NCERT Solutions for Class 12 Biology Chapter 11 Biotechnology: Principles and Processes PDF – eSaral

NCERT Solutions for Class 12 Biology Chapter 11 Biotechnology: Principles and Processes PDF

Hey, are you a class 12 student and looking for ways to download NCERT Solutions for Class 12 Biology Chapter 11 Biotechnology: Principles and Processes PDF? If yes. Then read this post till the end.

In this article, we have listed NCERT Solutions for Class 12 Biology Chapter 11 Biotechnology: Principles and Processes in PDF that are prepared by Kota’s top IITian Faculties by keeping Simplicity in mind.

If you want to learn and understand class 12 Biology Chapter 11 “Biotechnology: Principles and Processes” in an easy way then you can use these solutions PDF.

NCERT Solutions helps students to Practice important concepts of subjects easily. Class 12 Biology solutions provide detailed explanations of all the NCERT questions that students can use to clear their doubts instantly.

If you want to score high in your class 12 Biology Exam then it is very important for you to have a good knowledge of all the important topics, so to learn and practice those topics you can use eSaral NCERT Solutions.

In this article, we have listed NCERT Solutions for Class 12 Biology Chapter 11 Biotechnology: Principles and Processes PDF that you can download to start your preparations anytime.

So, without wasting more time Let’s start.

Question 1: Can you list 10 recombinant proteins which are used in medical practice? Find out where they are used as therapeutics (use the internet).

Solution. Recombinant proteins are obtained from the recombinant DNA technology. This technology involves the transfer of specific genes from an organism into another organism using vectors and restriction enzymes as molecular tools.

Ten recombinant proteins used in medical practice are –

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NCERT Solutions for Class 12 Biology Chapter 11 Biotechnology: Principles and Processes PDF Image 2

Question 2: Make a chart (with diagrammatic representation) showing a restriction enzyme, the substrate DNA on which it acts, the site at which it cuts DNA and the product it produces.

Solution. The name of the restriction enzyme is Bam H 1.

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Question 3: From what you have learnt, can you tell whether enzymes are bigger or DNA is bigger in molecular size? How did you know?

Solution. Enzymes are smaller in size than DNA molecules. This is because DNA contains genetic information for the development and functioning of all living organisms. It contains instructions for the synthesis of proteins and DNA molecules. On the other hand, enzymes are proteins which are synthesised from a small stretch of DNA known as ‘genes’, which are involved in the production of the polypeptide chain.

Question 4: What would be the molar concentration of human DNA in a human cell? Consult your teacher.

Solution. The molar concentration of human DNA in a human diploid cell is as follows:

$\Rightarrow$ Total number of chromosomes $\times 6.023 \times 10^{23}$

$\Rightarrow 46 \times 6.023 \times 10^{23}$

$\Rightarrow 2.77 \times 10^{18}$ Moles

Hence, the molar concentration of DNA in each diploid cell in humans is $2.77 \times 10^{23}$ moles.

Question 5: Do eukaryotic cells have restriction endonucleases? Justify your answer.

Solution. No, eukaryotic cells do not have restriction endonucleases. This is because the DNA of eukaryotes is highly methylated by a modification enzyme, called methylase. Methylation protects the DNA from the activity of restriction enzymes . These enzymes are present in prokaryotic cells where they help prevent the invasion of DNA by virus.

Question 6: Besides better aeration and mixing properties, what other advantages do stirred tank bioreactors have over shake flasks?

Solution. The shake flask method is used for a small-scale production of biotechnological products in a laboratory. On the other hand, stirred tank bioreactors are used for a large-scale production of biotechnology products.

Stirred tank bioreactors have several advantages over shake flasks:

(1) Small volumes of culture can be taken out from the reactor for sampling or testing.

(2) It has a foam breaker for regulating the foam.

(3) It has a control system that regulates the temperature and pH.

Question 7: Collect 5 examples of palindromic DNA sequences by consulting your teacher. Better try to create a palindromic sequence by following base-pair rules.

Solution. The palindromic sequence is a certain sequence of the DNA that reads the same whether read from $5^{\prime} \rightarrow 3$ ‘ direction or from $3 \rightarrow 5$ ‘ direction. They are the site for the action of restriction enzymes. Most restriction enzymes are palindromic sequences.

Five examples of palindromic sequences are:

(1)

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(2)

NCERT Solutions for Class 12 Biology Chapter 11 Biotechnology: Principles and Processes PDF Image 5

(3)

NCERT Solutions for Class 12 Biology Chapter 11 Biotechnology: Principles and Processes PDF Image 6

(4)

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(5)

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Question 8: Can you recall meiosis and indicate at what stage a recombinant DNA is made?

