Carbon-based molecules are the foundation of life and come in three main structures: straight chains, branched chains, and rings. The four main types of carbon-based molecules in living things are carbohydrates, lipids, proteins, and nucleic acids. Carbohydrates are made of carbon, hydrogen, and oxygen and include sugars and starches. Lipids include fats, oils, and cholesterol and have many functions like energy storage. Proteins are polymers of amino acids and have different shapes that influence their functions. Nucleic acids like DNA and RNA are made of nucleotides and perform roles like storing genetic information.

1. KEY CONCEPTCarbon-based molecules are the foundation of life.

3. straight chain

4. branched chain

8. Monosaccharides are simple sugars.

10. Many contain carbon chains called fatty acids.

12. make up cell membranes

16. Twenty different amino acids are used to build proteins in organisms.Amino acids differ in side groups, or R groups.

18. Twenty different amino acids are used to build proteins in organisms.

19. Amino acids differ in side groups, or R groups.Amino acids are linked by peptide bonds.

26. Energy is released when bonds form.

27. A reaction is at equilibrium when reactants and products form at the same rate.CO2 + H2O H2CO3

28. Chemical reactions release or absorb energy. Activation energy is the amount of energy that needs to be absorbed to start a chemical reaction.

32. A catalyst lowers activation energy. Catalysts are substances that speed up chemical reactions. decrease activation energy increase reaction rate

34. Changes in temperature and pH can break hydrogen bonds.

37. bonds in substrates weakened