Carbohydrates and Their Functions in Biological Molecules

1. Day 3 Carbohydrates Adapted from

2. 3.1 Why Is Carbon So Important in Biological Molecules? • Organic/inorganic molecules • Organic - molecules containing a carbon skeleton bonded to hydrogen atoms • Inorganic - carbon dioxide and all molecules without carbon

3. 3.2 How Are Organic Molecules Synthesized? • Small organic molecules (called monomers) are joined to form longer molecules (called polymers)

4. Author Animation: Monomers and Polymers

5. 3.2 How Are Organic Molecules Synthesized? • All biological molecules fall into one of four categories • Carbohydrates • Lipids • Proteins • Nucleotides/nucleic acids

6. 3.3 What Are Carbohydrates? • Carbohydrate molecules are composed of C, H, and O in the ratio of 1:2:1 (CH2O)n “hydrated” carbon • monosaccharide – consists of a single sugar molecule (C6H12O6) • Disaccharide - 2 linked monosaccharides • Polysaccharide - a polymer of many monosaccharides

7. 3.3 What Are Carbohydrates? • Glucose (C6H12O6) is the most common monosaccharide in living organisms Fig. 3-3

8. 3.3 What Are Carbohydrates? • Additional monosaccharides are: • Fructose (“fruit sugar” found in fruits, corn syrup, and honey) • Galactose (“milk sugar” found in lactose) • Ribose and deoxyribose (found in RNA and DNA, respectively)

9. 3.3 What Are Carbohydrates? • Examples of disaccharides include: • Sucrose (table sugar) = glucose + fructose • Lactose (milk sugar) = glucose + galactose • Maltose (malt sugar) = glucose + glucose

10. 3.3 What Are Carbohydrates? • Examples of polysaccharides include • Starch • Glycogen • Cellulose • Chitin • All 4 made of glucose/modified glucose monomers

11. 3.3 What Are Carbohydrates? • Functions: • Energy source/storage (sugar, starch, glycogen) • Structural molecule (cellulose, chitin)

12. Testing for Carbohydrates • Test for simple sugar – glucose test strips • Test for starch - iodine

13. Day 4 Lipids, Proteins, and Nucleic Acids Adapted from

14. 3.4 What Are Lipids? • Lipids are a diverse group of molecules • All lipids contain large chains of nonpolar hydrocarbons (hydrogen and carbon) • Most lipids are therefore hydrophobic and water insoluble

15. Author Animation: Lipids

16. 3.4 What Are Lipids? • Functions • Energy storage (fats, oils) • Waterproof coverings on plant and animal bodies (waxes) • Primary component of cellular membranes (phospholipids) • Many hormones (steroids)

17. 3.6 What Are Nucleic Acids? • Nucleotides are the monomers of nucleic acid chains • Nucleotides act as energy carriers and intracellular messengers • Made of a sugar (deoxyribose or ribose), a phosphate group (contains phosphorus), and a nitrogenous base (contains nitrogen and differs among nucleotides)

18. 3.6 What Are Nucleic Acids? • Adenosine triphosphate (ATP) is a deoxyribose nucleotide with three phosphate functional groups • Functions as an energy carrier

19. 3.6 What Are Nucleic Acids? • DNA and RNA, the molecules of heredity, are nucleic acids • There are two types of polymers of nucleotides called nucleic acids • DNA(deoxyribonucleic acid) is found in chromosomes and carries genetic information needed for protein construction • RNA (ribonucleic acid) makes copies of DNA and is used directly in the synthesis of proteins

20. 3.5 What Are Proteins? • Proteins are formed from chains of amino acids joined by peptide bonds • Monomer = ?