Solution. Meiosis is a process that involves the reduction in the amount of genetic material. It is two types, namely meiosis I and meiosis II. During the pachytene stage of prophase I, crossing over of chromosomes takes place where the exchange of segments between non-sister chromatids of homlogous chromosomes takes place. This results in the formation of recombinant DNA.

Question 9: Can you think and answer how a reporter enzyme can be used to monitor transformation of host cells by foreign DNA in addition to a selectable marker?

Solution. A reporter gene can be used to monitor the transformation of host cells by foreign DNA. They act as a selectable marker to determine whether the host cell has taken up the foreign DNA or the foreign gene gets expressed in the cell. The researchers place the reporter gene and the foreign gene in the same DNA construct. Then, this combined DNA construct is inserted in the cell. Here, the reporter gene is used as a selectable marker to find out the successful uptake of genes of interest (foreign genes). An example of reporter genes includes lac Z gene, which encodes a green fluorescent protein in a jelly fish.

Question 10: Describe briefly the followings:

(a) Origin of replication

(b) Bioreactors

(c) Downstream processing

Solution. (a) Origin of replication -Origin of replication is defined as the DNA sequence in a genome from where replication initiates. The initiation of replication can be either unidirectional or bi-directional. A protein complex recognizes the ‘on’ site, unwinds the two strands, and initiates the copying of the DNA.

(b) Bioreactors – Bioreactors are large vessels used for the large-scale production of biotechnology products from raw materials. They provide optimal conditions to obtain the desired product by providing the optimum temperature, $\mathrm{pH}$, vitamin, oxygen, etc. Bioreactors have an oxygen delivery system, a foam control system, a PH, a temperature control system, and a sampling port to obtain a small volume of culture for sampling.

(c) Downstream processing – Downstream processing is a method of separation and purification of foreign gene products after the completion of the biosynthetic stage. The product is subjected to various processes in order to separate and purify the product. After downstream processing, the product is formulated and is passed through various clinical trials for quality control and other tests.

Question 11: Explain briefly

(a) PCR

(b) Restriction enzymes and DNA

(c) Chitinase

Solution. (a) PCR: – Polymerase chain reaction (PCR) is a technique in molecular biology 10 arripmy a gerie or a piece of DNA to obtain its several copies. It is extensively used in the process of gene manipulation. The process involves in-vitro synthesis of sequences using a primer, a template strand, and a thermostable DNA polymerase enzyme obtained from a bacterium, called Thermus aquaticus. The enzyme utilizes building blocks dNTPs (deoxynucleotides) to extend the primer. In the first step, the double stranded DNA molecules are heated to a high temperature so that the two strands separate into a single stranded DNA molecule. This process is called denaturation. Then, this ssDNA molecule is used as a template strand for the synthesis of a new strand by the DNA polymerase enzyme and this process is called annealing, which results in the duplication of the original DNA molecule. This process is repeated over several cycles to obtain multiple copies of the rDNA fragment.

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(b) Restriction enzymes are molecular scissors used in molecular biology for cutting DNA sequences from a specific site. It plays an important role in gene manipulation. The enzymes recognize a specific six-box pair sequence known as the recognition sequence and cut the sequence at a specific site. For example, the recognition site for enzyme ECORI is as follows:



Restriction enzyme are categorized into two types –

(i) Exonuclease – It is a type of restriction enzyme that removes the nucleotide from either 5 ‘ or 3 ends of the DNA molecule.

(ii) Endonuclease − It is a type of restriction enzyme that makes a cut within the DNA at a specific site. This enzyme acts as an important tool in genetic engineering. It is commonly used to make a cut in the sequence to obtain DNA fragments with sticky ends, which are later joined by enzyme DNA ligase.

(c) Chitinase – Chitinase is a class of enzymes used for the degradation of chitin, which forms a major component of the fungal cell wall. Therefore, to isolate the DNA enclosed within the cell membrane of the fungus, enzyme chitinase is used to break the cell for releasing its genetic material.

Question 12: Discuss with your teacher and find out how to distinguish between

(a) Plasmid DNA and chromosomal DNA

(b) RNA and DNA

(c) Exonuclease and Endonuclease

Solution. (a) Plasmid DNA and chromosomal DNA



(b) RNA and DNA





(c) Exonuclease and Endonuclease



Also Read,

Download Class 12 Chemistry Notes Free.

Download Class 12 Biology Book Chapterwise Free.

Download Class 12 Biology Exemplar Chapterwise Free.

If you have any Confusion related to NCERT Solutions for Class 12 Biology Chapter 11 Biotechnology: Principles and Processes PDF then feel free to ask in the comments section down below.

