Properties of Life and Basic Chemistry Concepts

Biology

study of life

Adaptation

how an organism gets fitted to their environment; result of evolution by natural selection, a trait that allows an organism success in their environment

Order

organisms are highly organized, coordinated structures with one or more cells (organelles => cells => organs...)

Response to Stimuli

respond to diverse stimuli (think plant reaching for sunlight)

Regulation

coordinate internal functions, respond to stimuli, and cope with environmental stresses => homeostasis

Reproduction

organisms reproduce (ranging from single celled replication and division to specialized reproductive cells)

Energy Processing

use energy for metabolic processes (photosynthesis, consumption)

Evolution

random changes in hereditary material (mutations) result in characteristics that make an organism more or less fit for the environment (more fit=more reproductive success=pass on)

Homeostasis

steady state, relatively stable internal environment required to maintain life

Macromolecule

large molecules that typically formed by polymerization (polymers made up of monomers)

Atom

smallest and most fundamental unit of matter that retains properties of an element - nucleus surrounded by electrons

Molecule

chemical structure of at least 2 atoms held together by one or more chemical bond

Organelles

A mass of macromolecules surrounded by a membrane that exist within cells and serve specific functions

Cell

smallest fundamental unit of structure and function in living organisms

Prokaryote

single-celled or colonial organism; do NOT have membrane-bound nuclei

Eukaryote

DO have membrane bound organelles and membrane bound nucleus

Tissues

comprised of cells that combine and carry out similar or related functions (ex: skin cells combine to form skin tissue)

Organs

collections of tissues grouped together performing a common function

Organ system

higher level of organization consisting of functionally related organs

Organism

individual living entity

Microorganisms

single-celled prokaryotes and single-celled eukaryotes

Matter

any substance that occupies space and has mass

Elements

unique forms of matter with specific chemical and physical properties that cannot break down into smaller substances by ordinary chemical reaction

Mass number

#protons + #neutrons

Atomic number

#of Protons

Isotopes

different forms of the same atom that vary only in the number of neutrons they possess; # of neutrons varies

Atomic mass

Mean of mass number for its isotopes.

Chemical reactivity

Ability to combine and chemically bond with one another (based on # and spatial distribution of e-); combine to form molecules.

Electrons in a chemically neutral atom

electrons = # protons.

Electron shells/energy levels

Electrons fill orbitals in consistent order = lowest energy shell (1n) to highest (3n).

Octet rule

Atoms are more energetically stable when they have 8 electrons in their valence shell (outermost electron shell).

Noble gases (Group 18)

Have 8 electrons in valence shell, highly stable, don't want to share electrons (form bonds).

Group 1 elements

Have 1 valence electron, want to donate or share 1 electron to gain stability.

Group 17 elements

Have 7 valence electrons, want to fill the shell with an electron from another atom or molecule.

Electron orbitals

Where electrons are most likely to be found and they form complex shapes.

s subshell

orbitals: 1; # of electrons it holds: 2; Shape: sphere.

p subshell

orbitals: 3; # of electrons it holds: 6; Shape: dumbbell.

d subshell

orbitals: 5; # of electrons it holds: 10; Shape: complex.

f subshell

orbitals: 7; # of electrons it holds: 14; Shape: complex.

Electron configuration of H

1s1.

Electron configuration of Ne

1s2,2s2,2p6.

Electron configuration of Li

1s2,2s1.

Electron configuration of C

1s2,2s2,2p2

Electron configuration of Cl

1s2,2s2,2p6,3s2,3p5

Valence shell electrons

Determine an atom's energetic stability and its tendency to form chemical bonds with other atoms.

Electrons in innermost shell

Max of 2 electrons; atoms will fill first.

Next two shells

Max of 8 electrons.

Chemical reaction

when 2 or more atoms combine or break apart

Molecule

2 or more atoms chemically bonded

Ionic bond

form between a cation and anion to form neutral charge (transfer of electrons)

Cation

+ charge (given away electrons)

Anion

-charge (received electrons, add -ide to the name ex: sulfur to sulfide)

Ionic bond example

Na+ + Cl- = NaCl (table salt!)

