Lectures 1&2

Question 1

Cell

Answer 1

Cell’s basic unit of structure and function
Enclosed by a membrane
Use DNA for genetic information
Formed by combination of molcules

Question 2

Atoms (O,H,C)

Answer 2

Foundation of molecules
Smallest unit of chemical elements

Question 3

Molecules (Lipids, proteins)

Answer 3

Formed of combinations of atoms
2 or more atoms combined

Question 4

Elements

Answer 4

Can’t be broken down (composed of only one type of atom)
96% of living matter is made up of C, O, N, H
Trace Elements: Fe, I, Zn, Cu

Question 5

Compounds

Answer 5

Molecule made up of two or more elements combined in a fixed ratio
ie: sodium chloride (NaCl)

Question 6

Covalent Bonds

Answer 6

Strong chemical bonds that involve sharing electrons between two atoms
Nonpolar: Equal sharing of electrons
Polar: Unequal sharing of electrons

Question 7

Ionic Bonds

Answer 7

Strong chemical bonds that involve the transfer (stealing) of electrons between two atoms

Question 8

Hydrogen Bond

Answer 8

Weak chemical bond when an H atom forms one covalent bond with another atom in the same molecule and a SECOND WEAKER BOND (the hydrogen bond) with an atom in another molecule

Question 9

Structure & Properties of Water

Answer 9

Composed of H and O
Two H atoms covalently bonded to an O atom
Polar Covalent bonds
Water structure provides interactions between water molecules, cohesion, and water and other molecules, solvent

Question 10

Cohesion

Answer 10

Formation of hydrogen bonds between H and O of water molecules
Maximum of four partners

Question 11

Solvent

Answer 11

a substance in which another
Substance dissolves

Question 12

Solvents and Solutes and Solution

Answer 12

Solvents: substance in which another substance dissolves
Solute: the dissolved substance
Solution: a mixture of solute and solvent

Question 13

Hydrophilic Substances

Answer 13

Affinity for water - substances with polar covalent or ionic bonds that can form hydrogen bonds with water

Question 14

Hydrophobic Substances

Answer 14

repels water (non-polar covalent bonds)
ie: lipids because they have dominant bonds but retain equal sharing of electrons

Question 15

Dissociation of Water Molecules and pH

Answer 15

Water can dissociate into a hydrogen and hydroxide ion
H20 <–> H+ + OH-
Acids increase proton [H+] concentration of a solution
Bases decrease proton [H+] concentration of a solution

Question 16

Buffers

Answer 16

Resists changes in the pH of a solution
Donates H+ when solution is depleted of hydrogen (makes more acidic)
Donates OH- or receives H+ when solution has excess hydrogen (bases)
ie: human blood is buffered by carbonic acid and bicarbonate