Marieb Anatomy + Physiology Chapter 2: Chemistry

Disaccharides

- "Double sugar" - Two monosaccharides joined by dehydration synthesis. - Too large to pass through cell membranes so they must be digested to their sugar units to be absorbed. - Type of carbohydrate. Ex: Sucrose (glucose + fructose), lactose (glucose + galactose), maltose (glucose + glucose).

Carbohydrates

- "Hydrated Carbon" - Contain: carbon, hydrogen + oxygen. - In general the hydrogen +oxygen atoms have a 2:1 ratio, the same as water. Ex. Monosaccharides, disaccharides, polysaccharides.

Triglycerides

- "Neutral Fats" - Called "fats" when solid or "oils" when liquid. - Composed of 2 building blocks: Fatty Acids + Glycerol, in a 3:1 radio of fatty acids to glycerol. - Fatty acids are linear chains of carbon + hydrogen atoms with an organic adic (-COOH) at one end. Glycerol is a modified simple sugar. - The glycerol backbone is the same in all triglycerides but the fatty acid chains vary, resulting in different kinds of fats and oils. - Large molecules that must be broken down into their building blocks before they can be absorbed. - Found mainly below the skin where they help insulate + protect. - Fatty acid chains w/ only a single covalent bond between carbon atoms are SATURATED. - Fatty acid chains w/ onr or more DOUBLE bonds between carbon atoms are UNSATURATED (or monounsaturated or polyunsaturated) - Includes both Trans fats (bad) + omega-3 (good) fatty acids. - Lipid

Monosaccharides

- "Simple Sugars" - Type of carbohydrate - Named according to the # of carbon atoms they contain: Pentose (five carbon), hexose (six carbon). - Glucose (a hexose) is a blood sugar. - Glactose + fructose are ISOMERS of glucose

Molarity

- 1 mole of an element or compound = Its atomic or molecular weight (sum of atomic weights) in grams - 1 mole of any substance contains 6.02 × 1023 molecules of that substance (Avogadro's number)

Strong Acid

- Acids that dissociate completely + irreversibly in water - Can dramatially change the pH of a solution Ex. Hydrolic acid + sulfuric acid

Nucleus + what 2 subatomic particles is it made of?

- Almost entire mass of the atom 2 Subatomic particles: 1.) Neutrons - Carry no charge - Mass = 1 atomic mass unit (amu) 2.) Protons - Carry positive charge - Mass = 1 amu

Oxidation-Reduction (Redox) Reactions

- Are decomposition reactions -- Reactions in which food fuels are broken down for energy - Are also exchange reactions because electrons are exchanged between reactants -- Electron donors lose electrons and are oxidized -- Electron acceptors receive electrons and become reduced

Atomic Structure

- Atoms are composed of subatomic particles: Protons, neutrons + electrons - Protons and neutrons found in nucleus - Electrons orbit nucleus in an electron cloud

Hydrogen Bonds

- Attractive force between electropositive hydrogen of one molecule and an electronegative atom of another molecule - Not true bond - Common between dipoles such as water - Also act as intramolecular (bonds WITHIN molecules) bridges/bonds, holding a large molecule in a three-dimensional shape - Responsible for the tendency of water molecules to cling together and form films (surface tension) - Help maintain shape of DNA

Protiens

- Basic structural material of the body. - Composes 10-30% of cell mass. - Amino acids are the building blocks of proteins. Ex: Enzymes, hemoblobin, contractile proteins of muscle.

Acids and Bases

- Both are electrolytes (Ionize and dissociate in water) - Acids are proton donors (Release H+ in a solution). Acids have a sour taste. - Bases are proton acceptors (Take up H+ from solution). Bases have a slippery feel.

Amino Acids

- Building blocks of protein. - 20 common types. - May either be a base or an acid. - All amino acids are identical except for differences in a single group of atoms in the R group. - The R group makes each amino acid chemically unique.

Organic compounds

- Carbohydrates, fats, proteins, and nucleic acids - Contain carbon, usually large, and are covalently bonded

Neutrons

- Carry no charge - Mass = 1 atomic mass unit (amu)

Protons

- Carry positive charge - Mass = 1 amu - # of protons is always = to # of electrons

Compounds

- Chemical bonding between components - Can be separated only by breaking bonds - All are homogeneous

Chemical Bonds

- Chemical bonds are energy relationships between electrons of reacting atoms - Electrons can occupy up to seven electron shells (energy levels) around nucleus - Electrons in valence shell (outermost electron shell)

Adenosine Triphosphate (ATP)

- Chemical energy in glucose captured in this important molecule - Directly powers chemical reactions in cells - Energy form immediately useable by all body cells

