BIOL-1115 Chapter 2

Question 1

Matter

Answer 1

All things which take up space and have mass.

Question 2

Elements

Answer 2

Basic component of matter. Can’t be reduced further through chemical reactions.

Question 3

Compounds

Answer 3

Composed of two or more elements in a fixed ratio. They have emergent properties.

Question 4

Essential elements

Answer 4

Required for life and reproduction.

O,C,H,N,Ca,P,K,S,Na,Cl,Mg

Question 5

Trace elements

Answer 5

Required in small amounts by an organism. (Less than 0.01% mass)

B,Cr,Co,Cu,F,I,Fe,Mn,Mo,Se,Si,Sn,V,Zn

Question 6

Atom

Answer 6

Smallest unit of matter that retains the properties of an element.

Question 7

What charges do neutrons, protons, and electrons have?

Answer 7

Neutrons -> neutral charge
Protons -> positive charge
Electrons -> negative charge

Question 8

Atomic nucleus

Answer 8

Where protons and neutrons are packed together tightly in a dense core (at the centre of an atom)

Question 9

Isotopes

Answer 9

Atoms of an element which have variable #’s of neutrons = isotopes

Eg. Carbon-12

Question 10

Radioactive isotopes

Answer 10

Spontaneous decay of atomic nucleus, releasing particles and energy.

Eg. Carbon-14
(Used in research/medical imaging)

Question 11

Energy vs. Potential energy

Answer 11

Energy: capacity to work

Potential energy: due to location or structure of matter

Question 12

What is a chemical bond? What are the three types?

Answer 12

Required for the formation of molecules

1.) covalent bonds
2.) ionic bonds
3.) hydrogen bonds
4.) James Bond >:)

Question 13

Covalent bond

Answer 13

Strongest bond
Occurs when 2 atoms share a pair of valence electrons.

Question 14

Electronegativity

Answer 14

Strength of attraction for an electron to an atom

Question 15

Non-polar bonds

Answer 15

Form between two identical elements: equal electronegativity.

Question 16

Polar bonds

Answer 16

Form between different elements: unequal electronegativity

Question 17

Ionic bond

Answer 17

Because their opposite charges, cations and anions attracts each other.

Question 18

Ion

Answer 18

An atom or group of atoms that bears one or more positive or negative electric charges.

Question 19

Ionic compounds

Answer 19

Also called salts, are formed when two ions form an ionic bond.

(Strength of the bond depends on the environment)

Question 20

Hydrogen bonds

Answer 20

Weak individually, but will maintain functional structure of bio molecules.

(Usually with oxygen and nitrogen in living organisms)

Question 21

Van der Waals interations

Answer 21

Results in temporary formation of slightly (+) and (-) regions which attract each other.

Individually weak, but also stabilize 3 dimensional shapes of bio molecules.

Ex. Gecko feet

Question 22

Cohesion

Answer 22

Due to hydrogen bonding between water molecules.

Question 23

Surface tension

Answer 23

The force needed to break the surface of a liquid.

(Surface tension of water is very high)

Question 24

Adhesion

Answer 24

Due to hydrogen bonding between water AND other molecules.

Question 25

Kinetic energy

Answer 25

Energy of motion

Question 26

Thermal energy

Answer 26

Energy associated with the movement of atoms or molecules.

Question 27

Temperature

Answer 27

Average kinetic energy of the molecules in a body of matter.

Question 28

Heat

Answer 28

Thermal energy transferred from one body of matter to another.

(Measured in calories)

Question 29

Specific heat

Answer 29

The amount of heat required for 1 gram of the substance to increase its temperature by 1°C.

It stabilizes water habitats, air in costal regions, and organisms.

Question 30

Heat of vaporization

Answer 30

Quantity of heat required for 1g of a substance to be converted from a liquid to a gaseous state.

Question 31

Evaporative cooling

Answer 31

Process of evaporation results in a reduction of the temperature of the remaining liquid.

Stabilizes temperature of water bodies and prevents overheating of organisms.

Question 32

Characteristics of ice

Answer 32

Hydrogen bonds are stable, molecules are held in place, lowers density and floats on water (prevents freezing of entire lake/ocean).

Question 33

Characteristics of liquid water

Answer 33

Hydrogen bonds break and reform. Molecules can move closer together.

Question 34

Solution

Answer 34

Homogenous liquid mixture of 2 or more substances.

Question 35

Solvent

Answer 35

Dissolving agent

Question 36

Solute

Answer 36

Substances dissolved into the solution

Question 37

Aqueous solution

Answer 37

Solvent is water

Question 38

Hydration shell

Answer 38

Water molecules form hydrogen bonds with each solute molecule and surround it.

Question 39

Hydration shell

Answer 39

Water molecules form hydrogen bonds with each solute molecule and surround it.

Question 40

Hydrophilic

Answer 40

Substance which has an affinity for water.
-> polar molecules and ions
-> not all hydrophilic molecules dissolve

Question 41

Hydrophobic

Answer 41

Do not have an affinity for water.
-> non-polar and non-ionic molecules

Question 42

Acid

Answer 42

Substance which increases the H+ concentration of a solution.

Question 43

Base

Answer 43

Substance that reduces the H+ concentration of a solution.

Question 44

Buffers

Answer 44

A substance which minimizes changes in the H+ concentration. Stabilizes pH.
-> comprised of an acid and a base
-> important in biological systems and the environment

Question 45

Ocean acidification

Answer 45

When CO2 dissolves in seawater, it reacts with the water to form carbonic acid, which lowers ocean pH.