Chapter 2 Flashcards
Matter
Anything that has mass and occupies space
Weight
The pull of gravity on mass
States of Matter
Solid
Liquid
Gas
Energy
The capacity to do work or put matter into motion
Types of Energy
Kinetic
Potential
Forms of Energy
Chemical- stored in bonds of chemical substances
Electrical- Results from movement of charged particles
Mechanical- Directly involved in moving matter
Radiant- Travels in waves (ultraviolet light)
Energy form Conversion
- May be converted from one form to another
- Conversion is inefficient (some energy is lost as heat)
Elements
Matter is elements
Cannot be broken into simpler substances by ordinary chemical methods
Human Body Elements (4)
Oxygen Carbon Hydrogen Nitrogen 96% of the human body
Atoms (overall)
Building blocks for each element
Gives each element its physical and chemical properties
Smallest particles of an element with properties of that element
Atoms (make-up)
composed of subatomic particles- protons, neutrons, and electrons
Protons and Neutrons found in nucleus
Electrons orbit nucleus in an electron cloud
Atom (nucleus)
Almost entire mass of the atom
Neutrons- Carry no charge
Protons- Carry positive charge
Atom (electrons)
Electrons orbit within electron cloud
- carry a negative charge
- 1/2000 the mass of a proton
- number of protons and electrons always equal
Atom (models)
Planetary model-2D simplified; outdated
Orbital model-3D current model, used by chemists
Isotyopes
Structural variations of atoms
Differ in the number of neutrons they contain
Atomic numbers same; mass numbers different
Atomic Weight
Average of mass numbers (relative weights) of all isotopes of an atom
Molecule vs. Compound
Molecule- 1 type
Compound- multiple types (at least 1)
Mixtures
Two or more components physically intermixed
-most matter exists as mixture
3 Types of Mixtures
Solutions
Colloids
Suspensions
Solutions
Homogeneous mixtures
Solvent- greatest substance, if a liquid; usually water
Solute- present in smaller amounts
Colloids
Heterogeneous mixtures
Larger solute particles do not settle out
Suspensions
Heterogeneous mixtures (blood) Large, visible solutes settle out
Mixtures Vs. Compounds
Mixture: -No chemical bonding between components -Can be separated -Heterogeneous or Homogeneous Compound: -Chemical bonding between components -Can be separated -All are homogeneous
Chemical Bonds
Energy relationships
Electrons can occupy up to 7 electron shells
Electrons in Valence Shell (outermost electron shell)
-have most potential energy
-are chemically reactive electrons
Chemically Inert Elements
Stable and unreactive
Valence shell fully occupied or contains eight electrons
Noble Gases
Chemically Reactive Elements
Valence shell not full
Tend to gain, lose, or share electrons (form bonds) with other atoms achieve stability
Types of Chemical Bonds (3)
Ionic
Covalent
Hydrogen
Ionic Bonds
Ions
-atoms gain or lose electrons and becomes charged
Transfer of electrons from one atom to another forms ions
-Anion (negative charge)
– atoms gains at least one electron
-Cation (positive charge)
– atoms loses at least one electron
Ionic Compounds
Most ionic compounds are salts
-when dry salts form crystals instead of individual molecules
Ex. NaCl (sodium chloride)
Covalent Bonds
Formed by sharing of two or more electrons
Allows each atom to fill its valence shell at least part of the time
Ionic Vs. Covalent
Ionic- giving
Covalent- sharing
Hydrogen Bonds
Attractive force between electropositive hydrogen of one molecule and an electronegative atom of another molecule
- not true bond
- common in water
- also acts as intramolecular bonds, holding a large molecule in a 3D shape
Chemical Reactions
Occur when chemical bonds are formed, rearranged, or broken
-Reaction is the combination of formed, rearranged, or broken
Patterns of Chemical Reactions
Synthesis (combination) reaction
Decomposition reactions
Exchange reactions
Synthesis Reactions
A + B = AB
- Atoms or molecules combine to form larger, more complex molecule
- Always involve bond formation
- Anabolic
Decomposition Reactions
AB = A + B
- Molecule is broken down into smaller molecules or its constituent atoms
- -Reverse of synthesis reactions
- Involving breaking of bonds
- Catabolic
Exchange Reactions
AB + C = AC + B
- Also called displacement reactions
- Involve both synthesis and decomposition
- Bonds are both made and broken
Energy Flow in Chemical Reactions
Two Types
All chemical reactions are either exergonic or endergonic
- Exergonic Reactions- Exer- Exit leaving
- -net release of energy
- -products have less potential energy than reactants
- -catabolic and oxidative reactions
- Endergonic Reactions- Ender- Enter gaining/absorbing
- -net absorption or energy
- -products have more potential energy than reactants
- -Anabolic reactions
Reversibility of Chemical Reactions
Chemical equilibrium AB = A + B A + B = AB Many biological reactions are essentially irreversible -due to energy requirements -due to removal of products
Rate of Chemical Reactions
Affected by
- Rising Temperature = Rising Rate
- Rising Concentration of Reactant = Rising Rate
- Lowering Particle Size= Rising Rate
