The thickness b of very thin film can be determined by the IR interference fringe method. Such interference can be observed between 2800 and 2000 cm-1 region of a polystyrene sheet, which has a refractive index considerably different from that of air. For this reason, significant reflection occurs at the two interfaces of the sheet which are often used to calculate the thickness of the polymer film. Using the 2000-2500 cm-1 region of the provided spectrum we can say that the polystyrene film has a mm thickness of: 100 90 M 80 70 60 50 40 30 20 10 3200 2800 2400 2000 Wavenumber, cm- Seleccione una: O a. 0.030 O b. 0.045 O. 0.090 O d. 0.018 O e. 0.060 Transmittance, %

Proteins are formed when the group of one amino acid forms a peptide bond with the group of a second amino acid. OR group; H-bond + O NH3*, R group + O -COO, NH3 -COO, R group

Please don't provide handwriting solution

2. A protein is a polymer of amino acids that assume a unique structure in space primarily using intermolecular forces. Identify/circle the IMF that give protein structure in the following picture. Briefly describe these key IMFs. 198

Which of these molecules is not a natural amino acid?

As we’ve discussed, a peptide bond is made when amino group of one amino acid combines with the carboxylic acid group of another amino acid (releasing a water molecule in the process). The C-N bond formed in this process is called a peptide bond. Peptide bonds have a few properties that might be unexpected. a) One property is that the molecular geometries around the C and N atom in the peptide bond are generally planar with bond angles of approximately 120 degrees. Provide an explanation for why the peptide bond would have this property, using Lewis structures, VSEPR theory and/or valence bond theory as appropriate.

What is the properIUPAC name for this

pls show the process, thank you. I have tried two other options and they have not worked

-Understand and be able to identify different interactions that factor into peptide/protein folding (e.g. hydrogen bonding, salt bridge interactions, disulfide bonding. Be able to predict these interactions given a peptide structure. -Understand basic molecular geometry in a peptide. What is the bond angle between amide N, C, and O atoms? Why is the angle like this?

please draw and the name of the R groups for all 20 amino acids.