(a) Draw a schematic diagram of the cloning vector pBR322 and label (1) Bam HI site (2) gene for ampicillin resistance (3) ‘ori’ (4) ‘rop’ gene.
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Solution and Explanation
- Bam HI site: A restriction site for cloning.
- Ampicillin resistance gene: A selectable marker.
- ‘Ori’: Origin of replication, essential for plasmid replication.
- ‘Rop’ gene: Regulates plasmid copy number.
Top Questions on Ecosystem
- Why are restrictions imposed on MTP in India? Up to how many weeks or trimesters, is MTP considered relatively safe for a female, if necessary to perform, by a medical practitioner?
Read the passage given below and answer the question.
Food chains ‘P’ and ‘Q’ form an interconnection. ‘P’ initiates with wheat grass whose population supports a few grasshoppers, frogs and snakes.
‘Q’ starts with dead decaying leaves of wheat grass which are eaten by earthworms and then food chain is continued with frog of food chain ‘P’.
Identify the types of food chains ‘P’ and ‘Q’:
Study the table given below showing the relationship between organism, its trophic level and kind of food chain it belongs to.
Student to attempt either option (A) or (B).
(A) Identify the type of pyramid given below and write two identifying features of such a pyramid:
OR
(B)
(i) Construct an ideal pyramid of energy when 10,00,000 Joules of sunlight is available.
(ii) Mention the energy obtained by the fourth level of this pyramid.}
- Analyse the following ecosystems and discuss, which will be more productive in terms of primary productivity:
A young forest, a natural old forest, a shallow polluted lake.
Questions Asked in CBSE CLASS XII exam
- Nandita and Prabha were partners in a firm. Nandita withdrew ₹ 3,00,000 during the year for personal use. The partnership deed provides for charging interest on drawings @ 10% p.a. Interest on Nandita’s drawings for the year ended 31st March, 2024 will be:
- CBSE CLASS XII - 2025
- Profit sharing ratio
Aakash and Baadal entered into partnership on 1st October 2023 with capitals of Rs 80,00,000 and Rs 60,00,000 respectively. They decided to share profits and losses equally. Partners were entitled to interest on capital @ 10 per annum as per the provisions of the partnership deed. Baadal is given a guarantee that his share of profit, after charging interest on capital, will not be less than Rs 7,00,000 per annum. Any deficiency arising on that account shall be met by Aakash. The profit of the firm for the year ended 31st March 2024 amounted to Rs 13,00,000.
Prepare Profit and Loss Appropriation Account for the year ended 31st March 2024.- CBSE CLASS XII - 2025
- Partnership
- Two dice are thrown. Defined are the following two events A and B: \[ A = \{(x, y) : x + y = 9\}, \quad B = \{(x, y) : x \neq 3\}, \] where \( (x, y) \) denote a point in the sample space. Check if events \( A \) and \( B \) are independent or mutually exclusive.
- CBSE CLASS XII - 2025
- Probability
- Draw circuit arrangement for studying V-I characteristics of a p-n junction diode.
(b) Show the shape of the characteristics of a diode.
(c) Mention two information that you can get from these characteristics.- CBSE CLASS XII - 2025
- Semiconductor electronics: materials, devices and simple circuits
- Find the shortest distance between the lines: \[ \mathbf{r}_1 = (2\hat{i} - \hat{j} + 3\hat{k}) + \lambda (\hat{i} - 2\hat{j} + 3\hat{k}) \] \[ \mathbf{r}_2 = (\hat{i} + 4\hat{k}) + \mu (3\hat{i} - 6\hat{j} + 9\hat{k}) \]
- CBSE CLASS XII - 2025
- Vector Algebra