Biochemistry Notes
Organic compounds:
Contain carbon
Originally from living or once living things
In addition to carbon, most contain
Hydrogen and oxygen
Other elements include:
Nitrogen, Sulfur, Phosphorus, Iron
Calcium, sodium, chlorine, magnesium, potassium
Inorganic compounds:
Do NOT contain carbon
CO2 and carbonate compounds, although found in living things, are not considered organic.
Water: Most important inorganic compound in living things
Ionic bonds: Transfer of electrons
Covalent bonds: Share electrons
Polar covalent bonds: Electrons “shared” unequally due to electro negativity of an atom
Hydrogen Bonds: Formed between hydrogen in one molecule and an electro-negative molecule in another
1/10th strength of covalent bond
Very important in interactions of biomolecules
Primary force in way proteins fold and DNA bases bond
Structure & types of organic compounds. Major difference between organic and inorganic compounds
Greater size and complexity because of carbon’s electron structure
Carbohydrates:
Main source of energy
Made of elements carbon, hydrogen, oxygen
ratio of hydrogen to oxygen is 2 to 1, like water H2O
example: C6H12O6 common monosaccharides
Many types of carbohydrates:
Sugars: names of sugars end in ~ose (glucose, fructose, dextrose)
Monosaccharides : simple sugars
C6H12O6 or C5H10O5
Monomer: small repeating unit that makes up a polymer, monosaccharide or amino acid
Polymer: large molecule made up of many small repeating units
Dehydration synthesis
A reaction in which two molecules are bonded together by the removal of a water molecule
dehydration: removing water
synthesis: put together
formation of a disaccharide:
Hydrolysis:
Process by which large molecules are broken apart by the addition of water molecules (requires
enzymes, too)
Hydro: water
Lysis: break down or apart
Disaccharides:
Formed by joining two simple sugars
Sucrose or table sugar is a disaccharide made of glucose and fructose
Lactose, a sugar found in milk, is made of glucose and galactose
Lactose intolerant: inability to digest, hydrolyze, lactose into galactose and glucose; not enough of the
enzyme lactase
Polysaccharides:
Polymer of many repeating sugar units
Starch: sugar is stored in plants as starch; found in seeds, roots, and stems
Glycogen: surplus sugar stored in the liver
Cellulose: found in plants,
humans cannot digest cellulose—called fiber
some animals, like rabbits, can digest cellulose using appendix
Lipids:
includes fats, oils, waxes
Made of carbon, hydrogen, oxygen like carbohydrates, however, much less oxygen
insoluble in water – hydrophobic, “water fearing
Triglycerides:
Nutritionally and medically important
Energy storage
Oils: liquid at room temperature; come from
Plants: corn oil, olive oil
Fats: solid to semisolid at room temp; from
animals store fat: prevents heat loss; cushions certain organs
Saturated and unsaturated fats:
Saturated: all carbon to carbon bonds are single bonds
Unsaturated: one or more carbon pairs are joined by a double or triple bond
c-c-c-c-c-c-c-c
c=c-c-c-cpolyunsaturated: more than one double or triple bond
Hydrogenated: process used to turn unsaturated fats into saturated fats
Phospholipids:
Found primarily in cell membrane
Head---hydrophyllic—literally water loving
Tail—hydrophobic—water fearing
Steroids:
Composed of three 6-carbon rings bound to a 5-carbon ring
Hormones, venoms, pigments
cholesterol:
Soft, waxy fat found in cell membrane
Part of some hormones
Too much cholesterol can contribute to cardiovascular disease
Proteins
made of the elements carbon, hydrogen, and oxygen like carbohydrates and lipids, but also contain nitrogen
and sometimes sulfur and phosphorous
Proteins perform many jobs
Structural-ex. Collagen (part of bone)
Enzyme-ex. Lactase
Transport-ex. hemoglobin
Contractile-ex. myosin-muscle contraction
Hormone-ex. Insulin
Antibody-ex. gamma globulin
Pigment-ex. Melanin
Recognition- ex. Cell surface
Toxins- ex. Botulism toxin (botox)
Protein are made of amino acids
20 amino acids, but they combine to form 1000’s of proteins
Two amino acids combine with a special bond called a peptide bond
The resulting molecule is called a dipeptide
A chain of amino acids connected by peptide bonds is called a polypeptide
Proteins are made of one or more of these polypeptides, containing anywhere from 50 to 100,000 amino
acids.
Structure of proteins
Primary: the “strand” of amino acids
Secondary: the chain of amino acids twists or bends to form a more complex structure, usually a coil or a “pleat
Tertiary: the coil or pleat fold to make a ball
Quaternary: two or more chains fold together
Nucleic Acids
Made of carbon, hydrogen, oxygen, phosphorous, and nitrogen
Two kinds
DNA or deoxyribonucleic acid
Hereditary material passed from one generation to the next
Genes: sequence of nucleotides of DNA that codes for a particular polypeptide
RNA or ribonucleic acid
Three kinds: rRNA, tRNA and mRNA
RNA is very important
Necessary to “unlock” DNA
Necessary to make proteins
Structure of nucleic acids
A backbone of 5 carbon sugars (ribose or deoxyribose) bonded to a phosphate group (PO4)
Attached to one of four nitorgenous bases: adenine, guanine, cytosine,or thymine (uracil in RNA)
In DNA there are two backbones and the bases align with each other
The “ladder” coils into the familiar double helix