Biotechnology and its Applications — BIOLOGY STD 12 Science — Question

Read the following and answer any four questions from 6(i) to 6(v) given below:

Rama lives in a society where a robbery occurred last night. Robbers came into the flat and murdered the old lady residing there. Police came and restricted the entry into the flat. They took samples from the room, where the dead body was found. While examining, they found that there is some blood and tissue in the nails of old lady. According to their observation, police filtered out their inspection to three suspects viz. servant, cook and milkman. Finally after two days of robbery, police caught the criminal. It was the old lady's cook. Rama was amazed to see that how quickly police completed and shut the case. She asked the inspector that how they did it? The police man told her that it become possible due to the sample collected from the victim, that lead them to the criminal. TI1e sample taken from nail scraping was amplified using PCR and then tested.

1. What technique was used by the police to identify the criminal?

1. DNA fingerprinting.
2. Gel electrophoresis.
3. Molecular diagnosis.
4. Clonning.

2. In PCR, the temperature used to denature the DNA is about:

1. 76º
2. 25º
3. 95º
4. 40º

3. Which of the following statements regarding PCR is correct?

1. Taq polymerase, which is isolated from bacterium Thermus aquaticus is stable at low temperature only.
2. With the help of DNA ligase, the complementary sticky ends of the DNA are joined to produce a rDNA.
3. Since the sequence of primers are complementary to 5' end of the template DNA, they anneal to it.
4. DNA purified from the cell is precipitated by adding hot ethanol.

4. Taq polymerase synthesises DNA region between the primers using:

1. Mg²⁺
2. dNTPs
3. DNA ligase
4. Both (a) and (b).

5. Given below are steps of polymerase chain reaction.

Select the option that correctly mention the sequence in which they occur.

1. (ii) → (iii) → (i)
2. (i) → (ii) → (iii)
3. (iii) → (i) → (ii)
4. (ii) → (i) → (iii)

Read the following and answer any four questions from (i) to (v) given below:
Enzymes are best known for their ability to catalise biochemical reactions without undergoing any change. A large number of enzymes are being used in biotechnological industry. Most of them are obtained from microbes. Proteases degrade proteins and polypeptides. Most of the commercially applicable proteases are alkaline and are biosynthesised mainly by bacteria such as Pseudomonas, Bacillus and some fungi like, Aspergillus. These enzymes are used in clearing beer, softening of bread and meat, degumming of silk, etc. Alkaline serine proteases have the largest applications in bio-industry. Alkaline proteases have shown their capability to work under high pH, temperature and in presence of inhibitory compounds. Another important group of enzymes is amylases. Amylolytic enzymes act on starch. These are obtained from Aspergillus, Rhizopus and Bacillus sp. These are used in softening and sweetening of bread, production of alcoholic beverages from starchy materials, clearing of turbidity in juices caused by starch, etc.

1. Polypeptides are degraded by:

1. Amylases.
2. Proteases.
3. Pectinases.
4. Lipases.

2. Amylolytic enzymes are not obtained from:

1. Aspergillus.
2. Aspergillus.
3. Mucor.
4. Bacillus.

3. Clearing of turbidity in juices caused by starch is achieved by:

1. Amylases.
2. Proteases.
3. Rennet.
4. Both (a) and (b).

4. Select the incorrect option from the following.

1. Enzymes are proteinaceous substances.
2. Enzymes are substrate specific.
3. Enzymes are large sized molecules.
4. Microbial enzymes can work only in normal temperature and pH.

5. A farmer harvests corns and prepares corn starch. He wants to prepare some corn syrup from this. for the conversion he needs to use enzyme ______.

1. Amylase.
2. Glucoamylases.
3. Glucoisomerases.
4. All of these.

Read the following text carefully and answer the questions that follow:
A lymphocyte isa type of white blood cell. Enlarge. Blood cells. Blood contains many types of cells: white blood cells (monocytes, lymphocytes, neutrophils, eosinophils, basophils, and macrophages), red blood cells (erythrocytes), and platelets. Blood circulates through the body in the arteries and veins.

i. Why are the antigens called antibody-generating chemicals? (1)
ii. Which two types of lymphocytes are involved in immunity? (1)
iii. Give the common site of formation of two types of lymphocytes. (2)
OR
What is the site of differentiation of two types of lymphocytes? (2)

Read the following and answer any four questions from (i) to (v) given below:
The DNA, which is transferred from one organism into another by joining it with the vehicle DNA is called passenger or foreign DNA. Generally three types of passenger DNAs are used. These are complementary DNA (cDNA), synthetic DNA (sDNA) and random DNA. Complementary DNA (cDNA) is synthesized on RNA template (usually mRNA) with the help of reverse transcriptase. Synthetic DNA (sDNA) is synthesized on DNA template or without a template. Random DNA are small fragments fanned by breaking a chromosome of an organism in the presence of restriction endonucleases.

