Terms Flashcards
Chemical element:
A fundamental substance containing only one kind of atom
Mass number
of protons and neutrons in the nucleus
Atomic mass:
Atomic weight, average or relative.
Average: protons and different # of neutrons
Radio isotopes:
Give off energy in the form of alpha, beta, and gamma radiation from the nucleus (radioactive decay)
Molecule
A stable association of atoms of an element
Orbital
Region where an electron is found 90% of the time
Electron shells/energy levels
Chemical bond:
• Attractive forces holding atoms together
• Attractive force that links atoms together to form molecules
• A lasting attraction between atoms, ions, or molecules that enables the formation of a chemical compound
Covalent bonds:
Atoms share electrons. Each atom contributes an electron.
Compound bonds:
Pure substance made of two or more different elements bonded together in a fixed ratio.
Ionic bonds:
When one atom is much more electronegative than the other a complete transfer of electrons may occur
Ion:
Electrically charged particles formed when atoms lose or gain electrons.
Hydrogen bonds:
Attraction between the δ⁻ end of one molecule and the δ⁺ end of another molecule
Vander Waals forces:
Attraction between nonpolar molecules (compounds) that are close together (brief and weak)
Chemical reactions:
The making and breaking of chemical bonds - transforms substances
Energy:
The capacity to do work or the capacity for change.
Mole:
(unit) a name for a specific amount of substance
Mass of one mole: molecular weight of a compound (one mole) = sum of atomic weights of all atoms in a molecule
Cohesion:
Something that sticks to itself (surface tension)
Adhesion
Something that sticks to other things (capillary action)
Solution:
substance dissolved in liquid (solvent)
Homeostasis:
Living organisms maintain constant internal conditions
Monomers
Small molecules that bond together to form more complex structures
Polymer:
A long molecule consisting of many similar building blocks (monomers) and contain thousands more atoms
Functional group:
A specific group of atoms or bonds within a compound that is responsible for the characteristic chemical reactions of that compound
Isomer
Molecules with the same chemical formula, but the atoms are arranged differently
Condensation:
(dehydration) reactions where energy is used to make covalent bonds between monomers to make a polymer; a water molecule is removed (loss or produce)
Hydrolysis
Reaction where polymers are broken down into monomers; energy is released and water is consumed
Protein:
A biologically functional macromolecule made from one or more polypeptide chains
polypeptide chain:
A single, unbranched polymer built from a set of 20 amino acids
amino acids:
Organic molecules (monomers) with carboxyl and amino groups - they function as an acid and a base
Oligo peptides or peptides:
Short polymers of 20 or fewer amino acids
Primary structure:
A unique sequence of amino acids
Secondary structure:
The coils and folds result from hydrogen bonds between repeating constituents of the polypeptide backbone
Tertiary structure:
Determined by interactions between R groups rather than interactions between backbone constituents
Quaternary structure:
Many proteins have two or more polypeptide chains or subunits
Carbohydrates:
Biomolecules with similar atomic composition but differ greatly in size, chemical function, and biological functions.
Monosaccharides:
Simple sugars
Disaccharides:
Two simple sugars linked covalently
Oligo saccharides
3-20 monosaccharides
Polysaccharides
Hundreds or thousands of monosaccharides, polymers
Glycosidic bond
covalent bonds of carbohydrates
Osmosis
A process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one
Lipids
Defined by their insolubility in water
Glycerol
An alcohol with each carbon with a hydroxyl group
Fatty acid
Nonpolar hydrocarbon chain with a polar carboxyl group
Ester linkages
Covalent bonds of fatty acids
Saturated fatty acid
No double bonds between carbons - it is saturated with H atoms
Unsaturated fatty acid
One or more double bonds in the carbon chain resulting in kinks that prevent packing
Trans fats
H atoms are on opposite sides of the C=C bond, results form hydrogenation of vegetable oils
Phospholipids
Fatty acids bound to glycerol; a phosphate group replaces a fatty acid
Amphipathic
1 hydrophobic end and 1 hydrophilic end
Nucleic acids
Biopolymers or large biomolecules, essential to all known forms of life. Specialized for storage, transmission, and use of genetic information.
Base (DNA)
Two forms of nitrogenous bases:
Pyrimidines: cytosine, thiamine, uracil - one ring
Purines: adenine, guanine - two rings
Phosphate groups
links the 3′ carbon in one sugar to the 5′ carbon in another sugar.
Characteristics of RNA
Single-stranded
Contains uracil rather than thiamine
In RNA the bases are attached to ribose
Characteristics of DNA
Two strands running in opposite directions held together by hydrogen bonds
Contains thiamine rather than uracil
Bases attached to deoxyribose
Complimentary base pairing
Purines pair with pyrimidines by hydrogen bonds
Genes
Sequences of DNA that are transcribed into RNA
The central dogma of molecular biology
The premise that information flows from DNA to RNA to polypeptides
