Molecular Biology Intro Flashcards
list all the ways in which the structure of DNA might facilitate its function as the carrier of genetic information
Double-stranded structure: The double helix structure of DNA allows one strand to serve as a template for the synthesis of a complementary strand. This is essential during replication, where an identical copy of DNA needs to be made, and during transcription, where a complementary RNA strand is synthesized.
Stable structure: The hydrogen bonding between base pairs (adenine-thymine and cytosine-guanine) in the DNA strand creates a stable, robust structure. This stability is important as it allows DNA to resist corruption and maintain the integrity of the genetic information it carries.
Capability for self-repair: The redundant information in the double strands allows DNA to repair itself when damaged. If one strand is damaged, the other strand can serve as a template for repair, ensuring the preservation of genetic information.
Conservation of Genetic Code: The specific pairing of base pairs in the DNA double helix allows for the genetic code to be conserved during replication. This feature is vital for the accurate transmission of genetic information from one generation to the next.
list all the ways in which the structure of RNA might facilitate its function as the carrier of genetic information
Single-stranded structure: Unlike DNA, RNA is typically single-stranded. This allows it to fold into a variety of complex three-dimensional structures, enabling a diversity of functions ranging from coding (mRNA), structure (rRNA) to catalysis (ribozymes).
Presence of Uracil instead of Thymine: RNA contains the base uracil (U), instead of thymine (T), which pairs with adenine (A). This does not have a significant impact on base pairing but is a key difference between DNA and RNA.
Ribose sugar: RNA contains ribose sugar, which has an hydroxyl group (-OH) at the 2’ carbon. This makes RNA more reactive and less stable than DNA, fitting with its typically transient roles in the cell.
Role in protein synthesis: Through its various forms (mRNA, tRNA, and rRNA), RNA plays a crucial role in protein synthesis. For instance, mRNA provides the template for protein synthesis, tRNA brings the appropriate amino acids to the ribosome during translation, and rRNA forms the core of the ribosome’s structure and catalyzes peptide bond formation.
Describe the differences between the structures of DNA and RNA, and explain how these differences are reflected in their respective functions.
DNA is double-stranded, highly stable, and contains deoxyribose sugar and thymine. Its stability and double-stranded nature make it suitable for long-term storage of genetic information, and for self-repair when damaged.
On the other hand, RNA is single-stranded, contains ribose sugar and uracil instead of thymine, and is less stable than DNA. The single-stranded structure allows RNA to fold into various complex structures, enabling a wide range of functions including coding (mRNA), structural roles (rRNA), and catalysis (ribozymes). The reduced stability of RNA fits its typically transient roles in the cell.
