Exam #2 (2 & 6) Flashcards
Element
A substance that consists of only one kind of atom and cannot be separated into simpler parts by chemical methods; 92 are naturally occuring;
4 Most Common Elements in Organisms
- Carbon
- Hydrogen
- Oxygen
- Nitrogen
Atoms
The basic units of all matter
Subatomic Particles Composing Atoms
- Neutrons: uncharged, found in the nucleus
- Protons: positively charged, found in the nucleus
- Electrons: negatively charged, form cloud around the nucleus
Atomic Number
The number of protons in the nucleus
Atomic Weight (Mass)
The sum of the number of protons and neutrons found in an atom
Isotope
Forms of the same chemical element that differ in their number of neutrons; useful tools in biological research
Molecule
Two or more atoms held together by chemical bonds
Chemical Bond
Form when atoms lose, gain, or share the electrons in their outer shell to achieve the most stable state
Ionic Bond
A strong chemical bond resulting from the attraction of positively and negatively charged ions; resulting product is called a salt
Covalent Bond
Strong chemical bond formed by the sharing of electrons between atoms; share pairs of valence electrons
Hydrogen Bond
Weak attraction between a positively charged hydrogen atom of one compound and a negatively charged atom of another compound; charges of the two atoms are due to polar covalent bonds
Ion
An atom that gains or loses an electron; becomes positively or negatively charged
Cation
Positively charged ion
Anion
Negatively charged ion
pH
Scale of 0 to 14 that expresses the acidity or alkalinity of a solution
Buffer
Substances in a solution that acts to prevent changes in pH
Macromolecules
Large molecules that contain 10s of atoms to billions of atoms; complex enough that life is usually necessary to make them
- organic: the molecules contain at least Carbon and Hydrogen
4 Types of Macromolecules
- Carbohydrates: sugars, starch, glycogen, chitin, celluose, peptidoglycan (most composed of ringed molecules)
- Lipids: triglycerides, phospholipids, steroids
- