Chemicals of Life A Unit on Biochemistry

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Chemicals of LifeA Unit on Biochemistry
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Important terms
Atoms Basic building block of matter.
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Composition of an atom
Made up of three subatomic particles Protons
in the nucleus Neutrons neutral
in the nucleus Electrons ---
electron shell
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Elements Substance made up of all one type
of atom. Six most common elements found in
living organisms C, H, N, O, P, S
hyperlink
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Molecules/compounds Two or more atoms bonded
together to create a new substance with
new properties..
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Molecules/compounds

• Two or more atoms bonded together to create a new
  substance with new properties.
• Example NaCl /Sodium Chloride

Sodium White crystal Solid Explosive in water
Chlorine Green Gas Very poisonous
Sodium Chloride White crystal Solid Not
explosive Not poisonous
Table Salt
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Most common compoundsin a living organism
Carbohydrates Lipids Proteins Nucleic Acids Water
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Two types of compounds

• Inorganic compounds
• Do not contain carbon
• Can not be decomposed
• Must be recycled
• Examples
• Sand, glass, styrofoam
• Soil, rocks, metals and
• water

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• Organic Compounds
• Contain carbon
• Are decomposed or broken down and nutrients
  returned to soil
• Examples
• Anything living or once living
• Dead plants and animals
• Proteins, lipids, carbs and
• nucleic acids

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Inorganic Compounds found in all living organisms
WATER
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Water H2O
1. Made up of two hydrogen atoms bonded to one
oxygen atom.
2. Atoms bond to form an angular molecule
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3. Water is classified as a polar molecule.
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Polar because like the Earth or a bar magnet it
has a partial positive and a partial negative end.

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One of the most important rules in biology is
that
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Opposites attract
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Therefore, one molecule of waters positive end
is attracted to another molecule of waters
negative end giving water many unique properties.
Weak Hydrogen bonds hold the molecules together.
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Waters unique characteristics
-1. Water is an inorganic molecule -Contains no
carbon -2. Water covers 75 of the Earths
surface -3. Water makes up 70 to 80 of a
living organism -4. Water is made up of two
hydrogen atoms and one oxygen atom -5.
Water forms an angular molecule -6. Water is a
POLAR MOLECULE -has a and a end
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• 7. Water occurs in three phases
• -Solid
• -molecules have a small amount of energy
• -molecules have just a little movement
• (just vibrating against each other)
• -molecules are close together and held in
• place with hydrogen bonds.
• -Liquid
• -molecules gain some energy and some movement
• -Hydrogen bonds are broken
• -molecules begin to spread out
• -Gas
• -molecules gain a lot of energy
• molecules have a lot of rapid movement
• (enough to escape the surface into the air as a
  gas )
• -molecules widely spaced out

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PHASE DIAGRAM OF WATER
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8. Water displays cohesion Co together
hesion or hesive to stick Cohesion
is the attraction between like molecules. (one
water molecule attracted to another water
molecule). This occurs due to the fact
that water is a polar molecule and
opposites attract.
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9. Water displays adhesion

• Adhesion
• is the tendency of certain dissimilar molecules
  to cling together due to attractive forces.

