Peptide molecules can be classified according to the number of amino acid units joined by peptide bonds in the molecule - Scottish Highers Chemistry - Question 6 - 2016

Based on the smaller peptide sequences provided (leucine-glycine-valine, isoleucine, glycine-valine), the amino acid sequence for the original pentapeptide can be identified as isoleucine-leucine-glycine-valine-serine.

The term used to describe amino acids that the body cannot synthesize is 'essential'.

Only four spots were obtained on the chromatogram because the peptide must contain an amino acid that is repeated in the sequence, meaning there are only four different amino acids present in the mixture.

The circle should be drawn around the spot that corresponds to the Rf value of 0.40, indicating the position of methionine on the chromatogram.

A structural formula for the amino acid can be represented as follows:

  H   O  
  |   || 
H2N-C-C
  |   |  
 H   CH3

This represents the amino acid formed after hydrolysis.

For a 75 kg adult, the lethal dose is:

$100 ext{ mg/kg} \times 75 ext{ kg} = 7500 ext{ mg}$

Since 1 g of death cap mushrooms contains 250 mg of alpha-amanitin, the minimum mass of mushrooms required would be:

$\frac{7500 ext{ mg}}{250 ext{ mg/g}} = 30 ext{ g}$