Protein Synthesis & DNA

It describes the process of Protein synthesis. Detailed explanation for each piece and step.

20 flashcards · Biology · by Bhrugu Patel

1. What is Central Dogma?

   Central Dogma is the process where DNA is converted into RNA through the process of Transcription. Then the RNA is translated by the ribosome to make proteins.

2. What is mRNA?

   mRNA or otherwise known as Messenger RNA is the product of Transcription. It is the RNA that carries the information from the DNA to the ribosome. It carries this information in a group of three nucleotide bases known as codons.

3. What is rRNA?

   rRNA or otherwise known as Ribosomal RNA is the building block of ribosomes. Ribosomes are mostly built up of rRNA and some structural proteins. rRNA is also the only RNA that has enzymatic activity. It is the rRNA in a ribosome that builds the peptide bonds between the amino acids.

4. What is tRNA?

   tRNA or otherwise known as Transfer RNA is the RNA that translates the mRNA in the process of Translation. It has anticodons that correspond to the codons on the mRNA. It is also the RNA that brings amino acids to the ribosome for Protein Synthesis.

5. What is the process of Transcription?

   Transcription is the process in which the RNA polymerase transcribes the DNA into mRNA. The RNA polymerase reads the nucleotide bases of the DNA and adds corresponding RNA bases to create mRNA.

6. What is the process of Translation?

   Translation occurs in the cytoplasm and ribosome. The mRNA created during Transcription binds onto a ribosome and starts the process of Translation. tRNA then reads the codons on the mRNA and translates them by using its anticodons. tRNA then brings amino acids to the ribosome to build a polypeptide chain. Translation starts at a Start codon known as AUG and stops at a stop codon. There are three stop codons: UAA, UAG, and UGA. The Start codon AUG also makes the protein Methionine(Met), so most…

7. What is a Polypeptide?

   A polypeptide is the polymer of amino acid, otherwise known as a protein. It is called polypeptide because amino acids are bonded by peptide bonds.

8. What is a Start Codon?

   A Start Codon is a codon at the start of mRNA. It signals the start of each Translation. The one and only start codon is AUG which also codes for the amino acid Methionine(Met). Most polypeptide chains begin with the amino acid Methionine(Met).

9. What is a Stop Codon?

   A Stop codon is a codon that signals the end of Translation. The three different Stop Codons are UAA, UAG, and UGA. Unlike the Start Codon AUG, these do not code for an amino acid. When the tRNA reads one of these, it stops bringing amino acids and the completed polypeptide chain un-attaches from the ribosome. It would then either go to the ER for modification or be used directly. The mRNA also un-attaches from the ribosome. The ribosome separates into two subunits and Translation is over.

10. What are Introns?

    Introns are parts of an mRNA that are excluded after the process of Transcription. Introns are intervened between Exons in genes and are removed before the mRNA leaves the nucleus. This process is called splicing and results in a mature mRNA. This step allows different amino acid sequences to be created.

11. What are Exons?

    Exons are the parts of an mRNA that are kept in an mRNA. After the Introns are removed Exons are kept to make a mature mRNA chain. However, sometimes Exons are removed in a process known as alternate splicing. At the end of splicing the remaining Exons in the mRNA are 'spliced' together.

12. Bonus Flashcard to explain Intron and Exons further.

    Introns and Exons are both transcribed by the RNA polymerase during Transcription. However, Introns are removed during splicing and Exons remain. At the end of splicing a 5' cap is added to the 5' end of the mature mRNA. A poly-A tail is added to the 3' end of the mature mRNA. A poly-A tail consists of many Adenine bases thus the name poly-A tail.

13. What are Transcription Factors?

    Transcription factors are molecules that attach to a certain gene to speed up, slow down, or stop transcription. The two Transcription factors are Activators and Repressors. Both bind to a an enhancer on the gene; an enhancer doesn't have to be close to the promoter. Activators speed up Transcription when they bind to the promoter or the enhancer. Represors slow down the reaction by interacting with the histones. They make the DNA wind tightly around the histone making the RNA polymerase unable…

14. What is a mutation?

    A mutation is a permanent change in the sequence of nucleotide bases in the DNA. Mutation have several different forms and causes. Mutations can be caused by environmental factors such as radiation. There are two types of radiation Ionizing radiation and Nonionizing radiation. Ionizing radiation knocks electrons out of the atoms causing chromosomes to break into pieces. Examples of Ionizing radiation are gamma rays. Non ionizing radiation overpowers electrons but not enough to knock them out of…

15. What are Frameshift muations?

    Frameshift mutations are mutation that cause the reading frame of the DNA to shift. This is most dangerous in mRNA because it codes for protein and if it has a shifted frame then the protein will be built wrong. Two types can cause Frameshift mutation Insertion and Deletion. Insertion is when there is a nucleotide base inserted to the sequence. Deletion is when there is a nucleotide base deleted from the sequence.

16. What is an insertion mutation?

    An Insertion mutation is when a nucleotide base is added to the sequence. This could cause the most damage in mRNA because the tRNA could misread it and make a different protein. An Insertion mutation is a type of Frameshift mutation.

17. What is a Deletion mutation?

    A deletion mutation is when a nucleotide base is deleted from the sequence. This could also wreak havoc on the mRNA sequence. The tRNA could misread and make protein not intended. A Deletion mutation is also a type of Frameshift mutation.

18. What is a Point mutation?

    A Point mutation is when a nucleotide base is mutated to another base. This is not particularly dangerous but it can be. For example the mRNA codon ACC and ACG both code for the amino acid Threonine(Thr). So if the last nucleotide base was mutated from a C to G it would not make much difference. However, if the first base was mutated from A to C then the codon would be CCC and the amino acid would change to Proline(Pro). It depends on the place the point mutation happens rather than the scale o…

19. What is a Substitution mutation?

    A Substitution mutation is similar to a point motion. It is substituted by another base, but it can happen on a larger scale. Instead of just one nucleotide base changing like in a point mutation, three can change. For example, in a point mutation, it would go from C to A, but in a substitution mutation, it can go from AUC to CGA. It can have the same results as the point mutation. It depends on the place of the mutation and the scale.

20. What is an Inversion mutation?

    An Inversion mutation is when a sequence of nucleotide bases are switched from end to end. This could have severe effects on the resulting protein. For example, AUC would turn to CUA. It turns backwards and the resulting protein would change from Isoleucine(Ile) for AUC to Leucine(Leu) for CUA.