A & P chapter 2

The simplest form of matter to have unique chemical properties

A chemical element

The major chemical elements inside of the body

Oxygen, Carbon, Hydrogen, Nitrogen, Calcium, and Phosphorus

Trace elements

present in minute amounts, but plays vital roles

Minerals

Inorganic elements extracted from soil by plant passed up food chain to humans

Ionization

transfer of electrons from one atom to another

Anion

Particle that has a net negative charge due to gain of electrons (negatively charged)

Cation

Particle that has a net positive charge due to the loss of electrons (positively charged)

Ions with------ are attracted to one another

opposite charges

Salts

attraction between opposite charges on ions form a compound; readily dissociate in water into ions and act as electrolytes

Electrolytes

Substances that ionize in water and form solutions capable of conducting electric currents

Free radicals

Unstable, highly reactive particles with an unusual number of electrons

Antioxidants

Chemicals that neutralize free radicals

Molecule

A particle composed of two or more atoms united by a chemical bond

Compound

A molecule composed of two or more different elements

Isomers

Molecules with identical molecular formula but different arrangements of their atoms

What holds atoms together within a molecule, or attract one molecule to another?

Chemical bonds

Ionic bonds

Attraction of a cation and an anion ( when electrons are transferred from one atom to another atom)

Ions bonds are --- broken down by something more attractive, such as water

easily

Covalent bonds

Strongest bond; Atoms share one or more pairs of electrons

Non-polar covalent bonds

Electrons are shared equally (when two atoms with similar electronegativity pull with equal force) : protons attract electrons

Polar covalent bonds

Electrons are shared unequally: then atoms with different electronegativity result in an unequal sharing of electrons (hydrogen bonding with oxygen, electrons spend more time with oxygen)

Valence electrons

In the outermost valence shell. Determines how an atom interacts with other atoms & wether it will form bonds with a specific atom.

Octet rule

An atom is most stable when it has 8 electrons in its valence shell.

Duet rule

States that an atom is most stable when its valence electron shell holds 2 electrons

Atoms can share what type of bonds

One single bond

Two double bond

Three triple bond

3 situations where a bond is non polar

Atom sharing electrons with the same element

Arrangement of atoms make one atom unable to pull more strongly (CO2)

bond is between carbon or hydrogen

What happens with the charges of a polar covalent bond

The atom with a higher electronegativity becomes partially negative as it pulls shared electrons close to itself

\
The atom with lower electronegativity becomes partially positive as shared electrons are pulled toward the other atom

Hydrogen bond

weak attraction between a slightly positive hydrogen atom in one molecule and a slightly negative oxygen or nitrogen atom in another

Water is attracted to each other by what type of bond?

Hydrogen bonds

Mixtures

Consist of substances that are physically blended but not chemically combined; each substance retains its own chemical properties

What are mixtures composed of

Chemicals dissolved or suspended in water

water is what percentage of body weight

50-75%

Waters’ set of properties from polar covalent bonds and a V-shape

Solvency

Cohesion

Adhesion

Chemical reactivity

Thermal stability

Solvency

The ability to dissolve other chemicals

Why is water the universal solvent

Because it dissolves more substances than any other solvent

Hydrophilic

Substances dissolve in water; are polarized or charged

Hydrophobic

Substances do not dissolve in water; are non polar or neutral

How can a molecule be soluble in water?

A molecule must be polarized or chared

attractions to water ---- ionic bond in NaCl

Overpower

Adhesion

Tendency of one substance to cling to another

Water adheres to membranes reducing what?

Friction around organs

Cohesion

tendency of molecules of the same substance to cling to each other

Why is water very cohesive?

Due to its hydrogen bonds

Why is there surface film on the surface of water?