Lipids

- Contain: Carbon, hydrogen + oxygen (same as carbohydrates but the porportion of of oxygen is much lower). May also contain phosphorus in the more complex lipid. - Insoluble in water but readily soluble in other lipids. Ex: Triglycerides, phospholipids, + steroids

Nucleic Acids

- Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) - Largest molecules in the body - Composed of nitrogen base, a pentose sugar, and a phosphate group

Eicosanosids

- Diverse lipids derived from a 20-carbon fatty acid found in all cell membranes. - Lipid Ex: Prostaglandins (important in blood clotting + blood regulation + labor contractions + inflammatory actions, which are blocked by NSAIDs)

Electrons

- Electrons in orbitals within electron cloud - Carry negative charge - 1/2000 the mass of a proton (0 amu) - Number of protons and electrons always equal

Nonpolar Covalent Bonds

- Electrons shared equally - Produces electrically balanced, nonpolar molecules such as CO2

Fibrous Proteins

- Extended and strandlike. - Chief building materials of the body and are therefore called "Structural Proteins" Ex. Collagen

Steroids

- Flat molecules made of four interlocking hydrocarbon rings. - Fat soluble + contain little oxygen. - Lipid Ex: Cholesterol

Radioisotopes

- Heavy isotopes decompose to more stable forms - Spontaneous decay called radioactivity - Similar to tiny explosion - Can transform to different element - Can be detected with scanners -Valuable tools for biological research and medicine - Most used for diagnosis - All damage living tissue - Some used to destroy localized cancers - Radon from uranium decay causes lung cancer

Carbonic Acid-Bicarbonate System

- Helps maintain the pH homeostasis of blood. - Uses carbonic acid (H+ donor + weak acid) and bicarbonate (H+ acceptor + weak base) to maintain pH of blood.

Suspensions

- Heterogeneous mixtures, e.g., blood - Large, visible solutes settle out - MAY scatter ligth - Type of mixture

Colloids (emulsions)

- Heterogeneous mixtures, e.g., cytosol - Large solute particles do not settle out - Some undergo sol-gel transformations e.g., cytosol during cell division + Jello - Type of mixture - Scatters light

Solutions

- Homogeneous mixtures of solvents and solutes - Most are true solutions in body - Gases, liquids, or solids dissolved in water - Usually transparent, e.g., atmospheric air or saline solution or mineral water - Does NOT scatter light - Solutes usually cannot be seen with naked eye - Type of mixture

Salts

- Ionic compounds that dissociate into ions in water - Ions (electrolytes) conduct electrical currents in solution - All ions are electrolytes (conduct electrical currents in a solution) - Ions play specialized roles in body functions (e.g., sodium, potassium, calcium, and iron) - Ionic balance vital for homeostasis

Elements

- Matter is composed of elements - Elements cannot be broken into simpler substances by ordinary chemical methods - 118 elements on the periodic table - 92 elements on the periodic table are found in nature

Phospholipids

- Modified triglycerides. They are diglycerides w/ a phosphorus contining group + two (rather than three as in triglycerides) fatty acid chains. The phosphorus group gives them their distinct chemical properties. The hydrocarbon portion (the "tail") is nonpolar and hydrophobic + the phosphorus containing part (the "head") is polar and attracts water (hydrophilic). - Used for building cellular membranes. - Lipid

Water in Living Organisms

- Most abundant inorganic compound - 60%-80% volume of living cells - Most important inorganic compound - Due to water's properties

3 ways to distinguish MIXTURES from COMPOUNDS

- No chemical bonded within a mixture (as only PHYSICALLY intermixed) and compounds ARE chemically bonded. - Depending on mixture, its components can be separated by PHYSICAL means (straining, filtering, evaporation, etc). Compounds can only be separated by CHEMICAL means. - ALL compounds are homogeneous but only SOME mixtures are homogeneous.

Chemical Reactions

- Occur when chemical bonds are formed, rearranged, or broken - Represented as chemical equations using molecular formulas

Atomic symbol

- One or two letter chemical shorthand for each element found on the periodic table. Ex. "H" is the atomic symbol for Hydrogen

Polysaccharides

- Polymers of simple sugars linked together by hydration synthesis. - Large, fairly insoluble molecules + therefore ideal storage products. - Type of carbohydrate. - Not as sweet as Mono or Disaccharides. Ex: Starch + glycogen (both polymers of glucose)

Solute

- Present in smaller amounts Ex. If glucose is dissolved in blood, glucose is solute; blood is solvent

