Chemistry of Life

Objectives

• 1. Identify the four macromolecules. Know their basic chemical compositions and how each is important to living organisms.

  2. Know how various molecular subunits polymerize to form chains of organic macromolecules.

  3. Understand the consequences of dehydration and hydrolysis reactions and how they are dependent upon water.

  4. Know the importance of an amino acid R group.

  5. Describe the six levels of protein structure and the forces that help maintain each level.

  6. Understand how chaperonins are involved in protein folding and unfolding.

  7. Understand the difference between a helix and a double helix in DNA and RNA.

  8. Compare DNA and RNA in terms of chemical composition and basic cellular function.

  9. Differentiate between saturated and unsaturated fats, in the types of bonds they possess, their relative amounts of hydrogen, their energy content, and their consistency at room temperature.

  10. Know how and why monosaccharides combine to form the various common disaccharides and polysaccharides.

  11. Compare cellulose and chitin to one another and to other polysaccharides in terms of their chemical composition and their digestibility.

  12. Contrast lipids and starches with respect to their solubility in water and their efficiency in storing chemical energy.

COMMON STUDENT MISCONCEPTIONS

• • After a chemical change it is believed that the original substances remain even though they are altered.

  • The chemistry in biological systems does not follow all the same rules of inorganic chemistry.

  • Molecules are glued together.

  • Food molecules are anything useful taken into the body such as water, minerals, and carbon dioxide.

  • Digestion is the breakdown of molecules that releases usable energy from food.

  • Students are unsure about the hierarchical order of atoms, molecules and cells.

  • Carbohydrates serve only as a source of for the body.

  • All polysaccharides are starches.

  • All carbohydrate polymers are for food storage.

  • Proteins are not energy sources for the body.

  • There are only 20 types of amino acids in nature.

  • Amino acids and proteins are not related molecules.

  • Fats produce more energy than carbohydrates.

  • Fats only serve as a stored source of energy.

  • Students often confuse amino acids and nucleic acids.

  • All proteins have tertiary structure.

  • Proteins are a 100% representation of the DNA information.

  • Nucleic acids solely serve the purpose of genetic material.

  • Saturated fats are bad, while unsaturated fats are good.

  • Cholesterol is bad for the body.

  • Fats travel as clumps of insoluble material in the blood.

  • Organic molecules are only produced by organisms.