RBSE Class 12 Biology Chapter 16- Plant tissue culture provides complete information related to the important terminologies used in the plant tissue culture, contribution of the various scientists in the field of plant tissue culture, necessary resources required for culture plants, culture medium and different types of culture. It also includes a detailed explanation of micropropagation, organogenesis, application of plant tissue culture, methods of gene transfer, GMO or transgenic plants and much more.
These important questions help students to ace their exams. By practising these important questions, students can analyze their preparation, get a thorough knowledge about all the important terminologies and perform their best in the examinations.
The Rajasthan Board Class 12 Solutions are the best study material for both class assignments and other board examinations. By practising these important questions, students can gain deep knowledge about the topics explained in this chapter and also help students to be well prepared for their upcoming examinations.
RBSE Class 12 Biology Chapter 16 Important Questions
RBSE Biology Chapter 16: MCQ Type Questions
Q.1. The haploid plants from another lobe culture were produced by _________.
(a) Johari and Maheshwari.
(b) Guha and Maheshwari.
Sol: (b) Guha and Maheshwari.
Q.2. Disease-free plants are obtained from virus-infected plants by _________.
(a) Embryo culture.
(b) Root culture.
(c) Pollen culture.
(d) Apical meristematic culture.
Sol: (d) Apical meristematic culture.
Q.3.Who is known as the father of Plant Tissue Culture?
(a) Robert Hooke.
Sol: (d) Haberlandt
Q.4. Ti plasmid is found in _________.
(b) A. Rahi-biogenesis.
(d) Bacillus thermogenesis.
Sol: (a) A.tumefaciens.
Q.5. Which of the following scientists obtained protoplast by enzymatic degradation of the plant cell wall?
(a) T. Murashige.
Sol: (c) E.C.Cocking.
Q.6.Which of the following explant is taken for triploid plant culture?
(c) Apical Meristematic tip.
(d) Anther lobe or Pollensa.
Sol: (b) Endosperm.
Q.7. Indirect gene transfer is done by_________.
(a) Gene gun.
Sol: (d) Agrobacterium.
Q.8. In which of the following Bacillus insect-resistant Bt genes is found?
(a) Bacillus subtilis.
(b) Bacillus thermogenesis.
(c) Bacillus anthracis.
(d) Pseudomonas citrus.
Sol: (b) Bacillus thermogenesis.
Q.9.Which of the following is a special feature of “Flavr-Savr” tomatoes?
(a) Drought resistant.
(b) Strong fruit wall.
(c) High salinity resistant
(d) All of the above.
Sol: (b) Strong fruit wall.
Q.10. Bt. gene containing cotton is called _________.
(a) Aseptic cotton.
(b) Romil cotton.
(c) Killer cotton.
(d) Golden cotton.
Sol: (c) Killer cotton.
RBSE Biology Chapter 16: Short Answer Type Questions.
Q.1. What is the importance of haploid plant production?
Sol: The importance of haploid plant production are:
- Haploid plant production through the anther and pollen cultures as well as the ovary or ovum culture is of immense use in plant breeding programmes carried out for improvement of crops.
- Haploid plants enable the raising of plants which express recessive traits.
- Haploid plants are helpful in producing homozygous plants genetically, which serve as parents in crossbreeding.
- Homozygous plant – a plant with two identical genes can be raised by depolarization of haploids through colchicine treatment.
- Haploid plants are of great interest to geneticists, as they facilitate the examination of genes in the hemizygous condition and to identify new mutations.
Q.2.What is micropropagation?
Sol: The modern technique of rapid multiplication of plants through the tissue culture is called micropropagation. This technique has been widely used for the production of novel plants at commercial level. By this technique, a large number of similar plants can be produced or raised in a small space in a relatively short period of time.
Q.3.What is an indirect method of gene transfer?
Sol: The process of transferring the desired gene through the biological vectors is called the indirect method of gene transfer. In this method, the desired gene is first transferred to the vector and then through the vectors, it is transferred into the target plants.
