Explain(in one or two lines)the function of the followings:
(a)Promoter
(b)tRNA
(c)Exons
(a)Promoter
(b)tRNA
(c)Exons
Solution and Explanation
(a) Promoter Promoter is a region of DNA that helps in initiating the process of transcription. It serves as the binding site for RNA polymerase.
(b) tRNA tRNA or transfer RNA is a small RNA that reads the genetic code present on mRNA. It carries specific amino acid to mRNA on ribosome during translation of proteins.
(c) Exons Exons are coding sequences of DNA in eukaryotes that transcribe for proteins.
Top Questions on Molecular Basis of Inheritance
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- CBSE CLASS XII - 2025
- Biology
- Molecular Basis of Inheritance
Construct and label a transcription unit from which the RNA segment given below has been transcribed. Write the complete name of the enzyme that transcribed this RNA.
- CBSE CLASS XII - 2025
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- The RNA triplet UAG acts as a stop codon which terminates the synthesis of a polypeptide. Below is given a strand of DNA which codes for four amino acids.
In which position will an insertion of a thymine nucleotide result in the termination of translation?
DNA strand:
3′ T C C A C C C G A T G C 5′- CBSE CLASS XII - 2025
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- The base sequence in one of the strands of DNA is: ‘TAGCATGAT’
- Give the base sequence of its complementary strand.
- How are these base pairs held together in DNA molecule?
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- CBSE CLASS XII - 2025
- Biology
- Molecular Basis of Inheritance
Student to attempt either option-(A) or (B):
(A) Write the features a molecule should have to act as a genetic material. In the light of the above features, evaluate and justify the suitability of the molecule that is preferred as an ideal genetic material.
OR
(B) Differentiate between the following:- [(i)] Polygenic Inheritance and Pleiotropy
- [(ii)] Dominance, Codominance and Incomplete dominance
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- Biology
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A current-carrying coil is placed in an external uniform magnetic field. The coil is free to turn in the magnetic field. What is the net force acting on the coil? Obtain the orientation of the coil in stable equilibrium. Show that in this orientation the flux of the total field (field produced by the loop + external field) through the coil is maximum.
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- Sudha, Sudama and Sulochna were partners in a firm sharing profits equally. On 31st March, 2020, Sudha retired. On the date of retirement ₹ 2,40,000 became due to her. Sudama and Sulochana agreed to pay Sudha in four equal yearly instalments plus interest @ 10% p.a. on the unpaid balance starting from 31st March, 2021. The firm closes its books on 31st March every year.
Prepare Sudha’s loan account till it is fully paid.- CBSE CLASS XII - 2025
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- Centurian Ltd. invited applications for issuing 2,00,000 equity shares of ₹ 10 each at a premium of ₹ 20 per share. The amount was payable as follows: On Application and Allotment – ₹ 20 per share (including premium ₹ 17 per share)
On First and Final call – ₹ 10 per share (including premium ₹ 3 per share)
Applications were received for 3,00,000 equity shares and allotment was made to the applicants as follows: (i) Applicants for 2,00,000 shares were allotted 1,50,000 shares.
(ii) Applicants for 1,00,000 shares were allotted 50,000 shares.
Excess money received on application and allotment was adjusted towards sums due on first and final call. Deepali, who had applied for 2,000 shares, failed to pay the first and final call money. Her shares were subsequently forfeited. Deepali belonged to Category (i).
Pass necessary journal entries for the above transactions in the Books of Centurian Ltd.
Open Calls-in-Arrears and Calls-in-Advance account, wherever necessary.- CBSE CLASS XII - 2025
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Concepts Used:
The Molecular Basis of Inheritance
DNA Replication:
DNA synthesis is commenced at particular points within the DNA strand referred to as ‘origins’, which are certain coding regions. There are numerous origin sites, and when replication of DNA starts, these sites are mentioned as replication forks. Within the replication, the complex is the enzyme DNA Helicase, so that they can be utilized as a template for replication. DNA Primase is another enzyme that's essential in DNA replication.
RNA:
Ribonucleic acid (RNA) is an essential biological macromolecule that exists all together in biological cells. It is principally involved in the synthesis of proteins, that carry the messenger instructions from DNA, which itself contains the genetic instructions needed for the event and maintenance of life. In some viruses, RNA, in spite of DNA, carries genetic information.
Genetic Code:
Genetic code is the term we use in the manner that the four bases of DNA--the A, C, G, and Ts--are strung together in a way that the ribosome, the cellular machinery, can read them and switch them into a protein. In the ordering, every three nucleotides during a row count as a triplet and code for one amino alkanoic acid.
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