Class 12 Biology: CBSE Sample Question Paper (2024-25) | Sample Papers for Class 12 Medical and Non-Medical PDF Download

 Page 1


Sample Question Paper  
Class XII  
044 Biology (2024-25) 
Maximum Marks: 70            Time: 3 hours 
 
General Instructions: 
 
(i) All questions are compulsory.  
(ii) The question paper has five sections and 33 questions.  
(iii) Section–A has 16 questions of 1 mark each; Section–B has 5 questions of 2 
marks each; Section– C has 7 questions of 3 marks each; Section– D has 2 
case-based questions of 4 marks each; and Section–E has 3 questions of 5 
marks each. 
(iv) There is no overall choice. However, internal choices have been provided in 
some questions. A student has to attempt only one of the alternatives in such 
questions. 
(v) Wherever necessary, neat and properly labeled diagrams should be drawn. 
 
 
Section – A 
Q. No. 1 to 12 are multiple choice questions. Only one of the choices is correct. 
Select and write the correct choice as well as the answer to these questions.  
Q. 
No 
Question Mark
s 
1 Signals for parturition in human female originate from 
A. Fully developed foetus only  
B. Both placenta as well as fully developed foetus 
C. Placenta only  
D. Oxytocin released from maternal pituitary  
1 
2 To produce 1600 seeds, the number of meiotic divisions required will be  
A. 2400  
B. 2000  
C. 1600 
D. 1800  
1 
3 A sample of normal double-stranded DNA was found to have thymine 
content of 27%. What will be the expected proportion of guanine in this 
strand?   
A. 23%  
B. 32%  
C. 36%  
D. 73%  
1 
Page 2


Sample Question Paper  
Class XII  
044 Biology (2024-25) 
Maximum Marks: 70            Time: 3 hours 
 
General Instructions: 
 
(i) All questions are compulsory.  
(ii) The question paper has five sections and 33 questions.  
(iii) Section–A has 16 questions of 1 mark each; Section–B has 5 questions of 2 
marks each; Section– C has 7 questions of 3 marks each; Section– D has 2 
case-based questions of 4 marks each; and Section–E has 3 questions of 5 
marks each. 
(iv) There is no overall choice. However, internal choices have been provided in 
some questions. A student has to attempt only one of the alternatives in such 
questions. 
(v) Wherever necessary, neat and properly labeled diagrams should be drawn. 
 
 
Section – A 
Q. No. 1 to 12 are multiple choice questions. Only one of the choices is correct. 
Select and write the correct choice as well as the answer to these questions.  
Q. 
No 
Question Mark
s 
1 Signals for parturition in human female originate from 
A. Fully developed foetus only  
B. Both placenta as well as fully developed foetus 
C. Placenta only  
D. Oxytocin released from maternal pituitary  
1 
2 To produce 1600 seeds, the number of meiotic divisions required will be  
A. 2400  
B. 2000  
C. 1600 
D. 1800  
1 
3 A sample of normal double-stranded DNA was found to have thymine 
content of 27%. What will be the expected proportion of guanine in this 
strand?   
A. 23%  
B. 32%  
C. 36%  
D. 73%  
1 
4 Observe the schematic diagram that depicts a small section of nucleic 
acid. The bases in two strands are paired through hydrogen bonds that 
are shown by the dark lines. Identify the correct sequence of nucleotide 
in the 5’-3’ direction.  
 