To watch Free Learning Videos on Class 12 Biology by Kota’s top Doctor Faculties Install the eSaral App
NCERT Solutions For Class 11 Biology Chapter 12
NCERT Solutions for Class 11 Biology chapter 12 Mineral Nutrition PDF – eSaral

NCERT Solutions for Class 11 Biology chapter 12 Mineral Nutrition PDF

Hey, are you a class 11 student and looking for ways to download NCERT Solutions for Class 11 Biology chapter 12 Mineral Nutrition PDF? If yes. Then read this post till the end.

In this article, we have listed NCERT Solutions for Class 11 Biology chapter 12 Mineral Nutrition in PDF that are prepared by Kota’s top Doctor’s Faculties by keeping Simplicity in mind.

If you want to learn and understand class 11 Biology chapter 12 “Mineral Nutrition” in an easy way then you can use these solutions PDF.

NCERT Solutions helps students to Practice important concepts of subjects easily. Class 11 Biology solutions provide detailed explanations of all the NCERT questions that students can use to clear their doubts instantly.

If you want to score high in your class 11 Biology Exam then it is very important for you to have a good knowledge of all the important topics, so to learn and practice those topics you can use eSaral NCERT Solutions.

In this article, we have listed NCERT Solutions for Class 11 Biology chapter 12 Mineral Nutrition PDF that you can download to start your preparations anytime.

So, without wasting more time Let’s start.

Download NCERT Solutions for Class 11 Biology chapter 12 Mineral Nutrition PDF



Question $1:$ ‘All elements that are present in a plant need not be essential to its survival’. Comment.

Solution. Plants tend to absorb different kinds of nutrients from soil. However, a nutrient is inessential for a plant if it is not involved in the plant’s physiology and metabolism. For example, plants growing near radioactive sites tend to accumulate radioactive metals. Similarly, gold and selenium get accumulated in plants growing near mining sites. However, this does not mean that radioactive metals, gold, or selenium are sential nutrients for the survival of these plants

Question 2: Why is purification of water and nutrient salts so important in studies involving mineral nutrition using hydroponics?

Solution. Hydroponics is the art of growing plants in a nutrient solution in the absence of soil. Since the plant roots are exposed to a limited amount of the solution, there are chances that the concentrations of oxygen and other minerals in the plant roots would reduce. Therefore, in studies involving mineral nutrition using hydroponics, purification of water and nutrient salts is essential so as to maintain an optimum growth of th plants.

Question $3:$ Explain with examples: macronutrients, micronutrients, beneficial nutrients, toxic elements and essential elements

Solution. Macronutrients: They are the nutrients required by plants in large amounts. They are present in plant tissues in amounts more than 10 mmole $\mathrm{kg}^{-1}$ of dry matter. Examples include hydrogen, oxygen, and nitrogen.

Micronutrients: They are also called trace elements and are present in plant bodies in very small amounts, i.e., amounts less than 10 mmole $\mathrm{kg}^{-1}$ of dry matter. Examples include cobalt, manganese, zinc, etc.

Beneficial nutrients: They are plant nutrients that may not be essential, but are beneficial to plants. Sodium, silicon, cobalt and selenium are beneficial to higher plants.

Toxic elements: Micronutrients are required by plants in small quantities. An excess of these nutrients may induce toxicity in plants. For example, when manganese is present in large amounts, it induces deficiencies of iron, magnesium, and calcium by interfering with their metabolism.

Essential elements: These elements are absolutely necessary for plant growth and reproduction. The requirement of these elements is specific and non-replaceable. They are further classified as macro and micro-nutrients.

Question 4: Name at least five different deficiency symptoms in plants. Describe them and correlate them with the concerned mineral deficiency.

Solution. The five main deficiency symptoms arising in plants are:

– Chlorosis

– Necrosis

– Inhibition of cell division

– Delayed flowering

– Stunted plant growth

Chlorosis or loss of chlorophyll leads to the yellowing of leaves. It is caused by the deficiencies of nitrogen, potassium, magnesium, sulphur, iron, manganese, zinc, and molybdenum.

Necrosis is the death of plant tissues as a result of the deficiencies of calcium, magnesium, copper, and potassium.

Inhibition of cell division is caused by the deficiencies of nitrogen, potassium, sulphur, and molybdenum.

Delayed flowering is caused by the deficiencies of nitrogen, sulphur, and molybdenum.

Stunted plant growth is a result of the deficiencies of copper and sulphur.

Question 5: If a plant shows a symptom which could develop due to deficiency of more than

one nutrient, how would you find out experimentally, the real deficient mineral element?


Solution. In plants, the deficiency of a nutrient can cause multiple symptoms. For example, the deficiency of nitrogen causes chlorosis and delayed flowering.

