ASSIGNMENT- MOLECULAR BASIS OF INHERITANCE

DOWNLAOD THE ASSIGNMENT HERE:

https://www.sciencearena.in/p/education-resources.html

BIOLOGY TOPICS:

rDNA TECHNOLOGY:

https://www.sciencearena.in/2025/06/recombinant-dna-technology.html

EUGLENA:

https://www.sciencearena.in/2025/05/euglena.html

MONOCYSTIS:

https://www.sciencearena.in/2025/05/monocystis.html

PARAMECIUM:

https://www.sciencearena.in/2025/05/paramecium.html

ATS COACHING CLASSES

BIOLOGY (XII)

MOLECULAR BASIS OF INHERITANCE

MULTIPLE CHOICE QUESTIONS (MCQs)

1	A DNA molecule is 160 base pairs long. It has 30% guanine. How many adenine bases are present in this DNA molecule? (a) 48 (b) 64 (c) 96 (d) 192	1
2	A DNA fragment has 3000 nucleotides, out of which 160 are guanine. How many bases having double hydrogen bonds between them does this DNA fragment possess? (a) 160 (c) 1340 (b) 320 (d) 2680	1
3	Meselson and Stahl carried out centrifugation in CsCl₂ density gradient to separate : (a) DNA from RNA (b) DNA from protein (c) the normal DNA from 15N-DNA (d) DNA from tRNA	1
4	Choose the chromosome in a human that possesses least number of genes. (a) 21st chromosome (c) X chromosome (b) Autosome (d) Y chromosome	1
5	What is the smallest part of a DNA molecule that can be changed by a point mutation? (a) Oligonucleotide (b) Codon (c) Gene (d) Nucleotide	1
6	Short stretches of DNA used to identify complementary sequence in a sample are called (a) probes (c) VNTRS (b) markers (d) primers	1
7	Which one of the following technique is used in DNA fingerprinting for the detection of DNA? (a) Northern blotting (b) Western blotting (c) Southern blotting (d) In-situ hybridisation	1
8	In a bacterium, when RNA polymerase binds to the promoter on a transcription unit during transcription, it (a) terminates the process (b) helps remove introns (c) initiates the process (d) inactivates the exons.	1
9	a 'transcription unit', the 'terminator' is located towards the (a) 3' end of the template strand (b) 5' end of the template strand (c) 5'end of the coding strand (d) 3'end of the coding strand.	1
10	When an amino acid is coded by more than one codon, the genetic code is said to be (a) universal (c) commaless (b) punctuated (d) degenerate	1

ASSERTION AND REASON QUESTIONS

(a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).

(b) Both Assertion (A) and Reason (R) are true and Reason (R) is not the correct explanation of the Assertion (A).

(c) Assertion (A) is true, and Reason (R) is false.

(d) Assertion (A) is false, and Reason (R) True.

11	Assertion (A): Lactose in lac operon is promoter gene. Reason (R): Lactose inactivates the repressor gene.	1
12	Assertion (A): Ribosomal RNA is synthesized in the nucleus of the cell. Reason (R): It is translated with the enzyme RNA polymerase III.	1
13	Assertion (A): Primary transcripts in eukaryotes are subjected to splicing to remove the introns. Reason (R): Primary transcripts contain both exons and introns and the introns are non-functional in eukaryotes.	1
14	Assertion (A): RNA is unstable and can mutate at a faster rate. Reason (R): The presence of 2' - OH group in every nucleotide of RNA makes it labile and easily degradable.	1

VERY SHORT ANSWER QUESTIONS

15	What is central dogma? Who proposed it?	2
16	Discuss the role, the enzyme DNA ligase plays during DNA replication.	2
17	Differentiate between a template strand and coding strand of DNA.	2
18	State the functions of ribozyme and release factor in protein synthesis respectively	2
19	What is aminoacylation? State its significance	2

