ANAPHY: LESSON 2 - THE CHEMICAL BASIS OF LIFE

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Chemicals

Chemicals make up the body’s structures, and the interaction of it with one another is responsible for the body’s functions.

Chemistry

The scientific discipline concerned with the atomic composition of substances and the reactions they undergo.

Matter

Anything that occupies space and has mass. All living and non-living things are composed of it.

Mass

The amount of matter in an object.

Weight

The gravitational force acting on an object of a given mass.

Kilogram (kg)

international unit for mass

Elements

The simplest type of matter with unique chemical properties.

1. Carbon (C)

2. Hydrogen (H)

3. Oxygen (O)

4. Nitrogen (N)

96% of the body's weight comes from these elements

Atoms

The smallest particle of an element that has the chemical characteristics of that element.

Element

composed of atoms of only one kind

Element or an atom of that Element

Often represented by a symbol. Usually the symbol is the first letter or letters of it’s name—for example, C for carbon, H for hydrogen, and Ca for calcium. Occasionally, the symbol is taken from the Latin, Greek, or Arabic name for it.

Atomic Structure

The characteristics of matter result from the structure, organization, and behavior of atoms.

Atoms

Are composed of subatomic particles, including neutrons, protons, and electrons.

Electrical Charge

The tendency of particles to be attracted to each other or repulsed from each other.

Positive and Negative

Two Types of Electric Charge

Opposite Charge

Charge that attract each other

Same Charge

Charge that repulsed from each other

1. Neutrons

2. Electrons

3. Protons

Three Major Types of Subatomic Particles

Neutrons

Have no electrical charge

Protons

Have positive charges

Electrons

Have negative charges

Atom

It is electrically neutral since it has equal number of protons and electrons, the positive and negative charges cancel each other.

Nucleus

Where protons and neutrons are found. It is the center of the atom.

nucleus

accounts for 99.97% of an atom’s mass, but only 1-ten-trillionth of its volume.

Electron Cloud

Where neutrons are found and constantly orbiting the nucleus.

Atomic Number

it is the number of protons in each atom. It is also equal to the number of electrons since the number of electrons and protons are equal.

Protons and Neutrons

Have about the same mass, and they are responsible for most of the mass of atoms.

Electrons

Have very little mass.

mass number

the number of protons plus the number of neutrons in each atom.

Isotopes

two or more forms of the sane element that have the same number of protons and electrons, but have different number pf neutrons

Chemical Bonds

interaction between atoms to form molecules by either sharing or transferring their outermost electrons.

Electron shells

energy levels are often drawn as concentric rings around the nucleus

Inner Shell

Holds a maximum of 2 electrons

Valence Shell

outer shell and holds a maximum of 8 electrons.

Octet

if an atom’s valence shell is not at maximum, it will form bonds with other atoms to achieve a full valence shell, called _______

Octet Rule

the tendency of atoms to combine with other atoms until each has 8 electrons.

1. transferring electrons between atoms

2. sharing electrons between atoms

two ways an atom achieve an octet

Electronegativity

the ability of the atom’s nucleus to pull electrons toward it.

Strong electronegativity

those with 6 or 7 electrons in the valence shell. These are very close to achieving an octet

Weak electronegativity

those with only 1 to 2 electrons in the valence shell. These are father away from achieving an octet.

Chemical Bonding

Occurs when the outermost electrons are transferred or shared between atoms.

outermost electrons

The chemical behavior of an atom is determined by it.

1. Ionic Bonding

2. Covalent Bonding

two major types of chemical bonds

Ion

Charged particle

Ionic Bonding

Occurs when electrons are transferred between atoms, creating oppositely charged ions.

Covalent Bonding

Forms when atoms share one or more pairs of electrons.

molecule

The resulting combination of atoms.

nonpolar covalent bond

forms when the electrons are shared equally between nuclei. It results in nonpolar molecule

polar covalent bond

two atoms involved in a covalent bond that have different electronegativities. It also results in polar molecules

Molecule

Formed when two or more atoms chemically combined to form a structure that behaves as an independent unit.

Compound

Substance resulting from the chemical combination of two or more different types of atoms.

