is not from marking scheme but correct 
competency is enumerated by the candidate, marks should be awarded.   
4. The Head-Examiner must go through the first five answer books evaluated by each 
evaluator on the first day, to ensure that evaluation has been carried out as per the 
instructions given in the Marking Scheme. The remaining answer books meant for 
evaluation shall be given only after ensuring that there is no significant variation in the 
marking of individual evaluators. 
5. Evaluators will mark( v ) wherever answer is correct.  For wrong answer ‘X’ be marked.  
Evaluators will not put right kind of mark while evaluating which gives an impression that 
answer is correct and no marks are awarded.  This is most common mistake which 
evaluators are committing. 
6. If a question has parts, please award marks on the right-hand side for each part. Marks 
awarded for different parts of the question should then be totalled up and written in the left-
hand margin and encircled.  This may be followed strictly. 
7. If a question does not have any parts, marks must be awarded in the left-hand margin and 
encircled. This may also be followed strictly. 
8. If a student has attempted an extra question, answer of the question deserving more marks 
should be retained and the other answer scored out. 
9. No marks to be deducted for the cumulative effect of an error. It should be penalized only 
once. 
XII_115_044_57/1/1_Biology # Page-2 
 
10. A full scale of marks 0-35 has to be used. Please do not hesitate to award full marks if the 
answer deserves it. 
11. Every examiner has to necessarily do evaluation work for full working hours i.e., 8 hours 
every day and evaluate 30 answer books per day in main subjects and 35 answer books 
per day in other subjects (Details are given in Spot Guidelines). This is in view of the 
reduced syllabus and number of questions in question paper. 
12. Ensure that you do not make the following common types of errors committed by the 
Examiner in the past: - 
• Leaving answer or part thereof unassessed in an answer book. 
• Giving more marks for an answer than assigned to it. 
• Wrong totalling of marks awarded on a reply. 
• Wrong transfer of marks from the inside pages of the answer book to the title page. 
• Wrong question wise totalling on the title page. 
• Wrong totalling of marks of the two columns on the title page. 
• Wrong grand total. 
• Marks in words and figures not tallying. 
• Wrong transfer of marks from the answer book to online award list. 
• Answers marked as correct, but marks not awarded. (Ensure that the right tick mark is 
correctly and clearly indicated. It should merely be a line. Same is with the X for incorrect 
answer.) 
• Half or a part of answer marked correct and the rest as wrong, but no marks awarded.  
 
13. While evaluating the answer books if the answer is found to be totally incorrect, it should be 
marked as cross (X) and awarded zero (0) Marks. 
  
14. Any unassessed portion, non-carrying over of marks to the title page, or totalling error 
detected by the candidate shall damage the prestige of all the personnel engaged in the 
evaluation work as also of the Board. Hence, in order to uphold the prestige of all 
concerned, it is again reiterated that the instructions be followed meticulously and 
judiciously. 
 
15. The Examiners should acquaint themselves with the guidelines given in the Guidelines for 
spot Evaluation before starting the actual evaluation. 
 
16. Every Examiner shall also ensure that all the answers are evaluated, marks carried over to 
the title page, correctly totalled and written in figures and words. 
 
17. The Board permits candidates to obtain photocopy of the Answer Book on request in an 
RTI application and also separately as a part of the re-evaluation process on payment of 
the processing charges.  
  
XII_115_044_57/1/1_Biology # Page-3 
 
MARKING SCHEME 
Senior Secondary School Examination TERM–II, 2022 
BIOLOGY   (Subject Code — 044) 
[ Paper Code — 57/1/1 ] 
Q. No. EXPECTED ANSWER / VALUE POINTS Marks 
 SECTION – ‘A ’  
1. • Common cold–nose / respiratory passage 
         - Pneumonia–(alveoli of) lungs / (air sacs of) lungs 
• causative agents–Streptococcus pneumoniae / Haemophilus influenzae  
(pneumonia)  
   - Rhino virus  (common cold ) 
½ 
½ 
 
½  
½  
  2 
2. Allows vigorous growth of microbes, formation of flocs to form mesh like 
structures, microbes consume major part of organic waste in the sewage, reduces 
BOD of the affluent / reduces polluting potential  
OR 
(a)  
• Biogas / Gobar gas 
• Methane, CO
2
 /?? 2
 / ?? 2
?? 
Note: any one component along with methane to be awarded one mark. 
(b) Anaerobic digestion of cellulose 
 
