Biology week 1
Vocabulary for Biology 212 with Professor John Mayfield, week 1 (lectures 1-3).
Terms
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- Hierarchial
- A system of ranking and organizing things or people, where each element of the system (except for the top element) is subordinate to a single other element.
- Covalent bond
- A type of strong chemical bond in which two atoms share one of more pairs of valence electrons.
- Hydrogen bond
- A type of weak chemical bond formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule.
- Polar molecules
- Molecules with opposit charges on opposite sides (example = water).
- Hydrophobic
- Having an aversion to water; tending to coalesce and form droplets in water (example = motor oil).
- Ion
- An atom that has gained or lost electrons, thus acquiring a charge.
- Hydrogen ion
- A single proton with a charge of 1+. The dissociation of a water molecule leads to the generation of a hydroxide ion and a hydrogen ion.
- pH
- A measure of hydrogen ion concentration equal to -log[H+] and ranging in value from 0 to 14.
- Polymer
- A long molecule consisting of many similar or identical monomers linked together.
- Macromolecule
- A giant molecule formed by the joining of smaller molecules, usually by a condensation reaction (examples = polysaccharides, proteins, nucleic acids).
- Hydrolysis
- A chemical process that lyses, or splits, molecules by the addition of water.
- Dehydration synthesis
- A chemical reaction in which two molecules covalently bond to each other with the removal of a water molecule.
- Protein
- A three-dimensional biological polymer constructed from a set of 20 different monomers called amino acids.
- Polypeptide
- A polymer (chain) of many amino acids linked together by peptide bonds.
- Peptide
- The makeup of a polypeptide, also made from amino acids.
- Amino acid
- An organic molecule possessing both carboxyl and amino groups. Amino acids serve as the monomers of proteins.
- Polysaccharide
- A polymer of up to over 1000 monosaccharides, formed by dehydration reactions.
- Monosaccharide
- The simplest carbohydrate, active alone or serving as a monomer for disaccharides and polysaccharides. Also known as simple sugars, the molecular formulas of monosaccharides are generally some multiple of CH20.
- Sugar
- Either a monosaccharide, disaccharide, or polysaccharide.
- Nucleic acid
- A polymer (polynucleotide) consisting of many nucleotide monomers; serves as a blueprint for proteins and, through the actions of proteins, for all cellular activities. The types are DNA and RNA.
- Nucleotide
- The building block of a nucleic acid, consisting of a five-carbon sugar covalently bonded to a nitrogenous bas and a phosphate group.
- Phosphate group
- A functional group important in energy transfer (ATP and ADP).
- Phospholipid bilayer
- Molecules that are constituents of the inner bilayer of biological membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail.
- Primary structure
- The level of protein structure referring to the specific sequence of amino acids.
- Secondary structure
- The localized, repetitive coiling or folding of the polypeptide backbone of a protein due to hydrogen bond formation between peptide linkages.
- Tertiary structure
- Irregular contortions of a protein molecule due to interactions of side chains involved in hydrophobic interactions, ionic bonds, hydrogen bonds, and disulfide bridges.
- Quaternary structure
- The paticular shape of a complex, aggregate protein, defined by the characteristc three-dimensional arrangement of its constituent subunits, each a polypeptide.
- Denaturation
- In proteins, a process in which a protein unravels and loses its native conformation, thereby becoming biologically inactive. Denaturation occurs under extreme conditions in pH, salt, concentration, and temperature.
- Renaturation
- Opposite of denaturation.
- Amphipathic
- A molecule that has both a hydrophilic region and a hydrophobic region.
- Micelle
- An electrically charged particle formed by an aggregate of molecules and occuring in certain colloidal electrolyte solutions.
- Biological membrane
- A membrane surrounding the cell. It does differ between plant membrae and animal membrane.
- Semi-permeable membrane
- Membrane that allows vertain particles to flow freely through the membrane without any energy required.
- Diffusion
- The tendenc of molecules of any substance to spread out evenly into the available space.
- Osmosis
- The diffusion of water across a selectively permeable membrane.
- Turgid
- Very firm; health state for most plant cells.
- Flaccid
- Limp due to isotonic environment, thus having no water enter and stay in.
- Plasmolyzed cell
- A cell involved in plasmolysis, which is when the cell is immersed in a hypertonic environment, and the cell will lose water to its surroundings and shrink. The plasma membrane pulls away from the cell wall, also.
- Hypertonic
- The cell wall will lose water to its environment, shrivel, and probably die.
- Hypotonic
- Water will enter the cell faster than it can leave, and the cell wall will burst (lyse) like an overfilled balloon.
- Passive transport
- The diffusion of a substance across a biological membrane.
- Facilitated transport
- The spontaneous passage of molecules and ions, bound to specific carrier proteins, across a biological membrane down their concentration gradients. It moves from high to low concentration.
- Active transport
- The movement of a substance across a biological membrane against its concentration or electrochemical gradient with the help of energy input and specific transport proteins. It moves from low to high concentration.
- Cotransport
- The coupling of the "downhill" diffusion of one substance to the "uphill" transport of another against its own concentration gradient.
- Ion pump
- Transports one ion into the membrane and takes another ion out. The protein changes its shape so the ion can fit in it for transport.
- Sodium-potassium pump
- A type of ion pump that transfers K+ ions into the cell and Na+ ions out of the cell.
- Hydrogen ion pump
- A hydrogen ion is forced out of the cell by ATP through a protein and comes back into the cell with a sucrose molecule. The hydrogen ion helps the sucrose enter the cell and keeps the cell alive.
- Exocytosis
- The cellular secretion of macromolecules by the fusion of vesicles with the plasma membrane.
- Endocytosis
- The cellular uptake of macromolecules and particular substances by localized regions of the plasma membrane that surround the substance and pinch off to form an intracellular vesicle.
- Vesicle
- A sac made of membrane inside of cells.