SHORT ANSWER TYPE QUESTIONS

20	The length of DNA in any cell is far greater than the dimension of its nucleus. Explain how this enormous DNA is packaged in a eukaryotic cell.	3
21	Explain the discovery made by Hershey and Chase using radioactive sulphur and phosphorus in their experiment	3
22	Describe the experiment where Matthew Meselson and Franklin Stahl used heavy isotope of nitrogen.	3
23	(i) How many types of RNA polymerases are there in a eukaryote cell? Mention which one of them transcribes hnRNA. (ii) Write the changes that hnRNA undergoes before it leaves the nucleus as mRNA.	3
24	What are 'SNPs'? Where are they located in a human cell? State any two ways the discovery of SNPs can be of importance to humans.	3
25	Why is DNA a better genetic material when compared to RNA.	3
26	A very small sample of tissue or even a drop of blood can help determine paternity”. Provide a scientific explanation to substantiate how it is possible.	3

LONG ANSWER TYPE QUESTIONS

27	How did Griffith prove transforming principle in genetics? Explain the procedure	5
28	How did Alfred Hershey and Martha Chase conclusively establish that DNA is the genetic material? Explain.	5
29	Explain the process of DNA replication with the help of a replicating fork.	5
30	Explain the process of transcription in eukaryotes.	5
31	Name and describe the steps involved in the technique widely used in forensic that serves as the basis of paternity testing in case of disputes.	5
32	Explain the role of different gene in a lac operon when in a switched on stake	5
33	Explain the role of lactose as an inducer in a lac operon.	5

CASE BASED STUDY QUESTIONS

34	Read the passage carefully and answer the following questions: In 1953, James Watson and Francis Crick proposed a double-helix model of DNA with the help of Rosalind Franklin's X-ray diffraction images. They described how DNA's structure enables it to carry genetic information and replicate. 1. What type of bond holds the two strands of the DNA helix together? 2. Name the components of a nucleotide. 3. Why is the base pairing in DNA said to be complementary? 4. How does the structure of DNA support its function of replication? 5. Mention the significance of Chargaff’s rule in DNA structure.	4
35	Read the passage carefully and answer the following questions: Two scientists, Meselson and Stahl, proved that DNA replication is semi-conservative. They used E. coli grown in a medium containing heavy nitrogen (^15N) followed by normal nitrogen (^14N), and analyzed DNA density using centrifugation. 1. What do you understand by "semi-conservative" replication? 2. Why was ^15N used in the experiment? 3. After one round of replication in ^14N, what was the density of DNA observed? 4. What conclusion can be drawn if both light and hybrid DNA are observed after multiple generations? 5. Which enzyme is responsible for the elongation of new DNA strands?	4
36	Read the passage carefully and answer the following questions: During translation, mRNA codons are read and converted into amino acids. The genetic code is nearly universal and degenerate. For example, UUU and UUC both code for phenylalanine. 1. What is the role of tRNA in translation? 2. What is meant by a “degenerate” genetic code? 3. Which amino acid is coded by the start codon? 4. Why is the universality of the genetic code important for genetic engineering? 5. How many codons code for amino acids and how many are stop codons?	4
37	Read the passage carefully and answer the following questions: The Human Genome Project was an international scientific research project with the goal of mapping all the genes of the human genome. It was completed in 2003 and revealed that humans have about 20,000–25,000 genes. 1. What was the main objective of the Human Genome Project? 2. What is the significance of sequencing the human genome? 3. How can data from the HGP be useful in disease treatment? 4. Which techniques were mainly used in the HGP for DNA sequencing? 5. What percentage of the human genome actually codes for proteins?	4
38	Read the passage carefully and answer the following questions: A murder case was solved by using DNA fingerprinting, which compared DNA samples from the crime scene with suspects. This method relies on unique patterns in VNTRs (Variable Number Tandem Repeats). 1. What are VNTRs and how are they used in DNA fingerprinting? 2. Name the scientist who developed DNA fingerprinting. 3. What is the role of restriction enzymes in DNA fingerprinting? 4. How does gel electrophoresis help in this technique? 5. Mention one application of DNA fingerprinting apart from criminal investigation.	4