Science - Category Questions

• In chemistry why is acetic acid (like in vinegar) classified as a weak acid despite being corrosive? What specifically about its molecular structure and dissociation in water leads to this classification?
• In PCR test reports I often see both Cq and Ct values mentioned. What's the actual technical difference between these two terms and does one have a specific advantage or standard usage over the other in diagnostics?
• In biology classes RNA and DNA are mentioned together so often that it gets confusing to separate their roles. What are the key differences between RNA and DNA in structure function and how they work inside living cells?
• In cell culture labs why is Fetal Bovine Serum (FBS) such a common and crucial additive to growth media? What specific nutrients or factors does it provide that cells can't synthesize on their own?
• Studying semiconductor physics I'm confused about Zener and Avalanche breakdowns in diodes. Can you clarify the fundamental physical mechanisms and key differentiating factors between these two types of reverse breakdown?
• I came across the name Paul Ehrlich in a biology discussion and want a clearer understanding of his significance. Based on his work and contributions how could Paul Ehrlich reasonably be described in scientific and historical terms?