Proteins (DP IB Biology: HL)

Amino acids consist of oxygen, hydrogen, carbon and nitrogen atoms. The diameter of each atom when bonded to another atom is shown in the table below.

Using the figures in the table, the approximate length of one amino acid is 0.7 nm, as shown below.

What would be the approximate length of a dipeptide of this amino acid after a condensation reaction has occurred?

Which of the following chemical groups does not bond directly with the central carbon of an amino acid?

All life (except for a few primitive, prokaryotic species) use the same 20 amino acids joined into polypeptides.

Which of the four statements above is not a possible hypothesis for why all life uses the same 20 amino acids?

Which of the following causes fibrous polypeptides to be insoluble?

Which row of the table best classifies common proteins with differing numbers of polypeptide chains?

Which of the following words best describes the structure of a large macromolecule (such as a protein) and its final 3-D shape?

Which of the following statements about the proteome is correct?

Which of the following diagrams correctly shows the structure of a dipeptide?

Using the nomogram below, what is the Body Mass Index of a person of height 1.65 m and mass 130 lbs?

When using molecular visualisation software to represent large biological molecules, which aspect of a macromolecule would not necessarily be distinguishable?

Human insulin is a peptide hormone consisting of 51 amino acids.

Which of the following would represent the minimum number of bases that the gene coding for insulin would consist of?

Trypsin is a digestive enzyme found in pancreatic juices that breaks down proteins into polypeptides in the small intestine. The image below represents the three dimensional structure of trypsin.

Image courtesy of 0fb1d8. Licensed under Creative Commons Attribution-Share Alike 4.0 International license. Reused and distributed under conditions found at: https://creativecommons.org/licenses/by-sa/4.0/deed.en

Which of the following would be the most accurate description of the conformation of trypsin?

Rituximab is an example of a therapeutic protein that is used to treat certain types of cancers and autoimmune diseases. It is very sensitive to temperature and pH changes and is typically injected into the bloodstream of patients.

Which of the following statements would explain why therapeutic proteins, such as rituximab, cannot be taken orally?

I. The molecule would vibrate so fast once in the stomach that the intermolecular bonds would break

II. The conformation of the protein will change once in the stomach and it may become non-functional

III. The protein may become insoluble once in the stomach and form a precipitate due to the breakage of ionic bonds

IV. Conditions in the stomach will cause the hydrophobic R-groups of the protein to be exposed to the outside of the molecule

The denaturation of three different proteins (P, Q and R) at different temperatures were investigated. The more denatured a protein is, the less stable the molecule becomes. The following graph shows the results of this investigation.

Which of the following would be the most valid conclusion that the scientists can draw from these results?

Which of the following statements applies to both the proteome and genome of an organism?

I. Every cell in an organism is reliant on this for its survival

II. It is a reflection of the actual events taking place inside the cells of an organism

III. There are slight variations present between individual organisms

IV. It can be variable over time depending on the activities of the cell