21. 3.5 What Are Proteins? • The sequence of amino acids in a protein dictates its function • Covalent bond linking the amino acids is a peptide bond • Chain of two amino acids is a peptide • Long chains of amino acids are polypeptides, or just proteins

22. 3.5 What Are Proteins? • Proteins exhibit up to four levels of structure • Primary structure is the sequence of amino acids linked together in a protein • Secondary structure is a helix, or a pleated sheet • Tertiary structure refers to complex foldings of the protein chain held together by disulfide bridges, hydrophobic/hydrophilic interactions, and other bonds • Quaternary structure occurs where multiple protein chains are linked together

23. The Four Levels of Protein Structure (b) Secondary structure: Usually maintained by hydrogen bonds, which shape this helix (a) Primary structure: The sequence of amino acids linked by peptide bonds leu val heme group lys lys gly his hydrogen bond ala lys val (d) Quaternary structure: Individual polypeptides are linked to one another by hydrogen bonds or disulfide bridges (c) Tertiary structure: Folding of the helix results from hydrogen bonds with surrounding water molecules and disulfide bridges between cysteine amino acids lys helix pro Fig. 3-20

24. 3.5 What Are Proteins? • The functions of proteins are linked to their three-dimensional structures • If proteins lose their structure (become denatured), they lose their function

25. 3.5 What Are Proteins? • Functions of proteins • Catalytic - enzymes promote chemical reactions • Structural - make up physical structure of organisms

26. 6.4 How Do Enzymes Promote Biochemical Reactions? • At body temperatures, spontaneous reactions proceed too slowly to sustain life • Reaction speed is determined by the activation energy required  how much energy is required to start the process • low activation energies  proceed rapidly at body temp. • high activation energies  move very slowly at body temp.

27. 6.4 How Do Enzymes Promote Biochemical Reactions? • Enzymes catalyze (speed up) chemical reactions by lowering the activation energy • Enzymes are biological catalysts and regulate all the reactions in living cells • They are very specific – dependent on enzyme’s 3-D structure • Not used up in chemical reactions

28. Author Animation: Activation Energy

29. Catalysts Such As Enzymes Lower Activation Energy high Activation energy without catalyst Activation energy with catalyst energy content of molecules reactants products low Fig. 6-10 progress of reaction

30. The Cycle of Enzyme-Substrate Interactions substrates active site of enzyme enzyme 1 Substrates enter the active site in a specific orientation The substrates and active site change shape, promoting a reaction between the substrates 3 2 The substrates, bonded together, leave the enzyme; the enzyme is ready for a new set of substrates Fig. 6-11

31. Liver Magic! • Let’s test it!

32. Day 5 Central Dogma of Molecular Biology and Energy Production Adapted from

33. Central Dogma of Molecular Biology Replication Transcription Translation DNA RNA Protein

34. ATP and Energy • Most organisms are powered by the breakdown of glucose • Energy in glucose cannot be used directly by our cells • Energy in glucose must first be transferred to an energy-carrier molecule (ATP) Glucose ATP Cell Process

35. ATP and Energy • ATP stores energy within its bonds • Phosphate groups negatively charged and don’t like being crowded together Base Sugar P P P High-energy bond

36. ATP and Energy • When bond is broken in ATP products are ADP (Adenosine Diphosphate), a phosphate group, and energy

37. ATP and Energy • Putting ATP back together again requires energy • Comes from breaking down glucose energy P P P  P P P ATP phosphate ADP

38. What’s Earth’s ULTIMATE source of energy?

39. How do WE get that energy?

40. How do WE get that energy? • Eat sugar  now what? • Remember, sugar’s the gold bar! • Cellular Respiration Glucose + Oxygen  Carbon dioxide + Water + ATP (+ heat) C6H12O6 + 6 O2 6 CO2 + 6 H2O + ATP (+ heat)

41. How does OUR FOOD get that energy? • Animals  they eat too! • Plants, Algae? • Photosynthesis Carbon dioxide + Water + Light Energy  Sugar + Oxygen 6 CO2 + 6 H2O + Light Energy  C6H12O6 + 6 O2

42. Author Animation: Overview: Photosynthesis and Respiration