Chapter 2: Chemistry of Life

Question 1

major elements in the human body

Answer 1

• oxygen (65%)
• carbon (18%)
• hydrogen (10%)
• nitrogen (3%)
• calcium (1.5%)
• phosphorus (1%)

Question 2

lesser elements in the human body

Answer 2

• sulfur
• potassium
• sodium
• chlorine
• magnesium
• iron

Question 3

trace elements in the human body

Answer 3

chromium, cobalt, copper, fluorine, iodine, manganese, molybdenum, selenium, silicon, tin, vanadium, zinc

Question 4

atoms

Answer 4

consist of:
- protons
- neutrons
- electrons

Question 5

isotope

Answer 5

an atom of an element containing a different number of neutrons (often unstable)

Question 6

valence electrons

Answer 6

electrons in the outer shell of an atom

Question 7

molecule

Answer 7

a particle composed of two or more atoms united by a chemical bond

Question 8

ionic bonds

Answer 8

one atoms transfers an electron from its outer shell to another atom

Question 9

ions

Answer 9

electrically charged atoms
- cations (+)
- anions (-)

Question 10

ionization

Answer 10

occurs when ionic bonds dissociate in water, forming a solution of positively and negatively charged ions thats capable of conducting electricity

Question 11

electrolytes

Answer 11

• compounds that dissociate in water and create a solution capable of conducting electricity
• crucial for heart, nerve, and muscle function, the distribution of water in the body, and the occurrence of chemical reactions

Question 12

covalent bods

Answer 12

• formed when two atoms share one or more pairs of electrons
• stronger than ionic bonds

Question 13

hydrogen bonds

Answer 13

a weak attraction between a slightly positive hydrogen atom in one molecule and a slightly negative oxygen or nitrogen atom in another

Question 14

potential energy

Answer 14

energy stored in the bonds of molecules

Question 15

kinetic energy

Answer 15

energy in motion

Question 16

metabolism

Answer 16

the sum of all chemical reactions in the body

Question 17

catabolism

Answer 17

• involves breaking down complex compounds into simpler ones
• breaking of chemical bonds releases energy
• some energy is released in the form of heat
• most energy is transferred to ATP molecules

Question 18

anabolism

Answer 18

• involves building more complex molecules from smaller subunits
• anabolic reactions require energy input
• required energy is obtained from ATP molecules

Question 19

ATP

Answer 19

adenosine triphosphate

Question 20

ADP

Answer 20

adenosine diphosphate

Question 21

types of chemical reactions

Answer 21

• synthesis
• decomposition
• exchange
  (all can be reversible)

Question 22

inorganic molecules essential to human life

Answer 22

• water
• oxygen
• carbon dioxide
• acids and bases

Question 23

solution

Answer 23

• a solute dissolved in a solvent
• can be gas, solid, or liquid
• solvent must be clear with no visible particles
• does not separate when left to stand

Question 24

colloid

Answer 24

• usually mixtures of protein and water
• can change from a liquid to a gel
• particles are small enough to stay mixed, but large enough that the mixture is cloudy

Question 25

suspension

Answer 25

• contain large particles, making the mixture cloudy or even opaque
• particles will separate and settle at the bottom if left to stand

Question 26

cellular respiration

Answer 26

the production of energy within cells