Central Dogma - questions.pdf

1. What is the central dogma of molecular biology? - The flow of genetic information from DNA to RNA to protein. 2. What is DNA replication? - The process of making an exact copy of DNA. 3. Which enzyme 'unzips' the DNA double helix during replication? - Helicase. 4. Explain the role of DNA po...

1. What is the central dogma of molecular biology? - The flow of genetic information from DNA to RNA to protein. 2. What is DNA replication? - The process of making an exact copy of DNA. 3. Which enzyme 'unzips' the DNA double helix during replication? - Helicase. 4. Explain the role of DNA polymerase in replication. - It adds new complimentary nucleotide bases to the DNA strand. 5. What are the two directions in which the DNA strands are oriented during replication? - 3' to 5' (leading strand) and 5' to 3' (lagging strand). 6. What are Okazaki fragments? - Short, newly synthesized DNA fragments formed on the lagging strand. 7. What enzyme catalyzes the removal of primer sequences during DNA replication? - Exonuclease. 8. What is the end result of DNA replication? - Two DNA molecules, each consisting of one old and one new chain of nucleotides. 9. Define transcription in molecular biology. - Copying DNA information into a new molecule of mRNA. 10. Which enzyme is responsible for transcription? - RNA polymerase. 11. How does transcription differ from DNA replication? - RNA strand is not permanently bonded to DNA template. 12. What are the classes of polymerases present in eukaryotes? - Pol I, Pol II, Pol III. 13. Why are RNA molecules shorter than DNA molecules? - RNA is copied from a limited region of the DNA. 14. What is the genetic code described as when one amino acid can be coded by more than one codon? - Degenerate or redundant 15. How does the cell read the DNA code? - In groups of three bases (triplets) 16. What are the two distinct types of molecular chaperones involved in guiding polypeptide chain folding? - HSP60 and HSP70 17. What is the role of molecular chaperones in preventing protein aggregation? - They recognize exposed hydrophobic patches on proteins 18. Describe the process by which misfolded proteins are degraded within the cell. - Ubiquitin ligase attaches ubiquitin to the misfolded protein, marking it for proteasomal degradation 19. Which chaperone system is involved in protein folding, refolding, and degradation? - HSP70 chaperone system 20. How is substrate binding and release regulated by HSP70? - Through an ATP-consuming cycle 21. Which co-chaperones regulate HSP70's folding activity and protein degradation? - Co-chaperones like HSP40, HIP, and CHIP 22. How do BAG1 and BAG3 modulate the function of HSP70? - BAG1 links HSP70 to the proteasome; BAG3 links HSP70 to macroautophagy 23. What is the function of transcription factors in gene expression? - Transcription factors bind to enhancer and promoter sequences to recruit RNA polymerase. 24. Describe the role of RNAs compared to DNA in length. - Most RNAs are much shorter than DNA, often only a few thousand nucleotides long. 25. Explain the function of a promoter region in transcription. - The promoter region signals the starting point of transcription and which DNA strand is transcribed. 26. What is an initiation bubble in transcription? - An initiation bubble is a space created for RNA polymerase to access a single DNA strand. 27. What is the significance of the TATA box in transcription? - The TATA box is a conserved promoter sequence that helps initiate transcription in eukaryotic genes. 28. What is the primary enzyme responsible for catalyzing transcription? - RNA polymerase is the enzyme responsible for catalyzing transcription. 29. Explain the process of RNA transcription initiation. - RNA polymerase and cofactors bind to DNA, causing it to unwind, leading to initiation. 30. In eukaryotes, what molecules mediate the binding of RNA polymerase to DNA? - In eukaryotes, transcription factors mediate the binding of RNA polymerase to DNA. 31. What initiates transcription in bacteria? - RNA polymerase binding to the promoter region in DNA 32. How is transcription initiation in eukaryotes mediated? - Transcription factors mediate RNA polymerase binding to DNA 33. What is the function of a promoter in transcription? - Signals the transcribed DNA strand and transcription direction 34. In which direction are bases incorporated during elongation? - In a 5' to 3' direction 35. What is the role of introns in pre-mRNA? - Non-coding sections spliced out before translation 36. What is the process where introns are removed? - RNA Splicing 37. What is the function of a 5' cap in mRNA processing? - Vital for ribosome recognition and RNA protection 38. Describe polyadenylation in pre-mRNA processing. - Adds a poly(A) tail to stabilize RNA 39. What is the role of mature mRNA? - Allows translation and protein synthesis 40. What is the open reading frame (ORF) in mature mRNA? - Region translated into protein 41. What is the process by which mRNA is translated into proteins? - Translation 42. Where does translation take place in the cell? - Cytoplasm on a ribosome 43. What kind of molecules are tRNA and rRNA? - Adaptor and catalytic molecules 44. What is the role of tRNA molecules in translation? - Reading mRNA codons and attaching specific amino acids 45. Which site on the ribosome ensures the correct amino acid is added to the growing polypeptide chain? - A (amino acyl) site 46. Which site on the ribosome is responsible for transferring the amino acid to the growing polypeptide chain? - P (peptidyl) site 47. Where does the 'empty' tRNA sit before being released back into the cytoplasm? - E (exit) site 48. What is the initiator tRNA's unique property in translation? - Binding in the P site of the ribosome 49. What signals the termination of translation and releases the completed polypeptide? - Release factor 50. How many possible codon permutations are there, including stop signals? - 64 51. How many codons represent amino acids in the genetic code? - 61 52. What are the three stop codons in translation? - TAA, TAG, TGA