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BIOCHEMISTRY
Elements - Four elements make up over 97% of your body by weight.___________________________
Ions Cation Anion Polar molecule - molecule with a slightly ______________end and a slightly ______________ end
Types of bonds - which is the strongest? the weakest?
1. Covalent bond - atoms ____________________ a pair of electrons
2. Ionic bond - an attraction between an anion and a cation; electron(s) are transferred from one atom
to another
3. Hydrogen bond - weak attraction between + end one molecule and - end of another molecule.
Chemical reaction Reactants - ____________________ materials
Products - substances formed at the _______________________ of the chemical reaction
TYPES OF CHEMICAL REACTIONS:
1. Synthesis reaction - chemical bonds are ________________ and a more complex structure is made.
2. Decomposition reaction - chemical bonds are ___________________ to form a simpler structure.
3.Exchange reaction - chemical bonds are broken and new bonds are formed.
4. Reversible reaction - the products can change back to the reactants
ACIDS,BASES & SALTS
Electrolytes - substances that release ___________ in water
Acids - electrolytes that release H+ (hydrogen ions) in water.
Bases - substances that release ions that can combine with H+ (hydrogen ions) in water.
Salts - electrolytes formed by the reaction between an acid and a base.
pH scale - indicates the concentration of _______________________ in solution
Neutral - pH __________; indicates equal concentrations of ___________________________
Acidic - pH ____________; indicates a greater concentration of ______________________
Basic, or alkaline - pH ____________: indicates a greater concentration of _______________
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CHEMICAL CONSTITUENTS OF CELLS
Organic molecules - contain ____ and _____. Usually ___________________than inorganic molecules.
Dissolve in __________________ or organic liquids. Ex: Carbohydrates, lipids, proteins, nucleic acids.
Inorganic molecules - generally do not contain _____. Usually dissociate in water, forming __________.
EX: Oxygen, carbon dioxide, inorganic salts.
Inorganic substances:
1. Water - most abundant compound in living material; major component of all _____________ fluid;
________ of adult human body weight; important for _____________________ substances throughout
body; _____________________ for most metabolic reactions; absorbs and transports ______________.
2. Oxygen - necessary for survival. Used by organelles to release ___________________ from
nutrients in order to drive the cell's ___________________________ activities.
3. Carbon dioxide - __________________ product released during metabolic activities. Must be
______________________ from the body.
4. Inorganic salts - abundant in body fluids. Provide ions such as ________________________ that
are needed for certain metabolic reactions to occur.
Organic substances:
1. Carbohydrates - provide _________________for cells; used to build cell components; water-soluble
Contain __________________ ; the ratio of H to O is close to __________ ie. CH₂O (_______________)
Monosaccharides Disaccharides Polysaccharides 2. Lipids - insoluble in _____________________; soluble in organic solvents. Uses - store energy; build
cellular components
A. Fats (triglycerides) - Primarily used for _______________. Most common lipid in the body.
Contain C, H, and O, but less O than carbohydrates
Basic structure: _____ glycerol + _________ fatty acid chains
EX: ________________________________ (1 glycerol, 2 fatty acid chains, and 1 phosphate)
B. Steroids - 4 connected carbon rings; various functions.
EX: _______________________________ - component of cell membrane; used to make other
steroids (sex hormones, adrenal hormones)
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3. Proteins - many function: build structures, enzymes, transport proteins, receptors, hormones,
antibodies, less commonly as an energy source
Basic structure - _________________________________ held together by ______________ bonds.
Four levels of protein structure:
______________________________ - sequence of amino acids
______________________________ - pleats or coils
______________________________ - 3-dimensional shape
______________________________- two or more polypeptide chains bonded together to form one
protein
Enzymes - (different ppt.) - enzymes work by _________________________ the activation energy of a
reaction=the energy needed to start the reaction.
Protein denaturation - when hydrogen bonds in a protein break as a result of exposure to excessive
heat, radiation, electricity, changes in pH, or various chemicals. The protein can no longer function,
because a protein's function depends on its _________________________.
4. Nucleic acids - contain genes. Each gene codes for the amino acid sequence in one protein
Structure - made of ________________________________
DNA - ____________________________________________________. Double polynucleotide
RNA - ____________________________________________; single polynucleotide