Protein Synthesis Flashcards
1
Q
Name the two general processes involved in protein synthesis.
A
- Transcription and translation
2
Q
State the name of the major enzyme involved in transcription.
A
- RNA polymerase
3
Q
State the function of a gene.
A
- A unique sequence of bases in DNA that codes for a polypeptide or RNA molecule.
4
Q
What is a codon and anti-codon?
A
- Codon – 3 bases on mRNA encoding an amino acid
- Anti-codon – 3 bases on tRNA complementary to the 3-base codon on mRNA
5
Q
State the role of mRNA in protein synthesis.
A
- To carry a temporary copy of the gene sequence from the DNA to the ribosome to be translated.
6
Q
State the role of tRNA in protein synthesis.
A
- To carry a specific amino acid to the ribosome for translation.
7
Q
Describe the process of transcription.
A
- DNA unwinds and unzips to expose the specific sequence of bases of the gene that codes for the protein.
- Nucleotides are added in a complementary manner to the exposed bases (A on DNA with U in mRNA, T with A, C with C and C with G) to form a single stranded mRNA molecule.
8
Q
Describe the process of translation.
A
- The mRNA attaches to a ribosome.
- tRNA molecules bring specific amino acids to the ribosome and align themselves in an order determined by complementary base pairing between the anti-codons on tRNA and the codons on the mRNA.
- The amino acids are then joined together by peptide bonds to form a polypeptide/protein.
9
Q
Explain why a triplet code is required to code for specific amino acids rather than just pairs.
A
- There exists 20 amino acids and each one requires a unique code.
- If a one-base code was used, there would only be four combinations (A, T, G, C); if a 2-base code was used, there would be 16 possible combinations – still not enough to cover all 20 amino acids.
- A triplet code (3 bases) produces 64 combinations – more than enough to provide a unique code for the 20 amino acids.
