the chemistry of life
DESCRIPTION
TRANSCRIPT
CHAPTER 2
A. Dictionary definitions are circularB. Life is defined as a series of
characteristics organisms share1. Use Energy2. Grow3. Develop4. Reproduce5. Cells6. Homeostasis7. Maintenance & Repair8. Heredity9. Sensitivity10. Death
A. ATOMS1. Smallest building blocks of matter2. Atomic structure
Living things are made of the same things as the rest of the universe• Organisms are chemical machines• Knowledge of chemistry is important in understanding life processes
Protons Positive charge p+
Determine chemical behavior Give ATOMIC NUMBER
Neutrons No charge n0
n + p = ATOMIC MASS
Give the isotope
Electrons Negative charge e-
Same number as protons making atoms neutral
Orbit nucleus in energy levels (2n2)
Higher the level the greater the energy
Carry energy through living systems
1
H1.0079
1
H1.0079
ATOMIC NUMBER
ATOMIC MASS
SYMBOL
HYDROGEN
ATOMIC NUMBER?
ATOMIC MASS?
NAME?
3
7
Lithium
p+e-
n0
a. Only 92 are naturally occurring Others only exist in the laboratory The way these naturally occurring
elements combine makes up everythingb. Only 20 of the 92 are common in living
thingsc. Only 4 of those 20 make up 97% of all living
matter
All others are considered TRACE ELEMENTS
C. CHEMICAL BONDS1. Force holding atoms together2. Atoms bond to fill outer shells
a. By gaining, losing, or sharing electronsb. Makes atoms stable
3. Types of bonds
11
Na22.9897
11
Na22.9897
1st Energy Level
2e-
1st Energy Level
2e-
2nd
Energy Level
8e-
2nd
Energy Level
8e-
3rd Energy Level
1e-
3rd Energy Level
1e-
17
Cl35.453
17
Cl35.453
1st Energy Level
2e-
1st Energy Level
2e-
2nd
Energy Level
8e-
2nd
Energy Level
8e-
3rd Energy Level
7e-
3rd Energy Level
7e-
Ions are charged particles (+ or -)• Occur when atoms gain or lose electrons• IONIC BONDS result from the attraction of
oppositely charged ions
Loses e- Loses e-
Gains e- Gains e-
+ -
Form MOLECULES• Occur when atoms share electrons to fill outer shells• Electrons are always in shared pairs• Follow the OCTET RULE
HydrogenHydrogen H2H2+ Hydrogen+ Hydrogen
Formed by COVALENT BONDING
Needs1
electron
Needs 2 electrons
ATOM
Shares
HHYDROGEN
OOXYGEN
Valence Electrons are in the outer energy level
NNITROGEN
CCARBON
1 2 3 4
B. COMPOUNDS1. Composed of two or more elements2. Elements are chemically combined
Lack CARBON Exceptions are:
Many in living things
CO2
CARBON DIOXIDE
CaCO3
CALCIUM CARBONATE
INORGANIC WATER Most essential nutrient Makes up 2/3 body weight Major component of blood Lubricates joints Biochemical Reactions Lost constantly
• sweat• elimination of waste• exhaling
In all living things Contain CARBON Can be gases like
These gases are referred to as HYDROCARBONS
CH4
METHANE
ORGANIC MACROMOLECULES Formed by Organic Compounds in living things Large complex molecules Long chains or rings of carbon atoms
Inorganic Molecules are much smaller
1. PROTEINS2. CARBOHYDRATE
S3. LIPIDS4. NUCLEIC ACIDS
4
3
2 1
A.CARBOHYDRATES1. Body’s primary
source of energy2. Supplied by plants3. Plants make food
by the process of PHOTOSYNTHESIS
CARBON DIOXIDECARBON DIOXIDE
WATERWATER CARBOHYDRATESimple Sugar
CARBOHYDRATESimple Sugar
OXYGENOXYGEN
Solar
Energy6CO2 6H2O C6H12O6 6O2++
a. MONOSACCHARIDES Single sugar units Examples:
GLUCOSE Main source of energy for cells Blood Sugar
FRUCTOSE Sweetest Honey, Fruit
GALACTOSE Part of milk sugar
GLUCOSE
C6H12O6
b. DISACCHARIDES Double sugar units Examples:
SUCROSE Table Sugar (cane sugar) glucose + fructose
MALTOSE Brewing glucose + glucose
LACTOSE Milk sugar glucose + galactose
Suffix OSE refers to sugars
a. POLYSACCHARIDES Many sugar units Long complex chains of sugars
b. Examples:
STARCH Store energy in plants 100’s of glucose subunits in a line
GLYCOGEN Animal starch Stored in muscles and liver 100’s of branched glucose subunits
B. LIPIDS1. Fats and Oils2. Store Energy in
living thingsa. Large number of
C to H bondsb. Store 2x the
energy per gram than carbohydrate
3. Triglycerides are the most common dietary fat
4. Types of Fats
a. SATURATED FATS
C – C are single Hold maximum
number of H atoms Usually solid at
room temperature Butter, fat on meat,
lard, etc.
SATURATED FATS High levels in
diet may lead to:
OBESITY
CARDIOVASCULAR DISEASE
CANCER
b. UNSATURATED FATS
One or more C – C bonds are double
Not saturated with H atoms
Usually liquid at room temperature
Olives, olive oil, peanuts, peanut oil, cooking oils, etc.
Food taste Fat soluble vitamins Calories (ENERGY) Prevents deficiencies in women and children Insulation
5. Other Lipidsa. Steroids
Sex Hormones Cholesterol Chlorophyll
b. Waxes Earwax Beeswax
C. PROTEINS1. Major part structural part of living things
COLLAGENSkin, Bone, Cartilage, Tendons
KERATINHair, Horns, Feathers
2. Act as enzymes3. Composed of long chains of amino
acids
NH2 COOH
R is the variable side (determines the acid)R = H then Glycine R = CH3 then Alanine
a. Twenty kinds of amino acids found in proteins (most end in “ine”)
Essential Amino Acids (8)Only in food
Nonessential Amino AcidsCan be produced by body using essential amino acids
b. A typical protein is at least 100 amino acids linked together called a polypeptide
Specific acids and sequence determine physical properties and function
20100 possible combinations for such a protein
a. PRIMARY • Order of acids
b. SECONDARY• Interactions
cause them to bend or twist
• Called a HELIX• Form fibrous
proteins like hair and nails
c. TERTIARY • Most fold into a
compact mass• Typical of
enzymes
d. QUATERNARY• Mix of two or
more protein chains
• Characteristic of hemoglobin and insulin
1. DNA Deoxyribonucleic Acid Forms a DOUBLE
HELIX Makes up
Chromosomes
2. RNA Ribonucleic Acid Directs formation of
proteins
D. NUCLEIC ACIDS
THE END