Q.4.What are artificial seeds? List out the components of artificial seeds.
Sol: The encapsulated somatic embryo is called the artificial seeds. The somatic embryo is protected by covering it with the calcium alginate beads or by desiccating it.
The different components of artificial seeds are the embryo, shoot bud, plant hormones, nutrients, pesticide and other antibiotic substances.
Q.5. What are the different types of nutrient media used in tissue culture?
Sol: There are three different types of culture or nutrient media, they are
- The culture media developed by Whit’s in 1953.
- The culture media developed by M.S.medium in 1962.
- The culture media developed by Gamborg et.al. in 1968.
Among all these three culture media, the culture media developed by M.S.medium – Murashige and Skoog medium is most commonly used for the general experiments of tissue culture.
Q.6.What is the direct method of gene transfer? List out the different types of gene transfer?
Sol: The transfer of DNA directly from the donor to a recipient is called the direct method of gene transfer. The different types of modules of direct gene transfer are:
- Gene gun method.
Q.7.What is the microinjection technique of gene transfer?
Sol: Microinjection is a technique of injecting genes into the plant’s protoplasts or cells with the help of a glass needle of 0.5 to 1.0mm in diameter or micropipette directly into the cytoplasm or the nucleus of the protoplasts or into the plant cells. This is a suitable method of transferring genes into the isolated protoplasts.
Q.8. Who discovered the Bt gene? Why was Bt cotton created?
Sol: The Bt gene was first discovered by Ernst Berliner.
About ten years ago, a variety of transgenic cotton was created by transforming the Bt gene into the plant DNA. This was created with the main objective to produce toxins to kill the caterpillar. The toxins released by the plant would paralyze the guts of the caterpillar when they feed on the plants.
Q.9. What is the difference between tissue culture and micropropagation?
Sol: Micropropagation is the modern technique of rapid multiplication of plants. In this process, many plants are produced from a small plant part. Tissue culture is that step of micropropagation where plant cells are placed in an artificial medium and grown into a large number.
Q.10. What are explants and how are they sterilized?
Sol: The explant is defined as the part of the plant, which is used for raising tissue – culture. Meristematic tissue, part of root, stem, leaves, flower and floral parts of the plant can be used as an explant. The explant are sterilized by a bleach solution and later it is added to a flask containing the explant and swirled. Rinse the bleach and wash the seeds with pure water.
Q.11. What are the different stages of micropropagation?
Sol: The different stages of micropropagation include:
- Selection of mother plants.
- Establishment of aseptic culture.
- Shoot multiplication.
- Root multiplication.
Q.12. What is an embryo rescue technique?
Sol: It is very difficult to produce hybrids in the case of interspecific and intergeneric crosses. This is mainly because the abnormal development of the endosperm causes the premature death of the hybrid embryo and leads to the sterile seeds. The embryo produced from such sterile hybrid seeds are removed at an appropriate time and cultured on a suitable nutrient medium to produce novel hybrids. This is known as embryo rescue, the process of saving the embryo. This technique is useful for producing a variety of crops.
Q.13. What is Tissue Culture? List out the different types of Tissue Culture?
Sol: The tissue culture is a technique in which fragments of plant or animal tissues are cultured and grown in a laboratory. Many times the organs are also used for tissue culture. The media used for the growth of the culture is broth and agar. The different types of tissue culture are:
Types of Tissue Culture
Following are the different types of tissue culture techniques:
- Seed Culture.
- Embryo Culture.
- Callus Culture.
- Organ Culture.
- Pollen Culture.
- Anther Culture.
- Protoplast Culture.
- Single Cell Culture.
- Suspension Culture.
- Somatic Embryogenesis.
Q.14. Give any three advantages and disadvantages of micropropagation
Advantages of micropropagation.
- It is a cost-effective process.
- A new variety of species can be propagated by this technique.
- It helps in the production and maintenance of pathogen-free plant varieties.
