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DNA denaturation occurs when hydrogen bonds between base pairs are disturbed. The non-covalent interactions between antiparallel strands in DNA can be broken in order to "open" the double helix when biologically important mechanisms such as DNA replication, transcription, DNA repair or protein binding are set to occur. [ 19 ]
Slipped strand mispairing (SSM, also known as replication slippage) is a mutation process which occurs during DNA replication. It involves denaturation and displacement of the DNA strands, resulting in mispairing of the complementary bases. Slipped strand mispairing is one explanation for the origin and evolution of repetitive DNA sequences. [1]
Each double-stranded DNA has a 'critical temperature' (Tc) lower than its Tm. The PCR amplification efficiency drops measurably below the Tc. The Tc is dependent on DNA sequence. Two template DNA fragments differing by only one or two nucleotide mismatches will have different amplification efficiencies if the denaturation step of PCR is set to ...
The process of DNA denaturation can be used to analyze some aspects of DNA. Because cytosine / guanine base-pairing is generally stronger than adenine / thymine base-pairing, the amount of cytosine and guanine in a genome is called its GC-content and can be estimated by measuring the temperature at which the genomic DNA melts. [ 2 ]
Translation can be downregulated by miRNAs (microRNAs). These RNA strands can cleave mRNA strands they are complementary to and will thus stop translation. [15] Translation can also be regulated via helper proteins. For example, a protein called eukaryotic initiation factor-2 can bind to the smaller subunit of the ribosome, starting translation.
The initiation phase is completed once a 50S subunit joins the 30S subunit, forming an active 70S ribosome. [11] Termination of the polypeptide occurs when the A site of the ribosome is occupied by a stop codon (UAA, UAG, or UGA) on the mRNA, creating the primary structure of a protein. tRNA usually cannot recognize or bind to stop codons.
S phase (Synthesis phase) is the phase of the cell cycle in which DNA is replicated, occurring between G 1 phase and G 2 phase. [1] Since accurate duplication of the genome is critical to successful cell division, the processes that occur during S-phase are tightly regulated and widely conserved.
A eukaryotic cell has a nucleus that separates the processes of transcription and translation. Eukaryotic transcription occurs within the nucleus where DNA is packaged into nucleosomes and higher order chromatin structures. The complexity of the eukaryotic genome necessitates a great variety and complexity of gene expression control.