Molecular Biology Chapter 2 Outline

Front 1

Matter

Back 1

Anything with mass that occupies space.

Front 2

Three states of matter

Back 2

Solid, Liquid, Gas

Front 3

Elements

Back 3

Substances that cannot be broken down into other substances - composed of only one kind of atom.

Front 4

Number of naturally occurring elements

Back 4

92

Front 5

Number of elements essential to life

Back 5

25

Front 6

The four elements that comprise 96% of total human body weight

Back 6

C, H, O, N (7 elements comprise most of the remaining 4%)

Front 7

Trace Elements

Back 7

Substances required in very small amounts, without which life could not exist.

Front 8

Number of trace elements required for life

Back 8

14 elements comprise 0.01% of total human body weight (e.g. Iodine = thyroid gland function, Fluoride = prevents tooth decay)

Front 9

Compounds

Back 9

Substances that contain two or more elements in a fixed ratio. (compounds are more common than pure elements)

Front 10

Atom

Back 10

Smallest unit of matter that still retains the properties of an element.

Front 11

Subatomic Particles

Back 11

Protons, Neutrons, and Electrons

Front 12

Proton

Back 12

Positively charged particle inside the nucleus.

Front 13

Neutron

Back 13

Neutrally charged particle inside the nucleus.

Front 14

Electron

Back 14

Negatively charged particle in orbit around the nucleus.

Front 15

Dalton

Back 15

Unit of measurement for atoms and subatomic particles (atomic mass unit - amu). 1.7x10^-24 g

Front 16

Mass of a proton

Back 16

1 Dalton

Front 17

Mass of a neutron

Back 17

1 dalton

Front 18

Mass of an electron

Back 18

1/2000th of a Dalton

Front 19

Atomic Number

Back 19

Represents the number of protons and electrons in an element. (The number of protons and electrons are always equal, maintaining a stable atom)

Front 20

Atomic Weight

Back 20

Mass of the atom's nucleus (protons + neutrons)

Front 21

Isotopes

Back 21

Different forms of the same element; same number of protons and electrons, but different numbers of neutrons.

Front 22

Radioactive Isotopes

Back 22

As the atomic nucleus decays, particles of energy are released. (bad effects = cancer, good effects = tracers in medicine)

Front 23

Energy levels of electrons

Back 23

1. Electrons orbit atoms in specific levels/shells.
2. Electrons in the outermost shells have the greatest amount of energy.
3. The innermost or first shell is full with two electrons.
4. Second and third shells are full with eight electrons.

Front 24

Valence electrons

Back 24

Electrons located in the outermost shell of an atom. (determines the behavior of an atom)

Front 25

Valence shell

Back 25

Outermost shell of an atom. (atoms with the same number of electrons in their valence shell exhibit similar behaviors)

Front 26

Electron orbitals

Back 26

Three dimensional space where an electron spends 90% of its time; path of an electron around the nucleus of an atom.

Front 27

Properties of orbitals

Back 27

1. Only two electrons can occupy a single orbital.
2. S orbitals are spherical, P orbitals are dumbbell shape.
3. Higher electron orbitals assume more complex shapes.

Front 28

Ionic Bonds

Back 28

Attraction in which one atom steals electrons from another atom. (creates two atoms with opposite charges that hold atoms together)

Front 29

Ions

Back 29

Either positively charged (loss of electrons) or negatively charged (gain of electrons) atoms.

Front 30

Cation

Back 30

An ion with a positive charge.

Front 31

Anion

Back 31

An ion with a negative charge.

Front 32

Covalent Bonds

Back 32

Attraction in which one atom shares electrons with another atom. (One or more shared pairs of electrons holds atoms together)

Front 33

Single bond

Back 33

One covalent bond formed between two atoms that share 1 pair of electrons.

Front 34

Double Bond

Back 34

Two covalent bonds formed between two atoms that share 2 pairs of electrons.

Front 35

Electronegativity

Back 35

The more electronegative an atom is, the more strongly it pulls shared electrons toward itself.

Front 36

Non-polar Covalent Bond

Back 36

Equal electronegativity

Front 37

Polar Covalent Bond

Back 37

Unequal electronegativity

Front 38

Polar Covalent Bond

Back 38

Covalent bond formed between two atoms that differ in electronegativity; shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive.

Front 39

Hydrogen Bond

Back 39

Weak chemical bond formed between a slightly positive hydrogen atom of a polar covalent bond of one molecule and a slightly negative atom of a polar covalent bond in another molecule.

Front 40

Van der Waal's Interactions

Back 40

A weak attractive force between atoms or non-polar molecules caused by a temporary change in dipole moment arising from a brief shift of orbital electrons to one side of one atom or molecule, creating a similar shift in adjacent atoms or molecules.

Front 41

Molecular Shape and Function

Back 41

Molecular shape is crucial in biology because it determines how biological molecules recognize and respond to one another with specificity. (e.g. opiates v. endorphins)

Front 42

Chemical Reaction

Back 42

Change in matter in which different chemical substances are created by making or breaking chemical bonds.

Front 43

Reactants

Back 43

Substances whose chemical bonds are broken and made (ingredients).

Front 44

Products

Back 44

Substances that result from the reaction.

Front 45

Energy

Back 45

Capacity to cause change – doing work.

Front 46

Potential Energy

Back 46

Energy that matter possesses because of its location or structure. (water in a reservoir behind a dam)

Front 47

Kinetic energy

Back 47

Energy associated with the relative motion of objects.
(water flowing over a dam generating energy)