Name the amino acid that would form at X, if a mutation caused Adenine to replace Uracil. Explain your Answer:

Here are the answers to the questions:

Protein synthesis:

• Give 3 reasons why this diagram represents transcription:

  • The DNA double helix is unwinding.
  • One strand of the DNA acts as a template.
  • RNA nucleotides are pairing with the exposed DNA bases (e.g., Uracil (U) pairs with Adenine (A) on DNA).
  • An mRNA molecule is being synthesized from the DNA template.

• Describe the role of DNA in Protein synthesis:

  • DNA contains the genetic code in the form of a sequence of nitrogenous bases.
  • It serves as a template for the synthesis of messenger RNA (mRNA) during transcription.
  • This genetic information dictates the specific sequence of amino acids, which determines the structure and function of a protein.

• Explain how a mutation on the DNA affects Protein Synthesis:

  • A mutation is a change in the DNA base sequence.
  • This change can lead to an altered mRNA codon during transcription.
  • An altered mRNA codon may result in a different amino acid being incorporated into the polypeptide chain during translation.
  • This change in the amino acid sequence can alter the protein's three-dimensional structure and, consequently, its function.

Transcription:

• What is given: DNA, mRNA or tRNA? Triplet, Codon or Anti Codon?

  • The sequence "UCAGG CACA" represents mRNA and the units are Codons.

• Identify the amino acid at:

  • Codon 1 (UCA): The DNA triplet that codes for UCA is AGT. From the table, AGT codes for Serine.
  • Codon 2 (GGC): The DNA triplet that codes for GGC is CCG. From the table, CCG codes for Glycine.
  • Codon 3 (ACA): The DNA triplet that codes for ACA is TGT. From the table, TGT codes for Threonine.

• Name the amino acid that would form at X, if a mutation caused Adenine to replace Uracil. Explain your Answer:

  • The original codon at X is UCA. If Uracil (U) is replaced by Adenine (A), the new codon becomes ACA.
  • The DNA triplet that codes for the mRNA codon ACA is TGT.
  • According to the table, the DNA triplet TGT codes for Threonine.
  • Therefore, the amino acid that would form at X is Threonine.

Translation:

• Three consecutive bases on the tRNA is known as an:

  • Anticodon

• Translation:

  • Translation is the process where the genetic information encoded in mRNA is used to synthesize proteins.
  • It occurs in the ribosomes, where tRNA molecules bring specific amino acids according to the mRNA codons.
  • The amino acids are then linked together to form a polypeptide chain.

• Functions of tRNA:

  • To transport specific amino acids from the cytoplasm to the ribosome.
  • To recognize and bind to complementary codons on the mRNA molecule via its anticodon.
  • To ensure the correct sequence of amino acids is added to the growing polypeptide chain.