Covalent bond

share electrons between atoms and are much stronger and more common than ionic bonds

Single bond

sharing 1 electron

Double bond

sharing 2 electrons

Triple bond

sharing 3 electrons

Polar covalent bond

atoms unequally share electrons, creating slightly negative (δ-) or positive charge(δ+) ex: H2O

Electronegativity

tendency of an atom to attract shared electrons

Nonpolar covalent bond

occur between two atoms of the same element or between different elements that share electrons equally ex: CH4

Hydrogen bond

weak interaction formed by slightly positive charge around hydrogen attracting neighboring negative charges

Van der Waals interactions

weak attractions between molecules dependent on slight fluctuations of electron densities around an atom

Hydrophilic

polar substance that interacts readily with or dissolves in water

Hydrophobic

nonpolar substances that do not interact readily or dissolve in water ex: fats and oils

States of water

Liquid, Gas, Solid - unique characteristics crucial to life

Liquid water

water molecules break/reform as they slide past each other due to kinetic energy

Ice

crystalline structure maintained by H bonds, decreasing density, allowing ice to float

Gas “liquid”

as temp rises with boiling, higher kinetic energy causes bonds to break completely and molecules escape (steam, water vapor)

High heat capacity

Water can absorb a lot of heat before its temperature changes.

Specific heat

The amount of heat one gram of a substance must absorb or lose to change its temperature by 1 degree Celsius (this amount of heat = 1 calorie).

High specific heat

Takes lots of heat to change the temperature of water and takes lots of time to heat and cool.

Heat of vaporization

The amount of energy required to change one gram of a liquid into a gas.

Evaporation

Below the boiling point (100℃), water's individual molecules gain enough energy from other molecules that some at the surface can escape and vaporize.

Solvent properties

Ions and polar molecules can readily dissolve in H2O, making it a solvent capable of dissolving other polar molecules and ionic compounds.

Dissociation

When ionic compounds (like NaCl) are added to water, their ions react with water molecules' polar regions and their bond is disrupted.

Sphere of hydration

Forms around the ions when they dissolve in water, with slight + or - charge attracted to ions.

Cohesion

Water molecules are attracted to each other (H bonding), keeping water molecules together at the liquid-gas (water-air) interface.

Surface tension

Capacity of a substance to withstand rupturing when placed under tension or stress; cohesion allows for surface tension.

Adhesion

Attraction between water molecules and other molecules; occurs in capillary tubes where adhesion > cohesion.

pH

Indicates the acidity or basicity of a solution on a scale.

Acid

Substance that increases the concentration of hydrogen ions (H+) in solution; stronger acids more readily donate H+.

Base

Substance that decreases the concentration of H+ in a solution, either by adding hydroxide ions (OH-) or other negatively charged ions.

Alkaline

A solution with a pH of 8 and up (14 being the most basic).

Acidic

A solution with a pH of 6 and down (1 being the most acidic).

Neutral

A solution with a pH of 7.

Buffers

Readily absorb excess H+ or OH- keeping pH consistent.

Organic molecules

Any carbon-containing liquid, solid, or gas.

Hydrocarbons

Organic molecules consisting entirely of H and C; successive bonds form hydrocarbon chains.

Isomers

Share the same chemical formula but differ in structure of atoms or bonds, resulting in differences in chemical properties.

Geometric Isomers

Isomers that differ in the arrangement of groups around a double bond.

Enantiomers

Same chemical structures and bonds, but different 3-D structure. (still mirror each other)

Functional group

Groups of atoms that occur within molecules and result in specific chemical properties.

Hydrogen bonds

Can link functional groups together, such as in DNA.

Hydroxyl group

consists of one hydrogen single-bonded to an oxygen atom (in sugars and alcohols)(polar)

Carbonyl

consists of a carbon atom double-bonded to an oxygen atom (polar)

Carboxyl group

consists of a carbon double bonded to an oxygen and also singlely bonded to a hydroxyl group (OH)

Amino group

consists of a nitrogen atom singly bonded to two hydrogen atoms (Charged; accepts H+ to form NH3+, since amino groups can remove H+ from solution, they are basic)

Phosphate group

consists of a phosphorus atom bonded to four oxygen atoms (3 singles and 1 double bonds) (sometimes there will be hydrogen/hydroxyl group)