Organisation : Central Board of Secondary Education (CBSE)
Class Name : 12th/HSC (Class XII)
Subject : Biology
Download : Sample Question Paper 2024-25
Website : https://cbseacademic.nic.in//SQP_CLASSXII_2024-25.html
CBSE Class XII Biology Sample Question Paper
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.
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
2. To produce 1600 seeds, the number of meiotic divisions required will be
A. 2400
B. 2000
C. 1600
D. 1800
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%
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
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]
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.
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)
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´
9. Idli – dosa dough rises due to production of which of the following gas?
A. CO
B. CO2
C. NO
D. NO2
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.
Download CBSE Class XII Biology Sample Question Paper
Download Sample Question Paper Here : https://www.pdfquestion.in/uploads/pdf2025/43572-Bio.pdf