A. GCAT 
B. CGTA 
C. TAGC 
D. ATCG 
- - - - - - - - - - - - - - - - - - -  
For Visual Impaired Students 
E. coli has 4.6 X 10 
6
 base pairs and completes the process of replication 
in 18 minutes, then the average rate of polymerization is approximately  
A. 2000 bp/s  
B. 4000 bp/s  
C. 3000 bp/s  
D. 1000 bp/s 
1 
5 Suresh and Rajesh have defective haemoglobin due to genetic disorders. 
In Suresh, the problem is qualitative as he is having incorrectly functioning 
globin molecules while in Rajesh the problem is quantitative as he is 
having very few globin molecules. Identify the disorder they are suffering 
from.  
 Suresh  Rajesh  
A Thalassemia - Autosomal 
Dominant blood disorder 
Sickle Cell Anaemia - Autosomal 
linked Recessive trait  
B Sickle Cell Anaemia - 
Autosomal linked Dominant 
trait 
Thalassemia - Autosomal 
Recessive blood disorder 
C Sickle Cell Anaemia – 
Autosomal linked Recessive 
trait  
Thalassemia – Autosomal 
Recessive blood disorder  
D Thalassemia - Autosomal 
Dominant blood disorder 
Sickle Cell Anaemia - Autosomal 
linked Dominant trait 
 
1 
Page 3


Sample Question Paper  
Class XII  
044 Biology (2024-25) 
Maximum Marks: 70            Time: 3 hours 
 
General Instructions: 
 
(i) All questions are compulsory.  
(ii) The question paper has five sections and 33 questions.  
(iii) Section–A has 16 questions of 1 mark each; Section–B has 5 questions of 2 
marks each; Section– C has 7 questions of 3 marks each; Section– D has 2 
case-based questions of 4 marks each; and Section–E has 3 questions of 5 
marks each. 
(iv) There is no overall choice. However, internal choices have been provided in 
some questions. A student has to attempt only one of the alternatives in such 
questions. 
(v) Wherever necessary, neat and properly labeled diagrams should be drawn. 
 
 
Section – A 
Q. No. 1 to 12 are multiple choice questions. Only one of the choices is correct. 
Select and write the correct choice as well as the answer to these questions.  
Q. 
No 
Question Mark
s 
1 Signals for parturition in human female originate from 
A. Fully developed foetus only  
B. Both placenta as well as fully developed foetus 
C. Placenta only  
D. Oxytocin released from maternal pituitary  
1 
2 To produce 1600 seeds, the number of meiotic divisions required will be  
A. 2400  
B. 2000  
C. 1600 
D. 1800  
1 
3 A sample of normal double-stranded DNA was found to have thymine 
content of 27%. What will be the expected proportion of guanine in this 
strand?   
A. 23%  
B. 32%  
C. 36%  
D. 73%  
1 
4 Observe the schematic diagram that depicts a small section of nucleic 
acid. The bases in two strands are paired through hydrogen bonds that 
are shown by the dark lines. Identify the correct sequence of nucleotide 
in the 5’-3’ direction.  
 
A. GCAT 
B. CGTA 
C. TAGC 
D. ATCG 
- - - - - - - - - - - - - - - - - - -  
For Visual Impaired Students 
E. coli has 4.6 X 10 
6
 base pairs and completes the process of replication 
in 18 minutes, then the average rate of polymerization is approximately  
A. 2000 bp/s  
B. 4000 bp/s  
C. 3000 bp/s  
D. 1000 bp/s 
1 
5 Suresh and Rajesh have defective haemoglobin due to genetic disorders. 
In Suresh, the problem is qualitative as he is having incorrectly functioning 
globin molecules while in Rajesh the problem is quantitative as he is 
having very few globin molecules. Identify the disorder they are suffering 
from.  
 Suresh  Rajesh  
A Thalassemia - Autosomal 
Dominant blood disorder 
Sickle Cell Anaemia - Autosomal 
linked Recessive trait  
B Sickle Cell Anaemia - 
Autosomal linked Dominant 
trait 
Thalassemia - Autosomal 
Recessive blood disorder 
C Sickle Cell Anaemia – 
Autosomal linked Recessive 
trait  
Thalassemia – Autosomal 
Recessive blood disorder  
D Thalassemia - Autosomal 
Dominant blood disorder 
Sickle Cell Anaemia - Autosomal 
linked Dominant trait 
 
1 
6 In E.coli, the lac operon gets switched on when lactose is 
 
A. present in the medium and it binds to the repressor.  
B. not present in the medium and the repressor binds to the operator.  
C. not present in the medium and RNA polymerase binds to the 
operator.  
D. Active lactose present in the medium binds to RNA polymerase.  
 
