Bio 101: Unit 2: The Chemistry of Life: Practice Quiz 2

If a solution has equal numbers of H+ and OH- ions, its pH is (*) and it is considered to be (*).

7 and neutral.

Solvent Capability

Ability to dissolve and transport materials to, from, and within organisms.

A chemical which can be added to solution to maintain the pH of that solution within narrow ranges is called a/an [*]

Buffer

The two elements that MUST be present for a molecule to be considered organic are

Carbon and Hydrogen

Capillary Action

Allows movement of water from roots to leaves in even the tallest of trees.

A water molecule has a slightly positive end, and a slightly negative end. As a result, water is said to be [*]

Polar

H2O is an example of a molecule with (*) bonds, CH4 is an example of a molecule with (*) bonds, and NaCl is an example of a molecule with (*) bonds.

Polar covalent, non polar covalent, ionic

If it loses an electron, its charge is (*) and it's called a/an (*)

Positive and cation

Surface Tension

Result of cohesion of water molecules where water meets air.

Polar covalent bonds form when the electronegativities of the atoms involved are (*) , and the atoms (*) electrons to fill their valence shells.

Slightly different and unequally share

Expansion upon freezing

Solid water is less dense than liquid water.

Ionic bonds form when the electronegativities of the atoms involved are (*), and the atoms (*) electrons to fill their valence shells.

Very different and transfer

Nonpolar covalent bonds form when the electronegativities of the atoms involved are (*), and the atoms (*) electrons to fill their valence shells.

Very similar and equally share

High heat capacity

Water's resistance to temperature change.

A molecule that removes H+ ions from solution is

a base.

A molecule which releases H+ ions into solution is

an acid.

List the four groups of organic molecules, in alphabetical order, with a comma followed by one space separating each word.

carbohydrates, lipids, nucleic acids, proteins.

In hydrogen bonds, a hydrogen atom from one water molecule is attracted to a hydrogen atom from an adjacent water molecule

False

Capillary action requires both cohesion and adhesion.

True

Cohesion results from hydrogen bonding, and hydrogen bonding occurs because water is polar.

True

An acid with pH 4 is [*] stronger than an acid with pH 6.

100 x

The six elements that are most often found in organic molecules are:

Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulfur.

The reaction which links small organic molecule building blocks together to form large organic molecules is called (*) while the reaction that breaks down large organic molecules to the smaller building blocks is called (*).

Dehydration Synthesis and Hydrolysis

Water is good at dissolving substances which are [*]

Hydrophillic, polar, and ionic.

An atom that gains or loses an electron is called a/an

Ion

Organic molecules can have small building blocks called (*), which can link together to form large macromolecules called (*).

Monomers and polymers.

If it gains an electron, its charge is (*) and it's called a/an (*)

Negative and anion

Most living organisms are made up of primarily water. The part of their mass which is NOT water is largely composed of [*] molecules.

Organic

The higher the concentration of H+, the (*) the acid, and the (*) the pH.

Stronger and lower.

A base with a pH of 11 is [*] than a base with pH 10.

Stronger.

Adhesion

The attraction of a water molecule to a different polar or ionic molecule.

Cohesion

The attraction of one water molecule to another water molecule.