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The water molecules are attracted to the sides
of the graduated cylinder causing the water to
raise up on the sides. Water forms a concaved
meniscus. The water molecules are attracted to
the sides of the glass container.
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10. Water expands when frozen.
When frozen, the water molecules slow down and
due to their polarity they will line themselves
up to end thus taking up more volume and
lowering its density.
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.
.
O H H
Occupies more volume
O
H
Occupies less volume
H
H
O
O
H
H
H
Solid
Liquid
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11. Water is known as the UNIVERSAL
SOLVENT It dissolves more substances than any
other substance on Earth. To dissolve means that
the molecules of one substance are picked up and
totally surrounded by water molecules.
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Demo of salt dissolving In water.
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Mini Experiment 1
What is cohesion? -waters attraction to other
water molecules
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Mini Experiment 2
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Mini Experiment 3
Cup 1 Cup 2 Ice in water
Ice in alcohol
Reason why this occurred?
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Mini Experiment 4
Substance Soluble/dissolves Insoluble/does not dissolve
Salt    
Sugar    
Oil    
Powder soap    
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Mini Experiment 5
STRING DEMO
Using the two terms you defined, adhesion and
cohesion, explain why the water is able to travel
down the string from position A to position B.
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13. Due to its polarity, water is excellent at
making two types of mixtures
1. Suspensions 2. Solutions
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What is a mixture
- 2 or more substances combined but not
chemically. -each substance retains its own
properties. -each substance can be separated
from the other.
Examples???????
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Suspensions
Example Oil and water
A substance is mixed with water and the 2
substances separate. The less dense substance
is suspended above the more dense substance.
This happens because water is polar and oil is
NONPOLAR (no or ends)
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Blood is a suspension
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Solutions
One substance dissolves into another
substance. Examples Kool aid Salt water
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Cytoplasm is a solution
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The Rule
Likes dissolves likes Polar substances dissolve
other polar substances Water dissolves
salt Nonpolar substances dissolve other
nonpolar substances Gasoline or lighter fluid
dissolves oil
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Parts of a solution Substance doing the
dissolving. (water) Solute
Substance being dissolved.
(salt) Solution Created when the solute
DISSOLVES in the solvent.
(salt water)
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Aqueous solution water is the solvent Saline
solution salt is the solute
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3 types of water solutions
Acids, Bases and Neutral
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Acids A substance that releases H ions when
dissolved in water.
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Acidic Solutions
HCl is Hydrogen Chloride
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• HCl is Hydrogen Chloride
• H is 1 and Cl is 1 therefore it is neutral
• Not dangerous to us and our tissues
• When HCl is dissolved into water, the H and Cl
  ions separate.
• HCl is now known as Hydrochloric Acid
• It is now very dangerous to us and our tissues

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Base A substance that releases -OH ions when
dissolved in water.

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Basic Solution
NaOH is Sodium Hydroxide
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NaOH is Sodium Hydroxide Na is 1 and OH is 1
therefore it is neutral Not dangerous to us When
NaOH is dissolved into water, the Na and OH ions
separate. NaOH, sodium hydroxide is now very
dangerous to us and our tissues
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Neutral
A substance that release no H or OH ions when
dissolved in water
A substance that releases and equal amount of
both the H and the OH ions and they cancel
each other out.
OR
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Neutral Solution
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pH Scale
-measures the strength and weaknesses of an acid
(H) and of bases (OH-) -based on a scale of
0 to 14
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pH scale
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pH and common substances
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Neutralization Reaction
When an acid and a base of equal strength are
mixed and cancel each other out creating a
neutral substance.
HCl NaOH ----? NaCl HOH Strong
Strong neutral neutral acid
base
no H or OH H OH
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Buffer
A substance which guards against shifts in the pH
level. Our blood is an example of a buffer.
Blood uses extra H and OH- ions substances to
help resist pH changes in our body.
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Lab Using Acid-Base Indicators
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Indicator Test
-special chemicals that can show whether a
substance is an acid, a base or is neutral. -Two
type of indicators -pH paper Used to
determine the strength or weakness of an acid or
a base. -litmus paper Used to determine the
presence of either or both H or OH ions.
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pH paper
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Litmus Paper -Two types of litmus
paper. -RED and BLUE
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Litmus Paper
Red Litmus Paper - stays red when H
ions are present. -turns blue when
OH- Ions are present.
Blue Litmus Paper - turns red when H
ions are present. -stays blue when OH-
Ions are present.
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Item Result of Test
Blue Litmus Red or Blue Red Litmus Red or Blue pH paper Color and Number Strong Acid, Weak Acid Strong Base, Weak Base
Benedicts solution