CBSE Class 12 Biology 2024-25: Chapter 10 Biotechnology And Its Applications Competency-Based Questions with Answers; Download Free PDF

Get ready for your CBSE Class 12 Biology exams with our easy guide on Chapter 10: Biotechnology And Its Applications. This chapter is very important, especially with the new exam pattern starting in the 2024-25 school year. The CBSE will include 50% more competency-based questions. These questions ask you to use what you've learned in real-life situations.

In this article, we focus on key questions from Chapter 10: Biotechnology And Its Applications. These questions help you think and solve problems. You’ll find different types of questions, such as multiple-choice, true-false, gap-filling, and short-answer questions. Each question has clear answers to help you understand the concepts better.

To help you study, you can download a free PDF that has all the competency-based questions from Chapter 10: Biotechnology And Its Applications along with their answer keys.

CBSE 12 Biology Chapter 10 : Biotechnology And Its Applications Competency-Based Questions

Q.1 There are two statements given below marked as Assertion (A) and Reason (R). Read the statements and choose the correct option.

Assertion: RNA interference (RNAi) is used to protect plants against nematode infestation.

Reason: RNAi method involves silencing of a specific mRNA by a complementary dsRNA molecule that binds to and prevents translation of the mRNA.

A. A is true but R is false.
B. A is false but R is true.
C. Both A and R are true and R is the correct explanation of A.
D. Both A and R are true and R is not the correct explanation of A.

Answer. C. Both A and R are true and R is the correct explanation of A.

Q.2 Which of the following chemicals will be involved in a step that would come before step 1?

lysozyme, ethanol, ribonuclease, cellulase, protease

A. only lysozyme and ethanol
B. only cellulase, lysozyme and ethanol
C. only lysozyme, ribonuclease, protease, and ethanol
D. all - lysozyme, ethanol, ribonuclease, cellulase, protease

Answer. D. all - lysozyme, ethanol, ribonuclease, cellulase, protease

Q.3 Polymerase chain reaction (PCR) mimics which of the following natural processes?

A. ligation
B. translation
C. replication
D. transformation

Answer. C. replication

Q.4 Which of the following correctly states the purpose of steam in a bioprocessor?

A. helps organisms grow faster
B. adds to the water content
C. maintains sterility
D. (Steam is not required in a bio-processing unit.)

Answer. C. maintains sterility

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Q.5 In which of the following natural processes is recombinant DNA made?

A. prophase in mitosis
B. prophase 1 in meiosis
C. prophase 2 in meiosis
D. (Recombinant DNA cannot be made naturally).

Answer. B. prophase 1 in meiosis

Q.6 Given below are two statements about polymerase chain reactions.

P) It mimics DNA replication that happens in a cell.
Q) It cannot be used to amplify RNA molecules. Which of these is/are TRUE?

A. only P
B. only Q
C. both P and Q
D. neither P nor Q

Answer. A. only P

Q.7 (a) What are transgenic animals?

(b) To produce transgenic animals, the gene of interest is introduced into embryonic stem cells. These stem cells are undifferentiated and the preferred target in the process of developing any transgenic animal. Give a reason why

Answer. (a) Animals that have had their DNA manipulated to possess and express an extra (foreign) gene are transgenic animals.

(b) Since embryonic stem cells are undifferentiated, they have the capability of forming all other cells of the body with their specialised functions and the inserted foreign gene.

Q.8 (a) Give a reason why, although a toxin, Bt toxins are deadly for insects but not for plants producing them.
(b) Describe the steps in which Bt toxins act on insects.

Answer. (a) Bttoxins exists asinactive protoxins when produced by the plant and become active only when they are ingested by insects.

(b) 0.5 marks for each of the following points:

- A plant/part of plant producing bt toxins is ingested by an insect.
- The inactive protoxin form of the bt toxin gets converted into an active form of toxin due to the alkaline pH of the gut which solubilises the crystals.
- The activated toxin binds to the surface of midgut epithelial cells and create pores.
- These pores cause cell swelling and lysis and eventually cause death of the insect.

Q.9 Identify if the following statement is true or false.

Between formation of the dsRNA and silencing of mRNA, the dsRNA needs to undergo an additional step.

Justify if true, and rewrite the correct statement, if false.

