Chapter 2 - Nature of Molecules & Properties of Water

Question 1

Matter

Answer 1

anything that takes up space & has mass

Question 2

Atomic #

Answer 2

of protons

Question 3

Element

Answer 3

substance that cannot be broken down into another substance

Question 4

Mass

Answer 4

amount of substance

Question 5

Weight

Answer 5

force that gravity exerts on a substance

Question 6

Atomic Mass

Answer 6

of protons + # of neutrons

Question 7

Isotope

Answer 7

atoms with the same # of protons & electrons but varying # of neutrons

Question 8

Oxidation

Answer 8

loss of electrons

Question 9

Reduction

Answer 9

gain of electrons

Question 10

What are the 4 main elements in living systems?

Answer 10

oxygen, carbon, hydrogen, nitrogen

Question 11

Molecule

Answer 11

group of atoms

Question 12

Compound

Answer 12

atoms of more than 1 element together

Question 13

Covalent Bond

Answer 13

electrons shared btwn atoms

Question 14

Ionic Bond

Answer 14

electrons transferred btwn atoms

Question 15

Nonpolar

Answer 15

electrons shared equally

Question 16

Polar

Answer 16

electrons shared unequally

Question 17

List bonds based on strength (strongest to weakest)

Answer 17

1. covalent
2. ionic
3. H-bond
4. hydrophobic interaction
5. van der waals

Question 18

What are radioactive isotopes used for in biology?

Answer 18

to tag & label amino acids in cell culture, NMR, tracing of molecules for metabolic processes

Question 19

In H-bonding what does H bond with?

Answer 19

F, N, O

Question 20

Cohesion

Answer 20

molecules attracted to one another (of the same type)

Question 21

Adhesion

Answer 21

attraction for other polar substances

Question 22

What are the properties of water?

Answer 22

• exerts organizing effect on nonpolar molecules
• high specific heat (to maintain temp)
• high heat of vaporization (cooling)
• solid water less dense than liquid water

Question 23

Hydration Shell

Answer 23

molecule surrounded by water molecules in a cloud

Question 24

Hydrophobic

Answer 24

fears water

Question 25

Hydrophilic

Answer 25

loves water

Question 26

Hydrophobic Exclusion

Answer 26

nonpolar molecules aggregate in water

Question 27

Acidity

Answer 27

concentration of H+ ions

Question 28

Basicity

Answer 28

concentration of OH- ions

Question 29

pH

Answer 29

power of Hydrogen

Question 30

What is the pH like in cells?

Answer 30

- usually neutral (7) - important to maintain constant pH

Question 31

Buffer

Answer 31

substance that resists changes in pH (can release or absorb H+ ions)

Question 32

What are the biologically important characteristics of water?

Answer 32

- expands when frozen - high specific heat - high cohesive strength - high surface tension - solvent of life - liquid over wide range of temps