CBSE 12 Biology Question Paper-2018 by Pavan | Practice Test to Test Your Knowledge
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  3. CBSE 12 Biology Question Paper-2018
CBSE 12 Biology Question Paper-2018

CBSE 12 Biology Question Paper-2018

This mock test includes actual CBSE Class 12 Biology board exam questions from the year 2018, helping students understand exam trends and practice real paper format

2025-08-05
Pavan Pavan
CBSE Class 12 Biology 2018 Grade 12

Duration

30 min

Questions

30

Marking

Negative

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Questions Preview

What is the chemical change that proinsulin undergoes to act as mature insulin?

A
Proinsulin is cleaved to form insulin and C-peptide
B
Proinsulin is phosphorylated to become active insulin
C
Proinsulin undergoes reduction to form active insulin
D
Proinsulin is methylated to become insulin

Which of the following diseases can be controlled by the eradication of Aedes mosquitoes?

A
Malaria
B
Dengue
C
Tuberculosis
D
Cholera

How do cytokine barriers provide innate immunity in humans?

A
By producing antibodies
B
By activating T-cells
C
By promoting inflammation
D
By preventing the entry of pathogens

Which of the following is the source plant of heroin?

A
Papaver somniferum
B
Cannabis sativa
C
Erythroxylum coca
D
Nicotiana tabacum

What is the dual purpose served by Deoxyribonucleoside triphosphates in polymerisation?

A
They act as precursors for DNA synthesis and provide energy
B
They help in protein synthesis and energy transfer
C
They aid in RNA transcription and replication
D
They are used in cellular respiration and energy production

Which two microbes can enrich the soil with nitrogen?

A
Rhizobium and Azotobacter
B
E. coli and Bacillus
C
Streptococcus and Lactobacillus
D
Clostridium and Salmonella

What is the reason why leguminous crops do not require enrichment of the soil with nitrogen?

A
They form symbiotic relationships with nitrogen-fixing bacteria
B
They have high levels of potassium
C
They grow better in acidic soils
D
They store nitrogen in their roots

What procedure ensures the retention of desired characteristics in future generations of a high-yielding tomato crop?

A
Selective breeding
B
Gene editing
C
Cross-pollination
D
Hybridization

Which process helps to improve water quality using Integrated Waste Water Treatment?

A
Treating wastewater with chemical agents
B
Using plant filtration systems
C
Implementing biological treatment with microbes
D
Filtering wastewater through sand and gravel

How did Hardy-Weinberg explain the frequency of allele occurrence in populations?

A
By providing an algebraic equation
B
By tracking gene mutations over generations
C
By analyzing gene flow between populations
D
By studying genetic drift over time

What is the difference between Parthenocarpy and Parthenogenesis?

A
Parthenocarpy refers to fruit development without fertilization, and Parthenogenesis refers to asexual reproduction
B
Parthenocarpy involves asexual reproduction, while Parthenogenesis involves fertilization
C
Parthenocarpy is found in animals, while Parthenogenesis is seen in plants
D
Parthenocarpy and Parthenogenesis are the same process

What are the advantages of breastfeeding for newborn babies?

A
It provides immunity and promotes bonding between mother and child
B
It reduces the risk of developing allergies
C
It enhances brain development in infants
D
All of the above

Which of the following is a key feature of recombinant DNA technology?

A
The use of restriction enzymes
B
The use of plasmids as vectors
C
Both A and B
D
None of the above

What is the role of plasmids in recombinant DNA technology?

A
Plasmids carry foreign genes into a host cell
B
Plasmids help in the synthesis of recombinant proteins
C
Plasmids provide energy to cells
D
Plasmids protect the host cell from external pathogens

What is the mechanism of ‘sex determination’ in birds, and how does it differ from that of human beings?

A
In birds, the sex is determined by the ZW system, while humans use the XY system
B
In birds, sex is determined by environmental factors, while humans use the XY system
C
In both birds and humans, sex is determined by the XY system
D
In both birds and humans, sex is determined by the ZW system

What is the role of bioreactors in biotechnology?

A
Bioreactors provide an optimal environment for the growth of microorganisms or cells for industrial purposes
B
Bioreactors are used to synthesize raw materials
C
Bioreactors are used to store genetic material
D
Bioreactors control the temperature of microbial cultures

What is out-breeding, out-crossing, and cross-breeding in animal husbandry?

A
Out-breeding refers to the mating of animals from different breeds, while cross-breeding is the mating of animals of different species
B
Out-breeding is mating between individuals from the same breed, while out-crossing involves different breeds
C
Cross-breeding involves the introduction of new breeds into a population
D
All of the above

What is the difference between Parthenocarpy and Parthenogenesis?

A
Parthenocarpy refers to fruit development without fertilization, and Parthenogenesis refers to asexual reproduction
B
Parthenocarpy involves asexual reproduction, while Parthenogenesis involves fertilization
C
Parthenocarpy is found in animals, while Parthenogenesis is seen in plants
D
Parthenocarpy and Parthenogenesis are the same process

Which of the following structures are analogous?

A
Wings of a butterfly and wings of a bird
B
Vertebrate hearts
C
Tendrils of bougainvillea
D
All of the above

What is the role of Agrobacterium in controlling Meloidegyne incognitia infestation in tobacco plants?

A
Agrobacterium is used as a vector to introduce resistance genes into the plants
B
Agrobacterium helps in the physical removal of the nematodes
C
Agrobacterium is used to destroy the nematodes directly
D
Agrobacterium increases the susceptibility of the plants to nematode infestations

Which of the following are homologous structures?

A
Vertebrate limbs
B
Wings of a butterfly
C
Tendrils of bougainvillea
D
All of the above

What are the harmful effects of air pollution on plants and humans?

A
Air pollution can cause respiratory diseases in humans and hinder photosynthesis in plants
B
Air pollution leads to global warming, which impacts both plant and human health
C
Air pollution can cause deforestation and soil erosion
D
Air pollution only affects human health, not plants

What are the two major causes of air pollution?

A
Industrial emissions and vehicle exhaust
B
Overpopulation and deforestation
C
Natural disasters and volcanic activity
D
Agricultural activities and illegal mining

How does urban sewage affect the characteristics of a river?

A
It increases the level of organic pollutants in the water, harming aquatic life
B
It leads to improved water quality due to the nutrient influx
C
It cools the river, making it more conducive to fish breeding
D
It adds oxygen to the water, helping aquatic organisms thrive

What is the importance of DNA fingerprinting in forensic science?

A
It helps to identify individuals based on their unique genetic patterns
B
It is used for cloning purposes
C
It assists in gene therapy for genetic disorders
D
It is used for plant breeding programs

What are the applications of recombinant DNA technology in medicine?

A
Production of insulin and vaccines
B
Development of drought-resistant crops
C
Production of biofuels
D
All of the above

Which process in plants is most responsible for the production of oxygen?

A
Photosynthesis
B
Respiration
C
Transpiration
D
Germination

What is the primary function of the stomata in plant leaves?

A
To allow water to exit the plant
B
To absorb sunlight
C
To allow gases like CO2 and oxygen to enter and exit the plant
D
To store energy for photosynthesis

What does the term 'biodiversity' refer to?

A
The variety of life forms in a given area
B
The number of species within a single species group
C
The variety of climates in a region
D
The soil fertility of an ecosystem

Which of the following is NOT a greenhouse gas?

A
Carbon dioxide
B
Methane
C
Oxygen
D
Nitrous oxide