9700 · 16.1
Passage of information from parents to offspring — FAQ
Frequently asked questions for 9700 Passage of information from parents to offspring. Direct answers first, then deeper explanation — then practise with marking.
What is the main role of DNA in inheritance?
DNA stores the genetic instructions for developing and functioning, acting as the blueprint passed from parents to offspring. It ensures the continuity of traits and biological information across generations. For a deeper dive into this and other topics, explore our free 9700 biology course and tackle past paper questions to solidify your understanding.
How is DNA replicated accurately?
DNA replication occurs semi-conservatively, meaning each new DNA molecule consists of one original (template) strand and one newly synthesised strand. Enzymes like DNA helicase unwind the double helix, and DNA polymerase adds complementary nucleotides to each separated strand, ensuring high fidelity in copying the genetic information. The process involves continuous synthesis on the leading strand and discontinuous synthesis (via Okazaki fragments and DNA ligase) on the lagging strand.
What are the key differences between transcription and translation?
Transcription is the process where a gene's DNA sequence is copied into an RNA molecule (mRNA) in the nucleus of eukaryotic cells. This is followed by post-transcriptional modification (splicing, capping, tailing). Translation is the process where the mature mRNA sequence is used to synthesise a protein on ribosomes in the cytoplasm. Essentially, transcription makes RNA from a DNA template, while translation uses that RNA template to make a polypeptide chain (protein).
What is the lac operon and why is it important?
The lac operon is a classic example of gene regulation in prokaryotes like E. coli. It's a cluster of genes responsible for lactose metabolism that can be switched on or off depending on the presence of lactose. It demonstrates how cells can efficiently control gene expression to produce proteins only when they are needed, conserving energy and resources.