Class 12th Biology 2012 Set3 Delhi Board Paper Solution
Change Subject
Physics
Biology
Chemistry
Mathematics
Accountancy
Change Question
Q1 Mention the difference between spermiogenesis and spermiation.
Q2 A garden pea plant (A) produced inflated yellow pod, and anothe...
Q3 What is an interaction called when an orchid grows on a mango p...
Q4 Write the names of two semi-dwarf and high yiuelding rice varie...
Q5 Write what do phytophagous insects feed on.
Q6 Mention the unique feature with respect to flowering and fruiti...
Q7 How does smoking tobacco in human lead to oxygen deficiency in ...
Q8 State the significance of biochemical similarities amongst dive...
Q9 Explain the work carried out by Cohen and Boyer that contribute...
Q10 (a) State the difference between meiocyte and gamete with re...
Q11 Draw a neat labeled sketch of a replicating fork of DNA.
Q12 Some organisms suspend their metabolic activities to survive in...
Q13 (a) State the role of DNA ligase in biotechnology. (b) ...
Q14 Where is sporopollenin present in plants? State its significanc...
Q15 Mention the importance of Lactic acid bacteria to humans other ...
Q16 (a) Name the Protozoan parasite that causes amoebic dysenter...
Q17 (a) Highlight the role of thymus as a lymphoid organ. (b...
Q18 Why do clown fish and sea anemone pair up? What is this relatio...
Q19 (a) Construct a complete transcription unit with promotor and t...
Q20 Write the function of each of the following: (a) Seminal v...
Q21 Study a part of the life cycle of malarial parasite given below...
Q22 Draw a schematic sketch of pBR 322 plasmid and label the follow...
Q23 State the theory of Biogenesis. How does Miller’s experiment su...
Q24 Given below is the representation of amino acid composition not...
Q25 (a) Why are the colourful polysterene and plastic packagings us...
Q26 Name the genes responsible for making Bt cotton plants resistan...
Q27 Name the two different categories of microbes naturally occurri...
Q28 Explain the carbon cycle with the help of a simplified model. <...
Q29 The following is the illustration of the sequence of ovarian ev...
Q30 Name the scientists who proved experimentally that DNA is the g...
Question 9
Explain the work carried out by Cohen and Boyer that contributed immensely in biotechnology.
Answer
Stanley Cohen and Herbert Boyer conducted one of the first genetic engineering experiments. They invented the technique of DNA cloning. Cohen developed a method of removing plasmids from the cell and then reinserting them in other cells. Combining this process with that of DNA splicing enabled Boyer and Cohen to recombine segments of DNA in desired configurations and insert the DNA in bacterial cells, which could then act as manufacturing plants for specific proteins. Stanley Cohen and Herbert Boyer accomplished this in 1972.
Popular Questions of Class 12th biology
Recently Viewed Questions of Class 12th biology
Q:- Explain in brief the role of animal husbandry in human welfare.
Q:- In which way has the study of biology helped us to control infectious diseases?
Q:- Group the following as nitrogenous bases and nucleosides: Adenine, Cytidine, Thymine, Guanosine, Uracil and Cytosine.
Q:- Name the parts of an angiosperm flower in which development of male and female gametophyte take place.
Q:- The second trophic level in a lake is- (a) Phytoplankton (b) Zooplankton (c) Benthos (d) Fishes
Q:- Explain antibiotic resistance observed in bacteria in light of Darwinian selection theory.
Q:- If one can induce parthenocarpy through the application of growth substances, which fruits would you select to induce parthenocarpy and why?
Q:- Three water samples namely river water, untreated sewage water and secondary effluent discharged from a sewage treatment plant were subjected to BOD test. The samples were labelled A, B and C; but the laboratory attendant did not note which was which. The BOD values of the three samples A, B and C were recorded as 20mg/L, 8mg/L and 400mg/L, respectively. Which sample of the water is most polluted? Can you assign the correct label to each assuming the river water is relatively clean?
Q:- Removal of gonads cannot be considered as a contraceptive option. Why?
Q:- Using various resources such as your school library or the internet and discussions with your teacher, trace the evolutionary stages of any one animal say horse.