DNA REPLICATION Flashcards
What is DNA?
DNA is the inherited genetic material that carries a code determining the sequences of proteins and the nature and function of cells.
What is mRNA and its role in protein synthesis?
mRNA is a messenger RNA copy that undergoes translation on the ribosome, determining the sequence of amino acids.
What are the main forms of RNA involved in transcription and translation?
- mRNA (messenger RNA)
- tRNA (transfer RNA)
- rRNA (ribosomal RNA)
What does DNA stand for?
Deoxyribonucleic acid.
What does RNA stand for?
Ribonucleic acid.
What is the structure of DNA?
DNA is a polymer of nucleotides with a sugar-phosphate backbone linked to four different bases (A, C, G, T).
What is the sugar component of DNA?
2-deoxyribose sugar.
What is the sugar component of RNA?
Ribose.
What is the significance of Chargaff’s findings?
Chargaff’s findings (A=T and G=C) revealed the base pairing rules in DNA structure.
Who used X-ray diffraction data to elucidate the structure of DNA?
Watson and Crick used X-ray diffraction data from Rosalind Franklin.
What is the helical structure of DNA described as?
A double helix with a sugar-phosphate backbone on the outside and base pairing between strands.
How many base pairs are in one turn of the DNA helix?
10 base pairs.
What is the melting temperature (Tm) of DNA?
The temperature at which DNA strands will separate.
What stabilizes the DNA double helix?
Hydrogen bonding between bases and interactions between stacked bases.
What are purines and pyrimidines?
Purines (A and G) have a double ring structure, while pyrimidines (C, T, U) have a single ring structure.
What type of bonds connect base pairs in DNA?
Hydrogen bonds.
What is hybridisation in nucleic acids?
The binding of two strands of nucleic acid by base complementarity.
What is the role of helicase in DNA replication?
Helicase untwists the DNA helix to give single-stranded DNA.
What is the function of topoisomerase during DNA replication?
Topoisomerase fixes increased coiling in the DNA template ahead of the replication fork.
What is the role of single-strand binding protein?
It stabilizes the single-stranded template during replication.
What is the direction of DNA synthesis?
DNA synthesis occurs in the 5’ to 3’ direction.
What are Okazaki fragments?
Short DNA fragments synthesized discontinuously on the lagging strand.
What occurs during the G1 phase of interphase?
Normal cell metabolism.
What happens during the S phase of interphase?
DNA replication occurs.
