1) Which fi gure best represents the bonding between adenine and thymine in the structure of DNA?

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2) Spider webs are very strong and elastic. Spider web silk is a protein that mainly consists of glycine and alanine residues.

a. Assuming that these amino acid residues alternate in a spider web, draw a section of the spider web protein that contains at least three amino acid residues

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b. What is the name of the bond between each amino acid residue?

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c. What type of polymerisation reaction occurs in the formation of spider web silk?
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d. Glycine forms an ion at a pH of 6 that has both a positive and negative charge. Draw the structure of a glycine ion at a pH of less than 4.

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e. Describe the bonds that contribute to the spiral secondary structure of this protein.

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3) Australian jellyfi sh venom is a mixture of proteins for which there is no antivenom. Jellyfish stings are painful, can leave scars and, in some circumstances, can cause death.
Some commercially available remedies disrupt ionic interactions between the side chains on amino acid residues.
These products most likely disrupt the protein's
A. primary structure only.
B. secondary structure only.
C. tertiary structure only.
D. primary, secondary and tertiary structures.

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