CBSE Questions for Class 12 Medical Biology Biotechnology: Principles And Processes Quiz 10 - MCQExams.com

$$\textbf{Correct answer: D}$$  

$$\textbf{Option (A):}$$  

$$\bullet$$ The restriction enzyme recognition sites are palindromic sequences. Palindromic sequences read the same on the two strands of DNA when read from the opposite direction.

$$\bullet$$ If the sequence is read from the opposite direction then the base sequence will be the same in the two strands. 

$$\bullet$$ The base sequence of one of the strands is given here as CGGCTT. The complementary sequence will be GCCGAA. 

$$\bullet$$ These two sequences do not read the same when read from the opposite direction. Hence, these are not palindromic. 

$$\textbf{Option (B):}$$  

$$\bullet$$ The base sequence of one of the strands is given as GGGCCA. The complementary sequence will be CCCGGT. 

$$\bullet$$ If read from the opposite direction, the base sequence of the two strands is completely different. 

$$\textbf{Option (C):}$$  

$$\bullet$$ The base sequence of one of the two strands is given here as GTAATG. The base sequence in the complementary strand will be CATTAC. 

$$\bullet$$ These two are not palindromic sequences even though they separately represent a palindrome.

$$\textbf{Option (D):}$$  

$$\bullet$$ The base sequence of one strand is given here as GTCGAC. The complementary base sequence will be CAGCTG. 

$$\bullet$$ If the complementary sequence is read from the opposite direction, it will be GTCGAC which is the same as the given sequence. This region shows a palindromic sequence. 

$$\bullet$$ Therefore, this sequence can act like the restriction enzyme recognition site. 

Hence, the correct answer is option (D).

• DNA is a long polymer of deoxyribonucleotides. The length of DNA is usually defined as the number of nucleotides(or a pair of nucleotide referred to as base pairs. It is a characteristic of the organism.
• (A)Bacteriophage λ -(iv) 48502 bp(base pairs) -The virus which causes diseases in bacteria are called bacteriophage. The bacteriophage λ causes diseases in E.coli bacteria. Its DNA is made up of 48502 bp.
• (B)E.coli - (iii) $$4.6\times 10^6$$ bp- E. coli, is a Gram-negative, facultatively anaerobic, rod-shaped, coliform bacterium of the genus Escherichia that is commonly found in the lower intestine of warm-blooded organisms. Its DNA is made up of  $$4.6\times 10^6$$ bp.
• (C)The human genome - (ii) $$3.3\times 10^9$$ bp-Human DNA is composed of  $$3.3\times 10^9$$ bp.
• (D)ϕ×174 - (i)5386 nucleotide-Bacteriophage ϕ×174 is a single-stranded DNA virus that infects Escherichia coli, and the first DNA-based genome to be sequenced. Its DNA is composed of 5386 nucleotides.
• So, the correct answer is 'A-(iv), B-(iii), C-(ii), D-(i)'.

• A chemical test for starch(polysaccharide) is to add an iodine solution (yellow/brown) and look for a color change. In the presence of starch, iodine turns into a  blue/black colour. It is possible to distinguish starch from glucose (and other carbohydrates) using this iodine solution test.
• Hence Polysaccharides can be tested by Iodine.
• So, the correct answer is 'Iodine'.

• Nucleotides are compound consisting of a nucleoside linked to a phosphate group. Nucleotides form the basic structural unit of nucleic acids such as DNA and RNA. For example, Adenylic acid, Guanylic acid, Thymidylic acid, and Cytidilic acid and 5'uridylic acid.
• Hence Adenylic acid, Cytidilic acid, Guanylic acid are all Nucleotides.
• So, the correct answer is 'Adenylic acid, Cytidilic acid, Guanylic acid'.

• Biolistics (gene gun), Microinjection and Electroporation are direct methods of gene transfer.
  
• Agrobacterium tumefaciens is a gram-negative soil bacterium, which can cause crown gall tumors at wound sites of infected dicotyledonous plants.
• Agrobacterium tumefaciens acts as a vector for the transfer of genetic material hence it cannot be used for direct gene transfer.
• Hence Agrobacterium tumefaciens cannot be used for direct gene transfer.
• So, the correct answer is 'Agrobacterium tumefaciens'.

• In gene therapy trials, the retrovirus is used as a vector to treat X-linked severe combined immunodeficiency (X-SCID) represent the most successful application of gene therapy. 
• The gene codes for enzyme ADA is introduced into the vector (retrovirus). The lymphocyte cells of the patient are extracted and cultured and infected by the vector. 
• The vector makes DNA copies of its RNA which is then inserted into the chromosome of the host cell (lymphocytes). Then these cells are injected into the patient's bone marrow. Thus, the lymphocytes produced by these bone marrow stem cells have a fully functional ADA gene.

• Southern blotting combines the transfer of electrophoresis-separated DNA fragments to a filter membrane and subsequent fragment detection by probe hybridization. 
• Western is used for the separation and analysis of proteins. 
• Northern blotting is used for the separation and analysis of RNA. 
• Eastern blotting is the technique used to detect post-translational modifications of a protein like the addition of a small lipid or sugar molecule in glycoproteins or lipoproteins.
  
• Gene transfer is a technique to transfer genes efficiently and stably into another cell or organism to alter their phenotype.
  

• Taq polymerase is a thermostable DNA polymerase that is used in the polymerase chain reaction. 
• It was named after the thermophilic bacterium Thermus aquaticus from which it was isolated by Thomas D. Brock in 1965. 
• The polymerase enzyme is stable at a high range of temperature.

• A DNA sequence whose 5'-to-3' sequence is identical on each DNA strand is known as a palindromic sequence, whereas the restriction enzyme is the type of enzyme which cuts DNA at a specific sequence in both the strands.  

• Agrobacterium tumefaciens is the agent of crown gall disease (the formation of tumors) in eudicots. 
• It is a rod-shaped, gram-negative soil bacterium. 
• To be virulent, the bacterium must contain a tumor-inducing plasmid (Ti plasmid or pTi), of 200 kb, which contains the T - DNA and all the genes necessary to transfer it to the plant cell. 

• Adenosine monophosphate (AMP) is a nucleotide that consists of three main structures: the nitrogenous base i.e. adenine, the ribose sugar, and a  phosphate group bound to ribose.
• In ADP there are two phosphate while in ATP there are three phosphate groups attached to ribose. Thus, the molecular weight of ATP is more than ADP which in turn have higher molecular weight than AMP.
• RNA is a linear polymer of nucleotides (ATP, CTP, UTP, and GTP) linked by a ribose-phosphate backbone. That means molecular weight of RNA is higher than ATP depending upon the number of nucleotides in RNA chain.
• DNA is also a polymer of nucleotides but DNA is double stranded while RNA is single stranded. This makes molecular weight of DNA higher than that of RNA.
• The arrangement of compounds in ascending order according to their molecular weight is AMP, ADP, ATP, RNA, DNA.

• Polymerase chain reaction (PCR) is a technique used to amplify a single copy or a few copies of a piece of DNA to produce multiple copies of the same sequence. PCR can be used as a diagnostic tool, where a sample of DNA is analyzed for the presence of genetic disease due to mutations.
• ELISA (enzyme-linked immunosorbent assay) is used to detect viral infectious disorder based on antibody-antigen interactions.
• ABO blood grouping is used to determine the blood group of an individual.
• NMR (nuclear magnetic resonance spectroscopy) is used to obtain complete information about the structure, reaction state, and chemical conditions of molecules.