1. Reverse transcriptase enzyme was discovered by:

1. Temin and Baltimore.
2. Cohen and Boyer.
3. Arber and Nathan.
4. Paul Berg.

2. During cDNA formation, what would happen if DNA formed by reverse transcriptase is not treated with the alkali?

1. cDNA will not be digested.
2. mRNA will not be digested.
3. Hydrogen bonds will not form between base pairs.
4. rnRNA will not be formed.

3. Enzyme that helps in the formation of double stranded cDNA is:

1. DNA synthetase
2. Ligase
3. DNA polymerase
4. Helicase.

4. DNA polymerase can be obtained form:

1. Retrovirus.
2. Agrobacteriurn.
3. Tobacco mosaic virus.
4. Thermus aquaticus.

5. DNA synthesised without a template is referred to as:

1. Complementary DNA.
2. Random DNA.
3. Synthetic DNA.
4. Z-DNA..

Read the following and answer any four questions from (i) to (v) given below:

In prokaryotes, DNA is circular and present in the cytoplasm but in eukaryotes, DNA is linear and mainly confined to the nucleus. DNA or deoxyribonucleic acid is a long polymer of nucleotides. In 1953, the first correct double-helical structure of DNA was worked out by Watson and Crick. Based on the X-ray diffraction data produced by Maurice Wilkins and Rosalind Franklin. It is composed of three components, i.e., A phosphate group, a deoxyribose sugar and a nitrogenous base. Different forms of DNA are B-DNA, Z-DNA, A-DNA, C-DNA and D-DNA.

1. Name the linkage present between the nitrogen base and pentose sugar in DNA.

1. Phosphodiester bond
2. Phosphodiester bond
3. Hydrogen bond
4. None of these

2. The double helix structure of DNA was proposed by.

1. James Watson and Francis Crick.
2. Earwin Chargaff
3. Federick Griffith
4. Hershey and Chase.

3. The double chain of B-DNA is coiled in a helical fashion. The spiral twisting of B-DNA duplex produces.

1. Right and left part.
2. Major and minor grooves.
3. Upper and lower side.
4. Linear and circular part.

4. Assertion: The two strands of DNA helix have uniform distance between them.

Reason: A large sized purine always paired opposite to a small sized pyrimidine.

1. Both assertion and reason are true and reason is the correct explanation of assertion.
2. Both assertion and reason are true but reason is not the correct explanation of assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

5. Which of the following describes the structure of B-DNA?

S.no	Polynudeotide chains	Polynudeotide chains
(a)	Parallel	5
(b)	Anti-parallel	10
(c)	Parallel	15
(d)	Anti-parallel	20

Read the following and answer any four questions from (i) to (v) given below:
IUCN maintains a Red Data Book or Red List which is a catalogue of taxa facing risk of extinction. The IUCN Red List (2004) documents the extinction of 784 species in the last 500 years. Some examples of recent extinctions include the dodo, quagga, thylacine and Steller's sea cow. The last twenty years alone have witnessed the disappearance of 27 species. Red List has eight categories of species.

1. Dodo, an extinct taxon, belongs to which country?

1. Mauritius
2. Africa
3. Australia
4. Russia

2. To which of the following categories of IUCN, Berberis nilghiriensis belongs?

1. Extinct.
2. Extinct in wild.
3. Endangered.
4. Critically endangered.

3. Steller's sea cow and passenger pigeon became extinct due to:

1. Alien species invasion.
2. Over-exploitation.
3. Coextinctions.
4. Intensive agriculture.

4. Bali, Javan and Caspian are:

1. Species of tiger.
2. Species of cheetah.
3. Subspecies of cheetah.
4. Subspecies of tiger.

5. Select the correct term for the following definitions (i, ii, iii, iv).

• The taxon is liable to become extinct if not allowed to realise its full biotic potential by providing protection from exotic species/ human exploitation/habitat deterioration/depletion of food.
• The taxon has been completely eliminated or died out from earth, e.g., Dodo.
• The taxon is facing a high risk of extinction in the wild in the near future due to decrease in its habitat, excessive predation or poaching.
• They are species with naturally small populations, either localised or thinly scattered, which are always at risk from pests/ pathogens/ predators/ exotic species.

	(i)	(ii)	(iii)	(iv)
(a)	Threatened	Extinct	Endangered	Rare
(b)	Endangered	Extinct	Threatened	Rare
(c)	Extinct	Rare	Threatened	Endangered
(d)	Threatened	Extinct	Rare	Endangered

Read the following and answer any four questions from (i) to (v) given below:

Gene manipulation is a fast emerging science. It started with development of recombinant DNA molecule. It is named variously as DNA manipulation biotechnology, recombinant DNA technology and genetic engineering. This technology, that mostly involves cutting and pasting of desired DNA fragments, is based on two important discoveries in bacteria, i.e., presence of plasmid in bacteria and restriction endonucleases. Paul Berg was able to introduce a gene ofSV-40 into a bacterium. The science of recombinant DNA technology took birth when Cohen and Boyer (1973) were able to introduce a piece of gene containing foreign DNA into plasmid of E.coli.