Disadvantages of micropropagation.
- The plants produced by the technique are not autotrophic.
- The plants find a problem acclimatizing to the natural environment.
- The process of micropropagation cannot be implemented in all the crops.
Q.15. What is the application of plant tissue culture?
Sol: The main applications of plant tissue culture are as follows:
- Tissue culture is used for developing thousands of genetically identical plants from one single parent plant, which are known as soma clones, and this process is known as micropropagation.
- This method can be used to develop disease-free plants from disease-rode plants by using their meristems as explants.
- This method has been used extensively for the production of commercially important plants including food plants like tomato, banana, apple etc.
- The most notable example of the application of micropropagation was observed in the farming of orchids as it rose exponentially due to the availability of millions of plantlets, thanks to tissue culture methods.
RBSE Biology Class 12: Long Answer Type Questions
Q.1. What are the different steps involved in tissue culture?
Sol: The three different steps of tissue culture are:
Selection of an explant and pretreatment.
The selection of an explant depends on the objective and the experimental requirements. For a callus culture, a healthy part of the plant is used as an explant. The explant washed under running tap water and then it is pretreated with the help of a chemical Tween-20. This treatment cleans dust and microbes present on the surface of the plant and its cells.
Surface Sterilization of explant.
The selected explants are surface-sterilized by appropriate disinfectant chemicals under the laminar airflow. This results in complete sterilization of an explant. Depending upon the nature of an explant, various types of disinfectants such as mercuric chloride, ethanol, silver nitrate, bromine or chlorine water can be used.
Initiation of culture.
The surface-sterilized explants are transferred on a suitable nutrient medium under specific conditions and transferred to the culture room. In a culture chamber, callus formation is initiated in due course of time. Later, both the explant and the callus are transferred into a fresh medium for multiplication.
Q.2.What is micropropagation? Describe the different stages of micropropagation?
Sol: Micropropagation is the artificial process of producing plants vegetatively through tissue culture or cell culture techniques. In this artificial process of propagation, plants are produced in-vitro by asexual means of reproduction or by vegetative propagation.
Stages of micropropagation
The stages involved in the process of micropropagation technique are:
The explants are established in a suitable culture medium. This stage involves the following steps:
Isolation of the explant.
The explant is established on an appropriate culture medium.
This stage involves the rapid multiplication of shoots or rapid somatic embryo formation in a defined culture medium.
In this stage, the shoots are transferred to a medium for the development of roots. The shoots are either transferred directly in the soil for the root development or transferred to a nutrient medium in the laboratory.
In this stage, the plantlets are established in the soil. The shoots from the laboratory are transferred to a greenhouse under controlled conditions of temperature, humidity and light.
Q.3.Define the following terms:
- Culture medium.
- Transgenic plants.
It is the part of the plant, which is used for raising tissue – culture. Meristematic tissue, part of root, stem, leaves, flower and floral parts of the plant can be used as an explant.
The content of the plant cell, devoid by the cell wall collectively constitutes the protoplasts. Protoplasts are thus a plant cell without the cell wall.
The nutrient medium, the chemical composition of which is precisely known and which is used to raise the tissue culture and its multiplication is known as culture medium.
The genetically modified plants are known as the transgenic plants. Transgenic plants are developed by introducing appropriate genes through the recombinant DNA technique using genetic engineering.
Q.4. Explain in detail about the tissue culture, its types and steps involved in the process of plant tissue culture.
Sol: Tissue culture is a technique in which fragments of plant or animal tissues are cultured and grown in a laboratory. Many times the organs are also used for tissue culture. The media used for the growth of the culture is broth and agar.
This technique is also known as micropropagation. It has proved beneficial for the production of disease-free plants and increased plant yield in developing countries. It only requires a sterile workplace, greenhouse, trained manpower and a nursery.
Oil palm, banana, plantain, eggplant, pineapple, rubber tree, tomato, sweet potato have been produced by tissue culture in developing countries.
