Atoms and Their Interactions
Water and Diffusion
Life Substances

Smallest particle of an element that has the characteristics of an element.
Basic unit of matter
Atomos = (greek) unable to be cut

Atomic Structure and Subatomic
Particles
Nucleus—strong forces bind protons and neutrons at center of the atom;
Protons - + charged particles
Neutrons - particles with no charge
Electrons - charged particle; 1/1840 mass of proton; constantly in motion in space surrounding nucleus; attracted to protons in nucleus

Electrons travel around the nucleus in certain regions known as Energy Levels .
The innermost level (small) maximum of 2 electrons.
2nd level (larger)-up to 8
3rd level-up to18 electrons.

Pure substance that consists entirely of one type of atom.
Earth
•Between 88 – 94 elements occur naturally
•About two dozen found living organisms)

Elements in living things in very small amounts.
(help maintaining healthy cells)
Examples: iron and magnesium

What is the most abundant element that exist in living things? (Number)

Periodic-Elements in same group have similar chemical and physical properties
• Elements and symbols are organized
• Rows-period; Same number of electron shells
• Vertical-groups; Electrons in outer energy level

# of Electrons = # of protons therefore have no net charge.
Same # Electrons = same chemical properties
Mass number= Protons + Neutrons

Atoms of the same elements that have different numbers of neutrons.
Atomic Mass= Average of the masses of an element’s isotopes.
Example: Carbon-14 (6 +, 6 -) is an isotope of carbon,
•
8 neutrons instead of 6 neutrons
•
Carbon 13- 7 neutrons, 6 protons
•
Isotopes-number of electrons
 same chemical properties

•Isotopes that have unstable nuclei and break down at a constant rate over time. (radiation)
•Medical
•Smoke detectors
•Archeological dating
RADIO ISOTOPES

• Detect and treat cance
•
Kill bacteria that causes food to spoil
• “Tracers” to follow movement of substances within an organism.

• Substance formed when atoms of two or more elements are chemically combined in definite proportions.
• Example: H
2
O (2:1), NaCl (1:1)

• Specific combination of elements in a fixed ratio.
• Chemically and physically different than elements its comprised. (eg. Water different than H and O)
• Cannot be broken down into simpler compounds or elements by physical means

• Force that holds substances together
• Stability
• Forming and breaking bonds-provides energy for growth, development, adaptation, and reproduction

Electrical attraction b/w 2 oppositely charged atoms or group of atoms.

An atom (or group of atoms) gains or loses electrons has an electrical charge.
An ION is a charged particle.

Molecules close together, slight attraction can form b/w oppositely charged portion of nearby molecules- the intermolecular forces
--Helps form water droplets, geckos climb using structures on toes and atoms on surface climbing.
VAN DER WAALS FORCES
-EX. HYDROGEN BONDS

A chemical bond formed when two atoms combine by sharing electrons .

Substances with covalent bonds and having no overall charge.
Most compounds in living things.
Example : Water, DNA

• Single-Each atom shares one electron
• Double- Each atom shares two electrons
• Triple- Each atom shares three electrons

process that changes, or transforms, one set of chemicals into another
Chemical bonds formed and broken

All chemical reactions that occur within an organism
•
Responsible for break down and building of molecules

•
Color change new substances might reflect different colors of light.
•
Heat change the container may get hotter or colder.
•
Gas produced bubbles or smoke may be observed.
•
Precipitate formed an insoluble solid might form in a liquid.

Substances that undergo chemical reactions.

a substance obtained from another substance through chemical change
PRODUCTS

• Energy changes- Some reactions release energy (spontaneous, form of heat), others absorb energy (will not happen w/o energy)
• Energy Sources-sun >plants>animals
• Activation Energy- Energy needed to get reaction started.

A material composed of 2 or more elements or compounds that are physically mixed but not chemically combined

Solute—Substance being dissolved. (salt)
Solvent—Substance that does the dissolving.
(water)
Universal solvent is water!!

Mixture containing non dissolved particles distributed within a solid, liquid or gas.
Examples: Orange Juice, Blood, Salad
Dressing.

A thick substance formed when very fine particles (such as large molecules) that cannot be dissolved stay scattered throughout liquid, solid, or gas without sinking.
Examples: Gelatin, Toothpaste, Shaving Cream,
Smoke and Milk

Scattering of light by colloidally dispersed particles.
Detected with the aid of a light beam.

• Liquid most of Earth’s surface
•
Expands slightly as it changes from liquid to solid
• Covers 75% of Earth’s surface
•
Most abundant compound in nearly all living organisms
•
Water resist temperature change

• Polar Molecule—Due to an uneven distribution of electrons, water molecules are slightly charged on each end.
– Oxygen has a slight negative charge
– Hydrogen have a slight positive charge.
• Strong attraction between water and other molecules; the universal solvent.
•
Dissolve ionic compounds, as well as sugars.

Weak chemical bond formed by the attraction of the hydrogen atoms to other negatively charged atoms. weak "hydrogen" bonds in water partially get their identity from stronger "covalent" bonds in the H2O molecule

Attraction between molecules of the same substance
•
Water forms beads on smooth surface
• reason insects can walk on water

How difficult it is to stretch or break the surface of a liquid.
•
Water has a high surface tension b/c of cohesion of hydrogen bonds.

