Topic 2 - Chemical Level of Organization Flashcards
Matter
Anything that occupies space and has mass
Mass
The actual amount of matter in an object
Weight
A measure of the gravitational pull of earth on an object
Element
Substance that cannot be split into smaller units through ordinary chemical means
Atom
Smallest unit of matter that retain the properties and characteristics of the element
Mass Number
The sum of the masses of all the protons and neutrons in an atom (can vary depending on number of neutrons)
Isotope
Atoms of an element that differ in the number of neutrons they contain
Atomic Weight
Average of the mass numbers of all the isotopes of an element, taking into account their relative abundance in nature
Molecule
Two or more atoms chemically bonded together
Compound
A molecule consisting of two or more different types of elements
Octet Rule
Only 8 electrons from each valence shell can participate in bonding (2 in first shell)
Non-polar covalent bond
Electrons are shared equally
Polar covalent bond
Electrons are more attracted to one atom than the other
Hydrogen bond
Attractive force between the electropositive hydrogen of one molecule and an electronegative atom of another molecule; gives water cohesion and surface tension
Chemical bonds from strongest to weakest
Covalent, ionic, hydrogen
Activation energy
The collision energy needed to break bonds and begin a reaction
Factors that increase the rate of a reaction
- Increasing temperature
- Increasing concentration
- Smaller particle size - move faster
- Catalysts - remain unchanged
Oxidation-reduction (redox) reaction
Electron donor loses electron (oxidized). Electron donor gaining electron is reduced. E.g. Reactions in which food fuels are broken down
Inorganic Compounds
Simple molecules that lack carbon. E.g. H20, acids, bases, and salts
Properties of Water
- Polar Solvent
- Important in chemical reactions of metabolism
- High heat capacity
- High heat of vaporization
- Protective lubricant and cushion
Mixture
combination of elements or compounds that are physically blended together but are not bound by chemical bonds
Homogeneous solution
Solvent and small solute particles are intimately mixed so the solutes do not settle out of the solution (transparent)
Heterogeneous suspension
Solutes are large, refract light, and tend to settle out unless the mixture is continuously resuspended.
Colloid
Large, undissolved particles are evenly distributed and form a cloudy suspension
Hydrolysis
Breaks large molecules down into simpler ones by adding a molecule of water
Dehydration Synthesis
Occurs when two simple molecules join together, eliminating a molecule of water in the process
Acid
Dissociates into H+ ions and one or more anions
Base
Dissociates into OH- ions and one or more cations
Salt
Dissociates into cations and anions that are not H+ or OH-
Buffer System
Maintains narrow range of pH of body fluids, usually includes weak acids and weak bases. E.g. carbonic acid-bicarbonate system. Changes acids or bases into less potent form.
Organic Compounds
- Always contain carbon
- Held together by covalent bonds
- Do not dissolve easily in water
- Contain hydrogen and oxygen
- Include carbohydrates, lipids, proteins, nucleic acids
Properties of Carbon
- Atomic number is 6
- Outer shell has 4 electrons
- Can form single covalent bonds with up to 4 atoms
- 1-100s of C atoms can bond together in rings or chains
Organic functional groups
- phosphate group (R-PO4)
- amino group (R-NH2 or NH3
- hydroxyl group (R-OH)
- carboxyl group (R-COOH)
- ester group (R-COOR)
Carbohydrate
- formed from C, H, O
- provide energy, used to build structures, function as food reserves
- includes sugars, glycogen, starches, and cellulose
Monosaccharide
- 3-7 carbon atoms
- C, H, O in 1:2:1 ratio
- glucose, fructose, galactose, deoxyribose, ribose
Disaccharide
- 2 monosaccharides joined by dehydration synthesis
- split back into simple sugars by hydrolysis
- sucrose –> glucose + fructose
- maltose –> glucose + glucose
- lactose –> galactose + glucose
Polysaccharide
- large complex carbohydrates
- glycogen: principal polysaccharide in body, stored in liver and skeletal muscles, hydrolyzed by liver to yield glucose when blood sugar drops
Lipid
- contains C, H, O
- few polar covalent bonds: hydrophobic, mostly insoluble in polar solvents, combine with polar proteins for transport in blood (lipoproteins)
- function: protection, energy, storage, insulation
- triglycerides, phospholipids, steroids, fat-soluble vitamins (A, D, E, K), eicosanoids
Triglycerides
- most plentiful lipid in body
- solid or liquid at room temp
- provide 2X as much energy as carbohydrates or proteins
- excess calories stored in adipose tissue as triglycerides
Saturated Fatty Acid
- single covalent bonds only
- more hydrogen atoms
- animal sources and tropical oils
- solid at room temp
Unsaturated Fatty Acid
- double and triple bonds present (kinks)
- less hydrogen atoms
- vegetable, fish, nut and seed oils, avocado
- liquid at room temp
Essential Fatty Acid
- cannot be made by the body, must be obtained from foods or supplements
- omega-3 fatty acids, omega-6 fatty acids, cis-fatty acids
Phospholipid
- important cell membrane component
- amphipathic (polar and nonpolar regions): polar head (phosphate group and glycerol molecule) and 2 nonpolar fatty acid tails
Steroid
- 4 rings of carbon atoms
- cholesterol, bile salts, Vit D, sex hormones, adrenocortical hormones
Structure of Protein
- contains C, H, O, N, and sometimes S
- amino acids are building blocks
- amino group (NH3+), a carboxyl group (COO-), a hydrogen atom and an R group around a central carbon atom
- determined by its R group
- joined together by peptide bond between the carboxyl group of one amino acid and the amino group of another through dehydration synthesis
Function of Protein
- give structure to body, regulate processes, provide protection, help muscles to contract, transport substances, and serve as enzymes
- 20 naturally occurring amino acids
Primary Structure
Unique sequence of amino acids in a polypeptide chain
Secondary Structure
Polypeptide chains form alpha-helix or pleated sheets
Tertiary Structure
3D shape of polypeptide
Quaternary Structure
2 or more polypeptide chains folded together into a functional protein
Means to stabilize tertiary and quaternary protein structure
- H-bonds
- Ionic bonds
- Hydrophobic interactions between amino acids
- Disulfide bridges
Denaturation
The unfolding or destruction of a protein by excess heat, acid, or salts that destroy its ability to function
Structural (fibrous) protein
- insoluble in water
- form structures like cytoskeleton or assist in movement
- collagen, keratin, elastin, actin, myosin
Functional (globular) protein
- water soluble
- catalysts in chemical reactions
- end with -ase
- enzymes, hormones, antibodies, receptors, transporters, chaperones
Nucleic Acid
- contains C, H, O, N, P
- 2 types: DNA (genetic information) and RNA (protein synthesis)
- nucleotides are building blocks, linked by covalent bonds between phosphate of one and the sugar of the next
- DNA consists of 2 strands of nucleotides joined by hydrogen bonds between nitrogenous bases
Nucleotide
- building block of nucleic acid
- consist of nitrogenous base, pentose sugar (ribose in RNA, deoxyribose in DNA), and phosphate (PO4)
- 5 types: adenine and guanine (purines), cytosine, thymine, and uracil (pyrimidines)
ATP
- temporary energy storage molecule
- energy currency of the cell
- consists of adenine, ribose, and 3 phosphate groups
