Chapter 2: Chemical Level of Organization Flashcards
Chemistry
The study of structure of matter
Matter
Anything that takes up space and has mass
Mass
The amount of material in matter
Protons
Positive electrical charge
Neutrons
Electrically neutral, which means that they are uncharged
Electrons
Much smaller and about 1/1800th the mass of either protons or neutrons; they bear a negative electrical charge
Nucleus of an atom
Contains one or more protons and it may contain neutrons
Mass of an atom
number of protons plus number of neutrons
Electron cloud
Electrons whirl around the nucleus; are attracted to positively charged protons in nucleus
Electron shell
Two-dimensional representation of the electron cloud; outermost shell represents the surface of the electron cloud
Isotopes
Atoms of a single element but with different numbers of neutrons; distinguishable based on mass
Principal elements
Thirteen most abundant elements to total body weight
Trace elements
Fourteen other elements in the body in very small amounts
Oxygen
A component of water and other compounds; gaseous for respiration
Carbon
Found in all organic molecules
Nitrogen
Found in proteins, nucleic acids, and other organic compounds
Calcium
Found in bones and teeth; important for membrane function, nerve impulses, muscle contraction, and blood clotting
Phosphorous
Found in bones and teeth; nucleic acids and high-energy compounds
Potassium
Important for proper membrane function, nerve impulses, and muscle contraction
Sodium
Important for blood volume, membrane function, nerve impulses, and muscle contraction
Chlorine
Important for blood volume, membrane function and water absorption
Magnesium
A cofactor for many enzymes
Sulfur
Found in many proteins
Iron
Essential for oxygen transport and energy capture
Iodine
A component of hormones of the thyroid gland
Ions
an atom that gave up or gained an electron
Molecule
Two or more atoms share electrons
Compounds
A substance that contains atoms of two or more different elements
Cation
Loss of electron, giving atom a positive charge
Anion
Gain of electron, giving atom a negative charge
Ionic bonds
Created by electrical between cations and anions; involves the transfer of electrons from one atom to another to achieve stability
Covalent bonds
Sharing of electrons between atoms
Single covalent bond
One electron contributed by each atom
Double covalent bond
Two electrons contributed by each atom
Nonpolar molecule
Electrons shared equally between atoms; no electrical charge on the molecule
Polar molecule
Unequal sharing of electron between atoms
Solid
Particles held tightly together; maintain their volume and shape at ordinary temperatures and pressures
Liquid
Particles held less tightly together; has a constant volume; container determines shape
Gas
Particles independent of each other; has neither a constant volume nor a fixed shape; can be compressed or expanded; will fill a container of any size
Hydrogen bond
Attraction of the small polar charges on hydrogen atoms to negative charges on other polar molecules; can change shape of molecules or pull molecules together; produces surface tension
Surface tension
Slows the rate of evaporation at water surface
Metabolism
All the cellular reactions of the body at a given moment
Work
Movement of an object or change in physical structure of matter
Energy
Capacity to perform work
Kinetic energy
Energy of motion
potential energy
Stored energy (potential to do work)
Chemical notation
a simple “chemical shorthand” to describe chemical structures and events
Reactants
Participants at reaction start
Products
Generated at end of reaction
Decomposition
Breaks molecule into smaller components
Hydrolysis
Decomposition using the insertion of water
Catabolism
Collective decomposition reactions of the body; releases kinetic energy
Synthesis
Combining of atoms or smaller molecules into larger molcules
Dehydration synthesis
Removal of water to form a larger molecule
Anabolism
Collective synthesis of new molecules in the body; requires energy
Exchange reactions
Reactants are “shuffled” to produce new products
Equilibrium
Rates at which the two reactions occur are in balance
Activation energy
Amount of energy to start a reaction
Enzymes
Special proteins that lower the activation energy for a reaction
Catalysts
Compounds that accelerate reactions without changing themselves; reactions continue until equilibrium is reached
Metabolic pathway
Series of reactions (each involving and enzyme) that support life
Exergonic
Release energy; common in the body and help to maintain body temperature
Endergonic
Absorb energy
Metabolites
All molecules that can be synthesized or decomposed in our bodies; processed by enzymatic reactions
Nutrients
Essential metabolites normally obtained from our diet
Organic nutrients
Always contain carbon and hydrogen
Inorganic nutrients
Generally do not contain carbon and hydrogen
Water
Most important constituent of the body; accounts for up to 2/3 of total body weight; changes in body water content can affect all systems
Hydration sphere
Sheath of water molecules around an ion
Electrolytes
Ions in solution that conduct electric current; movement of ions across the plasma membrane of cells is important in many body cells; ion concentrations in bodily fluids is carefully regulated
Hydrophilic
Polar covalent bonds
Hydrophobic
Non-polar covalent bonds
Colloid
Large molecules that stay in solution
Suspension
Larger molecules that may settle out of solution due to gravity
Hydrogen ion
Hydrogen atom that has lost electron; extremely reactive in solution; concentration in body regulated precisely
Hydroxide ion
Produce when water decomposes
Blood pH
Normally ranges from 7.35-7.45
Acidosis
Below 7.35
Alkalosis