Answer. - True [1 mark]

- Justification: Since dsRNA is double stranded, it cannot automatically bind to the mRNA. So the two strands must be separated so that a single stranded RNA is obtained which can bind to the single stranded mRNA, silencing it. [1 mark]

Q.10 (a) What is a disadvantage of the traditional hybridisation procedure?

(b) How has rDNA technology overcome the disadvantage identified in (a)?

Answer. (a) Traditional hybridisation procedures very often lead to inclusion and multiplication of undesirable genes along with the desired genes.

(b) Using rDNA technology, only the desired gene can be introduced into an organism without introducing other undesirable gene.

Q.11 Golden rice is a variety of rice that has been genetically modified to produce a compound called β-carotene, which gets converted to Vitamin A when metabolised in the human body. This was done by introducing the genes coding for three enzymes - 'psy' and 'LCYB' from daffodil and 'crtI' from the soil bacterium Erwinia uredovora.

(a) With the help of a diagram, describe the process by which golden rice can be made.
(b) Name the vector used in the process.
(c) Give a reason why the vector identified in (b) should be used.

Answer. (a) Correct illustration of the process - drawing 3 genes of interest from 2 sources, inserting them into a plasmid cut with the same restriction enzyme, introducing the plasmid into rice embryos/cells [2 marks]

- Step by step description of the process with correct terminology [2 marks]

(b) Ti plasmid

Q.12 Papaya is a widely cultivated crop in several regions. However, its production was limited by papaya ringspot disease which is caused by the Papaya ringspot virus (PRSV). Papaya plants infected by PRSV show symptoms of yellowing, discolouration of leaves and 'ringspots' on the fruit. PRSV belongs to the genus Potyvirus which has a single-stranded RNA as its genetic material.

(a) Explain the step-by-step process to inhibit the viral RNA from surviving in the papaya plants thus creating disease-resistance varieties of papaya.
(b) Name the biotechnological process described in (a) and give a reason why it is the appropriate process to be used in this case.

Answer. (a) 0.5 marks each for the following:

- The viral RNA is isolated and converted to a dsDNA structure.
- The dsDNA so formed is inserted into an appropriate vector (Agrobacterium or viral vector).
- The vectors are then introduced into the host plant where it transcribes the mRNA for this gene.
- Whenever the virusinfectsthe plant and injectsits RNA into the host plant, the host plant transcribes the viral RNA.
- The mRNA produced from the vector binds to the transcribed viral RNA.
- This prevents the viral RNA from being transcribed and therefore survives in the host plant without infecting the plant.

(b) 1 mark each for the following:

- RNAi or RNA interference
- RNAi helps in in-vitro silencing of a gene/set of genes so that they lose their function.

Q.13 Explain why vectors that have restriction site/s within a marker gene are preferred, for recombinant DNA technology.

Answer. 1 mark each for the following:

- When a target gene gets inserted into a marker gene which has a restriction site, it inactivates the production of the marker

- The absence of a characteristic that was coded for by the marker is useful in the detection of cells with the recombinant vectors.

[Accept any other valid answer]

Q.14 Give a reason why:

(a) Transgenic animals are used for the production of biological components of medicines over synthetic industrial production.

(b) In the process of testing for effects of chemicals, transgenic animals are used rather than non-transgenic ones.

Answer. (a) 1 mark for any one correct reason such as:

- Industrial production is expensive when compared to production through transgenic animals.
- The components produced by transgenic animals have the possibility of being as close to the natural product as possible.

(b) Transgenic animals are made that carry genes which make them more sensitive to toxic substances than non-transgenic animals allowing for results in lesser time.

Q.15 Hormones are broadly categorised assteroid hormones and protein hormones. Patients with type 2 diabetes, generally, have to take insulin externally. Researchers across the world believe that if insulin can be given orally it would be ideal as it would closely mimic the movement of natural insulin. Yet, injectable insulin is commonly prescribed by doctors.

What type of a hormone is insulin and why can't it be administered orally?

Answer. 1 mark each for the following:

- Insulin is a protein hormone.
- If taken orally, they will get digested by pepsin and trypsin in the stomach and small intestine into their simpler forms, thereby losing their function.

👉 CBSE Class 12 Study Materials

CBSE Class 12 Syllabus 2024-25	CBSE Class 12 Previous Year Papers
NCERT Books For Class 12 Books	NCERT Class 12 Solutions
CBSE Class 12 Full Study Material	CBSE Class 12 Sample Paper 2024-25