Because molecules are being held together by surface tension

Chemical reactivity

Ability to participate in chemical reactions

Water ionizes into H+ and OH (acids, salts) which is involved in

hydrolysis and dehydration synthesis reactions

Thermal stability due to high heat capacity

Amount of heat needed to raise the temperature of 1g of a substance by 1c

Calorie (cal)

Is the base unit of heat: 1 cal is the amount of heat to raise the temperature of 1g of water by 1c

Water stabilizes internal temperature because

hydrogen bonds resist temperature increases by inhibiting molecular motion

Mixtures are classified into:

Solutions, colloids, and suspensions

Solution

consists of particles called the solute mixed with a more abundant substance ( usually water) called the solvent

A solute can be

A gas, solid, or liquid

Colloids

Colloids in the body are often mixtures of protein and water (cloudy)

What state can colloids be in

They can change from liquid to gel state within and between cells

Suspensions

BIG and separates on standing

Emulsion

Suspension of one liquid in another ( salad dressing )

An acid

a proton donor; releases ions in water (higher concentration, more hydrogen more acidic)

A base

a proton acceptor; accepts ions in water (higher concentration of OH more basic)

PH of 7

Neutral (hydrogen ions and base ions are equal)

PH less than 7

Acidic (hydrogen ions greater than base ions)

PH more than 7

Basic ( base ions greater than hydrogen ions)

PH in blood is

7\.35-7.45…. 7.4 in the middle

Buffers

are chemical solutions that resist changes in the PH

prevents large swings in PH when acid or base is added to a solution

Solution A has a hydrogen ion concentration of 10-3

A. what is the concentration expressed in decimal form

B. What is the PH?

C. What is the hydroxide \[OH-} ion concentration?

D. Is the solution acidic or basic?

Which concentration is higher?

A) .001

B) 3

C) 10-11

D) Acidic

E) H+

Intracellular PH is

7\.2

Energy

The capacity to do work (has to move some place else)

Potential energy

energy stored in an object, but not currently doing work; water in a dam ( needs something to intiate energy)

Chemical energy

Potential energy in molecular bonds

Free energy

Potential energy available in a system to do work

Kinetic energy

Energy of motion; energy doing work (muscle movements)

Heat

Kinetic energy of molecular motion

Electromagnetic energy

Kinetic energy of protons

Electrical energy

Both potential and Kinetic energy

Chemical reaction

a process in which a covalent or ionic bond is formed or broken

Chemical equation

Symbolizes the course of a chemical reaction

\
reactants--→ products

Classes of chemical reactions are

Decomposition reactions

Synthesis reactions

Exchange reactions

Decomposition reactions

Large molecules break down into two or more smaller ones

AB---→ A+B

Synthesis reactions

Two or more small molecules combine to form a larger one

A+B----→ AB

Exchange reactions

Two molecules exchange atoms or groups of atoms

\
AB + CD ---→ AC + BD

Reversible Reactions

Can proceed in either direction under different circumstances

What is a reversible reaction symbolized with

A double-headed arrow

Reversible reactions follow the

Law of mass action

Law of mass action

Direction of reaction determined by relative abundance of substances on either side of the equation

Equilibrium

Reached when ratio of products to reactants is stable

When do reactions occur

When molecules collide with enough force and correct orientation

Reaction rates occur when

Concentration of reactants increases

Temperature rises

Catalyst is present

What do enzyme catalysts do

They bind to reactants and hold them in orientations that facilitate the reaction

Catalysts are not changed by the ---- and can ----- the process frequently

Reaction, repeat

Metabolism

All chemical reactions of the body: two divisions

Catabolism

Energy-releasing exergonic decomposition reactions

breaks covalent bonds

produces smaller molecules

Anabolism

Energy storing endergonic synthesis reactions

Requires energy input

production of protein or fat

Catabolism and anabolism

inseparably linked

Anabolism is driven by energy released by catabolism

Oxidation

A chemical reaction in which a molecule gives up electrons and releases energy

Molecule is oxidized

When it loses electrons

Oxidizing agent

Electron acceptor (Often oxygen)

Reduction

Any chemical reaction in which a molecule gains electrons and energy

Molecule is reduced

When it accepts electrons

The reducing agent

Is the molecule that donates the electron

Oxidation-reduction reactions (redox reactions)

Special kind of exchange reaction; occur when electrons and energy are exchanged instead of atoms

Redox reactions

Exergonic reactions capable of releasing large amounts of energy