Chapter 2: Chemical Composition of Body

atoms

smallest unit of chemical elements

nucleus

Center of an atom

protons and neutrons

nucleus contains

mass number

protons + neutrons =

atomic number

# of protons

number of protons

what determines elements

isotopes

Atoms of the same element that have different numbers of neutrons

number of electrons

_________ is equal to number of protons

2 electrons

1st shell can hold

8 protons

2nd shell can hold

valence electrons

outermost shell of electrons

1

hydrogen - # of electrons in shell 1

1

hydrogen - number of chemical bonds

4

carbon - # of electrons in shell 2

4

carbon - number of chemical bonds

5

nitrogen - # of electrons in shell 2

3

nitrogen - number of chemical bonds

6

oxygen - # of electrons in shell 2

2

oxygen - number of chemical bonds

6

sulfur - # of electrons in shell 3

2

sulfur - number of chemical bonds

covalent bonds

sharing of valence electron pairs

nonpolar bonds

electrons equally distributed between 2 bonds

polar bonds

unequal electrons distributed between 2 different atoms, electrons pulled more towards one direction than the other

more electronegative

the end of molecule towards which electron is pulled in a polar bond is

carbon and hydrogen

two molecules that have similar electronegativity that they are considered the same and nonpolar bonds

polar covalent bond

H2O is what type of bond

nonpolar covalent bond

CH4

ionic bonds

one or more valence electrons from one atom are completely transferred to second atom

ions

atoms that have positive or negative charge

anions

atoms that have negative charged ions

cations

atoms that have positive charged ions

hydrogen bonds

weak attraction between partially negative oxygen and partially positive hydrogen located near each other

heat capacity, surface tensions

hydrogen bonds are responsible for

acid

protons donors

bases

proton acceptors

strong acid

complete dissociation of H+

strong base

complete dissociation of OH-

weak acid

substance that donates proton but does not completely disassociate

pH

-log [H+], molar concentration of H+ in aqueous solutions in moles/liters

high concentration of H+

acid is high or low concentration of H+

low concentration of H+

base is high or low concentration of H+

buffer

stabilizes pH in solution

weak acid and weak base

buffer's two components

organic molecules

contain carbon and hydrogen

hydrocarbons

bonds that contain carbon and hydrogen

linear and cyclic

two common forms of hydrocarbons

functional groups

common molecular arrangements with a carbon hydrogen backbone

carbonyl

hydroxyl

sulfhydryl

amino

carboxyl

phosphate

ketone

organic acid

aldehyde

Alchohol

isomer

same molecular formula, different structure

stereoisomers

isomers that have different biological properties depending on configuration

cis vs trans

stereoisomers example

carbohydrates, lipids, proteins, nucleic acids

4 major macromolecules

monomer

simple molecule, acts as building block to chemically bond with similar molecules to form a polymer

polymer

many monomers built together

energy source and storage, cell recognition, and part of cell structure

carbohydrate function

monosaccharides

monomer of carbohydrates, simple sugar

glucose

example of monosaccharides

linear and cyclic form

carbohydrates exist in what two forms

linear form of carbohydrate

contain a carbonyl group (aldehyde or ketone) and multiple hydroxyl (-OH) groups

cyclic form of carbohydrate

oxygen included in ring

disaccharides

double sugar, two monosaccharides joined covalently - ie: maltose

polysaccharide, glycosidic bond

polymer of carbohydrates + bond used

repeating glucose subunits

polysaccharides are often

starch

polysaccharide, energy storage in plants - humans CAN digest

glycogen

polysaccharide, energy storage in animals - humans CAN digest

cellulose

polysaccharide, cell wall of plants - humans CANNOT digest

dehydration synthesis

binds monomers together to form polymers by removing a water molecule

hydrolysis

water molecules are used to break down complex compounds into smaller components

lipids

all are insoluble in polar substances (water)

fatty acids, triglycerides, phospholipids, steroids, prostaglandins

lipid categories

fatty acid

long hydrocarbon chain with hydroxyl group at end

store energy

fatty acid function

saturated fatty acid

all single bonds

unsaturated fatty acid

contains double bonds

cis unsaturated fatty acid

hydrogen on same side, body CAN digest

trans unsaturated fatty acid

hydrogen on opposite side, body CANNOT digest

triglyceride

1 glycerol with 3 fatty acids

store and transport fatty acids

triglyceride function

ketone bodies

used as alternative to glucose if unavailable

phospholipids

2 fatty acids (hydrophobic) with polar head group (hydrophilic)

amphipathic

has hydrophobic and hydrophilic portion

forms bilayer of plasma membrane

phospholipids function

hydrogen bond with water

hydrophilic head of phospholipids forms

steroids

3 cyclohexanes + 1 cyclopentane

nonpolar and insoluble in water

steroids are

form plasma membrane and found in some hormones

steroid functions

prostaglandins

5 carbon sugar with 2 fatty acid tails

communication molecules between cells locally, regulate vasodilation and vasoconstriction, and uterine contractions

prostaglandins functions

proteins

amino group on one end and carboxyl group on other

amino acid

protein monomer