HSC Biology Syllabus - Genetics: The Code Broken? (Option) - All Dot Points Answered
9.7 - Genetics: The Code Broken? (Option)1. The structure of a gene provides the code for a polypeptide:•Describe the processes involved in the transfer of information from DNA through RNA to the production of a sequence of amino acids in a polypeptide:-The structures involved in polypeptide synthesis are:DNA: A gene contains a sequence of bases to code for a protein. Every set of 3 bases is called a codon.
RNA: RNA is similar to DNA except that instead of deoxyribose as the sugar, it has ribose. It is single stranded, and instead of thymine, there is uracil. There are 3 forms involved in polypeptide synthesis:mRNA: Messenger RNA carries the genetic code outside the nucleus, into the cytoplasm, where it can be read by ribosomestRNA: Transfer RNA carries the amino acids to the ribosomes to link and form a polypeptide chain. tRNA are shaped like clover leaves; there is a different type for every amino acid. At the bottom of every tRNA molecule is an anti-codon that binds to the codon on the mRNA strand. That is how the amino acid is linked to the codon.
Ribosomal RNA: Ribosomes are made up of protein and RNARibosomes: The ribosome is the active site for protein synthesis. It is made up of protein and RNA molecules. It can accommodate 2 tRNA at a time.
Enzymes: The enzyme that controls the formation of mRNA is RNA polymerase. There are, of course, many other enzymes that control the process.
-STAGE ONE - Transcription:A double stranded DNA molecule in the nucleus unwinds a section of itself that consists of a single gene.
One of the strands coding for the gene exposes itself to the nucleoplasmThe enzyme, RNA polymerase moves along the strand, attaching loose RNA nucleotides to the DNA, with A-U and C-G, until the whole gene is copied.
This new RNA strand is called messenger RNA (mRNA)A start codon, and a stop codon determine the length of the gene-STAGE TWO - Translation:The mRNA strand binds to a ribosome in the cytoplasm, with the start codon being AUG
RNA: RNA is similar to DNA except that instead of deoxyribose as the sugar, it has ribose. It is single stranded, and instead of thymine, there is uracil. There are 3 forms involved in polypeptide synthesis:mRNA: Messenger RNA carries the genetic code outside the nucleus, into the cytoplasm, where it can be read by ribosomestRNA: Transfer RNA carries the amino acids to the ribosomes to link and form a polypeptide chain. tRNA are shaped like clover leaves; there is a different type for every amino acid. At the bottom of every tRNA molecule is an anti-codon that binds to the codon on the mRNA strand. That is how the amino acid is linked to the codon.
Ribosomal RNA: Ribosomes are made up of protein and RNARibosomes: The ribosome is the active site for protein synthesis. It is made up of protein and RNA molecules. It can accommodate 2 tRNA at a time.
Enzymes: The enzyme that controls the formation of mRNA is RNA polymerase. There are, of course, many other enzymes that control the process.
-STAGE ONE - Transcription:A double stranded DNA molecule in the nucleus unwinds a section of itself that consists of a single gene.
One of the strands coding for the gene exposes itself to the nucleoplasmThe enzyme, RNA polymerase moves along the strand, attaching loose RNA nucleotides to the DNA, with A-U and C-G, until the whole gene is copied.
This new RNA strand is called messenger RNA (mRNA)A start codon, and a stop codon determine the length of the gene-STAGE TWO - Translation:The mRNA strand binds to a ribosome in the cytoplasm, with the start codon being AUG