Oils, fats and waxes

• Waxes:• Composed by long Carbon and Hydrogen

chains that are highly hidrophobic.• They are saturated.• Are found in: hair, insect skeletons, leaves,

stems and beehives.

FIGURE 3-12b Lipids. Bees build their homes with wax hexagons.

Phospholipids

- Are found in cell membranes.

Structure:2 fatty acids + glycerol + phosphate group + 1 functional polar group

FIGURE 3-15 Phospholipids.

Cabeza polar (hidrofílica)

Columna vertebral de glicerol

Colas de ácido graso (hidrofóbica)

Phospholipids

• They have hydrophobic and hydrophilic portions.– Polar “heads”: water soluble.– Non polar “tails”: not water soluble.

•Hydrophilic = lipophobic•Hydrophobic = lipophilic

Steroids

• They consist in 4 fusioned carbon rings.• Examples:

– Cholesterol• Found in animal cell membranes.

– Masculine and Femenine hormones.

Cholesterol

Estrogen

Testosterone

What are proteins?

Functions :– They are formed with amino acid chains.– Aminoacids join to form chains by dehydration

synthesis.– A protein can have 1,2,3 or 4 structure levels.– Enzimes catalize (speed up or accelerate)

reactions.– Elastin provides suport.

FIGURE 3-17a Structural proteins. Exaples: queratin, found in: a) hair b) horns c) spider silk.

Proteins´s functions

Function ExampleStructure Collagen in the skin and

keratin in hair.Movement Actin and myosin in the

muscles.Defense Antibodies in blood.Storage Albumin in egg white.Signals Growth hormone in blood.Catalysis Enzymes (EX: amylase

digests carbohydrates)

• Proteins are composed of amino acids.

• Aminoacids are proteins´s main units.

• They all have amino and carboxyl groups.

• They all have an “R” group:• Some are hydrophobic.• Some are hydrophilic.

Proteins

FIGURE 3-18 Amino acids structure.

Aminogroup

Hydrogen

“R” group

Carboxylgroup

FIGURE 3-19a Amino acid diversity.

• The amino acid sequence determines the properties and functions of every protein.

Amino acids

Dehydration synthesis

• Process by which amino acids join to form chains.

• The covalent bond that is formed between the C and the N is called peptide bond.

• The long amino acid chains are called polypeptides or proteins.

FIGURE 3-20 Protein synthesis.

4 structure levels

The primary structure is the amino acid sequence that forms the protein.

The secondary structure is composed of helix and chains that fold.

The tertiary structure consists in one complex peptidic chain that holds the structure with different links.

The quaternary structure is found where several proteic chains link.

Structure example: hemoglobin.

This folded plate is an example of the secondary proteic structure.

Hydrogen Links

Folded plate

FIGURE 3-23 Queratin structure.

queratin

Tridimensional structures

• The kind, position and number of amino acids determine the protein´s function.

– If bonds or links break, that causes the denaturing of the protein and lost of its biological functions.

FIGURE 3-24 Desoxyrribose nucleotide.

• There are 2 kinds of nucleotides:

– Ribose nucleotides:– The ones that contain: Adenine, Guanine,

Cytosine, Uracil. They are found in RNA.

– Deoxyrribose nucleotides:– The ones that contain:Adenine, Guanine,

Cytosine, Thymine. They are found in DNA.

– DNA• It spells the genetic info necesary to build proteins.

– RNA• Are DNA copies or replicas used at the protein

synthesis.

Inheritance molecules

FIGURE 3-25 Nucleotide chain.

base

sugar

phosphate

Hydrogen links

Other nucleotides

• AMP carries chemical signals inside the cell.

• ATP carries energy.

• NAD+ and FAD carry electrons.

ATP