1. Biotechnology is also known as:

1. DNA manipulation biotechnology.
2. Recombinant DNA technology.
3. Genetic engineering.
4. All of these.

2. A bacterial plasmid is a/ an,

1. Extra chromosomal material that do not replicate.
2. Extra chromosomal material that undergo replication with or without chromosomal DNA.
3. Tubular structures that help in conjugation.
4. Bristle like solid structure that help in adhesion.

3.  Father of genetic engineering is:

1. Paul Berg.
2. Arber.
3. Nathan.
4. Smith.

4. Which of the following is used by Paul Berg to introduce a gene of SV-40 in a bacterium?

1. E. coli.
2. cos-plasmids.
3. Lambda phage.
4. None of these.

5.  Read the given statements and select the correct option.

Assertion: Biotechnology started with the development of recombinant DNA molecule.

Reason: Biotechnology mostly involves cutting and pasting of desired DNA fragments.

1. Both assertion and reason are true and reason is the correct explanation of assertion.
2. Both assertion and reason are true but reason is not the correct explanation of assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

How interesingly Gene is amplified by using PCR? Explain with diagram.

Read the following and answer any four questions from (i) to (v) given below:
In recombinant DNA technology, the fragments of DNA generated after cutting the DNA by restriction enzymes are separated according to their size or length by gel electrophoresis. Gel electrophoresis is performed in a gel matrix so that molecules of similar electric charges can be separated on the basis of size. Most commonly used matrix in gel electrophoresis is agarose. The fragments are separated under the influence of electric field. The separated DNA fragments can be seen only after staining the DNA with compound known as ethidium bromide (EtBr) followed by exposure to UV radiation as bright orange band.

1. Gel electrophoresis is used for the separation of

1. DNA only.
2. DNA and RNA only.
3. DNA and proteins only.
4. DNA, RNA and proteins.

2. Most commonly used matrix is _____ which is a ______ extracted from _______.

1. (i) agarose (ii) polysaccharide (iii) sea weed
2. (i) agarose (ii) protein (iii) sea weed
3. (i) EtBr (ii) polysaccharide (iii) sea weed
4. (i) EtBr (ii) protein (iii) bacteria

3. A DNA molecule was treated with a restriction endonuclease and three fragments of size (i) 426kb, (ii) 129kb and (iii) 46kb were obtained. Identify the order in which these bands will arrange themselves in the gel plate after gel electrophoresis is completed. (Assuming that negative part of electrode is towards the well)

1. (iii) → (ii) → (i)
2. (i) → (ii) → (iii)
3. (i) → (iii) → (ii)
4. (iii) → (i) → (ii)

4. Which of the following statements regarding gel electrophoresis is incorrect?

1. Separated DNA fragments can be seen only after staining DNA with EtBr.
2. DNA fragments are separated according to their size.
3. Under the influence of electric field, positively charged molecules move towards the anode and negatively charged molecules move towards the cathode.
4. None of these.

5. The factor that will not affect the rate of DNA migration in gel electrophoresis is:

1. Size of DNA molecule.
2. Concentration of DNA.
3. Voltage supplied.
4. Concentration of the gel.

Read the following and answer any four questions from S(i) to S(v) given below:

Rajat is a student of biotechnology. His professor tells him that for transformation with recombinant DNA the bacterial cells must be made capable of taking up DNA as DNA do not pass through membrane. While doing experiment in the lab, Rajat noticed that bacterial cells were not taking up the foreign DNA even after treating it with sodium ion. He asked his professor, the reason behind this. His professor explained that he should check the valency and charge of the ion that he is using for the treatment.

1. It is difficult for DNA to pass through the membrane as

1. It is a hydrophilic molecule.
2. It is a hydrophobic molecule.
3. It is a circular molecule.
4. It changes its shape when it comes in contact with host cell.

2. What type of ions are used for DNA mediated gene transfers?

1. Divalent anions.
2. Divalent cations.
3. Monovalent cations.
4. Monovalent anions.

3. rDNA stands for,

1. reduced DNA
2. red DNA
3. recombinant DNA
4. related DNA.

4. Which of the following statements with regard to DNA is correct?

1. DNA is a positively charged molecule having two polynucleotide chains.
2. Nitrogen bases of two polynucleotide chain form complementary pairs, i.e., A opposite G and T opposite C.
3. Backbone of DNA chain is built up of alternate deoxyribose sugar and phosphate group.
4. Both (a) and (c)

5. Assertion: Competent host is essential for transformation with rDNA.

Reason: Transfer of DNA in a prokaryotic cell is called transfection.

1. Both assertion and reason are true and reason is the correct explanation of assertion.
2. Both assertion and reason are true but reason is not the correct explanation of assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.