PSEB 12th Sample Paper 2026 Biology

Punjab Board

Sample Academic Year
2026

Paper

Punjab School Education Board
Sample Question Paper
10+2 Biology
Session 2025-26
Note:

a) Question paper will consist of four sections A, B, C and D with total of 19
questions.
b) Section-A will contain question number 1 having 20 parts of 1 mark
each. 12 questions will be of Multiple-choice question type, 4 fill in the
blanks, 4 are True/false.
c) Section-B will contain questions number 2 to 11-total 10 short answer
type questions of 2 marks each. Question 4,5,9,11 will have internal
choice.
d) Section-C will contain questions number 12 to 16 –total 5 questions of 3
marks each. Question 12 and 15 will have internal choice.
e) Section-D will consist of question 17 to 19 total 3 questions of 5 marks
each. All the questions have 100% internal choice.

Section A
Q1)
Each question carries one mark
Multiple Choice Questions

I. The nuclei present in central cell of embryo sac is called
a. Egg Nuclei
b. Antipodal nuclei
c. Polar Nuclei
d. Synergid nuclei
II. Delivery of developed fetus is scientifically called
a. Parturition
b. Ovulation
c. Abortion
d. Oviposition
III. Disadvantages of amniocentesis is
a. Determination of disease in advance
b. Sex determination of unborn child
c. Both a and b
d. None of these
IV. A cross between F1 hybrid and any of of parent is
a. Monohybrid cross
b. Dihybrid cross
c. Back Cross
d. Test Cross
V. Vertebrate forelimbs are example of
a. Homologous organs
b. Analogous organs
c. Vestigial Organ
d. Nonfunctional organ
VI. The genes causing cancer are
a. Structural genes

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b. Promotor genes
c. Oncogenes
d. Regulatory genes
VII. If BOD of water sample is very high, the sample is
a. Highly polluted
b. Less polluted
c. Not polluted
d. Potable
VIII. Plasmids are used as cloning vectors because they
a. Can be multiplied on culture
b. Are self-replicating in bacterial cell
c. Can be multiplied in lab with help of enzymes
d. Replicate freely outside the cell
IX. Golden rice is enriched with
a. Vitamin A
b. Vitamin K
c. Vitamin C
d. Vitamin D
X. Mycohhroezais example of
a. Antibiosis
b. Mutualism
c. Commensalism
d. Parasitism
XI. At each tropic level in which form energy is lost
a. Heat
b. Chemical
c. Light
d. Electrical
XII. In national park protection is given to
a. Flora only
b. Fauna only
c. Both Flora and fauna
d. None of these

Write True or False

XIII. Copper T is used as birth control device by women
XIV. Sickle cell anaemia is an example of point mutation.
XV. Vaccination is a type of innate immunity
XVI. In gel electrophoresis DNA fragments separate according to their charge

Fill in the blanks
XVII. Zygote divides to form ……….which is implanted in uterine wall
XVIII. Substances which cause allergy are called ……..
XIX. Dragonflies are usedas biocontrol agents to protect the crops
from …………….
XX. Sacred groves is an example of…………….conservation

Section B
Each question carries 2 marks.
Q2) Write two functions of tapetum.
Q3) What are the major components of seminal plasma?
Q4) Name two permanent methods of birth control.
OR
Expand
ZIFT
ICSI

2

Q5) What do you mean by law of segregation.
OR
What will the progeny be if a woman carrier for haemophilia marries
a normal man?
Q6) What is convergent evolution. Give an example
Q7) Differentiate between innate and acquired immunity.
Q8) Define sewage. Why is it harmful to us?
Q9) What are bioreactors. Name its two types.
OR
Expand PCR. Mention itsany one importance in biotechnology.

Q10) Write two advantages of GM crops.
Q11) Write any two points of differences between grazing and detritus
food chain.
OR
What do you mean by hotspots of biodiversity?

Section C
Each question carries 3 marks

Q12) What is DNA fingerprinting? Mention its two applications.
OR
Explain the structure of transcription unit with diagram.

Q13) Write a short note on industrial melanism.
Q14) Name the causing agent of Typhoid. Also write down its symptoms
and modes of transmission.
Q15) With help of diagram, show the steps of recombinant DNA
technology.
OR
What is gene therapy? Illustrate using the example of adenosine
deaminase deficiency.
Q16) Name and explain the type of interaction between crown fish and
sea anemone.
Section D
Each question carries 5 marks
Q17) Define Oogenesis. Briefly describe the process of Oogenesis with
the help of labelled diagram.
OR
Observe the given diagram and answer the following questions.

a) Which type of cell division occurs in the diagram marked A
b) The two cells formed in B are called _______
c) In figure marked C, four cells are formed. What are they?
d) What happens to the cells marked C?
e) What is the total process called? 1X5=5

3

Q18) Describe the individuals with the following chromosomal
abnormalities
1. Trisomy of chromosome 21
2. XXY
3. XO
OR
Observe the given diagram and answer the following questions.

a) Who performed thisexperiment? 1
b) What was theconclusion after thisexperiment? 2
c) Writethe results of theexperiment A-D. 2

Q19) How can the loss of biodiversity be prevented.

OR

Read the passage carefuly and answer the following questions
A constant input of solar energy is the basic requirement for any ecosystemto
function and sustain. Primary production is defined as the amount ofbiomass
or organic matter produced per unit area over a time period byplants during
photosynthesis. It is expressed in terms of weight (g–2) orenergy (kcal m–2).
The rate of biomass production is called productivity.It is expressed in terms of
gm–2 yr–1 or (kcal m–2) yr–1 to compare theproductivity of different
ecosystems. It can be divided into gross primaryproductivity (GPP) and net
primary productivity (NPP).
(NPP). Gross primaryproductivity of an ecosystem is the
rate of production of organic matterduring photosynthesis. A considerable
amount of GPP is utilised by plantsin respiration. Gross primary productivity
minus respiration losses (R),is the net primary productivity (NPP).

a. Define gross primary productivity 2
b. What is the main requirement of ecosystem functioning 1
c. What is the unit of productivity 1
d. GPP-Respiration=………………. 1

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