Chemical Bonds Continued, and Functional Groups

Lecture 3

ionic bonds

transfer of electrons from one atom to another

results in the formation of cations and anions

oppositely charged ions are strongly attracted to each other

hydration shell

what does water form around charged solutes

the positive ion

the negative side of the water molecule orients to what?

the negative ion

the positive side of the water molecule orients to what?

van der waals bonds

are weak intermolecular interactions observed in condensed phrases like solid and liquid

van der waals bonds

are secondary bonds (uneven charge distribution) in molecules where ionic and covalent bonds form the primary bonds

they can attract atoms or molecules from all directions

Van der waals interactions are non-directional, which means what?

weaker

Are van der waals interactions stronger or weaker than ionic and covalent bonds?

helps in stabilizing the protein structure

responsible for stability of polymer chain

account for the cohesion of inert gases in solid and liquid states

accounts for physical absorption of molecules to solid surfaces

What are the major roles of van der waals interactions

autoionization of water

pure water or indeed any aqueous solution, water acts both as an acid and a base

acid

What increases the concentration of H+ in the solution and decreases the concentration of OH-

Base

What decreases the concentration of H+ in the solution and increases the concentration of OH-

Acids

donate H+ in aqueous solutions

bases

donate OH- or accept H+ in aqueous solutions

Acids and Bases

homeostatic imbalances are caused by what?

acidosis

excessive acidity of the blood

alkalosis

excessive alkaline (basic) of blood

buffers

substances that minimize changes in concentration of H+ and OH- in a solution

hydrophilic

water loving

able to interact with water

polar and or charged (ions) molecules

hydrophobic

water fearing

do not interact with water

nonpolar molecules

Nonpolar molecules

no significant partial charges

symmetrical distribution of electrons

polar molecules

unequal distribution of electrons

partial positive and a partial negative charge

asymmetrical

Carbon

can form 4 bonds and therefore has the ability to form large, diverse and complex molecules

carbon skeletons

molecular diversity arises from variations in length and shape of carbon chains

hydrocarbon

any of a class of organic chemical compounds composed only of the elements carbon (C) and hydrogen (H)

non-polar (hydrophobic)

insoluble

functional groups

determine the characteristics and chemical reactivity of organic molecules

less stable than carbon backbone

more likely to participate in chemical reactions

hydroxyl group

polar, involved in hydrogen bonding. Often participates in condensation reactions. Required inside chain for phosphorylation of proteins

example: alcohols

carbonyl group

polar, very reactive. Important in energy releasing reactions

examples: Aldehydes

Carboxyl group

charged and acidic. ionizes in cells to form R-COO^- and H+

amino group

charged and basic. In cells, accepts H+ to form R-NH₃⁺

Examples: amines

Sulfhydryl group

polar. Can form disulfide bridges

examples: Thiols

phosphate group

charged and acidic

ionizes cells to form O-P-O₃^2-

example: organic phosphates

hydroxyl group

what functional group is this?

carbonyl

What functional group is this?

Carboxyl group

What functional group is this?

Amino Group

What functional group is this?

Sulfhydryl group

What functional group is this?

Phosphate Group

What functional group is this?

Methyl group

What functional group is this?