Biochemistry

Atoms

* consists of protons and neutrons and surrounded by electrons
* many share electrons in shells as molecules are most stable when their shell is complete

Complete Shell Equation

2N^2

Combining Atoms

* chemical reaction occurs whenever a chemical bond is formed, rearranged or broken

Ions

* atoms that have a charge because of an unequal number of protons and electrons

Molecules

* two or more atoms that share electrons

Compunds

* contain atoms of 2 or more elements

Free Radicals and Their Effects on Health

* an atom or molecule with an unpaired electron in its outer shell that is unstable, highly reactive and destructive to nearby molecules
* generation of free radicals is increased when exposed to UV light, X-rays, chemical and certain normal metabolic processes
* effects can be partially offset by antioxidants

Chemical Bonds

* forces that hold together the atoms of molecules and compounds
* likelihood depends on the number of valence electrons
* atoms of the most biologically diverse elements do not have eight valence electrons

Formation of Methane

4H+C>CH4

* carbon has 4 valence electrons that form with hydrogens 4 valence electrons to make it complete

Energy Flow in Chemical Reactions

* Chemical reactions either use or release energy that was present in the chemical bonds
* can be exergonic or endergonic

Exergonic

* spontaneous chemical reaction where there is a net release of energy

Endergonic

* nonspontaneous chemical reaction where energy is absorbed from the surroundings

What determines whether energy is released or absorbed?

* the change in potential energy in the chemical bonds

Organic Compounds

* contain carbon
* are usually large molecules

Inorganic Compounds

* do not contain carbon and include water, salts, acids and bases

Water Qualities

* boiling point: 100°C
* Freezing point: 0°C
* Density: 1g/cm^3
* High heat capacity making it resistant to temperature changes
* High heat/energy required to vaporize/boil
* High surface tension as water molecules stick together

Water as a Solvent

* negative side associates with positive end of solute molecule
* Positive side associates with negative end of solute molecule

Salts

* contain positive ions (cations) other than H+
* Contain negative ions (anions) other than OH-
* Typically dissociate readily in water

Salts to Know

* NaCl (sodium chloride)
* CaCo3 (calcium carbonate)
* KCl (potassium chloride)
* CaPO4 (calcium phosphate)

Acids

* release H+ ions sin large amounts
* Are proton donors
* pH of 0-6.9
* Example is HCl found in the stomach

Bases

* accept H+ ions and are called proton acceptors
* pH of 7.1-14
* examples are bicarbonate found in blood and ammonia found in waste products

Buffers

* living cells and tissues are very sensitive to changes in pH and need to maintain a constant pH of 6.5 to 7.2
* regulation is completed by molecules that resist abrupt changes in pH

What makes carbon so special?

* carbon forms bond with many other carbon atoms
* large number of shapes and sizes
* unique structure and function

Macromolecules

* carbohydrates
* lipids
* proteins
* nucleic acids

Carbohydrates

* sugars and starches
* contains carbon, hydrogen and oxygen
* only make up 2-3% of total body mass
* provide energy
* glucose produces ATP

Monosaccharides

* simple sugars
* general formula is (CH2O)n

Glucose

* formula is C6H12O6
* type of monosaccharide that can be absorbed directly into blood
* does not require digestion
* important when looking at diabetes

Diasaccharides

* formed when 2 simple sugars join together
* glucose + fructose > sucrose
* 2 carbohydrates form one carbohydrate

Lactose

* formed by glucose and galactose
* disaccharide

Maltose

* formed by 2 glucose molecules
* disaccharide

Polysaccharides

* many simple sugars linked together
* form in ways most carbohydrates are found

Homopolysaccharides

* many molecules of one sugar
* such as glycogen, starch and cellulose

Heteropolysaccharides

* most of these contain only 2 types of sugars and are associated with proteins
* such as glycoprotein

Glycogen

* most important homopolysaccharide in humans
* used for the storage of glucose
* made and stored primarily in the liver, skeletal muscle and cardiac muscle
* storage varies dramatically with diet, exercise and stress

Starch

* equivalent storage product of humans found in plants
* most common carbohydrate in human diets
* large amounts in wheat, potatoes, rice and corn
* made by leaves during the day and used as an energy source at night
* also used for nonfood purposes

Lipids

* contain carbon, hydrogen and oxygen (lower proportion than carbohydrates)
* make up 18-25% of total body mass
* macromolecules made of fatty acid monomers
* used for structural support for the cell, energy storage, protection of body organs and cell signalling (steroid hormones for chemical messages)
* nonpolar
* includes triglycerides, phospholipids, steroids and waxes

Fatty Acids

* simplest lipids that can be broken down to produce ATP

Triglycerides

* neutral fats
* fat when solid and oil when liquid
* large molecules used for storage that is found just below the skin

Phospholipids

* modified triglycerides that contain phosphorus
* found in cell membranes

Steroids

* structurally different than triglycerides

Cholesteral

* type of lipid (steroid) that is essential for human life

Proteins

* basic structural material of the body that has many functions
* 12-18% of total body mass
* contains carbon, oxygen, hydrogen and nitrogen
* some may also contain sulphur
* composed of amino acids

Amino Acid Functional Groups

* amine group (common)
* organic acid group (common)
* unique group

Amino Acids

* link to form peptides
* 20 common ones
* either obtained from nutrition (essential) or synthesized by the body (non-essential)

Essential Amino Acids

* Leucine
* Isoleucine
* Valine
* Histidine
* Lysine
* Methionine
* Phenylalanine
* Threonine
* Tryptophan

Non-Essential Amino Acids

* alanine
* arginine
* asparagine
* aspartic acid
* cysteine
* glutamic acid
* glutamine
* glycine
* proline
* serline
* tyrosine

Dipeptide

* two amino acids

Tripeptide

* three amino acids

Primary Structure

* amino acids in polypeptide chains

Secondary Structure

* polypeptide chains form spirals or sheets

Tertiary Structure

* spirals or sheets folded up

Quaternary Structure

* two or more chains combine to form function protein

Enzymes

* proteins that acts as catalysts to speed up biochemical reactions
* not used up during the reactions
* reduce the energy needed to start the reaction

Nucleic Acids

* largest molecules in the body
* composed of carbon, oxygen, hydrogen, nitrogen and phosphorus
* DNA and RNA

Nucleotides

* structural unit of nucleic acids
* adenine and guanine are purines with 2 ring bases
* cytosine, thymine and uracil are pyrimidines with 1 ring bases

DNA

* found in the nucleus
* replicates itself and is found in nearly all cells
* provides information for building proteins

RNA

* usually found outside the nucleus
* works for DNA by carrying out orders for protein synthesis
* different types of RNA carry out different parts the building process


* single strands of nucleic acids

Adenosine Triphosphate (ATP)

* provides energy that is directly used by cells

Cellular Respiration

* exergonic reaction
* glucose in oxidized
* oxygen is reduced