Chapter 2 Flashcards
Acid
A molecule held together by hydrogen bonds that releases hydrogen ion (H+) when added to water.
Addition of an acid to water will cause the pH to drop below 7.
Adhesion
The property of being attracted to or sticking to a different type of molecule or substance.
One of the characteristics of water that makes it a very good solvent is that is sticks to a lot of different types of molecules.
Amino Acid
The subunits that make up proteins.
Amino acids differ by their R side groups.
One of the reasons that proteins are so diverse is that there are 20 different amino acids.
Anion
A negatively charged ion that results from an atom taking on additional electrons.
Chlorine will take an electron from sodium during the formation of a ionic bond.
Atom
The smallest piece of element that retains the characteristics of that element.
Consists of protons, neutrons, and electrons.
Atomic Number
The number of protons in the nucleus of an atom.
On the periodic table elements are listed by their atomic number.
Atomic Weight
The weight of one atom of a particular element.
Determined by adding the number of protons and neutorns.
Electrons are not included because they are too small.
ATP
Adenosine Tri-Phosphate
ATP is the energy currency of all living organisms.
Carbohydrates, lipids, and proteins are broken down by respiration to produce ATP for the cell.
ATP is a nucleic acid consisting of a single nucleotide with three phosphate groups.
Base
A molecule held together by hydrogen bonds that releases hydrogen ion (OH-) when added to water.
Addition of a base to water will cause the pH to rise above 7.
Carbohydrate
An organic molecule composed of C, H, and O with a 2:1 ratio of H to O.
Common funtions are:
Energy source: monosaccharide
Energy storage: polysaccharide
Structure: cell walls
Surface recognition
Cation
A positively charged ion that results from an atom giving up one or more electrons.
Sodium will give up an electron to chlorine during the formation of a ionic bond.
Cellulose
A structural carbohydrate that makes up plant cell walls.
It is undigestable by most organisms, therefore it is not a form of stored energy.
Chitin
A structural carbohydrate that makes up fungi cell walls and the exoskeleton of crustaceans and insects.
It is undigestable by most organisms, therefore it is not a form of stored energy.
Cohesion
The property of being attracted to or sticking to itself.
One of the characteristics of water that makes it form drops and travel up a tree by capillary action.
Compound
A molecule composed of two or more different types of elements.
Covalent Bond
A chemical bond formed when two or more atoms share valence electrons.
There are two forms of covalent bonds.
polar = unequal sharing
nonpolar = equal sharing
Dehydration Synthesis
The formation of a bond between organic molecule monomers that releases water.
Denaturation
The loss in normal shape and function of a protein.
Factors that can denature a protein are heat, acid, and base.
Disaccharide
A small carbohydrate consisting of two linked monosaccharides.
Examples are sucrose and maltose.
DNA
Deoxyribonucleic acid.
A nucleic acid that carries genetic infromation for making proteins.
It is a long double standed molecule that makes up chromosomes.
Electron
A small subatomic particle with a negative charge that orbits the nucleus of an atom.
It is the part of the atom responsible for bond formation.
They are equal to the number of protons in an atom.
If an atom gains or loses an electron it becomes an ion.
Electronegativity
The tendency of an atom to attract electrons.
Some elements are stronger at attracting electrons (carbon and nitrogen) and others are weaker (hydrogen and carbon).
The eletronegativity determines if polar or nonpolar covalent bonds form.
Element
Matter that cannot be broken down into simpler substances.
Each element on the periodic table has a different number of protons.
Energy Shell
The discrete distance from the atomic nucleus that the electrons are found.
The 1st energy shell contains 2 electrons and the 2nd and 3rd energy shells contain 8 electrons.
Fatty Acid Chain
A long chain of carbon and hydrogens associated with lipids.
The long hydrocarbon chains are responsible for the nonpolar nature of lipids.
Glycerol
A subunit of simple lipid that contains 3 carbons and may attach to as many a 3 fatty acid chains.
