Newly formed DNA copies may not be identical at times. Give one reason.
Newly formed DNA copies may not be identical at times. Give one reason.
Official answer
Newly formed DNA copies may not be identical because no biochemical reaction is absolutely reliable; variations occur during the process of DNA replication.
Marking scheme
- 1.1 mark for mentioning that biochemical reactions are not absolutely reliable or for mentioning inaccuracies in DNA copying.
Hint
Think about the reliability of biochemical reactions during replication.
Quick oral answer
DNA copies are not identical because biochemical reactions involved in replication have inherent inaccuracies, leading to variations.
Common mistakes
- 1.Attributing it only to external mutations.
- 2.Stating that DNA copying is always accurate.
Analysis and explanation
As discussed in the NCERT text (Section 1.2), chemical reactions involve the breaking and making of bonds between atoms. DNA copying is a complex set of biochemical reactions. Since no chemical process is accurate, small inaccuracies in the bonding or sequence during replication lead to variations, meaning the daughter DNA is not an exact identical copy of the original.
Interesting facts
These minor inaccuracies in DNA copying are the basic source of variations that lead to evolution over long periods.
Question details
Q2 of 36 questions
- Board
- CBSE
- Class
- Class 10
- Subject
- Science
- Year
- 2017
- Section
- Section A
- Marks
- 1
- Type
- Very Short Answer
- Chapter
- Chemical Reactions and Equations
- Topic
- DNA Copying
- Bloom's level
- Understand
- Syllabus topic
- How do Organisms Reproduce: The importance of variation
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Frequently asked questions
How many marks does this question carry in CBSE Class 10 Science 2017?
This question carries 1 mark in the CBSE Class 10 Science 2017 examination.
Which chapter does this question come from in Science?
This question is from the chapter "Chemical Reactions and Equations" in the CBSE Class 10 Science syllabus.
What topic does this question cover in Science?
This question covers the topic "DNA Copying" from CBSE Class 10 Science.
What type of question is this in the CBSE Class 10 Science 2017 paper?
This is a Very Short Answer question from Section A in the CBSE Class 10 Science 2017 paper.