1. Consider the following statements regarding DNA Polymorphisms:
- DNA polymorphisms are used to differentiate individuals from one another.
- DNA polymorphisms occur due to errors in DNA replication.
- DNA polymorphisms are found only in the non-coding regions of DNA.
Which of the statements given above are correct?
- (a) 1 and 2 only
- (b) 1 and 3 only
- (c) 2 and 3 only
- (d) 1, 2, and 3
Explanation:
- Statement 1 is correct. DNA polymorphisms are genetic variations that differentiate individuals.
- Statement 2 is correct. They often occur due to mutations in DNA replication.
- Statement 3 is incorrect. DNA polymorphisms can occur in both coding and non-coding regions, although they are more common in non-coding regions.
- Correct Answer: (a) 1 and 2 only
2. With reference to Short Tandem Repeats (STRs), consider the following statements:
- STRs are short sequences of DNA base pairs that are repeated multiple times.
- STRs are highly polymorphic and vary among individuals.
- STRs are used in forensic science for DNA fingerprinting.
Which of the statements given above are correct?
- (a) 1 and 2 only
- (b) 2 and 3 only
- (c) 1 and 3 only
- (d) 1, 2, and 3
Explanation:
- All three statements are correct. STRs are short, repeated sequences of DNA base pairs. Due to their polymorphic nature, they differ among individuals and are widely used in forensic investigations for DNA fingerprinting.
- Correct Answer: (d) 1, 2, and 3
3. Consider the following statements about Polymerase Chain Reaction (PCR):
- PCR is used to amplify specific DNA segments.
- Taq polymerase is commonly used in PCR because it can withstand high temperatures.
- PCR is a technique primarily used for sequencing the entire genome of an individual.
Which of the statements given above are correct?
- (a) 1 and 2 only
- (b) 2 and 3 only
- (c) 1 and 3 only
- (d) 1, 2, and 3
Explanation:
- Statement 1 is correct. PCR is used to amplify or make multiple copies of specific DNA segments.
- Statement 2 is correct. Taq polymerase, derived from a thermophilic bacterium, remains stable at high temperatures used in PCR.
- Statement 3 is incorrect. PCR is not typically used to sequence entire genomes. Instead, it is used to amplify target regions of DNA.
- Correct Answer: (a) 1 and 2 only
4. Which of the following best describes the term 'DNA Fingerprint'?
- (a) A unique sequence of DNA base pairs in an individual’s genome.
- (b) A pattern of short tandem repeats (STRs) unique to an individual.
- (c) The entire genome of an individual mapped for identification purposes.
- (d) A genetic record of mutations within an individual’s DNA.
Explanation:
- DNA fingerprinting involves analyzing specific STR patterns that vary between individuals. This makes it a powerful tool for identification purposes.
- Correct Answer: (b) A pattern of short tandem repeats (STRs) unique to an individual.
5. Which of the following are possible applications of DNA fingerprinting?
- Establishing parent-child relationships.
- Identifying victims of disasters.
- Detecting genetic diseases.
- Solving criminal cases.
Select the correct answer using the code given below:
- (a) 1, 2, and 3 only
- (b) 1, 2, and 4 only
- (c) 2, 3, and 4 only
- (d) 1, 2, 3, and 4
Explanation:
- DNA fingerprinting is widely used for parentage testing, criminal investigations, and identifying disaster victims. However, detecting genetic diseases usually involves other genetic tests like whole-genome sequencing or specific genetic assays.
- Correct Answer: (b) 1, 2, and 4 only
6. Consider the following pairs:
|
Term |
Description |
|
1. DNA Polymorphism |
Variation in DNA sequence among individuals |
|
2. Short Tandem Repeats (STRs) |
Repeated DNA sequences used for DNA profiling |
|
3. Polymerase Chain Reaction |
A technique to amplify DNA segments |
|
4. Capillary Electrophoresis |
A method to sequence an entire genome |
Which of the pairs are correctly matched?
- (a) 1 and 2 only
- (b) 1, 2, and 3 only
- (c) 2, 3, and 4 only
- (d) 1, 2, 3, and 4
Explanation:
- Pair 1 is correct. DNA polymorphisms are variations in DNA sequences that help in identifying individuals.
- Pair 2 is correct. STRs are repeated sequences used for DNA fingerprinting.
- Pair 3 is correct. PCR is used to amplify specific DNA segments.
- Pair 4 is incorrect. Capillary electrophoresis is not used for sequencing entire genomes; it is mainly used to analyze DNA fragments like STRs.
- Correct Answer: (b) 1, 2, and 3 only
7. With reference to DNA fingerprinting, consider the following statements:
- DNA fingerprinting is based on analyzing single nucleotide polymorphisms (SNPs) only.
- It can be used to identify individuals as well as their ancestry.
- DNA fingerprinting cannot be performed if the DNA sample is partially degraded.
Which of the statements given above are correct?
- (a) 1 and 2 only
- (b) 2 only
- (c) 2 and 3 only
- (d) 1, 2, and 3
Explanation:
- Statement 1 is incorrect. DNA fingerprinting mainly uses Short Tandem Repeats (STRs) instead of SNPs.
- Statement 2 is correct. DNA fingerprinting is used to identify individuals and trace ancestry.
- Statement 3 is incorrect. Even degraded DNA can sometimes be analyzed using PCR amplification.
- Correct Answer: (b) 2 only
8. Which of the following factors can affect the accuracy of DNA fingerprinting?
- Contamination of the sample.
- Number of STR markers used in the analysis.
- Use of degraded DNA for analysis.
- Presence of identical twins in the population.
Select the correct answer using the code given below:
- (a) 1 and 2 only
- (b) 1, 2, and 3 only
- (c) 1, 3, and 4 only
- (d) 1, 2, 3, and 4
Explanation:
- All the factors mentioned affect DNA fingerprinting.
- Contamination can introduce foreign DNA.
- Using more STR markers improves the accuracy.
- Degraded DNA may yield incomplete results.
- Identical twins have identical DNA fingerprints, complicating differentiation.
- Correct Answer: (d) 1, 2, 3, and 4
9. Consider the following statements regarding the use of DNA in forensic investigations:
- DNA samples from different tissues of the same person will have different DNA fingerprints.
- Capillary electrophoresis separates DNA fragments based on their size.
- PCR amplification is essential for DNA fingerprinting even when large DNA samples are available.
Which of the statements given above are correct?
- (a) 1 and 2 only
- (b) 2 and 3 only
- (c) 1 and 3 only
- (d) 1, 2, and 3
Explanation:
- Statement 1 is incorrect. DNA from different tissues (e.g., blood, saliva, or bones) of the same person has identical DNA fingerprints.
- Statement 2 is correct. Capillary electrophoresis is used to separate DNA fragments based on size.
- Statement 3 is correct. PCR is used to amplify DNA, even when a sample is large, to ensure accurate and efficient analysis.
- Correct Answer: (b) 2 and 3 only
10. DNA extracted from human remains is often used in ancient DNA studies. Which of the following factors are important for the successful extraction of ancient DNA?
- Age of the sample.
- Environmental conditions of the burial site.
- The presence of microbial contamination.
- The extent of DNA degradation.
Select the correct answer using the code given below:
- (a) 1 and 2 only
- (b) 2 and 4 only
- (c) 1, 2, and 4 only
- (d) 1, 2, 3, and 4
Explanation:
- All the factors mentioned play a role in DNA extraction.
- DNA degrades over time, so older samples are harder to analyze.
- Cooler and dry environments preserve DNA better.
- Microbial contamination accelerates DNA degradation.
- Correct Answer: (d) 1, 2, 3, and 4
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