Term | Definition |
Matter | anything that takes up spaces and has mass |
Atoms | the smallest chemical units of matter |
Electrons | negatively charged subatomic particles circling a nucleus |
Nucleus | structure containing neurons and protons |
Neurons | uncharged particles |
Protons | positively charged particles |
Element | pure chemical substance consisting of one type of atom |
Atomic number | equal to the number of protons in the nucleus |
Atomic mass (atomic weight) | sum of masses of protons, neutrons, and electrons |
Isotopes | atoms of a given element that differ in the number of NEUTRONS in their nuclei |
Valence electrons | electrons in outermost shell that interact with other atoms |
Chemical bonds | atoms combine by sharing or transferring valence electrons |
Molecule | two or more atoms held together by chemical bonds |
Compound | a molecule composed of more than one element |
Covalent bond | sharing of a pair of electrons by two atoms |
Nonpolar covalent bonds | -shared electrons spend equal amounts of time around each nucleus
-no poles exist
-equal sharing |
Polar covalent bonds | -unequal sharing of electrons
-polarity |
Ionic bonds | -atoms with either positive (cation) or negative (anion) charges
-no electrons shared |
Hydrogen bonds | -electrical attraction between charged H+ and negative charge on same or different molecule
-Weaker than covalent bonds but essential for life |
Oxidation | -release of electrons
-more + |
Reduction | -gain of electrons
-more - |
Synthesis reaction | -involve the formation of larger molecules
-require energy (endothermic) |
Dehydration synethesis | loss of water in a polymerization reaction |
Anabolism | all the synthesis reactions in an organism |
Decomposition reactions | -break bonds within larger molecules
-release energy (exothermic) |
Hydrolysis | the breaking of polymers into its units, by adding water |
Catabolism | all the decomposition reactions in an organism |
Water | -most abundant substance in organism
-most of its special characteristics due to 2 polar covalent bonds |
Water freezes | 0 C |
Water boils | 100 C |
Acids and bases are | dissociated by water into component cations and anions |
Acid | dissociates into one or more H+ |
Base | binds with B+ when dissolved into water; OH- |
Metabolism requires.. | relatively constant balance of bases and acids |
Organic macromolecules | large molecules used by all organisms
-lipids
-carbs
-proteins
-nucleic acids |
Monomers | basic building blocks of macromolecules |
Lipids | not composed of regular subunits, but are all hydrophobic
4 groups: fats, phospholipids, waxes, steroids |
Fats | triglycerides |
Phospholipids | -2 fatty acid form dehydration synthesis with glycerol and phosphate
- building block of membranes |
Waxes | contain one long-chain fatty acid covalently linked to long-chain alcohol by ester bond
-completely insoluble in water |
Steroids | -4 ring structure
-hydrophobic
-smaller
-can be imbedded in membrane and can pass through |
Carbohydrates | Organic molecules composed of carbon, hydrogen, and oxygen (CH2O) |
Carbohydrates Functions | 1.) long-term storage of chemical energy
2.) ready energy source
3.) structural support |
Carb types: | Monosaccharides
Disaccharides
polysaccharides |
Glycosidic bonds | links carbs |
Dextrans | secreted by some bacteria to form slime layers-biofilms |
Agar | used to make solid culture media; comes from seaweeds; complex of galactose and sulfur containing carbohydrates |
Chitin | polymer of glucosamine; major component of many fungi |
Peptidoglycan | glycans (polysaccharides) linked by small peptides; component of bacterial cell walls |
Lipopolysaccharide (LPS) | complex of lipids and polysaccharides; component of gram-negative cell walls |
Biofilm | extra cellulose layer; form dome around organism |
Protein functions | -structure
-enzymatic catalysis
-regulation-respond to stimuli
-transportation
-defense |
Amino acids | look in notes |
Peptide bond | a covalent bond that is formed between amino acids by dehydration synthesis reaction |
Peptide bond structure | has a central C, carboxyl group, H, amino acid, and side group (R) |
Linkage of amino acids by | peptide bond |
nucleic acids | DNA and RNA |
Monomers | nucleotides
-three parts
--phosphate
--pentose sugar(deoxyribose or ribose) (5 sugar)
--one of the 5 nitrogenous bases |
DNA bases | A,T,G,C |
RNA bases | A,U,G,C |
Bonds between C and G | 3 H bonds |
Bonds between T and A in DNA or U and A in RNA | 2 H bonds |
DNA is | double stranded in most cells and viruses
- 2 stands are complentary
- 2 strands are antiparellel |