Enzymes

- Regulate and increase speed of chemical reactions - Lower the activation energy, increase the speed of a reaction - Enzymes are specific - Enzymes are proteins - Accelerate the rate of chemical reactions but are NOT used up or changed in the process

pH: Acid-base Concentration

- Relative free [H+] of a solution measured on pH scale - As free [H+] increases, acidity increases - As free [H+] decreases alkalinity increases - pH scale ranges from 0-14 - pH scale is logarithmic: A pH 5 solution is 10 times more acidic than A pH 6 solution

Buffers

- Release hydrogen ions if pH rises - Bind hydrogen ions if pH falls - Convert strong (completely dissociated) acids or bases into weak (slightly dissociated) ones - Carbonic acid-bicarbonate system (important buffer system of blood)

Neutralization

- Results from mixing acids and bases - Displacement reactions occur forming water and A salt

Covalent Bonds

- SHARES two or more valence shell electrons - Allows each atom to fill its valence shell at least part of the time

Carbon

- Small, electroneutral. Never gains of gains or looses electrons. Always SHARES electrons. - Has four valence shell electrons so it can form FOUR covalent bonds with other elements. As a result can form long, chainlike molecules. - All organic compounds contain carbon (EXCEPT: carbon dioxide + carbon monoxide, as they are considered inorganic compounds).

Chemically Inert Elements

- Stable and unreactive - Valence shell fully occupied or contains eight electrons - Noble gases

Isotopes

- Structural variations of atoms - Differ in the number of neutrons they contain - Atomic numbers same; mass numbers different

Biochemistry

- Study of chemical composition and reactions of living matter - All chemicals either organic or inorganic

Solvent

- Substance present in greatest amount in a solution - Usually a liquid; usually water

Carbohydrates: 3 classes

- Sugars and starches - Polymers 3 classes: 1.) Monosaccharides - one sugar 2.) Disaccharides - two sugars 3.) Polysaccharides - many sugars

Ionic Bonds

- TRANSFER of valence shell electrons from one atom to another forms ions - Atom that gained one or more electrons becomes an anion (negative charge) - Atom that lost one or more electrons becomes a cation (positive charge) - Attraction of opposite charges results in an ionic bond - Most ionic compounds are salts: When dry salts form crystals instead of individual molecules Ex. NaCl (sodium chloride)

Function of carbohydrates

- To provide a ready, easily used source of cellular fuel. - When energy sources are high + plentiful the body converts glucose (a monosaccaride/carbohydrate) into either glycogen (a polyscaccharide/carbohydrate) or fat and are stored.

Mass number

- Total number of PROTONS + NEUTRONS in nucleus - Total mass of atom

Mixtures + 3 types

- Two or more components PHYSICALLY intermixed - Most matter exists as mixtures - No chemical bonding between components - Can be separated by physical means, such as straining or filtering - Either heterogeneous or homogeneous Three types of mixtures: 1.) Solutions 2.) Colloids 3.) Suspensions

Polar Covalent Bonds

- Unequal sharing of electrons produces polar (AKA dipole) molecules such as H2O - Atoms in bond have different electron-attracting abilities

Atoms

- Unique building blocks for each element - Give each element its physical & chemical properties - Smallest particles of an element with properties of that element

Chemically Reactive Elements

- Valence shell not full - Tend to gain, lose, or share electrons (form bonds) with other atoms to achieve stability

Inorganic compounds

- Water, salts, and many acids and bases - Do NOT contain carbon

Orbital model of Atom

- current model used by chemists - Probable regions of greatest electron density (an electron cloud) - Useful for predicting chemical behavior of atoms

Endergonic reactions

- net absorption of energy - Products have more potential energy than reactants - Anabolic reactions

Exergonic reactions

- net release of energy - Products have less potential energy than reactants - Catabolic and oxidative reactions

Acid-base Homeostasis

- pH change interferes with cell function and may damage living tissue - Even slight change in pH can be fatal - pH is regulated by kidneys, lungs, and chemical buffers

Planetary model of Atom

- simplified; outdated - Incorrectly depicts fixed circular electron paths - But useful for illustrations (as in the text)

4 Forms of Energy

1.) Chemical energy - Stored in bonds of chemical substances 2.) Electrical energy - Results from movement of charged particles 3.) Mechanical energy - Directly involved in moving matter 4.) Radiant or electromagnetic energy - Travels in waves (e.g., visible light, ultraviolet light, and x-rays)

