RNA

RNA stands for Ribonucleic Acid It’s a lot like DNA, except: It’s single-stranded It has Ribose, not Deoxyribose Instead of Thymine, it has Uracil

There are 3 different kinds of RNA, and they all have special jobs There are 3 different kinds of RNA, and they all have special jobs. They are: mRNA, or Messenger RNA tRNA, or Transfer RNA rRNA, or Ribosomal RNA They all come together to make protein.

That strand of RNA is used to make a protein. Sometimes, instead of replicating, DNA is used to make a strand of RNA. That strand of RNA is used to make a protein. When DNA is used to make RNA, it is called “Transcription”. When RNA is used to make a protein, it is called “Translation” V

Remember how DNA “unzips” so it can be copied Remember how DNA “unzips” so it can be copied? Well, sometimes it “unzips” and a piece or RNA is made instead. Then, that piece of RNA is used to make a protein. Proteins make up almost everything inside us. The shape of the protein determines what it does.

GENE EXPRESSION

TRANSCRIPTION RNA Polymerase clamps on to DNA, opens it up, and creates a strand of RNA A binds with U, G binds with C

TRANSLATION Every 3 nucleotides on a strand of mRNA are referred to as a “CODON”. It codes for a specific amino acid. When creating a protein, we add the appropriate amino acid by matching a codon with it’s “ANTICODON”, which is a corresponding 3-nucleotide sequence that matches the codon perfectly. Anticodons are found on tRNA. tRNA has an amino acid bound to it, that joins the amino acid chain to create a protein.

TRANSLATION This entire process occurs in the ribosome, and continues until a STOP CODON is reached.

OPERONS How does our body know when to make the protein and when not to? What if we have too much of something, or not enough? Prokaryotic and some select eukaryotic organisms use OPERONS to regulate gene expression. Operons are like switches that get turned on or off, depending on whether or not something is needed, or there is too much of it. These are categorized as INDUCTIVE or REPRESSIVE.

INTRONS AND EXONS Not all of our DNA codes for proteins we use, or even need. The areas that we use are called EXONS. The areas we do not use are called INTRONS. EXONS are EXPRESSED, introns are not.

MUTATIONS

POINT MUTATION INSERTION – a new nucleotide is inserted into the sequence DELETION – a base pair is deleted from the sequence GENE REARRANGEMENT TRANSPOSITION – two sections of a chromosome trade places READING ERRORS FRAMESHIFT MUTATION – When creating the mRNA, the template is “off” by a base pair, resulting in a strand of mRNA that is in the correct order, just missing a base pair. This results in creating a completely different protein, or creating nothing at all.