\n| Tortoise<\/td>\n | 100 – 150 years<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Question 5.
\nThe DNA fragments can be separated using get electrophoresis.
\na) Name the gel used in this technique.
\nb) Write the name of technique used to remove the DNA from the gel.
\nAnswer:
\na) Agarose
\nb) Elution<\/p>\n Question 6.
\nObserve the following figure:
\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2019\/01\/Plus-Two-Botany-Previous-Year-Question-Paper-March-2018-1.png\")
\na) Identify the figure
\nb) What does (i) tetR<\/sup> (ii) rop (iii) ori denote?
\nAnswer:
\na) Cloning vector – pBr322
\nb) i) tetR<\/sup> – tetracycline resistant gene
\nii) rop – Gene codes for proteins involved in the replication of plasmid
\niii) ori – Orgin of replication<\/p>\nQuestion 7.
\nSynergids have special cellular thickening at micropylar tip. Write the name and function of this structure.
\nAnswer:<\/p>\n \n- Filiform apparatus<\/li>\n
- It guides pollen tube into synergid<\/li>\n<\/ul>\n
Question 8.
\nControlled breeding experiments can be carried out using artificial insemination. What are the advantages of this process?
\nAnswer:
\nThe semen is collected from the male partner and injected into the reproductive tract of selected female. The collected semen can be stored in freezing state and used at later date.<\/p>\n Question 9.
\nBio-fortification is a practical approach to improve the public health. Name any four such crops released by IARI.
\nAnswer:
\nVitamin A enriched carrot and spinach
\nProtien enriched beans – lablab<\/p>\n Question 10.
\nThe products of ecosystem processes are named as ecosystem services. List out any four such services.
\nAnswer:<\/p>\n \n- Ecosystems purify air and water<\/li>\n
- Mitigate droughts and floods<\/li>\n
- Cycle nutrients<\/li>\n
- Provide wildlife habitat<\/li>\n<\/ol>\n
Question 11.
\nIn 1990\u2019s Delhi ranked fourth among the most polluted cities of the world. What are the parallel steps taken to reduce vehicular pollution?
\nAnswer:<\/p>\n \n- Avoid the use of old vehicles<\/li>\n
- use of unleaded petrol<\/li>\n
- use of low-sulphur petrol and diesel<\/li>\n
- use of catalytic converters in vehicles<\/li>\n<\/ol>\n
Question 12.
\nIncrease in the level of green house gases leads to global warming. How can it be controlled?
\nAnswer:
\nGlobal warming is controlled by<\/p>\n \n- cutting down use of fossil fuel<\/li>\n
- improving efficiency of energy usage<\/li>\n
- reducing deforestation<\/li>\n
- planting trees<\/li>\n<\/ol>\n
Question 13.
\nGenetically modified plants have been used in many ways. Give any four advantages of such plants.
\nAnswer:<\/p>\n \n- crops are tolerant to abiotic stresses<\/li>\n
- reduced reliance on chemical pesticides<\/li>\n
- helped to reduce post harvest losses.<\/li>\n
- increased efficiency of mineral usage by plants<\/li>\n<\/ol>\n
Question 14.
\nIn 1943 American Company Eli lilly produced human insulin artificially. Write down the method followed in this technique.
\nAnswer:
\nAmerican company Eli Lilly prepared Genetically engineered insulin. Steps are given below<\/p>\n \n- Isolation of desired genes.<\/li>\n
- Insertion of desired Genes into plasmids of E. coli.<\/li>\n
- Introduction of plasmids into E coli cells.<\/li>\n
- Culture of E coli cells.<\/li>\n
- After this, a polypeptide chains A and B are separated and connected together by disulphide linkages.<\/li>\n<\/ol>\n
Question 15.
\nPyramid of energy is never been inverted, why?
\nAnswer:
\nWhen energy flows from one trophic level to the next higher trophic level, energy is lost as heat. This is based on 10 % law.<\/p>\n III. (Questions 16 to 18) : Write any two from the following questions. Each question carries 3 Scores. (Scores : 2 \u00d7 3 = 6)<\/span><\/p>\nQuestion 16.
\nMeloidogyne incognitia is a nematode parasite infects the root of tobacco plants. It\u2019s infection can be prevented by biotechnological methods.
\na) Name the strategy.
\nb) Explain the principle behind this strategy.
\nAnswer:
\na) RNA interference<\/p>\n b) Nematode Meloidegyne incognitia infects the roots of tobacco plants and reduces the yield. Nematode-specific genes are introduced into the host plant by Agrobacterium vectors, it produce both sense and anti-sense RNA in the host cells that initiated RNAi and prevent the translation of the specific mRNA of the nematode.<\/p>\n Question 17.
\nThe following graph shows two types of population growth curves:
\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2019\/01\/Plus-Two-Botany-Previous-Year-Question-Paper-March-2018-2.png\")
\na) Name the growth curves.
\nb) What does ‘K\u2019 stand for?
\nAnswer:
\na) Exponential growth (J shaped growth curve)
\nLogistic growth (S shaped growth curve)<\/p>\n b) Carrying capacity<\/p>\n Question 18.
\nIn Angiosperms female gametophyte is known as embryo sac. Explain it’s development.
\nAnswer:
\nA single megaspore mother cell differentiates in the micropylar region of the nucellus. It undergoes meiotic division to form four megaspores.<\/p>\n Out of four, three degenerates and one megaspore is functional. The functional megaspore undergoes three repeated mitotic division to form 8 nucleate and 7 celled embryosac (female gametophyte).<\/p>\n |