In a similar way, the deficiency of a nutrient can cause the same symptom as that caused by the deficiency of another nutrient. For example, necrosis is caused by the deficiency of calcium, magnesium, copper, and potassium.

Another point to be considered is that different plants respond in different ways to the deficiency of the same nutrient.

Hence, to identify the nutrient deficient in a plant, all the symptoms developed in its different parts must be studied and compared with the available standard tables.

Question 6: Why is that in certain plants deficiency symptoms appear first in younger parts of the plant while in others they do so in mature organs?

Solution. Deficiency symptoms are morphological changes in plants, indicating nutrient deficiency. Deficiency symptoms vary from one element to another. The plant part in which a deficiency symptom occurs depends on the mobility of the deficient element in the plant. Elements such as nitrogen, potassium, and magnesium are highly mobile. These elements move from the mature organs to the younger parts of a plant. Therefore, the symptoms for the deficiencies of these elements first appear in the older parts of the plant. Elements such as calcium and sulphur are relatively immobile. These elements are not transported ol of the older parts of a plant. Therefore, the symptoms for the deficiencies of these elements first appear in the younger parts of the plant.

Question 7: How are the minerals absorbed by the plants?

Solution. The absorption of soil nutrients by the roots of plants occurs in two main phases – apoplast and symplast.

During the initial phase or apoplast, there is a rapid uptake of nutrients from the soil into the free spaces of plant cells. This process is passive and it usually occurs through trans-membrane proteins and ion-channels.

In the second phase or symplast, the ions are taken slowly into the inner spaces of the cells. This pathway generally involves the expenditure of energy in the form of ATP.

Question 8: What are the conditions necessary for fixation of atmospheric nitrogen by Rhizobium. What is their role in $\mathrm{N}_{2}$-fixation?

Solution. Rhizobium is a symbiotic bacterium present in the root nodules of leguminous plants. The basic requirements for Rhizobium to carry out nitrogen fixation are as follows:

(a) Presence of the enzyme nitrogenase

(b) Presence of leg-haemoglobin

(c) Non-haem iron protein, ferrodoxin as the electron-carrier

(d) Constant supply of ATP

(e) $\mathrm{Mg}^{2+}$ ions as co-factors

Rhizobium contains the enzyme nitrogenase – a Mo-Fe protein – that helps in the conversion of atmospheric free nitrogen into ammonia.

The reaction is as follows:

$\mathrm{N}_{2}+8 \mathrm{e}^{-}+8 \mathrm{H}^{+}+16 \mathrm{ATP} \rightarrow 2 \mathrm{NH}_{3}+\mathrm{H}_{2}+16 \mathrm{ADP}+16 \mathrm{Pi}$

The Rhizobium bacteria live as aerobes under free-living conditions, but require anaerobic conditions during nitrogen fixation. This is because the enzyme nitrogenase is highly sensitive to molecular oxygen. The nodules contain leg-haemoglobin, which protects nitrogenase from oxygen.

Question 9: What are the steps involved in formation of a root nodule?

Solution. Multiple interactions are involved in the formation of root nodules. The Rhizobium bacteria divide and form colonies. These get attached to the root hairs and epidermal cells. The root hairs get curled and are invaded by the bacteria. This invasion is followed by the formation of an infection thread that carries the bacteria into the cortex of the root. The bacteria get modified into rod-shaped hacterniclec A. the nericurle underan division leadina to the formation of root nodules. The nodules finally get connected with the vascular tissues of the roots for nutrient exchange.

Question 10: Which of the following statements are true? If false, correct them:

(a) Boron deficiency leads to stout axis.

(b) Every mineral element that is present in a cell is needed by the cell.

(c) Nitronen as a nutrient element is hiahly immobile in the nlants

(d) It is very easy to establish the essentiality of micronutrients because they are required only in trace quantities.

Solution. (a) True

(b) All the mineral elements present in a cell are not needed by the cell. For example, plants growing near radioactive mining sites tend to accumulate large amounts of radioactive compounds. These compounds are not essential for the plants.

(c) Nitrogen as a nutrient element is highly mobile in plants. It can be mobilised from the old and mature parts of a plant to its younger parts.

(d) True

Also Read,

Class 11 Chemistry Notes Free pdf Download.

Class 11 Biology Book Chapterwise Free pdf Download.

Class 11 Biology Exemplar Chapterwise Free pdf Download.

If you have any Confusion related to NCERT Solutions for Class 11 Biology chapter 12 Mineral Nutrition PDF then feel free to ask in the comments section down below.

To watch Free Learning Videos on Class 11 Biology by Kota’s top Doctor’s Faculties Install the eSaral App