Download Chapter 3 PArt II - Relufeas

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
Cabeza polar
(hidrofílica)
Columna
vertebral
de
glicerol
FIGURE 3-15 Phospholipids.
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.
Estrogen
Cholesterol
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
Structure
Movement
Defense
Storage
Signals
Catalysis
Example
Collagen in the skin and
keratin in hair.
Actin and myosin in the
muscles.
Antibodies in blood.
Albumin in egg white.
Growth hormone in blood.
Enzymes (EX: amylase
digests carbohydrates)
Proteins
•
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.
“R” group
Amino
group
Carboxyl
group
Hydrogen
FIGURE 3-18 Amino acids structure.
FIGURE 3-19a Amino acid diversity.
Amino acids
• The amino acid sequence
determines the properties and
functions of every protein.
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.
Hydrogen
Links
Folded plate
This folded plate is an example of the secondary
proteic structure.
queratin
FIGURE 3-23 Queratin structure.
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.
Inheritance molecules
– DNA
• It spells the genetic info necesary to build proteins.
– RNA
• Are DNA copies or replicas used at the protein
synthesis.
base
sugar
phosphate
FIGURE 3-25 Nucleotide chain.
Hydrogen links
Other nucleotides
• AMP carries chemical signals inside the cell.
• ATP carries energy.
• NAD+ and FAD carry electrons.
ATP