Post on 03-Jan-2016
BIOCHEMISTRY
THE NATURE OF MATTER
• REMEMBER…• Atoms are made up of electrons (-),
neutrons (neutral), and protons (+)• Proton number = atomic number =
type of element
Bonds
•Ionic bond – when electrons are transferred from one atom to another–Example NaCl
•Covalent bond – electrons are shared between atoms
–Example H2O
PROPERTIES OF WATER
•Polarity – uneven distribution of electrons between the hydrogen and oxygen atoms –Oxygen is bigger and attracts the electrons more than hydrogen
•Hydrogen bonds – slightly positive, polar H atoms are attracted to polar negative atoms like O
Acids and Bases• Acids
– Compounds that form hydrogen ions ( H+) when dissolved in water
– Ex. Lemon juice
• Bases– Compounds that reduce the amount of
hydrogen ions in a solution. Usually bases form hydroxide ions (OH -) instead of hydrogen ions when dissolved in water.
– Ex. Ammonia
MACROMOLECULES
•Monomers (smaller units) join to make polymers or macromolecules–Carbohydrates –Lipids–Proteins –Nucleic acids
CARBOHYDRATES
•Organic compounds composed of carbon, hydrogen and oxygen with a ratio of two hydrogen atoms to every one oxygen atom
• Made up of sugars
USE OF CARBOHYDRATES
• Source of energy for many living things
• Examples: sugar and starch
TYPES OF CARBOHYDRATES
• Monosaccharides
• Disaccharides
• Polysaccharides
MONOSACCHARIDES
• Only one sugar molecule• Examples -glucose,
fructose, and galactose • All three are C6H12O6, but
they are isomers• Draw Glucose
DISACCHARIDES
• Double sugars (two monosaccharides combined)
• Examples: sucrose, lactose, and maltose
• All are isomers with the chemical formula C12H22O11
POLYSACCHARIDES
• Long chains of monosaccharides joined together
• Examples: starch, glycogen, and cellulose
• Plants store excess sugar as starch, and break it down for energy
• Humans store excess sugar as glycogen, & break it down for energy
• Cellulose used by plants to build cell walls.
Carbohydrates and Nutrition
• Beware of low carbohydrate diets– Low carbohydrates cause your body
to break down muscle (protein)– Low carbohydrates can cause your
appetite to increase (your body thinks it is starving)
• Eat whole grains! – Whole grains provide fiber and help to
prevent heart disease and cancer.
DEHYDRATION SYNTHESIS
• Two molecules join together by losing a molecule of water
• DRAW
HYDROLYSIS REACTION
• Larger molecules broken down into smaller molecules by the addition of water
• Draw
LIPIDS
• Include fats, oils, steroids & waxes
• Composed of carbon, hydrogen and oxygen, but the # of H atoms per molecule is much greater then the # of O atoms
• An example, C57H110O6
USES OF LIPIDS
• Stored for energy • Form basic structure of cell
membranes• Protection • Insulation • Waterproof coverings
THE STRUCTURE OF SOME FATS
• Fatty Acids (a common type of fat): –a long carbon chain with a -COOH (carboxyl group) at one end
• Different types of fatty acids: –Saturated - all single, covalent
bonds in between carbons in chain
–Unsaturated - one double bond between carbons in chain
–Polyunsaturated - many double bonds between carbons in chain
•Steroids include:–Cholesterol -made by animals and is both helpful & harmful
–Testosterone/Estrogen – male/female hormones
–Cortisone – medicine used to reduce swelling/itching
Fats and Nutrition• Unsaturated fat is better for you
than saturated fat. Double bonds are easier to break than single bonds.
• High fat diet actually increases appetite.
• To increase fat break down, you must increase physical activity.
• Good fats are found in some fish, olives, and nuts and actually help to prevent heart disease.
PROTEIN
• Made up of amino acids linked together
• Composed of C, H, & O as well as nitrogen, N, and possibly sulfur
USES OF PROTEINS
• Build living materials like muscle• Act as enzymes to help carry out
chemical reactions• Fight disease• Transport particles into or out of
cells• Act as markers on cells
AMINO ACID STRUCTURE
• Have a central C that is bound to: –carboxyl group (-COOH)–a hydrogen atom –a amino group (-NH2)–an “R” group (Draw)
Alanine Serine
General structure
• There are 20 main amino acids.
• Each has same basic structure with the only difference being the “R” group
• Amino acids are linked by peptide bonds (formed by dehydration synthesis)
• Peptide bond is between two amino acids
• Polypeptide – (a protein) many amino acids joined
Protein and Nutrition
• Proteins help to suppress appetite so eat a little at every meal.
• Proteins help build lean body mass.• Increased lean body mass increase
your BMR (basal metabolic rate).– This means that you burn more
calories.• Yo-yo dieting decreases BMR and
makes your body store fat.
NUCLEIC ACIDS
• Composed of nucleotides• Nucleotides consist of a
sugar, a nitrogenous base, and a phosphate
• Nucleic acids include: DNA, RNA, ATP, and NAD
Figure 16.5 The double helix
CHEMICAL REACTIONS
• Chemical reactions always involve breaking bonds in reactants and making bonds in products
• Some reactions release energy and therefore usually occur spontaneously
• Other reactions need energy to happen
• Activation energy – the minimum amount of energy needed to start any reaction
• Enzymes are catalysts which speed up chemical reactions
• Enzymes are proteins that lower activation energy and allow reactions to occur at normal temperatures
• Without enzymes, too much energy would be needed to start all of the thousands of reactions your body performs all of the time!
Reaction pathwaywith enzyme
Reaction pathwaywithout enzyme
Activation energywithout enzyme
Activation energywith enzyme
• Each enzyme is specific and has a specific shape
• Enzymes are not permanently changed and are not used up in the reaction
• Most enzyme names end in -ase
• Reactants are called substrates.
• Enzymes work on substrates (either breaking them down or adding something to them.
• Example: Lactase (enzyme) breaks down lactose (substrate), which is the sugar in milk.
Factors that affect enzyme activity
• Enzymes are made of protein and there are certain factors that affect protein shape
• If the proteins shape is altered it will no longer work
• Factors– pH– Temperature– Salt concentration