The structure and Function of Macromolecules

IB Biology HL

Mr. E. McIntyre

The Principles of Polymers

Condensation (dehydration)

Hydrolysis

Monomers Polymers

Figure 5.2 The synthesis and breakdown of polymers

Carbohydrates serve as fuel and building material

• Carbohydrates include both sugars and their polymers.

Figure 5.3 The structure and classification of some monosaccharides

Different views of the same monosaccharide monomer

Figure 5.4 Linear and ring forms of glucose

Figure 5.5 Examples of disaccharides

Figure 5.5x1 Disaccharides. Glucose (left), moltose (middle), and sucrose (right).

Figure 5.6 Storage polysaccharides

Glycogen:

Figure 5.6a Storage polysaccharides, starch and chloroplast in a plant cell

Figure 5.6b Storage polysaccharides, glycogen

Figure 5.7 Starch and cellulose structures compared

Figure 5.7x1 Starch and cellulose, molecular models. Starch (left) and cellulose (right)

Figure 5.8 The arrangement of cellulose in plant cell walls

Figure 5.x1 Cellulose digestion, termite and Trichonympha

Figure 5.x2 Cellulose digestion, cow

Figure 5.9 Chitin, monarch emerging and surgical thread

Unnumbered Figure (page 65) Monomer of chitin

Lipids are a diverse group of hydrophobic molecules

Figure 5.10 The synthesis and structure of a fat, or triacylglycerol

02_19_fatty side chains.jpg

Figure 5.11 Saturated and unsaturated fats and fatty acids

Figure 5.11x Butter and oil

The partial hydrogenation reconfigures most of the double bonds that do not become chemically saturated, twisting them so that the hydrogen atoms end up on different sides of the chain.

Figure 5.12 The structure of a phospholipid

02_20_lipid membranes.jpg

Figure 5.13 Two structures formed by self-assembly of phospholipids in aqueous environments

Figure 5.14 Cholesterol: a steroid

Figure 5.14x Cholesterol, computer model

Proteins have many structures and many functions

Proteins constitute most of the dry mass of a cell. Percent of total cell weight

Component E. coli Mammalian cell

H2O 70 70Inorganic ions 1 1Proteins 18 18RNA 6 1.1DNA 1 0.25Phospholipids 2 3Polysaccharides 2 2Miscellaneous small metabolites 3 3

Total cell volume 210-12cm3 410-9cm3

Relative cell volume 1 2000

Protein structure and Function

Functions of proteins:

Antibodies, toxins, hormones, antifreezing, antibioling, elastic fibers, etc.

On membrane: channels and pumps - traffic control

Enzymes: Control chemical reactions (metabolism)

Message: from one cell to another, or from membrane to nucleus.

Movement: Actin, tubulin, kinesin.

Table 5.1 An Overview of Protein Functions

Unnumbered Figure (page 68) Amino acid structure

Unnumbered Figure (page 82) L-amino acid and D-amino acid

Figure 5.15a The 20 amino acids of proteins

Figure 5.15b The 20 amino acids of proteins

Figure 5.15c The 20 amino acids of proteins

Figure 5.16 Making a polypeptide chain

02_31_protein fold.jpg

Figure 5.17 Functional conformation of a protein, the enzyme lysozyme

Figure 5.18 The primary structure of a protein

Sickle-cell anemia

Glutamic acid

Valine

Figure 5.19 A single amino acid substitution in a protein causes sickle-cell disease

Figure 5.19x Sickle cells, light micrograph

Figure 5.20 The secondary structure of a protein

Figure 5.21 Spider silk: a structural protein

Figure 5.22 Examples of bonds contributing to the tertiary structure of a protein

Figure 5.23 The quarternary structure of proteins

Figure 5.24 Review: the four levels of protein structure

Figure 5.25 Denaturation and renaturation of a protein

Figure 5.26 DNA to RNA to protein: a diagrammatic overview of information flow in a cell

Figure 5.27 The structures of nucleotides and polynucleotides

Figure 5.28 The double helix

Figure 5.x3 James Watson and Francis Crick

Figure 5.x4 Rosalind Franklin

Table 5.2 Polypeptide Sequence as Evidence for Evolutionary Relationships