Molecular Diagrams: Amino Acids, Glucose, Ribose & Fatty Acids

Posted on Feb 8, 2025 in Biology

Molecular Diagrams of Key Biochemicals

Drawing Molecular Diagrams

Skill: Drawing molecular diagrams of glucose, ribose, a saturated fatty acid, and a generalized amino acid.

Amino Acid

  • Composed of an amine (NH2) group, a carboxyl (COOH) group, and an R group.
  • 20 amino acids exist that compose all proteins.
  • Each amino acid differs because the R groups are different.

Glucose

  • Is a reducing sugar that contains C6H12O6.
  • Most commonly found in a ringed structure and is the main product formed by photosynthesis.
  • Energy molecule used in aerobic respiration.
  • Monomer of starch, glycogen, and cellulose.

Ribose

  • Pentose (5 carbon) sugar of RNA and RuBP (Calvin cycle).
  • C5H10O5
  • Differs from Deoxyribose (sugar in DNA) because it has an extra –OH group on the 2nd carbon of the ring.

Fatty Acids

  • Main component of triglycerides and phospholipids.
  • Fatty acids are non-polar and therefore hydrophobic.
  • Chains consist of covalently bonded carbon with hydrogen.
  • Saturated FAs are all single bonds and are therefore saturated with hydrogen.
  • Unsaturated FAs contain a double bond or double bonds.

Identifying Biochemicals from Molecular Diagrams

Skill: Identification of biochemicals such as sugars, lipids, or amino acids from molecular diagrams.

  • The generalized formula for carbohydrates is CH2O. All carbohydrates contain C, H, and O.
  • Proteins also contain C, H, and O, but they all have N. Some proteins also contain S in their R-groups.
  • Lipids contain C, H, and O as well, but in different ratios and much less O than carbohydrates.

Metabolism: Enzyme-Catalyzed Reactions

Metabolism is the web of all the enzyme-catalyzed reactions in a cell or organism.

  • Metabolism is the set of life-sustaining chemical reactions within the cells of living organisms.
  • These reactions are catalyzed by enzymes and allow organisms to grow and reproduce, maintain their structures, and respond to their environments.
  • Many of these reactions occur in the cytoplasm, but some are extracellular including digestion and the transport of substances into and between different cells.
  • The word metabolism can refer to the sum of all chemical reactions that occur in living organisms.

Anabolism: Synthesis of Complex Molecules

Anabolism is the synthesis of complex molecules from simpler molecules, including the formation of macromolecules from monomers by condensation reactions.

  • Metabolism is divided into two components: anabolism (building large molecules from smaller ones) and catabolism (breaking down of large molecules into their component parts).
  • Anabolic reactions require energy as you are building large molecules from small ones (takes energy to build things).
  • Some anabolic processes are protein synthesis, DNA synthesis and replication, photosynthesis, and building complex carbohydrates, such as cellulose, starch, and glycogen.
  • If you can’t remember which one is which, think anabolic steroids are used to build muscles in athletes and body builders, and catapults are used to break down walls in wars.

Catabolism: Breakdown of Complex Molecules

Catabolism is the breakdown of complex molecules into simpler molecules, including the hydrolysis of macromolecules into monomers.

  • Catabolism are reactions that break down larger molecules into smaller ones or their component parts.
  • Catabolic reactions release energy (sometimes captured in the form of ATP).
  • Some examples of catabolic reactions are digestion of food, cellular respiration, and breakdown of carbon compounds by decomposers.
  • Think of “catapults” used to break down enemy walls during wars.