Simple Pharmanotes

  Takes place in cytoplasm. Messenger RNA (mRNA) brings instructions for making ONE protein from the nucleus to the ribosome. The mRNA binds with a small ribosomal unit. This binding initiates binding of a large ribosomal unit with the small ribosome unit-mRNA complex to form an assembly line for protein production. The large Ribosomal unit has three binding sites A : Attachment site. P : Pairing Site. E : Exit site. The completion of small ribosomal unit-mRNA- large ribosome unit complex activates movement of tRNA . Transfer RNA (tRNA) molecules bring amino acids from the cytosol into the ribosome to build the protein. Different types of tRNA bring different types of amino acids to the ribosome. Different types of tRNA also have different 3 base anticodon sequences that bond to mRNA “ codons ”.  The codon-anticodon binding takes place at the attachment site. The start codon is the first codon of a messenger RNA. It is always AUG which stands for amino acid Methionine...

  Introduction: Transcription is the first step in gene expression. Synthesis of an RNA molecule involves copying the DNA sequence of a gene . RNA polymerases, which link nucleotides to create an RNA strand using a DNA strand as a template, carry out transcription. Transcription has three stages:  initiation,  elongation, termination. Transcription is controlled separately for each gene in our genome. RNA polymerase: RNA polymerase, the primary enzyme responsible for transcription, builds a complementary strand of RNA using a template made of single-stranded DNA .  Specifically, RNA polymerase builds an RNA strand in the 5' to 3' direction, adding each new nucleotide to the 3' end of the strand . Initiation: RNA polymerase binds to a sequence of DNA called the promoter , found near the beginning of a gene .  Each gene has its own promoter.  Once bound, RNA polymerase opens the DNA strands, providing the single-stranded template needed for transcription . El...

  Introduction: DNA replication is similar to transcription in its most general idea: a polymerase enzyme reads a strand of DNA one nucleotide at a time, it takes a random nucleotide from the nucleoplasm, and if it is complementary to the nucleotide in the DNA, the polymerase adds it to the new strand it is creating.  Although, there are significant differences between replication and transcription too, not the least of which is that both strands of DNA are being read simultaneously in order to create two new complementary strands that will eventually result in a complete and nearly perfect copy of an entire organismal genome . Models proposed for DNA Synthesis: Conservative Model. Semiconservative Model. Dispersive Model. One of the most important concepts of DNA replication is that it is a semi-conservative process.  It means that every double helix in the new generation of an organism consists of one complete “old” strand and one complete “new” strand wrapped around ea...

  Introduction: The organic components known as nucleic acids are found in all living things in the form of DNA or RNA .  These nucleic acids are created by combining n itrogenous bases, sugar molecules, and phosphate groups that are connected by various bonds in a series of sequences .  The fundamental genetic make-up of our body is defined by the DNA structure.  T he Swiss biologist Johannes Friedrich Miescher first recognized and named DNA in 1869 while conducting research on white blood cells. James Watson and Francis Crick later made the discovery of the DNA molecule's double helix . types of DNA. A-DNA:  The double helix is right-handed and resembles the B-DNA form. DNA that has been dehydrated adopts an A form that shields it from harmful conditions like desiccation.  Protein binding also removes the solvent from DNA, and the DNA takes an A form. B-DNA:  A right-handed helix is the most typical DNA conformation .  The majority of DNA has a...