The Chemical Composition of Living Things. Physical Properties Describe physical appearance ...
Transcript of The Chemical Composition of Living Things. Physical Properties Describe physical appearance ...
BIOCHEMISTRYThe Chemical
Composition of Living Things
PHYSICAL & CHEMICAL PROPERTIES & CHANGES
Physical Properties Describe physical
appearance Color, texture,
shape Physical Changes
Change in appearance only
Reversible Melting, freezing,
breaking, etc.
Chemical Properties Describe how
material reacts Flammability,
reactive, & pH Chemical Changes
Change in composition
Irreversible Burning, oxidizing,
digesting, etc.
CHEMICAL RXNS W/IN LIVING ORGANISMS
Chemical rxns require energy (activation energy)
Enzymes lower the activation energy needed to start a chemical rxn. Catalyst = speed
things up Allows biological
processes to happen faster
ENZYMES: HOW THEY WORK
Shape determines function Specific enzyme
for each different chemical rxn
Ex: Lactase enzyme speeds up the metabolism of lactose
Denature If an enzyme’s
shape changes, it won’t work as effectively
Caused by: Change in temp Toxins (acids, bases) Radiation
ATOMIC STRUCTURE
# protons =
+ charge
# neutrons =
No charge
# electrons =
- charge
Atomic Number
Atomic Mass
Symbol
C
6
12.01
ATOMIC DIAGRAMS Nucleus –
protons + neutrons
Electron clouds Surround nucleus 1st – 2nd – 3rd – 4th – 5th – 6th – 7th -
ATOMIC DIAGRAMS
Valence Electrons – Electrons in the
outer most energy level
Octet Rule Must fill 1st level
before move onto the next
CARBON
Protons -
___________
Neutrons -
_________
Electrons -
_________
Valence - __________
SODIUM
Protons -
___________
Neutrons -
_________
Electrons -
_________
Valence - __________
BORON
Protons -
___________
Neutrons -
_________
Electrons -
_________
Valence - __________
CHLORINE
Protons -
___________
Neutrons -
_________
Electrons -
_________
Valence - __________
BONDING
2/more atoms join to become more stable Atoms become stable when they have a
full outer energy level Most organic elements need 8 electrons Hydrogen is the exception – it only needs 2
IONIC BONDS
Atoms gain/lose electrons to increase stability Gains (-) ion Loses (+) ion
Opposing charges attract forming a bond
IONIC BONDS
Formulas 1st – (+) ion 2nd - (-) ion # indicates how
many of each element are needed
NaCl
Sodium & Oxygen
COVALENT BONDS
2/more atoms share electrons to increase their stability
Occurs when neither element can “give away” electrons
Atoms joined by covalent bonds are called molecules
COVALENT BONDS
Carbon & Sulfur
BONDING
Nitrogen & Oxygen
Bond ____________ Formula ___________
Unique Characteristics of Water
Most dense in liquid form Allows ice to float Importance to living things?
Aquatics Terrestrial
Unique Characteristics of Water
Water has a high surface tension Cohesion – molecules “stick” to themselves Adhesion – molecules “stick” to another
substance Capillary Action – molecules drawn up a tube Importance to living things?
Blood Plants
Unique Characteristics of Water
High Specific Heat Resists changes in temperature Requires increased energy to raise temp Importance for Living Things?
Aquatic Organisms Mammals Climate
Unique Characteristics of Water
Versatile Solvent Water is “polar” or charged Any polar substance will dissolve in water “Like dissolves Like” Gives water the ability to form mixtures, acids
& bases Importance to living things?
Structure Nutrient/waste exchange Buffer
Unique Characteristics of Water
pH Scale
Water forming Mixtures
Solutions: Homogeneous 1
substance equally dissolved in another
Examples:
Suspensions: Heterogeneous
2/more layers form; particles “hanging”
Examples:
Water forming Mixtures
COLLOID Gel-like substance
w/clusters large molecules spread throughout
Properties both liquid & solid depending upon pressure applied
Examples: