Biochemistry the chemistry of living things
Macromolecules Biochemistry is the study of 4 groups of very large molecules/macromolecules… • Carbohydrates • Lipids • Proteins • Nucleotides
Macromolecules are composed of MONOMERS …repeating subunits • Each type of macromolecule is composed of different monomers. • Chains of monomers are called POLYMERS
All polymers are assembled from their respective monomers by the same process… DEHYDRATION SYNTHESIS AKA CONDENSATION • A molecule of H2O is removed between the joined monomers.
Likewise, polymers are broken down into monomers by putting water back. • This process is called HYDROLYSIS
It doesn’t make any difference what macromolecule you are building or which you are breaking down. You will always use… DEHYDRATION SYNTHESIS and HYDROLYSIS
So monomers join to form polymers - macromolecules. Then these macromolecules come together to form the structures of living things such as ribosomes or membranes.
Carbohydrates Source of energy & building material
Carbohydrates consist of C + H2O in a ratio of 1:1 example: 3C + 3 H2O = C3H6O3 • usually end in ose: example: glucose
3 classes of carbohydrates • Monosaccharides • Disaccharides • Polysaccharides
Monosaccharides = Simple Sugars • Pentoses (5 C sugars) • Hexoses (6 C sugars)
Pentoses • Ribose used to make RNA • Deoxyribose (1 less O atom) used to make DNA
The 3 hexoses are isomers. • Hexoses are the monomers of carbohydrates.
Glucose (AKA Dextrose) is the most important of the HEXOSES Living things like to “burn” or oxidize glucose to get ENERGY
Disaccharides Disaccharides Are made by putting 2 monosaccharides together with the removal of water. The bond is called a glycosidic linkage
C6H12O6 + C6H12O6 C12H24O12 - H2O C12H22O11
Polysaccharides • can be used to store energy by chaining glucose monomers - plants store amylose (starch) - animals store glycogen • can be used to build structures - plants have cellulose - animals have chitin
Plants make sugar during photosynthesis. This sugar is then sent to a storage organ where it is converted to plant starch called amylose
Animals convert sugar they take in to glycogen. Glycogen is then stored in the liver and muscles so it is readily available for energy needs by breaking it down to sugars.
Cellulose is the structural polysaccharide of plants. It is used to make plant cell walls. It is the most abundant organic compound on earth! It is also known as fiber. We cannot breakdown fiber, so it speeds digestion, keeping us healthy!
Chitin is a structural polysaccharide used by animals. It forms the exoskeleton of insects and crabs.
Lipids Fats, waxes, oils, sterols, and steroids
Lipids differ from the other macromolecules in that they are… • nonpolar molecules • hydrophobic • classified on basis of solubility alone They have no general characteristics other than these.
Lipids include the following groups: • Triglycerides (AKA fats) • Phospholipids • Steroids
TRIGLYCERIDES (FATS) • 1 glycerol + 3 fatty acids
Glycerol is an alcohol. Can you identify Its functional group?
Fatty acids are organic acids. Can you identify their functional group? There are 2 types of fatty acids: Saturated – have all single bonds Unsaturated – have 1 or more double bonds
Saturated Fatty Acids • have all single bonds • are produced by animals • are solid at room temp
Unsaturated Fatty Acids • are produced by plants • contain 1 or more double bond • are liquid at room temperature
Fats are the best source of energy • They release twice the amount of energy as carbohydrates (gram for gram)
Triglycerides are assembled from glycerol and 3 fatty acids by dehydration synthesis. The bonds formed when water is removed are called ester linkages. Can you find the ester group?
Phospholipids Consist of… 1 glycerol + 2 fatty acids + P group The P “head” is charged and polar, while the fatty acid tails are nonpolar. This gives phospholipids some unique properties.
Because of the polar/hydrophilic P head and nonpolar/hydrophobic fatty acid tails they form a bilayer when placed in water. • Phospholipids are the main constituent of membranes.
Steroids • hydrophobic compounds • consist of 4 fused rings • vary with functional group attached to rings • all formed from cholesterol
Cholesterol • found in animals only • precursor to forming steroid hormones and vitamin D • UV rays convert cholesterol into vitamin D • Found in animal cell membranes where it keeps them fluid at low temperatures
Steroid Hormones • estrogens • progesterone • testosterone
Proteins - the building blocks of life
Functions of Proteins • Support silk, tendons, hair • Storage of amino acids for young egg white, milk • Transport hemoglobin • Hormones insulin, growth hormone • Receptors detect chemical signals • Movement muscle, cilia, flagella • Defense antibodies • Enzymes control chemical rxns
Genes are the recipes for proteins.
Amino acids are the monomers of proteins. Amino acids contain an amino and a carboxyl group. They differ only in their R group.
5’ end 3’ end Amino acids are amphoteric – they become charged (+ at amino end and – at carboxyl end) .