CK-12-Chemistry Intermediate

http://www.ck12.org Chapter 26. Biochemistry

• Enzymes are proteins that catalyze biochemical reactions. A substrate binds to an enzyme at its active site,
  where the chemical reaction occurs.

Lesson Review Questions

Reviewing Concepts

1. What gives each of the twenty common amino acids its unique structure and properties?


2. What type of organic reaction is required to form a dipeptide from individual amino acids?


3. How many peptide bonds are present in the sequence Ala-Glu-Phe-Asn?


4. Does the amino acid sequence Leu-Ser-His have the same structure as the His-Ser-Leu sequence? Explain
   why or why not.


5. Distinguish between the primary structure and the secondary structure of a protein.


6. Describe the two common secondary structures found in proteins. What interactions are primarily responsible
   for secondary structure?


7. Distinguish between the tertiary structure and the quaternary structure of a protein.


8. Why can a cell function normally even if the concentrations of essential enzymes in the cell are very low?


9. Explain why multiple different molecules generally cannot act as substrates for a given enzyme.

Problems

10. Draw the structure of the dipeptide given by the sequence Thr-Asp.

Further Reading / Supplemental Links

• IntroducingAminoAcids, http://www.chemguide.co.uk/organicprops/aminoacids/background.html


• TheStructureofProteins, http://www.chemguide.co.uk/organicprops/aminoacids/proteinstruct.html


• ProteinsasEnzymes, http://www.chemguide.co.uk/organicprops/aminoacids/enzymes.html

Points to Consider

The class of biomolecules called lipids is comprised of fats, oils, and other water-insoluble compounds.

• What is the structure of a triglyceride?


• What are phospholipids?