Chapter 2: Chemical Basis of Life

Question 1

Water

Answer 1

Where life first evolved

required by all organisms

chemical reactions in body consisting of 70-95%

Question 2

Elements

Answer 2

substance that cannon be broken down to other substances

contains on type of atom

92 in nature

Question 3

Compound

Answer 3

Composed of two or more elements in a fixed state

Question 4

Atom

Answer 4

smallest unit of matter that retains property of element, made of protons, electrons, neutrons (subatomic particles)

Question 5

Atom Structure

Answer 5

Neutron and protons packed in nucleus, electrons orbit nucleus, negative charge of electrons and positive charge of protons keep electrons near nucleus

Question 6

Atomic Number

Answer 6

number of protons

Question 7

Mass Number

Answer 7

sum of protons and neutrons

Question 8

Atomic Mass

Answer 8

Approximately equal to Mass Number (protons + neutrons)

Question 9

Electrons

Answer 9

negative charge, determine chemical nature, reactivity, and interactions with other elements, Energy shells (Octet rule: 2, 8, 8)

Question 10

Bonds

Answer 10

interaction of outer shells or valance electrons, forms molecules out of atoms and compounds out of molecules

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Question 11

Covalent Bonds

Answer 11

atoms share electrons between pairs to satisfy each of their valance shells, strongest

Question 12

Ionic Bonds

Answer 12

Unequally charged ions (pos and neg attracted) - electrons transferred from one ion to another

Question 13

Hydrogen Bonds

Answer 13

weak, crucial to cell function, includes H, polar molecules - one end more positive than other allows attraction to negative end of nearby molecules

Question 14

Solvent

Answer 14

dissolves substances (solutes) to form aqueous solution

Question 15

Water as solvent

Answer 15

Water molecules dissociate leaving H+ (hydrogen ions = acidic, low pH) and OH- (Hydroxide ion = basic, higher pH)

Question 16

Matter

Answer 16

anything that occupies space and has mass (weight). Living organisms made of

Question 17

C

Answer 17

Carbon

Question 18

O

Answer 18

Oxygen

Question 19

H

Answer 19

Hydrogen

Question 20

N

Answer 20

Nitrogen

Question 21

Ca

Answer 21

Calcium

Question 22

P

Answer 22

Phosphorus

Question 23

K

Answer 23

Potassium

Question 24

S

Answer 24

Sulfer

Question 25

Na

Answer 25

Sodium

Question 26

Cl

Answer 26

Clorine

Question 27

Mg

Answer 27

Magnisium

Question 28

Most abundant elements in human body

Answer 28

O, C, H, N