Hydrolysis
The chemical reaction that uses water to separate the subunits of large organic molecules.
Proteins are split into amino acids.
Polysaccharides are split into monosaccharides.
Lipids are split into glycerol and fatty acid chains.
Nucleic acids are split into nucleotides.
Hydrophobic
“Water fearing”
Molecules that repel water are hydrophobic.
Nonpolar molecules are hydrophobic because they do not have a positive or negative charge for water to bind.
Hydrophilic
“Water loving”
Molecules that attach to water are hydrophilic.
Polar molecules are hydrophilic because they have positive and negative charges for water to bind.
Inert Gas
Elements that have their outer most electron shell filled.
Because they do not have any empty electron spaces to fill, they do not combine with other elements to make molecules.
Ionic Bond
The force that holds two oppositely charged ions together.
When an atom gives up an electron to become a cation it is strongly attracted to an anion which is an atom that has gained an electron.
Although ionic bonds are strong, they dissociate in polar solvents like water.
Ions
Atoms in which the number of protons does not equal the number of electron because the atom has either gained or lost electrons.
Isotopes
Forms of the same element that contain differing numbers of neutrons.
Because the isotopes have varying numbers of neutrons they will have varying atomic masses.
If the istopes are unstable and degrade, they are called radioactive.
Lipids
Organic molecules composed of carbon, hydrogen, and oxygen that are nonpolar because they have a low amount of oxygen.
The typical lipid is a triglyceride, a glycerol backbone with three fatty acid chains.
Molecule
A combination of two or more atoms bonded together.
Monosaccharide
A single sugar unit.
Monosaccharides are the subunits of larger carbohydrates like polysaccharides.
Neutron
A neutral subatomic particle found in the nucleus of an atom. It contributes to the atomic mass and the stability of the atom.
Oxidation
The removal of an electron from an atom or molecule.
If an atom undergoes oxidation, it becomes a positively charged cation because it has more protons than electrons.
Polar Covalent Bonds
The force that holds two or more atoms together when they share electrons unequally.
Because one of the moleucles is stronger than the other in attracting electrons (electronegativity) there is an unequal distribution of electrons.
Polar covalent bonds result in molecules that have a positive charge at on end an negative charge on the other.
Polar moleucles are hydrophilic.
Polysaccharide
A molecule composed of a long chain of monosaccharide subunits.
Usually function either as a form of stored energy (starch and glycogen) or cell wall (cellulose and chitin)
Primary Structure
(of a protein)
The amino acid sequence of a protein.
This is the most important level of structure because it is the basis for all the other levels of structure.
Proton
A positively charged subatomic particle found in the nucleus of an atom.
Protons define the element because every element has a unique number of protons and if the proton number changes, then the element changes.
Quaternary Structure
(of a protein)
This level of structure occurs in large proteins that are composed of multiple smaller proteins.
Not all proteins have this level of structure.
Reduction
The addition of an electron to an atom or molecule.
If an atom undergoes reduction, it becomes a negatively charged anion because it has more electrons than protons.
RNA
Ribonucleic acid.
A nucleic acid that is responsible for the production of proteins.
It is a long single stranded molecule that degrades quickly.
Salt
NaCl is commonly known as salt.
A salt is a molecule that dissociates in water without releasing either H+ or OH- and as a result does not affect the pH of the solution.
Secondary Structure
(of a protein)
The folding of a protein due to hydrogen bonds.
This is the most fragile level of structure because hydrogen bonds are very weak.
Common secondary shapes are helices and pleated sheets.
Sterols
A form of lipids composed of ring structures.
The most common is cholesterol which is used by the cell to strengthen cell membranes and produce hormones.
Tertiary Structure
The folding of a protein due to interactions between amino acid R side groups.
All protiens have this level of structure.
Valence Electrons
The electrons in the outer most shell of an atom.
The number of valence electrons will determine the kind of bond an atom forms.
It is the valence electrons that are either shared or given and taken to create chemical bonds.