1 
7 Which of the following features shows the mechanism of sex 
determination in honey-bee?  
 
(i) An offspring formed from the union of a sperm and egg develops 
as a female.  
(ii) Males have half the number of chromosomes than that of female.  
(iii) The males are haploid having 32 chromosomes.  
(iv) All workers and males are diploid having 16 chromosomes  
A. (i) and (ii)  
B. (ii) and (iii)  
C. (i) and (iv)  
D. (ii) and (iv)  
1 
8 The following diagram shows a fragment of DNA which is going to be 
transcribed, the upper strand with polarity 3’ to 5’ is the template strand:  
3´ ATTGCC 5´  
5´ TAACGG 3´ 
 
After transcription the mRNA can be represented by:  
A. 5´ AUUGCC 3´  
B. 5´ AUUGCC 3’  
C. 5´ UAACGG 3´  
D. 5´ GGCAAU 3´  
 
1 
9 Idli – dosa dough rises due to production of which of the following gas? 
A. CO  
B. CO2  
C. NO 
D. NO2 
 
1 
10 Adaptive radiation leads to which of the following?  
A. Increased competition among species  
B. Decreased speciation rates  
C. Limited morphological diversity among species  
D. Rapid divergence of traits among populations inhabiting a given 
geographical area. 
1 
Page 4


Sample Question Paper  
Class XII  
044 Biology (2024-25) 
Maximum Marks: 70            Time: 3 hours 
 
General Instructions: 
 
(i) All questions are compulsory.  
(ii) The question paper has five sections and 33 questions.  
(iii) Section–A has 16 questions of 1 mark each; Section–B has 5 questions of 2 
marks each; Section– C has 7 questions of 3 marks each; Section– D has 2 
case-based questions of 4 marks each; and Section–E has 3 questions of 5 
marks each. 
(iv) There is no overall choice. However, internal choices have been provided in 
some questions. A student has to attempt only one of the alternatives in such 
questions. 
(v) Wherever necessary, neat and properly labeled diagrams should be drawn. 
 
 
Section – A 
Q. No. 1 to 12 are multiple choice questions. Only one of the choices is correct. 
Select and write the correct choice as well as the answer to these questions.  
Q. 
No 
Question Mark
s 
1 Signals for parturition in human female originate from 
A. Fully developed foetus only  
B. Both placenta as well as fully developed foetus 
C. Placenta only  
D. Oxytocin released from maternal pituitary  
1 
2 To produce 1600 seeds, the number of meiotic divisions required will be  
A. 2400  
B. 2000  
C. 1600 
D. 1800  
1 
3 A sample of normal double-stranded DNA was found to have thymine 
content of 27%. What will be the expected proportion of guanine in this 
strand?   
A. 23%  
B. 32%  
C. 36%  
D. 73%  
1 
4 Observe the schematic diagram that depicts a small section of nucleic 
acid. The bases in two strands are paired through hydrogen bonds that 
are shown by the dark lines. Identify the correct sequence of nucleotide 
in the 5’-3’ direction.  
 