Types of Tissue Culture
There are two main types of cultures:
Primary Culture– It consists of normal tissues excised from the living organisms by biopsy. They model the natural function of the tissue. These cultures are generally mortal.
Cultures of established Cell Lines– These are either derived from the tumour biopsies, or from the primary cells that had undergone mutation and continued to replicate.
Steps of Tissue Culture
The steps of tissue culture are given below:
At this stage, the tissue is initiated into the culture. The tissue of interest is obtained, introduced and sterilized to prevent the process from any contamination.
In this stage, the sterilized explant is introduced into the medium composed of growth regulators and appropriate nutrients. They are responsible for the multiplication of cells. This undifferentiated mass of cells is known as a callus.
The roots start forming. Plant growth hormones are added to initiate the root formation. Consequently, we obtain a complete plantlets.
The plant growth hormones for the formation of shoot are added and the growth is observed for a week.
When the plant starts developing, it is transferred to the greenhouse to develop under controlled environmental conditions. It is finally transferred to the nurseries to grow under natural environmental conditions.
Q.5. What is Growth Medium?
Sol: A growth medium is also referred to as culture medium or nutrient broth. It is a solution, which is free from all microorganisms through the process of sterilization. Sterilization is achieved by applying heat under pressure for a specific time period. However, the solution contains all the microorganisms required for growth, such as algae, fungi, bacteria and protozoans. When the Agar is added to the medium it solidifies.
Some media are made up of inorganic salts and one or more inorganic compounds. This is a chemical or synthetic defined media. Different types of living cells or tissue cultures can also be used as part of the media. There are types of media which are made up of an assortment of ingredients like plant or animal tissue extracts. Some of the examples are peptone, meat extract, yeast extract.
There are special-purpose media like enriched media and selective media. Enriched media consists of nutrients that help in growth and selective media consists of substances that help in the growth of selective organisms and prevent the growth of other organisms.
Q.6. Explain the following three terms:
- How are cells grown?
- How are cultures grown?
- How to start a culture?
How are cells grown?
Cells can be grown in three ways.
- Chemically defined synthetic medium using tissue extract.
- The culture media of biological origin like blood serum.
- A mixture of the culture medium of biological origin and chemically defined synthetic medium.
Some of the important prerequisites in a medium are it must have the essential nutrients for the cells in the right proportions and it must be suitably acid or alkaline.
How are cultures grown?
- Usually grown as a single layer
- Usually grown either on glass or a plastic surface or as a suspension in a liquid or a semi-solid medium.
How to start a culture?
A small sample of the tissue is spread out on the medium or in the medium. Later the tube or plate or flask containing the culture is incubated. The temperature maintained should be approximately that of the tissue environment. Usually, at the start of the culture, single cells are used, this results in the growth of clones, which are a set of uniform biological populations.
Q.7. Write a short note on insect-resistant plants.
Sol: There are several important crop plants, which are attacked by a variety of insects and pests. Bacillus thermogenesis bacteria is known as Bt in short. It was discovered that it was instrumental in causing the death of the larvae of four species of Bollworm. In the year 1961, this bacterium was registered as a biopesticide in the U.S.A. A gene called cry gene is found in this bacterium, which codes for the protein that kills the insect pests. This gene was separated from the Bt Bacterium and was incorporated into the genome of the cotton plant. The cotton variety so developed is called Bt.cotton or killer cotton. This cotton is resistant to the Bollworm insect.
Q.8. What are the advantages and disadvantages of Bt Crops?
Sol: The advantages and disadvantages of Bt Crops:
Advantages of Bt Crops
- They help in controlling soil pollution as the use of synthetic pesticides is reduced.
- Bt crops help in protecting beneficial insects.
- It leads to more productivity in a small area of land.
- It can easily feed an increasing population due to increased yields in a short time.
- It leads to the production of disease-free crops owing to the reduction of pesticides.
- They help in controlling soil pollution as the use of synthetic pesticides is reduced.