Attraction b/w molecules of different substances.
Eg. Water molecule in a graduated cylinder

Unique property of being able to creep up thin tubes.
Water tension and capillary action allow water to move from soil to top of trees.

• Result of hydrogen bonds b/w water molecules is that it takes large amount of heat energy to cause molecules to move faster
– Large bodies of water absorb large amounts of heat w/ small changes in temperature
– Organisms in water are protected from drastic change
– Cell level-water absorbs heat produced by cell processes, regulating cell temperatures

pH Scale—A measurement system that indicates the relative concentrations of hydrogen and hydroxide ions.

Compounds that release hydrogen ions (H+) into a solution.
Acids have a pH between 0-6

Compounds that release hydroxide ions (OH-) into a solution.
Bases have a pH between 8-14

strong acid (H+) + strong base (OH-) = water and salt.
pH of 7

Weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH

Net movement of particles from an area of higher concentration to an area of lower concentration.

• Concentration of substance. The more concentrated the substance, the more rapid diffusion.
•
Temperature
—The higher the temperature the more rapid the molecules will move and the speedier diffusion will be.
•
Pressure
—As pressure increase, the more rapid molecular movement, the speedier diffusion will occur.

Dynamic Equilibrium
—A condition in which there is a continuous movement of particles (Brownian
Motion) but no overall change in concentration.

Differences in concentration of substances across space.

• Chemical compounds that exist or derived from plants or animals, (all carbon compounds)
• No manufactured chemicals

•
2 electrons 1 st energy level,
•
4 electrons on outer energy level
•
6 protons, 6 neutrons
•
Bonds well with other carbon atoms, as well as with other elements.
•
Single, double and triple bonds

• Straight chains, branched chains, or rings.
• Isomers—compounds that have the same simple formula but different three-dimensional structure.

Macromolecules—Large molecules
Example Proteins
(meros-part)
Polymer—large molecule formed when many smaller molecules bond together. (repeating units)
Monomer—simple compound whose molecules can join together to form polymers

A chemical reaction by which polymers are formed.
Water is formed

•A method by which polymers can be broken apart.
•H+ and OH- from water attach to bonds between subunits that make up polymer, thus breaking the polymer.

Carbohydrates
Lipids
Proteins
Nucleic Acids

An organic compound composed of
C arbon, Hydrogen, and Oxygen
(CHO Family) .
2 hydrogen:1Oxygen:1Carbon
Source of energy; structural

Simple sugar
Example: Fructose and Glucose

Two monosaccharides linked together;
A two-sugar carbohydrate.
Example:
Glucose and Fructose

Sucrose
(condensation reaction)

Largest carbohydrate molecules; polymers composed of many monosaccharide sub units.
Examples:
Starch (Food storage in plants)
G lycogen (form in which animals store food in their liver),
Cellulose (in plant cell wall, gives structural support.

Cereals
Breads
Fruits
Vegetables
SOURCES OF
CARBOHYDRATES

• A large portion (much greater then 2 to 1) of C-H bonds and less oxygen than carbohydrates (CHO family).
• Fats and oils
• Insoluble (non-polar, no charge, therefore not attracted)
• Cells uses: Energy, storage, insulation, and protective coatings.
• Useful in food preparation.
• Subunits: Glycerol, fatty acids.
Sources: nuts, butter, vegetable oil, and cheeses

Phospholipids- contain glycerol, two fatty acids, and a phosphate group, and are important in cell structures.
Steroids- are complex ring structures, and include cholesterol, which is used to synthesize the sex hormones.

Fatty acids with hydrogen at every position along the carbon chain are saturated
Fatty Acids with one or more double bonds are called unsaturated fats

A large, complex polymer composed of carbon, hydrogen, oxygen, nitrogen and usually sulfur.
(CHO + NS)
•structure for tissues and organs
• metabolism (all of the body’s chemical reactions)

Soybeans
Milk products
Meat
Eggs
Fish
Beans
SOURCES OF PROTEINS

• Basic building blocks of proteins.
• 20 common amino acids
• AA combinations can make thousands of proteins
(vary more in structure then any other organic molecule)
• Amino Acids link together when a (+H) from one amino acid and an (-OH) group from another amino acid are removed to form a water molecule.
• Covalent bond formed between the two amino acids--peptide bond.
• # amino acids and order determine protein.

Types of Proteins/ Functions
Enzymes -catalyze chemical reactions
Antibodies -Immune System
Hemoglobin -Oxygen transport in blood
Hormones -regulate metabolism
Actin and Myosin -Muscle proteins
Glycoproteins -Cell membrane
Keratin and Collagen - structural, or support proteins.

Substances that speeds up the rate of chemical reactions

Proteins that act as biological catalyst (lower activation energy)
• Site where reactants brought together to react
• Reactants are call substrates
• The products are released
•
Site where substrate binds to enzyme is called active site.
•
Temperature, pH and regulatory molecules can affect the activity of enzymes.

A complex macromolecule that stores cellular information in the form of a code.

• Nucleic acids are polymers made of smaller subunits called nucleotides .

Consist of carbon, hydrogen, oxygen, nitrogen, and phosphorus atoms arranged in three groups—A nitrogen base, simple sugar (ribose) and phosphate group.
Examples : DNA (deoxyribonucleic acid) and RNA (ribonucleic acid)