Basics of Chemistry (A&P)

What substances cannot be broken down into simpler forms (because they are elements)

Carbon, Hydrogen, Oxygen

Elements

a single substance (periodic table)

Molecules

a combination of two or more atoms (same element) held together by chemical bonds

Compounds

a combination of two or more different kinds of atoms (different elements) held together by chemical bonds

Mixture

substance composed of two or more components that are physically intermixed (no bonds)

Solutions

homogeneous mixtures of components (gas, liquid, or solid)

Solvent

substance present in the greatest amount

Solute

substance present in smaller amount dissolve in the solvent

What is the body chief’s solvent

water

Concentration

the percent of solute dissolved in solution

Chemical bonds

electrons are found in electron shells orbiting the nucleus of an atom; the outermost shell (valence shell) participates in chemical reactions. Atoms will try to achieve a complete valence shell

What are the different types of chemical bonds

Ionic, covalent, and hydrogen bonds

Ionic bonds

electrons donated from one atom to another (NaCl)

Covalent bonds

electrons are shared between atoms

Hydrogen bonds

not true bonds but weak attractive forces between a hydrogen atom of one molecule and an electronegative atom of a different molecule… they are important in maintaining shape and structure of molecules

What is the most abundant and important inorganic compound found in living

Water

What are the important properties of water?

High heat capacity, temperature stability, polar solvent, cohesion and adhesion, density

What causes chemical reactions to occur?

When electrons are donated or shared

Metabolism

Sum of all chemical reactions that occur in the body

Anabolic reactions

“Building up” reactions; requires input of energy. A.k.a. dehydration, synthesis reactions.

Catabolic reactions

“Breaking down” reactions; generally release energy. Aka hydrolysis reactions.

What does the rate of chemical reactions depend on?

Concentration of reactants, temperature, size of molecules involved in reaction, and presence of catalysts (in the body, this means enzymes)

What are the major elements that make up the human body?

Carbon, hydrogen, oxygen, nitrogen

Inorganic substances

Do not contain carbon

Examples of Inorganic substances

Water, salt, acids and bases

Organic substances

Contain carbon (life)

Examples of Organic substances

Carbohydrates, lipids, proteins, and nucleic acids

Electrolytes

Salts that exist as charged particles in a solution

What kind of compound is salt?

Ionic compound; when dissolved it disassociate into ions

What are the common ions in the body?

Na+, K+, Ca2+, Cl-

What is the role of salt in the body

Impulse conduction, muscle contraction, and fluid balance

Acids

Are proton donors; they release H+ in solution

Bases

Are proton acceptors; they bind H+ in solution

What does the pH scale measure?

It measures the concentration of hydrogen ions, (H +) in solution; ranges from 0 to 14

Lower pH

More H + in solution = more acidic

Higher pH

Less H + in solution = more basic (alkaline)

What is the pH of our blood?

It is maintained at a pH of 7.35- 7.45

What is a buffer system?

It is a mechanic that ensures that the pH stays within this range; buffer systems minimize changes in pH by accepting or donating H+ to the solution

Many biological molecules are macromolecules (macro=large) which can exist as…

Polymers and monomers

Polymer

Long chain like molecules made up of subunits called monomers

Monomers

The smallest form of a macromolecule

How are macromolecules formed?

Dehydration synthesis, and broken down by hydrolysis

What are the four macromolecules of the body?

Carbohydrates fats, proteins, and nucleic acids

Dehydration synthesis

Monomers are joined by removal of OH from one monomer and removal of H from the other at the site of bond formation

Hydrolysis

Monomers are released by the addition of a water molecule, adding OH, to one monomer and H to the other

An example of dehydration synthesis

Dehydration synthesis of sucrose, and it’s breakdown by hydrolysis

Why are macromolecules important to the body?

Provides building blocks for making new body components (hormones cells, fibers, etc) and energy source for cellular respiration to produce ATP (our body’s, energy currency)

We ingest polymers, however

Our digestive track can only absorb monomers

How do we break down food like table sugar(sucrose) into its monomers

Hydrolysis

Carbohydrates

Provide an easily used energy source for the body

Monomer

Monosaccharide (simple sugars); examples: glucose, fructose, and galactose

Disaccharides

Are double sugars

Examples of disaccharides

Sucrose: table sugar: glucose + fructose

Lactose: dairy sugar: glucose + galactose

Maltose: glucose + glucose

Polymer poly saccharide(long chains of glucose)

Glycogen: in animals, stored in the liver and muscles

Starch and cellulose: in plants

Examples of polysaccharides

Plant polysaccharides: starch and cellulose

Animal polysaccharides: glycogen

Lipids

Insulate and protect body organs, build cell membranes and provide stored energy

Examples of lipids

Fatty acids triglycerides, phospholipids, and steroids

Triglycerides

Long-term energy storage, cushioning and insulation. Fatty acids. Nonpolar hydrophobic. Can be saturated or unsaturated

Saturated:solid at room, temperature; animal fats, unhealthy in large amounts.(butter, fat in meat and eggs.)

