BIOL V01 Algiers

Chapter 2 Notes
(Atoms, Molecules, and Life)

Atom-Fundamental ______unit of ______

Subatomic Particles-

1.  proton

2.  neutron

3.  electron

Periodic Table (pg 904)

Element – A substance that cannot be ______nor ______to another substance by ordinary ______

­  Common elements in living organism (% by weight in humans- pg 22

Nitrogen ______%
Carbon ______%

Oxygen ______%

Hydrogen ______%

Examples:

a) Oxygen O 8 protons Atomic # ______

8 neutrons

8 electrons Atomic mass ______

b) Fill in the following:

6

BIOL V01 Algiers

Element ______

Atomic # ______

Atomic mass ______

Protons ______

Neutrons ______

Electrons ______

6

BIOL V01 Algiers

Isotope – atoms of the same ______with different ______numbers

­  C12 ( ____ p ____ n)

­  C14( ____ p ____ n)

­  Some isotopes are ______
Spontaneously ______& form ______
while releasing ______

­  Read Scientific Inquiry: Radioactivity in Research (pg 24)

Electrons

­  Electrons orbit through diff. energy levels
Rule for electron numbers in shells

o  1st shell à

o  2nd shell à

o  3rd shell à

And so on…

-  Examples:

Atoms React with One Another

Molecules - ______atoms of the same or of different elements held together with ______

–  Compound –molecules with atoms of ______types

§  Tend to have different physical ______

Atoms can form chemical bonds w/ one another when the outer shell is not full

Chemical Bonds (pg. 25; table 2-2)

1.  ______

2.  ______

a.  ______(use Greek small letter delta δ)

b.  ______

3.  ______(weak interaction)

Example Example

Free Radicals –very ______that ______other molecules quickly
Radiation, ______, and ______chemicals increase the activity of free radicals

Diseases attributed to free radicals are:

–

–

–

–

Antioxidants (pg 26, Health Watch)

Molecules that ______with free radicals and make them stop

Some foods that have high amts of antioxidants:

Properties of Water

·  Living organisms are composed of ______water

·  Involved in many reactions

1.  Water molecules attract one another

______interconnect water molecules

-  Water has ______ (sticks to itself)

a)  ______– how difficult it is to break the water surface

http://www.youtube.com/watch?v=Qhsxo7vY8ac

b)  ______allows water molecules to stick together

c)  ______(stickiness to charged surfaces) allows them to stick to the tiny tubes of plants, helping them ‘climb’ up the plant against gravity

2.  Water Interacts with many other molecules

Solvent - ______
(usually found in higher concentration)

Solute -______
(usually found in higher concentration)
Water is a ______(Fig 2-9 pg 30)

Hydrophilic molecules ______water

Hydrophobic molecules ______water

3.  Water based solutions can be Acidic, Basic, or Neutral

H2O OH- + H+


(water) (hydroxide ion) (hydrogen ion)


Acidic solutions contain more ______

Acids increase ______in solution


Basic solutions contain more ______

Bases increase ______in solution

pH Scale – expresses the degree of ______in a solution ( )

Acidic Neutral Basic
______
0 7 14

Buffer – a compound that tends to ______at
______

Ex: bicarbonate and carbonic acid (pg 32)
Basic (HCO3-) (H2CO3) Acidic

4.  Water moderates the Effects of temperature
Water ______and ______slowly
Water moderates ______and ______temperatures

5.  Water forms an unusual solid-Ice

Ice is ______than liquid water
Ponds/Lakes -

Key Terms to define from Chapter 2:

6

BIOL V01 Algiers

  1. acid
  2. antioxidant
  3. atom
  4. atomic number
  5. base
  6. buffer
  7. chemical bond
  8. cohesion
  9. compound
  10. covalent bond
  11. electron
  12. electron shell
  13. element
  14. free radical
  15. hydrogen bond
  16. hydrophilic
  17. hydrophobic
  18. ion
  19. ionic bond
  20. isotope
  21. molecule
  22. neutron
  23. non-polar covalent bond
  24. pH scale
  25. polar covalent bond
  26. proton
  27. radioactive
  28. solvent
  29. surface tension

6

BIOL V01 Algiers

Chapter Questions: Pg 34

Fill in the Blank

Review Questions 2, 3, 5, 6

7