- It helps in improving the crop yield, thereby, raising the farmer’s income. This results in increased farm production.
Disadvantages of Bt Crops
- Bt crops have a few disadvantages as well:
- It can disrupt the natural process of gene flow.
- Bt crops are costlier than naturally grown crops.
- The pests might become resistant to the toxins produced by these crops and the crop production might decline.
Q.9. What are the advantages of micropropagation?
Sol: The micropropagation technique has proved beneficial in many ways. Following are the advantages of micropropagation in plant production:
- This is an alternative method for vegetative propagation with enhanced multiplication rate.
- Large quantities of identical plants can be obtained from a single plant tissue within a very short time period.
- The shoot multiplication has a very short cycle and each cycle results in a logarithmic increase in the number of shoots.
- The small-sized propagules can be stored and transported easily.
- The germplasm stocks can be maintained for several years using this technique.
- It helps in the production and maintenance of pathogen-free plant varieties.
- In a dioecious plant, the seed progeny yield is 50% male and 50% female. This method helps in obtaining the desired sex of the plant.
- Millions of plantlets can be maintained in the cultural vials.
- Genetic uniformity of the propagules can be maintained through this technique.
- It is a cost-effective process.
- New varieties of species can be propagated.
- A requirement of less space and human resources.
- This method is independent of season and can be carried out anytime.
- Assists in regenerating genetically modified cells after protoplast fusion.
- Often produces healthier plants, leading to quicker growth compared to those plants produced by a conventional method.
Q.10. What are Genetically Modified Plants
Sol: Genetically modified crops are the crops whose genes are modified using genetic engineering techniques. These are also called transgenic crops. The main goal of producing GMOs is to increase the yield of the crop and to produce disease-resistant crops.
An example of a genetically modified crop is Golden Rice. It was genetically modified to generate beta-carotene twenty times more than the previous varieties of rice. Golden rice is intended for Asia. One more rice variety was also created to fight iron deficiency. A gene from the bean plant is taken and inserted into the rice gene and the resultant rice helps to fight iron deficiency.
Q.11. Brief out the history of tissue culture.
Sol: Plant tissue culture was first conducted and observed in 1902 by haberland. This was the beginning of the culture of a plant cell under aseptic conditions. Extensive work was carried out by various scientists in this field and presently it is widely used for the regeneration of commercial useful novel plants and for developing transgenic plants.
According to the cell theory, plant cells possess all characteristics through which the whole plant can be regenerated. The capacity of producing complete plants from any cell is called Totipotency. The term Totipotency was first used by Morgan in 1909.
Due to the totipotency property, the whole plant can be regenerated from a plant cell. This was experimentally proved by Gottlieb Haberlandt in 1902.
Here is the list of contributions of various scientists in the field of plant tissue culture.
|Year||Name of the Scientists||Discovery|
|1902||Gottlieb Haberlandt||The first attempt to culture plant cells on artificial culture medium.|
|1922||W.J.Robbins and W.Kotte||Culture of plant root and shoot tip.|
|1926||F.W.Went||Discovered growth plant hormone – Auxin (Indole acetic acid)|
|1939||R.J.Gautheret, P.R.White P. Nobecourt||The established culture which can grow for a long duration.|
|1941||Van Overbeek||First to use coconut milk in the culture medium for cell division.|
|1946||E.BalL||Developed clones of the whole plant from the culture of an apical meristem.|
|1954||W.H.Murr||Developed clones of the whole plant from the culture of the apical meristem.|
|1955||F.Skoog and miller||Established the role of the kinetic hormone in tissue culture technique for cell division.|
|1959||J.Rennert||Development of an embryo from carrot root culture.|
|1960||E.C.Cocking||Separation or Isolation of protoplast by enzymatic digestion of plant cell wall.|
|1962||T.Murashige and F. Skoog||Developed the most widely used culture medium (MS medium) in plant tissue culture.|
|1964||S.Guha, S.C Maheshwari and Mukherjee.||Developed the first haploid plant by the culture of pollen grains of Datura.|
|1970||J.B.Power||First to demonstrate the protoplast fusion|
|1978||G.Melchers et.al||Developed somatic hybrid Pomato by the fusion of potato and tomato.|
|1983||M.D.Chilton||Culture of transgenic plants of tobacco.|
Q.12. What is Tissue Culture? What are the discoveries in biological sciences due to research in Tissue culture?