above 7.45
Acid
Solute that dissociates and releases hydrogen ions; often referred to as proton donors; strong acids dissociate completely
Base
Solute that removes hydrogen ions from solution; proton acceptor; strong bases dissociate completely
Buffers
Compounds that stabilize pH by removing or replacing hydrogen ions; help to maintain normal pH of body fluids
Buffer systems
Usually involve a weak acid and its related salt
Organic compounds
Always contain carbon and hydrogen and generally oxygen; many are long chains of carbon linked with covalent bonds; many are soluble in water
Functional group
Attached groupings of atoms that occur commonly in many organic molecules; influence the properties of the overall molecule
Carbohydrates
Contain carbon, hydrogen, and carbon in ration near 1:2:1
Monosaccharide
Simple sugar; contains 3-7 carbon atoms
Isomers
Molecules with the same molecular formula but different structures; can be important in molecular function
Disaccharide
Two monosaccharides joined; dehydration synthesis creates disaccharides; hydrolysis breaks them down to monosaccharides
Polysaccharides
Many disaccharides and/or monosaccharides connected together
Lipids
Carbon to hydrogen ratio is near 1:2; much less oxygen compared to carbohydrates with similar number of carbon atoms; most are insoluble in water; essential components of all cells; provide twice as much energy as carbohydrates
Fatty acids
The building blocks of lipids, which includes a tail and head composed of a carboxylic acid group; energy sources
Glycerides
Fatty acid chains attached to a glycerol molecule; energy sources, energy storage, insulation, and physical protection
Eicosanoids
Derived from arachidonic acid; chemical messengers coordinating local cellular activities
Steroids
Large molecules with four carbon rings; differ in attached functional groups; structural components of cell membranes, hormones, digestive secretions in bile
Phospholipids, glycolipids
Structurally related; can be synthesized by cells primarily from fatty acids; structural components of cell membranes
Saturated fatty acid
Each carbon has four attached hydrogens
Unsaturated fatty acid
Contains double bonds; one double bond = monounsaturated; >1 double bond = polyunsaturated; has fewer attached hydrogens; changes metabolism of the molecule
Monoglyceride
glycerol + one fatty acid
Diglyceride
glycerol + two fatty acids
Triglyceride
glycerol + three fatty acids
Leukotrienes
Produced by cells in response to injury
Prostaglandins
Released by cells to coordinate local cellular activities
Cholesterol
Functions to maintain plasma membranes, growth, and division
Hormones
Regulation of sexual and other metabolic functions
Phospholipid
Phosphate linking a diglyceride to a non-lipid group
Glycolipid
Carbohydrate attached to a diglyceride
Proteins
Most abundant organic molecule in the body; in many ways, are most important; contain carbon, hydrogen, oxygen, and nitrogen, possible sulfur and phosphorus as well; consist of long chains of amino acids; 20 amino acids in the body; Typical protein contains 1000 amino acids
Amino acids
All have the same structural components: central carbon, amino group, carboxyl group, R group (variable side chain)
Peptides
Amino acids linked through dehydration synthesis; covalent bond connects the carboxylic acid group of one amino acid to the amino group of another; peptides of over 100 amino acids are called proteins
Dipeptide
Two amino acids linked together
Polypeptides
Three or more amino acids linked together
Primary structure
Sequence of amino acids
Secondary structure
Molecule shape changes due to bonds at different parts of the polypeptide chain
Tertiary structure
Coiling and folding giving the protein a final 3D shape; from interactions of the protein and surrounding water molecules and interactions between R groups (variable side chain groups)
Quaternary structure
Interaction between multiple polypeptide chains to forma protein complex
Hemoglobin
Binds oxygen in red blood cells
Keratin and collagen
Fibrous proteins that give strength to tissues
Denaturation
Protein shape and function deteriorate; occurs under extreme conditions: temperature, pH, heavy metals; Irreparable damage can occur to tissues and organs
Substrates
Reactants in enzymatic reactions; must bind to a specific region of an enzyme
Enzyme-substrate complex
Once binding to enzyme occurs
Saturation limit
Substrate concentration required to have maximum rate of concentration
High-energy bonds
Donate energy to chemical reactions to form products; contain high-energy bonds (covalent), release energy when broken
Adenosine triphosphate (ATP)
Most common high-energy compound; provides energy for many vital body functions; adenosine, ribose sugar, three phosphate
Adenosine monophosphate (AMP)
Adenosine, ribose sugar, one phosphate
Adenosine diphosphate (ADP)
Adenosine, ribose sugar, two phosphate
Nucleic acids
Large organic molecules; composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus; primary function is storage and transfer of information, particularly synthesis of proteins; Consists of two long chains formed from dehydration synthesis of subunits (nucleotides)
Purines
Adenine and Guanine
Pyrimidines
Cytosine, thymine, and uracil
Deoxyribonucleic Acid
Two complementary nucleotide chains are linked by hydrogen bonds between complementary base pairs; the two strands of DNA twist around one another in a double helix that resembles a spiral staircase
RNA
Single chain of nucleotides
Messenger RNA (mRNA)
Transcribed from DNA and carries message from nucleus to cytoplasm
Transfer RNA (tRNA)
Translates mRNA message to amino acid sequence during protein synthesis
Ribosomal RNA (rRNA)
Guides protein synthesis