Photo AI
a. List the three components of a DNA nucleotide - VCE - SSCE Biology - Question 6 - 2010 - Paper 1
Question 6
a. List the three components of a DNA nucleotide. b. What is the amino acid sequence for the TSD individual in Table Y? Use the information in Table Y to explain ho... show full transcript
Worked Solution & Example Answer:a. List the three components of a DNA nucleotide - VCE - SSCE Biology - Question 6 - 2010 - Paper 1
Step 1
List the three components of a DNA nucleotide.
Answer
The three components of a DNA nucleotide are:
- Phosphate Group: This group contains phosphorus and oxygen and is crucial for forming the backbone of DNA.
- Deoxyribose Sugar: This five-carbon sugar differentiates DNA from RNA.
- Nitrogenous Base: There are four types: Adenine (A), Thymine (T), Cytosine (C), and Guanine (G).
Step 2
What is the amino acid sequence for the TSD individual in Table Y?
Answer
The amino acid sequence for the TSD individual can be derived from the DNA nucleotide sequence (CTT GTA AAA) using Table Y:
- C T T → leucine (leu)
- G T A → valine (val)
- A A A → lysine (lys)
Thus, the sequence is leu - val - lys.
Step 3
Use the information in Table Y to explain how changing one amino acid in a polypeptide may adversely affect the function of a protein of which the amino acid is part.
Answer
The change in the amino acid sequence can significantly alter the protein's structure and function. For the TSD individual, the alteration from the normal sequence (glu - arg - phe) to the mutated sequence (leu - val - lys) indicates a change from an acidic to a non-polar amino acid. This could affect:
- Protein Structure: The amino acids interact with each other, influencing the folding and stability of the protein. Thus, a single amino acid change can lead to the misfolding of the protein.
- Protein Function: Enzymatic activity may change if the active site is altered. In this case, the enzyme hexosaminidase A may not function properly, leading to accumulation of substrates and resulting in Tay Sachs disease.