The growth of cells or tissues in an artificial or synthetic medium, separate from the organism is called tissue culture. This is achieved by the use of a solid or liquid, or semi-solid growth media, such as agar or broth.
Tissue culture commonly refers to the culture of a plant cell or tissues.
Tissue culture means growing cells in vitro, from tissues taken from a multicellular organism. The term tissue culture is often substituted with the word cell culture. After the cells are extracted from a donor organism, they are bathed in the culture medium, which helps in the revival of the cells, as they contain energy sources and important nutrients.
Listed below are the discoveries in biological sciences due to research in Tissue culture
- The biochemical and genetic activity of cells.
- Differences between normal cells and abnormal cells
- Metabolism, nutrition and specialized function of cells
- Information on cells regarding their composition and form.
- The effects caused on cells by physical, chemical and biological agents.
- Assisted in identifying infections, enzyme deficiencies, and other deficiency disorders.
Q.13. Explain the different methods involved in the process of micropropagation.
Sol: This is an artificial process of producing plantlets. There are five different methods involved in the process of micropropagation.
In this method of micropropagation, subtending leaf primordial and a meristem is placed into their respective growing media culture and allowed to grow. After some weeks, an elongated rooted plantlet is produced. Once after they reach a considerable height, these plantlets are transferred into the soil. In this method, a disease-free plant can be produced and can be successfully used for rapid multiplication of various herbaceous plants.
In this method, selected plant tissue is placed in an artificial growing medium culture until the callus is formed. After the production of callus, they are transferred into a culture medium containing plant growth regulators for the induction of adventitious organs. After a few weeks, a new plantlet is exposed gradually to the environmental condition.
In this method of micropropagation, cells or groups of cells are dispersed and allowed to grow in an aerated and sterile liquid culture medium.
In the method of embryo culture, the embryo is extracted and placed into a culture medium with proper nutrients in aseptic condition.
In this method, the plant cell is isolated and cultured in an appropriate medium to reform the cell wall and callus. Later, under suitable conditions, the cell develops a cell wall followed by an increase in cell division and cellular differentiation and grows into a new plant.
Q.14.What is the Purpose of Genetically Modified Crops?
Sol: The multiple purposes behind genetically modified crops are listed below.
- Higher yields.
- Longer shelf life.
- Enhanced nutritional value.
- Increase resistance to droughts.
- Increased resistance to herbicides.
- Increase resistance to insects and pests.
Q.15.What are the advantages and importance of tissue culture?
Advantages of Tissue Culture
Following are the various advantages of tissue culture technique:
- The plantlets are obtained in a very short time with a small amount of plant tissue.
- The new plants produced are disease-free.
- The plants can be grown throughout the year, irrespective of the season.
- A large space is not required to grow plants by tissue culture technique.
- The production of new varieties in the marketplace speeds up.
- This technique is being used for the production of ornamental plants such as dahlia, chrysanthemum, orchids, etc.
Importance of Tissue Culture
- Tissue culture is very important in biology due to its wide range of applications.
- The plant tissues can be used for culturing and also in preserving an organ or tissue.
- It is a technique of quickly producing plants without any tubers, seeds or bulbs.
- It also helps in the conservation of plant biodiversity by the production of endangered plants.
- This technique utilizes the plant’s ability to improve or modify the tissues rapidly. It produces exact copies of itself known as clones.
- Plant tissue culture may be used for genetic modification of a plant or simply increase its yield. The cells of the plants can be genetically altered to produce plants with desirable characteristics.
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