 
½×4 
 
 
½  
½+½ 
 
½  
  2 
3. (a) Baculoviruses /  Nucleopolyhedrovirus 
(b) Species specific, narrow spectrum insecticidal application, no negative 
impact on plants / mammals / birds / fish / non-target insects, desirable for 
integrated pest management        (any two) 
1 
 
½+½ 
  2 
4. Female Anopheles mosquito takes up gametocytes with blood meal, Fertilization 
and development take place in the mosquito’s gut, Mature infective stage 
(sporozites) escape from the gut and migrate to mosquito salivary gland, Female 
Anopheles bites the humans transmitting the plasmodium to its second host to 
complete its life cycle. 
// 
Completes sexual stages of life cycle in female Anopheles mosquito / female 
Anopheles mosquito acts as primary host, acts as vector to transfer parasites from 
infected person to healthy person to complete its life cycle. 
// 
½×4 
 
 
 
 
 
1+1 
 
 
XII_115_044_57/1/1_Biology # Page-4 
 
 
 
 
 
 
 
 
½ x 4 
 
 
 
  2 
5. 
(a) Carrying capacity is the maximum possible number of organisms (beyond 
which no further growth is possible) in a habitat. 
(b) Limited resources lead to competition, fittest survives and reproduces 
1 
 
½+½ 
  2 
6. (a) Shark harvest increases over the years from 1992 to 2003. 
(b) Biodiversity decreases due to over exploitation/ excessive harvesting 
OR 
Tilman conducted experiments in out door plots, plots with more species shows 
less year to year variation in biomass (more stability). 
 
1+1 
 
 
1+1 
  2 
 SECTION – ‘B ’  
7. (i) Panama—Tropic 
 Canada—Temperate 
 Denmark—Polar                           
(ii) Latitudinal gradient, species diversity decreases as we move away from 
equator toward poles / species diversity vary due to different climatic 
conditions present at different places of world. 
 
½×3 
 
 
½+1 
  3 
8. (a) 
• Five extinctions have already occurred  
• sixth is in progress 
(b) 
• Sixth extinction is much faster / sixth extinction is 100 to 1000 times faster 
• Human activities like industrialisation, loss of habitat, over 
exploitation,land reforms.                                      (Any two) 
 
½+½ 
 
 
1 
½+½ 
  3 
XII_115_044_57/1/1_Biology # Page-5 
 
9. • Agrobacterium tumefaciens—(plants pathogen), The disarmed Ti Plasmid 
is used as a vector to introduce the gene of interest in the variety of plants. 
• Retrovirus—(animals), Disarmed Retroviruses are used to transfer genes of 
interest in to mammalian host cells. 
½+1 
 
½+1 
                            3 
10. Bacteria—Rhizobium / Azospirillum / Azotobacter 
Fungi—Mycorrhiza / Glomus 
Cyanobacteria—Anabaena / Nostoc / Oscillatoria 
½+½ 
½+½ 
½+½ 
  3 
11. Do not eradicate pests but keep them at manageable level by various checks and 
balances, pests may be food for otherwise beneficiary predators and parasites who 
would suffer and not survive, more varieties in a landscape more sustainable it is 
(or any other correct reason) 
 
 
1×3 
  3 
12. (i) Helps in identifying non-transformants from transformants / Recombinants 
from non Recombinants 
(ii) Genes encoding resistance to antibiotics such as ampicillin / tetracycline/ 
kanamycin / chloramphenicol / amp
R
 / tet
R
 
(iii) (The normal E. coli cells do not carry resistance against any of these 
antibiotics.) It helps to identify and select transformants / identification of 
recombinants. 
OR 
• Plasmids are extra chromosomal self-replicating (double stranded) circular 
DNA molecules (generally found in bacterial cell) 
• Plasmid is circular extra chromosomal DNA of bacterial cells whereas 
cloning vector is a vehicle that carries foreign DNA into another cell. 
• Bacteriophage, pBR322 
1 
 
1 
 
1 
 
 
 
1 
 
1 
½+½ 
  3 
 SECTION – ‘C ’  
13. (i)  
• Species A 
• The leaf area damaged by species - A  in Bt-corn is the least 
 
(ii) Species-B 
(iii) Not to grow Bt variety as seeds are expensive and  of not much benefit 
(productivity wise) / advise to grow Bt corn with its proper justification 
(iv) Cry IAb.             (No marks if only cry gene is written) 
 
OR 
 
 
 
1+1 
 
1 
 
1 
 
1