- Catalysts: Rising Rate without being chemically changed or part of product
- -enzymes are biological catalysts
Biochemistry
Study of chemical composition and reactions of living matter
All chemicals either organic or inorganic
Classes of Compounds
Inorganic- water, salts,and many acids and bases; does not contain carbon
Organic- carbohydrates, fats, proteins, and nucleic acids; contains carbon
Both equally essential for life
Water in Living Organisms
Most abundant inorganic compound
Most important inorganic compound
-due to water’s properties
Properties of Water
High heat capacity
-absorbs and release heat with little temperature change
-prevents sudden changes in temperature
High heat evaporation
-evaporation requires large amounts of heat
-useful cooling mechanism
Polar solvent properties
-universal solvent
-dissolves and dissociates ionic substances
-body’s major transport medium
Cushioning
-protects certain organs from physical trauma (cerebrospinal fluid)
Salts
Ionic compounds that dissociate into ions in water
- ions (electrolytes) conduct electrical currents in solution
- ions plat specialized roles in body functions
- ionic balance vital for homeostasis
Acids and Bases
Both are electrolytes Acids- proton donors - release in H+ solution Bases- proton acceptors -Take up H+ from solution
pH: Acid base Concentration
-Free H+ of a solution measured on pH scale
-As free H+ increases, acidity increases
-As free H+ decreases alkalinity increases
pH= negative logarithm of H+ in mole per liter
pH scare ranges from 0-14
pH: Levels
Acidic Solutions -rising H+, lower pH -acidic pH = 0- 6.99 Neutral Solutions - equal number of H+ and OH- - All neutral solutions are pH 7 -pure water is pH neutral Alkaline (basic) Solutions -lowering H+, higher pH -Alkaline pH = 7.01-14
Neutralization
Mixing acids and bases
- forming water and a salt
- neutralization reaction
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
Organic Compounds
Molecules that contain carbon
-except CO2 and Co, which are considered inorganic
-Carbon is electroneutral
Unique to living systems
Carbohydrates, lipids, proteins, and nucleic acids
Carbohydrates
Sugars and starches Polymers Three classes: -Monosaccharides -Disaccharides -Polysaccharides Function- cellular fuel -Ex. glucose
Disaccharides
Double sugars Too large to pass through cell membranes Important disaccharides -sucrose -maltose -lactose
Polysaccharides
Polymers of monosaccharides
Important polysaccharides
-starch and glycogen
Not very soluble
Lipids
Insoluble in water Main Types: -Triglycerides or neutral fats -Phospholipids -Steroids -Eicosanoids
Triglycerides
Energy storage
Insulation
Protection
Phospholipids
Important in cell membrane structure
Steroids
Interlocking 4-ring structure
Cholesterol, vitamin D, steroid hormones, and bile salts
Most important steroid is Cholesterol
Eicosanoids
Prostaglandin (most important eicosanoid
-Role in blood clotting, control of blood pressure, inflammation, and labor contractions
Other Lipids in the Body
Other fat-soluble vitamins (A, D, E, K)
Lipoproteins- transport fats in the blood
Proteins
Proteins are polymers Amino acids (20 types) are the monomers in proteins
Fibrous Proteins
- Structural
- Strandlike, water-insoluble, and stable
- Provide mechanical support and tensile strength
- Ex. keratin, elastin, collagen
Globular Proteins
- Functional
- 3D structure
- Specific functional regions (active sites)
- Ex. antibodies, hormones, molecular chaperons, and enzymes
Protein Denaturation
Proteins unfold and lose function-active sites destroyed
Can be caused by decreased pH or increased temperature
Usually reversible if normal conditions restore
Irreversible if changes extreme
-Ex. Cooking an egg
Enzymes
Proteins that act as biological catalysts
-regulate and increase speed of chemical reactions
Lower the activation energy, increase the speed of a reaction
Characteristics of Enzymes
Usually end in -ase
Often named for the reaction they catalyze
-Ex. hydrolases, oxidases
Nucleic Acids
Deoxyribonucleic Acid (DNA) Ribonucleic Acid (RNA) largest molecules in the body
Deoxyribonucleic Acid (DNA)
Located within the nucleus
Utilizes 4 nitrogen bases
-Adenine (A), Guanine (G)
-Cytosine (C), Thymine (T)
–base pair rule- each base pair with its complementary base (A and T); (G and C)
Double-stranded helical molecule (double helix) in the cell nucleus
Provides instructions for all protein synthesis
Replicates before cell division ensuring genetic continuity
Ribonucleic RNA
Located outside the nucleus Utilizes 4 nitrogen bases -Cytosine (C), Guanine (G) -Adenine (A), Uracil (U) Single-stranded molecule Three varieties of RNA carry out the DNA orders for protein synthesis
Adenosine Triphosphate (ATP)
Chemical energy in glucose captured in this important molecule
Directly powers chemical reactions in cells
Energy form immediately usable by all body cells
Structure of ATP
-Adenine-containing RNA nucleotide with two additional phosphate groups
Function of ATP
Phosphorylation:
- Terminal phosphates are enzymatically transferred to and energize other molecules
- Such “primed” molecules perform cellular work (life processes) using the phosphate bond energy
