1. Chapter 2 The Chemistry of Life Part 2

2. Carbohydrates are Polymers of Monosaccharides

3. TABLE 2.4
REVIEW OF SOME COMMON CARBOHYDRATES

4. Three different ways to represent a monosaccharide
FIGURE 2.14
Monosaccharides are simple sugars, generally having a backbone of three to six carbon atoms. Many of these carbon atoms are also bonded to hydrogen (H) and a hydroxyl group (OH). In the fluid within our cells, the carbon backbone usually forms a ring like structure. Here, three representations of the monosaccharide glucose (C6H12O6) are shown.

5. Carbohydrates
Carbohydrates are sugars and starches and provide fuel for the body.
Sucrose and lactose are examples of disaccharides or double sugars.

6. (Dehydration) Synthesis of a Disaccharide
FIGURE 2.15
Disaccharides are built from two monosaccharides. Here, a molecule of glucose and one of fructose combine to form sucrose.

7. Polysaccharides
Polysaccharides: thousands of monosaccharides joined in chains and branches
Starch: made in plants; stores energy
Glycogen: made in animals; stores energy
Cellulose: indigestible polysaccharide made in plants for structural support

8. FIGURE 2.16b
Polysaccharides may function in storage (as in glycogen) or provide structure (as in cellulose).

9. Lipids
Lipids are water-insoluble molecules that store long-term energy, and form cell membranes

10. Lipids
Fats and oils are examples of triglycerides, a polymer made of one molecule of glycerol and three fatty acids

11. Lipids
The fatty acids bond to glycerol through dehydration synthesis

12. FIGURE 2.17a
Triglycerides are composed of a molecule of glycerol joined to three fatty acids.

13. Lipids
If there are no double bonds between carbon atoms and fatty acids triglycerides are classified as saturated
Solid at room temperature
If there are double bonds they are called unsaturated
Liquid at room temp

14. FIGURE 2.17b
Triglycerides are composed of a molecule of glycerol joined to three fatty acids.

15. Oleic acid: a cis unsaturted fat

16. Elaidic acid: a trans unsaturated fat
Trans fats are artificial unsaturated fats that are not “kinked”
and therefore are not soluble at room temperature
Elaidic acid: a trans unsaturated fat

17. Phospholipids Components of cell membranes
Warm-blooded animals have saturated
Cold-blooded and plants have more unsaturated

18. Phospholipids Phospholipid molecules have a
Glycerol head that is polar and water soluble (hydrophilic) and a
Fatty acid tail that is nonpolar and water insoluble (hydrophobic)
Phospholipids function as essential structural components of membranes

19. FIGURE 2.18a
Structure of a phospholipid. Phospholipids are the main components of the plasma membrane encasing a cell and separating its internal and external watery environments.

20. Phospholipids
Phospholipids are arranged in a bilayer with the hydrophilic heads of each layer facing the aqueous side of the memb.

21. FIGURE 2.18b
Structure of a phospholipid. Phospholipids are the main components of the plasma membrane encasing a cell and separating its internal and external watery environments.

22. Steroids Cholesterol and Hormones
Estrogens and testosterone are examples of steroids

23. FIGURE 2.19
The steroid cholesterol is a component of cell membranes and is the substance from which steroid hormones such as estrogen and testosterone are made. All steroids have a structure consisting of four carbon rings. Steroids differ in the groups attached to these rings.

24. Proteins
Amino acids consist of a central carbon atom bound to a hydrogen (H) atom, an amino group (NH2), and a carboxyl group (COOH) in addition to a unique side chain called a radical (R)

25. FIGURE 2.20
Structure of an amino acid. Amino acids differ from one another in the type of R group (side chain) they contain.

26. FIGURE 2.21
Formation of a peptide bond between two amino acids through dehydration synthesis. The carboxyl group (COOH) of one amino acid bonds to the amino group (NH2) of the adjacent amino acid, releasing water.

27. Proteins
Proteins have four distinct levels of structure—primary, secondary, tertiary and quaternary—that affect their function in the body

28. Proteins
Changes in the chemical environment of a protein can cause it to lose its structure (called denaturation) resulting in a loss of function

29. FIGURE 2.22
Levels of protein structure.

30. Proteins
A special group of proteins are called enzymes and they serve as catalysts for chemical reactions

31. FIGURE 2.23a
The working cycle of an enzyme.

32. FIGURE 2.23b
The working cycle of an enzyme.

33. Characteristics of Enzymes
Biological catalysts
Make chemical reactions go fast (very)
Active Site has affinity for its substrate
Each enzyme is specific for a substrate

34. Nucleic acids include DNA and RNA
Functions
Store genetic information
Provide information used in making proteins

35. Nucleic Acids
Genes are segments of polymers called deoxyribonucleic acid (DNA)

36. Nucleic Acids
DNA and ribonucleic acid (RNA) are the two types of nucleic acids and both are polymers of smaller units called nucleotides

37. Nucleic Acids A nucleotide is made up of:
One five-carbon sugar bonded to
One of five nitrogen-containing bases and
One phosphate group

38. FIGURE 2.24
Structure of a nucleotide. Nucleotides consist of a five-carbon (pentose) sugar bonded to a phosphate molecule and one of five nitrogencontaining bases. Nucleotides are the building blocks of nucleic acids.

39. Nucleic Acids
The sequence of the nucleotides in DNA and RNA determine the sequence of amino acids in protein (i.e., primary structure of the protein)

40. Nucleic Acids
RNA and DNA have structural differences related to sugar, bases, and number of strands

41. TABLE 2.5
REVIEW OF THE STRUCTURAL DIFFERENCES BETWEEN RNA AND DNA

42. Nucleic Acids
RNA is single-stranded

43. RNA
FIGURE 2.25
RNA is a single-stranded nucleic acid. It is formed by the linking together of nucleotides composed of the sugar ribose, a phosphate group, and the nitrogen-containing bases cytosine (C), adenine (A), guanine (G), and uracil (U).

44. RNA

45. Nucleic Acids
DNA has two strands to form a distinctive double helix

46. DNA (double stranded) FIGURE 2.26
DNA is a nucleic acid in which two chains of nucleotides twist around one another to form a double helix. The two chains are held together by hydrogen bonds between the nitrogen-containing bases. Each nucleotide of DNA contains the pentose sugar deoxyribose, a phosphate group, and one of the following four nitrogen-containing bases: adenine (A), thymine (T), cytosine (C), and guanine (G).

47. Adenosine Triphosphate (ATP)
Adenosine triphosphate (ATP) is a special nucleotide
ATP molecule is capable of storing energy in its phosphate-to-phosphate bonds

48. ATP molecule stores energy in its phosphate-to-phosphate bonds
FIGURE 2.27
Structure and function of adenosine triphosphate (ATP). This nucleotide consists of the sugar ribose, the base adenine, and three phosphate groups. The phosphate bonds of ATP are unstable. When cells need energy, the last phosphate bond is broken, yielding adenosine diphosphate (ADP), a phosphate molecule, and energy.

49. ATP
All energy from the breakdown of molecules such as glucose must be captured in ATP before the body can use it.
It is often described as the energy currency of cells