Unsaturated:liquid at room temperature;vegetable and nut oils;healthier

Efficient way to store energy:(9 kcal/g vs 4 kcal/g for proteins and carbs)

Phospholipids

Major component of cell membranes; most are unsaturated.

Polar end(phosphate head) interacts with water

Nonpolar end(fatty acid tails) shielded from water

Steroids

Composed cell membranes, serve as hormones and basis of vitamin D

Nonpolar: made of four interlocking hydrocarbon rings with little oxygen

What is the most important steroid?

Cholesterol; it is the basis for all steroids in the body; steroids differ by the chemical groups, attached to the rings

Proteins

Monomer: amino acid

Polymer: polypeptide

Structure of an amino acid

Central carbon, amino and carboxyl

Radical group

Chemical group that is attached to the central carbon, and determines an amino acid to chemical behavior

What type of bond holds amino acids together?

Peptide bond (holds 2 amino acids together)

Radical groups of amino acids determine their chemical behavior(structure determines function)

Protein structure

Most proteins are large molecules that contain hundreds to thousands of amino acids. Proteins fold upon themselves to form unique shapes, proteins shape determines proper functioning.

Denaturation

Proteins have an optimal environment in which they function. If conditions are not optimal, they may slow or stop working, example high temperature, or acidity.

Protein function depends on

Structure

Fibrous proteins

Structural strand like insoluble and stable. Examples collagen, keratin, And contractile proteins of muscle

Globular proteins

Functional; compact and spherical. Water soluble.

Fxns:

Hormones(insulin/growth hormone) communication

Immunity(antibodies/complement) protected against disease

Transport(hemoglobin) carry substances in the body

Enzymes(lactase) increases the rate of chemical reactions in the body

Structural proteins

Function: Mechanical support

Example: collagen found in all connective tissue is the single most abundant protein in the body. It is responsible for the tensile strength of bones, tendons, and ligaments.

Enzymes proteins

Function: catalyst. Proteins enzymes are essential for virtually every biochemical reaction in the body.

Examples: disaccharides hydrolyze disaccharides, proteases hydrolyze proteins, and oxidases oxidize food fuels

Transport proteins

Function: moving substances(in blood or across plasma membranes)

Examples: hemoglobin transports oxygen in blood. Some plasma membrane proteins transport substances (such a ions) across the plasma membrane

Contractile proteins

Function: movement

Example: actin and myosin cause muscle cell contraction and function in cell division in all cell types.

Communication proteins

Function: transmitting signals between cells. Can act as chemical messengers (e.g. hormones) or as receptors in the plasma membrane.

Example: insulin(a protein) acts as receptor to regulate blood sugar levels

Defensive proteins

Function: protect against disease

Example: antibodies released by certain immune cells are specialized proteins that bind and inactivate foreign substances (e.g. Bacteria, toxins, and viruses.)

Characteristics of enzymes

Reusable: specific for a substrate (substrate interacts with enzyme at the active site)

Optimal conditions

Enzyme function: lower the activation energy(amount of energy required to start a reaction)

Nucleic acids

Deoxyribonucleic acid(DNA)

Ribonucleic acid(RNA)

Function: stores transmits, and helps to express genetic information

Monomer: nucleotide

Made up of: phosphate group, pentose(five carbon sugar), nitrogenous base(guanine, cytosine, adenine, thymine(DNA only), uracil(RNA only)

Nitrogenous bases are complementary to one another: they are held in place by hydrogen bonds

Add a nine pairs with I mean in DNA; with uracil in RNA.

Guanine pairs with cytosine in both DNA and RNA.

Differences between DNA and RNA (DNA)

Double stranded and helical, specifies proteins structure, pentose sugar: deoxyribose, nitrogenous bases:a,t,g,c

Differences between DNA and RNA (RNA)

Single stranded, three different types: messenger, ribosomal, and transfer RNA. Out DNAs instructions for proteins synthesis, pentose sugar: ribose. Nitrogenous bases: A,U,G,C

ATP (adenosine triphosphate)

Our body’s fuel. ATP is made in our cells by a process called cellular respiration.

Glucose + O2 → H2O +CO2 + ATP

What does phosphorylation do

This is how ATP powers work in the cell. It transfers a phosphate group to another molecule to power a specific process.