Chemistry of Life

substances that cannot be broken down into simpler substances by chemical means

elements that are required by organisms but only in very small quantities (ex: iron, iodine, copper)

the smallest unit of an element that retains its characteristic properties; building blocks of the physical world

protons, neutrons, and electrons (protons & neutrons in the nucleus)

atoms with the same number of protons but different number of neutrons in the nucleus

2+ individual elements combined in a fixed ratio

transfer of electrons from one atom to the other; consist of cations (+) and anions (-)

sharing of electrons between atoms (single, double, triple)

unequal distribution of shared electrons

equal distribution of shared electrons

weak chemical bonds that form when a hydrogen atom is covalently bonded to one electronegative atom and attracted to another (O, F, N)

adhesion and cohesion

the ability of a substance to resist temperature changes

hydrogen ions (H+)

hydroxide ions (OH-)

-log[H+] ; changes are represented by tenfold (pH 3 is ten times more acidic than pH 4)

carbon AND hydrogen (other things too)

made up of a chain of building blocks, individually called monomers

C_nH_2nO_n (1:2:1)

monosaccharides, disaccharides, and polysaccharides

“saccharide” = sugar

ex: glucose, fructose, galactose, ribose, deoxyribose

glucose: C₆H₁₂O₆

• most abundant

• most popular sugar: photosynthesis, breaking down for energy

fructose: C₆H₁₂O₆

• common sugar in fruits

two monosaccharides brought together: hydrogen (-H) from one sugar molecule combines with the hydroxyl group (-OH) of another — results in the formation of water

ex: maltose (2 glucose), sucrose (table sugar), and lactose (dairy)

when two monosaccharides are joined and a water molecule is lost during the process

the bond between two monosaccharides that results in a disaccharide

process of breaking 2 monosaccharides by adding a water molecule; breaks the glycosidic linkage

many repeated units of monosaccharides (branched or unbranched)

ex: starch, cellulose, glycogen [starch & glycogen are sugar storage molecules]

• starch: stores sugar in plants

• glycogen: stores sugar in animals

• cellulose: beta-glucose (b-glucose) - major part of the cell walls in plants (structural support)

  • chitin: polymer of b-glucose molecules; structural molecule in the walls of fungus & exoskeletons of arthropods

perform most of the work in cells (structure, function, and regulation of tissues & organs); made up of amino acids

building blocks of protein (CHON)

4 central parts:

• amino group (-NH₂)

• carboxyl group (-COOH)

• hydrogen (-H)

• R-group: side chain

1. composition of elements (CHONS)

2. polarity - affects whether an amino acid is hydrophilic, hydrophobic, or ionic

3. charge

4. shape (long/short chain, ring-shape)

non-polar & uncharged

polar & uncharged

polar & charged

two amino acids; the carboxyl group of one amino acid combines with the amino group of another amino acid

the bond between two amino acids

a group of amino acids is joined together in a string resulting in an organic compound

a polypeptide chain twists and folds on itself forming a 3D structure

N-terminus/amino terminus

C-terminus/carboxyl terminus

4

linear sequence of amino acids

when a polypeptide begins to twist, forming either a coil (alpha helix) or a zigzagging pattern (beta-pleated sheets)

• formed by amino acids that interact with other amino acids close by in the primary structure

after the secondary structure reshapes the polypeptide, amino acids that were far away in the primary structure arrangement can now interact with each other

• most proteins are found in aqueous environments - hydrophilic amino aids & regions of the peptide chain are often located on the exterior of the protein

• hydrophobic amino acids & regions are usually found on the interior of proteins

• minimizes free energy of the molecule & locks into a stable 3D shape

different polypeptide chains sometimes interact with each other; come together to be called subunits of the final whole protein

ex: hemoglobin (helps distribute oxygen in to the tissues in the body) - formed when 4 separate polypeptide chains interact with each other; each of the 4 chains create a subunit of the final hemoglobin protein

helps proteins fold properly and make the process more efficient

consist of carbon, hydrogen, oxygen; same ratio as carbs

ex: triglycerides, phospholipids, steroids

made up of glycerol molecule/backbone - 3 fatty acid chain attached; each of the carboxyl groups of the three fatty acids must react with one of the three hydroxyl groups of the glycerol molecule (dehydration synthesis)

long chain of carbons in which each carbon is covered in hydrogen (one end of the chain has a carboxyl group); can be saturated with hydrogens along its long carbon chain or it can have a few gaps where double bonds esit instead of hydrogen

link formed between glycerol molecule & fatty acids

many double bonds within the fatty acid

2 fatty acid tails & 1 negatively charged phosphate head

• tails = hydrophobic (non-polar)

• head = hydrophilic (polar)

amphipathic molecule: both hydrophilic & -phobic regions

• important type of lipid

• 4-ringed (sometimes found in membranes)

• increase in membrane fluidity (except at very high temps when it helps to hold things together instead)

• important for making certain types of hormones & vitamin D

CHONP

made up of nucleotides

ex: deoxyribonucleic acid (DNA) [blueprints of life] & ribonucleic acid [protein synthesis]