Dihedral angles are important in the secondary structure of proteins. Two types of dihedral angles have the greatest impact on peptide conformation, with these derived from rotation around:

(Note that the main-chain atoms of an amino acid backbone are here denoted N–Cα–C)

Fibrous proteins often have functions related to:

The image below is a helical wheel representation of part of an alpha helix (top-down view), with each amino acid a numbered circle.

Without knowledge of any R groups, non-covalent interactions between which ONE of the following pairs of amino acids will likely help stabilise the helix?

You are researching the impact of rising CO₂ levels on ocean acidification. Below are several potential sources of information. Which source would be the most credible and reliable for your research? Explain your choice. When/how might each of the different sources be useful? Finally, how does this relate to synthesizing the feedback you received during the paper prototyping session?

1. A blog post written by a non-scientist discussing their personal views on climate change.

2. A peer-reviewed journal article published in Nature Climate Change on the effects of CO₂ on marine ecosystems.

3. A Wikipedia entry on ocean acidification.

4. A news article summarizing a recent scientific study on CO₂ emissions.

Why is cysteine (shown below) able to form disulphide bonds?

• Currency outside banks: $15 billion
• Personal and business chequable deposits: $40 billion
• Personal non-chequable deposits: $50 billion
• Business non-chequable deposits: $125 billion
• Currency held by banks: $200 billion

The value of M1+ is $________ billion and the value of M2+ is $________ billion.