Botany: Solved Previous Year’s Question Paper for   NCERT/ CBSE  Class 12th Botany Paper Code (HSEIIRKO14-1703-Z)

Botany: Solved Previous Year’s Question Paper for   NCERT/ CBSE  Class 12th Botany Paper Code (HSEIIRKO14-1703-Z)

 (Long Answer Type) 

Question: What is Co-dominance? Describe with special to ABO human blood 

 Ans: When both alleles of a gene are equally expressed in an individual’s phenotype, this sort of genetic inheritance is known as co-dominance. In other words, neither allele is predominant. One allele is expressed more strongly than the other in contrast to dominant and recessive inheritance. The ABO blood type system and the passing down of white and red flower colouring are two examples of co-dominance.

The four main blood groups of ABO human blood are determined by whether or not specific antigens are present in red blood cells. These antigens, primarily carbohydrate antigens, are either present (A and B) or not present (O). The presence of antigens establishes compatibility in blood transfusions and identifies the type of blood a person has. The four ABO blood types in humans are A, B, AB, and O, with A and B being the most prevalent. A person’s blood type, which is determined by inherited genetics, plays a key role in deciding whether or not they can get blood transfusions and undergo other medical treatments.

Question: Why should we conserve Biodiversity?

Ans: A healthy and balanced environment depends on biodiversity. It supports several ecosystems, such as forests, oceans, coral reefs, and wetlands. By preserving biodiversity, we support the preservation and sustainability of these essential ecosystems that give us access to resources like food, medicine, and wood. By supplying habitats for plants and animals that can adapt to shifting temperatures and maintain the balance of the natural world, biodiversity also helps to shield humanity from the effects of climate change. The beauty and uniqueness of the natural world are also preserved for future generations to enjoy thanks to the conservation of biodiversity.

(Short Answer Type Questions) 

Question: Differentiate between Continuous and Discontinuous variations. 

Ans: Continuous variation is the progressive alteration of a trait across a range of values. The majority of features, including height, weight, and eye colour, exhibit this kind of variance.

When a trait is either present or absent with no variation in between, it is said to exhibit discontinuous variation. This kind of variance can be observed in characteristics like blood type, which can only be A, B, AB, or O and not in between.

Question: What are Biofertilizers? Write the sources of biofertilizers.

Ans: Biofertilizers are organic, natural fertilisers produced by microbes. They are incorporated into the soil to give plants vital nutrients. Algae, cyanobacteria, fungi, bacteria, and fungi are examples of biofertilizer sources. Rhizobium, Azotobacter, Azospirillum, and Bacillus are a few types of bacteria that are employed as biofertilizers. Mycorrhizal fungi, Trichoderma, and Glomus are some types of fungi that are employed as biofertilizers. Spirulina, Chlorella, and Ulva are three types of algae utilised as biofertilizers. Anabaena, Nostoc, and Oscillatoria are three cyanobacteria that are utilised as biofertilizers.

Question: Differentiate between Mutualism and Commensalism. Give an example of each. 

Ans: Mutualism is a sort of symbiotic connection in which both species gain from their association. The relationship between bees and flowers is an illustration of mutualism. The bees gather nectar from the flowers, which gives them sustenance, while the blooms gain from pollination.

Commensalism is a sort of symbiotic interaction in which one organism gains while the other is unaffected. The interaction between barnacles and whales is an illustration of commensalism. The whales are unaffected as the barnacles adhere to them and eat the food scraps they churn up while swimming.

 (Very Short Answer Type Questions) 

The following very short answer type questions of two marks, each may be answered in a few words or few as may be required: 

Question: (a) What is Micropropagation? 

Ans: The process of micropropagation includes growing plant material in a lab setting from small explants of plant tissue. This process is used to rapidly create a large number of genetically identical plants from a single parent plant. Additionally, it can be utilised to grow plants with desirable traits like increased flavour or disease resistance.

Question: (b) Define the terms: 

 (i) Somatic embryo 

 (ii) Somatic hybrids. 

Ans: (i) Somatic embryo: The term “somatic embryo” refers to an embryo created from somatic (non-reproductive) cells. They develop either in vivo or in vitro using somatic cell culture (in a living organism). Somatic embryos can be utilised to create plants with the features you want, such as increased disease resistance, increased yield, and other desirable attributes.

(ii) Somatic hybrids: Somatic hybrids are, plants, or other organisms produced by fusing genetic material from two separate sources. This is typically accomplished by fusing somatic cells from two different species, resulting in a hybrid with characteristics from both parents. Somatic hybrids can be utilised for plant breeding and can be used to add new features or change already-existing traits in plants.

Question:  (c) List two adaptive features that evolved in parasites enabling them to live successfully on their host. 

Ans: 1. increased surface area for nutrition uptake from the host.

2. Extremely specialised organs and body parts that help in attachment, feeding, and mobility

Question: (d) Distinguish between Primary productivity and Secondary productivity. 

Ans: The rate at which an ecosystem produces organic matter is known as primary productivity. It measures how quickly energy is transformed into the organic matter during chemosynthesis or photosynthesis. This energy serves as the foundation of the food chain.

The pace at which organic matter is broken down and respired into fresh biomass is known as secondary productivity. This entails how plants, animals, and microbes break down organic compounds. The pace at which energy in an ecosystem transforms from one form to another is measured by secondary productivity.

(Objective Type Questions) 

Choose the correct/most appropriate answer and write it in your Answer-book 

Question: (i) Define Allogamy. 

Ans: Allogamy is the process of fertilization between two individuals with different genetic backgrounds.

Question:  (ii) An anther having four microsporocytes shall produce pollen grains 

A. 24 

B. 12 

C. 8 

D. 16 

Ans: D. 16

Question: (iii) The Term Genetics was first used by Benzeer

Ans: No,

Question: (iv) Haploid culture technique was developed by 

Ans: Hans M. Ris in the early 1970s.

Question: (v) The term used for live microbial food supplement is (True/False)

Ans: True.