A. GCAT 
B. CGTA 
C. TAGC 
D. ATCG 
- - - - - - - - - - - - - - - - - - -  
For Visual Impaired Students 
E. coli has 4.6 X 10 
6
 base pairs and completes the process of replication 
in 18 minutes, then the average rate of polymerization is approximately  
A. 2000 bp/s  
B. 4000 bp/s  
C. 3000 bp/s  
D. 1000 bp/s 
1 
5 Suresh and Rajesh have defective haemoglobin due to genetic disorders. 
In Suresh, the problem is qualitative as he is having incorrectly functioning 
globin molecules while in Rajesh the problem is quantitative as he is 
having very few globin molecules. Identify the disorder they are suffering 
from.  
 Suresh  Rajesh  
A Thalassemia - Autosomal 
Dominant blood disorder 
Sickle Cell Anaemia - Autosomal 
linked Recessive trait  
B Sickle Cell Anaemia - 
Autosomal linked Dominant 
trait 
Thalassemia - Autosomal 
Recessive blood disorder 
C Sickle Cell Anaemia – 
Autosomal linked Recessive 
trait  
Thalassemia – Autosomal 
Recessive blood disorder  
D Thalassemia - Autosomal 
Dominant blood disorder 
Sickle Cell Anaemia - Autosomal 
linked Dominant trait 
 
1 
6 In E.coli, the lac operon gets switched on when lactose is 
 
A. present in the medium and it binds to the repressor.  
B. not present in the medium and the repressor binds to the operator.  
C. not present in the medium and RNA polymerase binds to the 
operator.  
D. Active lactose present in the medium binds to RNA polymerase.  
 
1 
7 Which of the following features shows the mechanism of sex 
determination in honey-bee?  
 
(i) An offspring formed from the union of a sperm and egg develops 
as a female.  
(ii) Males have half the number of chromosomes than that of female.  
(iii) The males are haploid having 32 chromosomes.  
(iv) All workers and males are diploid having 16 chromosomes  
A. (i) and (ii)  
B. (ii) and (iii)  
C. (i) and (iv)  
D. (ii) and (iv)  
1 
8 The following diagram shows a fragment of DNA which is going to be 
transcribed, the upper strand with polarity 3’ to 5’ is the template strand:  
3´ ATTGCC 5´  
5´ TAACGG 3´ 
 
After transcription the mRNA can be represented by:  
A. 5´ AUUGCC 3´  
B. 5´ AUUGCC 3’  
C. 5´ UAACGG 3´  
D. 5´ GGCAAU 3´  
 
1 
9 Idli – dosa dough rises due to production of which of the following gas? 
A. CO  
B. CO2  
C. NO 
D. NO2 
 
1 
10 Adaptive radiation leads to which of the following?  
A. Increased competition among species  
B. Decreased speciation rates  
C. Limited morphological diversity among species  
D. Rapid divergence of traits among populations inhabiting a given 
geographical area. 
1 
11 Eco R1 cuts the DNA between bases G and A only when the sequence 
of GAATTC is present. The number of nucleotides present in the resultant 
sticky ends that will be formed in each of the two strands of DNA after this 
enzyme cuts the DNA will be: 
 Vector DNA Foreign DNA 
A. 1 & 5 5 &1 
B. 2 & 4 4 &2 
C. 2 & 5 5 & 2 
D. 3 & 4 4 & 3 
 
1 
12 During the secondary treatment of sewage, which of the following change 
in the effluent occur due to flocs? 
A. Reduction in BOD 
B. Increase in BOD 
C. Decrease in DO 
D. No change in DO or BOD 
1 
Question No. 13 to 16 consist of two statements – Assertion (A) and Reason (R). Answer 
these questions selecting the appropriate option given below:  
A. Both A and R are true and R is the correct explanation of A.  
B. Both A and R are true and R is not the correct explanation of A.  
C. A is true but R is false.  
D. A is False but R is true. 
13 Assertion (A): Cells of tapetum have more than one nucleus. 
Reason (R): They undergo meiosis without cytokinesis. 
1 
14 Assertion (A): Deoxyribonucleoside triphosphates serve dual purposes. 
Reason (R): They act as proof readers and provide energy. 
1 
15 Assertion (A): A floating cover placed over the slurry in a biogas plant 
keeps on rising. 
Reason (R): This cover keeps on rising due to the gas produced in the 
tank by the microbial activity. 
1 
16 Assertion (A): DNA fragments can be isolated by Gel electrophoresis on 
the basis of their size. 
Reason (R): The larger the fragment size, the faster it moves. 
1 
Section - B 
17 Attempt either option A or B. 
A. 
(i) A blood test reported negative for hCG. 
What does negative hCG imply? Name the tissue which 
produces hCG?  
2 
Page 5