5 Important Properties of Water

1.) High heat capacity - Absorbs and releases heat with little temperature change - Prevents sudden changes in temperature 2.) High heat of vaporization - Evaporation requires large amounts of heat - Useful cooling mechanism (Ex. sweating) 3.) Polar solvent properties - Dissolves and dissociates ionic substances - Forms HYDRATION LAYERS (layers of water molecules) around large charged molecules, e.g., proteins (colloid formation) - ody's major transport medium 4.) Reactivity - Necessary part of hydrolysis and dehydration synthesis reactions 5.) Cushioning - Protects certain organs from physical trauma, e.g., cerebrospinal fluid

3 types of chemical bonds

1.) Ionic bonds 2.) Covalent bonds 3.) Hydrogen bonds

4 levels of protein structure

1.) Primary Structure: Forms a linear chain 2.) Secondary Structure: Forms alpha helices + beta sheets 3.) Tertiary Structure: Supterimposed on secondary structure. Alpha helices or beta sheets are folded up to form a compact globular molecule 4.) Quaternary Structure: Two or more polypeptide chains, each with its OWN tertiary structure

Rate of Chemical Reactions Affected by 4 Things

1.) ↑ TEMPERATURE ↑ Rate 2.) ↑ CONCENTRATION of reactant = ↑ Rate 3.) ↓ Particle SIZE = ↑ Rate 4.) Presence of CATALYSTS

Avogadro's Number

6.02 x 10(to the 23rd power...cannot write superscript)

Synthesis (combination) reactions

A + B → AB - Atoms or molecules combine to form larger, more complex molecule - Always involve bond formation - Anabolic

Exchange Reactions

AB + C → AC + B - Also called displacement reactions - Involve both synthesis and decomposition - Bonds are both made and broken

Decomposition Reactions

AB → A + B - Molecule is broken down into smaller molecules or its constituent atoms - Reverse of synthesis reactions - Involve breaking of bonds - Catabolic

Weak Acid

Acids that do not dissociate completely in water. Ex. Carbolic acid + acetic acid

Energy Flow in Chemical Reactions

All chemical reactions are either exergonic or endergonic

Structural Proteins

Another name for "Fibrous Proteins". Called "structural proteins" as they are the chief building blocks of the body.

Functional Protiens

Another name for "Globular Proteins". Called "functional proteins" as they play a role in virtually all biological processes in the body.

What is matter? What are its 3 states?

Anything that has mass and occupies space. 3 states: 1.) Solid—definite shape and volume 2.) Liquid—changeable shape; definite volume 3.) Gas—changeable shape and volume

Atomic weight

Average of mass numbers (relative weights) of ALL isotopes of an atom

What is energy? What are two types of energy?

Capacity to do work or put matter into motion. 2 Types of energy: 1.) Kinetic—energy in action 2.) Potential—stored (inactive) energy -Energy can be transferred from potential to kinetic energy. - Energy can easily be converted from one form to another. - Energy conversions are INEFFICIENT. Some initial energy is always lost to the environment as HEAT. - All energy conversions in the body liberate heat.

Four elements make up 96.1% of body mass

Carbon Hydrogen Oxygen Nitrogen

Polymers

Chainlike molecules made of many similar or repeating units (monomers) which are joined together by dehydration synthesis.

Globular Proteins

Compact, spherical proteins that are water soluble + play a role in virtually all biological processes and are therefore called "Functional Proteins"

Strong Base

Dissociate completely in water + tie up the H+. Strong bases are not themselves proton acceptors. They form OH- which is a proton acceptor.

Weak Base

Does not dissociate completely in water.

Electronegativity

Electron hungry + strongly attract electrons as they have nearly full (six or seven electrons) valence shells Ex: Oxygen, Nitrogen and Chlorine

Energy Conversions

Energy may be converted from one form to another Energy conversion is inefficient Some energy is "lost" as heat (partly unusable energy)

Octet rule (rule of eights)

Except for the first shell (full with two electrons) atoms interact to have eight electrons in their valence shell (outermost electron shell)

Isomers

Have the same molecular formula but their atoms are arranged differently, giving them different chemical properties. Ex: Galactose + fructose are isomers of glucose (a hexose)

Molecular Chaperones

Help proteins achieve their 3D shape.

Crystals

Large arrays of cations and anions held together by ionic bonds

Electropositive

Low electron attracting capability as they only have one or two valence shell electrons + therefore usually give up their electrons

Anion

Negative charge gains electrons=electron acceptor

Atomic number

Number of PROTONS in nucleus

O.I.L. R.I.G.

Oxidation Involves Loss (of electrons) Reduction Involves Gain (of electrons)

Cation

Positive charge looses electrons=electron donor

Denatured Protiens

Proteins that have lost their 3D structure.

Molecule

Two or more atoms bonded together

Compound

Two or more different kinds of atoms BONDED together

Catalysts

↑ Rate without being chemically changed or part of product - Enzymes are biological catalysts