create a concept map showing the synthesis and degradation of nucleic acids
The Correct Answer and Explanation is :
Concept Map: Synthesis and Degradation of Nucleic Acids
Central Node: Nucleic Acids
- DNA Synthesis (Replication)
- Enzyme: DNA Polymerase
- Template: Existing DNA strand
- Substrates: dNTPs (deoxyribonucleotide triphosphates)
- Direction: 5′ to 3′
- Process: Initiation → Elongation → Termination
- RNA Synthesis (Transcription)
- Enzyme: RNA Polymerase
- Template: DNA strand (coding region)
- Substrates: NTPs (ribonucleotide triphosphates)
- Direction: 5′ to 3′
- Process: Initiation → Elongation → Termination
- Nucleotide Biosynthesis
- Pathways: De novo synthesis, Salvage pathways
- Components: Ribose sugar (from pentose phosphate pathway), Nitrogenous bases, Phosphate groups
- Degradation of Nucleic Acids
- Enzyme: Nucleases
- DNA: Deoxyribonuclease (DNase)
- RNA: Ribonuclease (RNase)
- Process:
- DNA → Oligonucleotides → Nucleotides → Nitrogenous bases, Sugar, Phosphates
- RNA → Nucleotides → Nitrogenous bases, Sugar, Phosphates
- Regulation
- Enzymes regulated by feedback inhibition
- Cellular conditions influence synthesis and degradation rates
Explanation (300 words)
Nucleic acids, DNA and RNA, are synthesized and degraded through tightly regulated enzymatic processes. DNA synthesis occurs during replication, where DNA polymerase uses a parental strand as a template to synthesize a complementary daughter strand. This process ensures genetic information is accurately copied for cell division. Similarly, RNA synthesis involves RNA polymerase transcribing DNA sequences into mRNA, tRNA, or rRNA, which are crucial for protein synthesis.
Nucleotide biosynthesis provides the building blocks for nucleic acid synthesis. These pathways include de novo synthesis, where precursors like ribose-5-phosphate are converted into nucleotides, and salvage pathways, which recycle free nitrogenous bases.
Degradation of nucleic acids prevents accumulation of defective or excess molecules. Enzymes called nucleases break down DNA and RNA. DNases degrade DNA into smaller oligonucleotides and eventually into free nucleotides, while RNases perform a similar role for RNA. These nucleotides are further broken into nitrogenous bases, sugars, and phosphates, which can be reused in metabolic processes or excreted.
Both synthesis and degradation are highly regulated. For example, feedback inhibition ensures that nucleotide pools remain balanced, while cellular signals such as DNA damage activate repair mechanisms involving nucleases.
This interplay between synthesis and degradation maintains genomic integrity, supports cellular function, and ensures that resources are efficiently used. Understanding these processes is fundamental in fields like molecular biology, genetics, and biotechnology.