Sample Question Paper  
Class XII  
044 Biology (2024-25) 
Maximum Marks: 70            Time: 3 hours 
 
General Instructions: 
 
(i) All questions are compulsory.  
(ii) The question paper has five sections and 33 questions.  
(iii) Section–A has 16 questions of 1 mark each; Section–B has 5 questions of 2 
marks each; Section– C has 7 questions of 3 marks each; Section– D has 2 
case-based questions of 4 marks each; and Section–E has 3 questions of 5 
marks each. 
(iv) There is no overall choice. However, internal choices have been provided in 
some questions. A student has to attempt only one of the alternatives in such 
questions. 
(v) Wherever necessary, neat and properly labeled diagrams should be drawn. 
 
 
Section – A 
Q. No. 1 to 12 are multiple choice questions. Only one of the choices is correct. 
Select and write the correct choice as well as the answer to these questions.  
Q. 
No 
Question Mark
s 
1 Signals for parturition in human female originate from 
A. Fully developed foetus only  
B. Both placenta as well as fully developed foetus 
C. Placenta only  
D. Oxytocin released from maternal pituitary  
1 
2 To produce 1600 seeds, the number of meiotic divisions required will be  
A. 2400  
B. 2000  
C. 1600 
D. 1800  
1 
3 A sample of normal double-stranded DNA was found to have thymine 
content of 27%. What will be the expected proportion of guanine in this 
strand?   
A. 23%  
B. 32%  
C. 36%  
D. 73%  
1 
4 Observe the schematic diagram that depicts a small section of nucleic 
acid. The bases in two strands are paired through hydrogen bonds that 
are shown by the dark lines. Identify the correct sequence of nucleotide 
in the 5’-3’ direction.  
 
A. GCAT 
B. CGTA 
C. TAGC 
D. ATCG 
- - - - - - - - - - - - - - - - - - -  
For Visual Impaired Students 
E. coli has 4.6 X 10 
6
 base pairs and completes the process of replication 
in 18 minutes, then the average rate of polymerization is approximately  
A. 2000 bp/s  
B. 4000 bp/s  
C. 3000 bp/s  
D. 1000 bp/s 
1 
5 Suresh and Rajesh have defective haemoglobin due to genetic disorders. 
In Suresh, the problem is qualitative as he is having incorrectly functioning 
globin molecules while in Rajesh the problem is quantitative as he is 
having very few globin molecules. Identify the disorder they are suffering 
from.  
 Suresh  Rajesh  
A Thalassemia - Autosomal 
Dominant blood disorder 
Sickle Cell Anaemia - Autosomal 
linked Recessive trait  
B Sickle Cell Anaemia - 
Autosomal linked Dominant 
trait 
Thalassemia - Autosomal 
Recessive blood disorder 
C Sickle Cell Anaemia – 
Autosomal linked Recessive 
trait  
Thalassemia – Autosomal 
Recessive blood disorder  
D Thalassemia - Autosomal 
Dominant blood disorder 
Sickle Cell Anaemia - Autosomal 
linked Dominant trait 
 
1 
6 In E.coli, the lac operon gets switched on when lactose is 
 
A. present in the medium and it binds to the repressor.  
B. not present in the medium and the repressor binds to the operator.  
C. not present in the medium and RNA polymerase binds to the 
operator.  
D. Active lactose present in the medium binds to RNA polymerase.  
 
1 
7 Which of the following features shows the mechanism of sex 
determination in honey-bee?  
 