Water

example of a substance that is a compound and molecule.

Covalent compounds

in which different types of atoms are held together by covalent bonds. These are molecules because the sharing of electrons results in distinct units.

ionic compounds

In which ions are held together by the force of attraction between opposite charges. These are not molecules because they do not consist of distinct units.

Molecules and compounds

an be represented by the symbols of the atoms forming it plus subscripts denoting the quantity of each type of atom present.

Intermolecular Forces

Weak charge attractions that exist between separate molecules, or between ions and molecules.

Intermolecular Forces

It has no exchange of electrons since these attractions are between already-formed molecules, any electron exchange has already occurred. It is also simply due to attractions between oppositely charged regions of molecules.

Hydrogen Bonds

If a positively charged hydrogen of one molecule is attracted to the negatively charged oxygen, nitrogen, or fluorine of another molecule

Hydrogen Bonds

Weaker than ionic or covalent bonds. It play an important role in determining the shape of complex molecules.

Hydrogen Bonds

can occur between different polar parts of a single large molecule to hold the molecule in its normal three-dimensional shape

Dissociation

When ionic compounds dissolve in water, their ions separate from each other because positively charged ions are attracted to the negative ends of water molecules, and negatively charged ions are attracted to the positive ends of water molecules.

electrolytes

dissociated ions. They have the capacity to conduct an electrical current

electrical current

the flow of charged particles.

Chemical Reactions

Formation or breaking of chemical bonds between atoms, ions, molecules, or compounds

Reactants

Substances that enter into a chemical reaction.

Products

Substances that result from a chemical reaction.

1. synthesis reactions

2. decomposition reactions

3. exchange reactions.

Classification of Chemical Reactions

Synthesis Reaction

Two or more reactants combine to form a larger, more complex product.

Anabolism

refers to synthesis reactions that occur in the body.

Dehydration Reactions

refers to synthesis reactions that occur in the water.

Decomposition Reaction

Reactants are broken down into smaller, less complex products.

Catabolism

refers to decomposition reactions that occur in the body.

Hydrolysis reactions

refers to synthesis reactions that occur in the water.

Metabolism

defines all of the anabolic and catabolic reactions in the body

Exchange Reaction

combination of a decomposition reaction and a synthesis reaction.

Reversible Reactions

Chemical reactions that can proceed from reactants to products and from products to reactants.

Reversible Reactions

the reaction that can run in the opposite direction, so that the products are converted back to the original reactants

equilibrium

When the rate of product formation is equal to the rate of reactant formation

equilibrium

the amount of the reactants relative to the amount of products remains constant

Energy

defined as the capacity to do work

work

movement of matter

energy

ability to put matter into motion

1. potential energy

2. kinetic energy

Energy can be subdivided into two

Potential energy

is stored energy that could do work,

kinetic energy

energy caused by the movement of an object and is the form of energy that actually does work.

1. chemical energy

2. mechanical energy

3. heat energy

4. electrical energy

5. electromagnetic (radiant) energy.

Potential and kinetic energy exist in many different forms

Mechanical Energy

energy resulting from the position or movement of objects

Energy

is neither created nor destroyed, but it can take on different forms

chemical energy

form of potential energy stored in chemical bonds of a substance.

Activation energy

energy necessary to start a chemical reaction

Rate of Chemical Reaction

Influenced by factors such as the ease of reaction, concentration of reactants, temperature, and the presence of a catalyst.

Reactants differ in their ability to undergo chemical reactions.

The greater the concentration of the reactants, the greater the rate at which a chemical reaction will occur because, as the concentration increases, the reacting molecules are more likely to come in contact with one another.

Because molecular motion changes as environmental temperature changes, the rate of chemical reactions is partially dependent on temperature.

catalyst

increases the rate of a chemical reaction, without itself being permanently changes or depleted

enzyme

increases the rate of chemical reactions by lowering the activation energy

enzyme

is protein catalyst that increases the rate at which a chemical reaction proceeds, without the enzyme being permanently changed.

Acids and Bases

Molecules and compounds that can alter body functions.

Acids

are proton donors