(i) An offspring formed from the union of a sperm and egg develops 
as a female.  
(ii) Males have half the number of chromosomes than that of female.  
(iii) The males are haploid having 32 chromosomes.  
(iv) All workers and males are diploid having 16 chromosomes  
A. (i) and (ii)  
B. (ii) and (iii)  
C. (i) and (iv)  
D. (ii) and (iv)  
1 
8 The following diagram shows a fragment of DNA which is going to be 
transcribed, the upper strand with polarity 3’ to 5’ is the template strand:  
3´ ATTGCC 5´  
5´ TAACGG 3´ 
 
After transcription the mRNA can be represented by:  
A. 5´ AUUGCC 3´  
B. 5´ AUUGCC 3’  
C. 5´ UAACGG 3´  
D. 5´ GGCAAU 3´  
 
1 
9 Idli – dosa dough rises due to production of which of the following gas? 
A. CO  
B. CO2  
C. NO 
D. NO2 
 
1 
10 Adaptive radiation leads to which of the following?  
A. Increased competition among species  
B. Decreased speciation rates  
C. Limited morphological diversity among species  
D. Rapid divergence of traits among populations inhabiting a given 
geographical area. 
1 
11 Eco R1 cuts the DNA between bases G and A only when the sequence 
of GAATTC is present. The number of nucleotides present in the resultant 
sticky ends that will be formed in each of the two strands of DNA after this 
enzyme cuts the DNA will be: 
 Vector DNA Foreign DNA 
A. 1 & 5 5 &1 
B. 2 & 4 4 &2 
C. 2 & 5 5 & 2 
D. 3 & 4 4 & 3 
 
1 
12 During the secondary treatment of sewage, which of the following change 
in the effluent occur due to flocs? 
A. Reduction in BOD 
B. Increase in BOD 
C. Decrease in DO 
D. No change in DO or BOD 
1 
Question No. 13 to 16 consist of two statements – Assertion (A) and Reason (R). Answer 
these questions selecting the appropriate option given below:  
A. Both A and R are true and R is the correct explanation of A.  
B. Both A and R are true and R is not the correct explanation of A.  
C. A is true but R is false.  
D. A is False but R is true. 
13 Assertion (A): Cells of tapetum have more than one nucleus. 
Reason (R): They undergo meiosis without cytokinesis. 
1 
14 Assertion (A): Deoxyribonucleoside triphosphates serve dual purposes. 
Reason (R): They act as proof readers and provide energy. 
1 
15 Assertion (A): A floating cover placed over the slurry in a biogas plant 
keeps on rising. 
Reason (R): This cover keeps on rising due to the gas produced in the 
tank by the microbial activity. 
1 
16 Assertion (A): DNA fragments can be isolated by Gel electrophoresis on 
the basis of their size. 
Reason (R): The larger the fragment size, the faster it moves. 
1 
Section - B 
17 Attempt either option A or B. 
A. 
(i) A blood test reported negative for hCG. 
What does negative hCG imply? Name the tissue which 
produces hCG?  
2 
(ii) If a blood test reported positive for hCG in a person, then which 
other hormones would also be secreted by the tissue secreting 
hCG? 
OR 
B.  
(i) The human male ejaculates about 200 to 300 million sperm 
during a coitus, however the ovum is fertilized by only one 
sperm. How does the ovum block the entry of additional 
sperms?  
(ii) All copulations will not lead to fertilization. Why?  
18 Attempt either option A or B. 
A. The schematic representation given below shows a DNA strand and 
two types of mutations in the DNA strand. 
 
 
(i) Identify the type of mutation exhibited in I and II. 
(ii) Which of the above mutation is more harmful? Give reason.  
 
OR 
 
B. Given below is a schematic representation of a mRNA strand 
 
  
(i) In the above sequence identify the translational unit in mRNA.  
(ii) Where are UTRs found and what is their significance?  
2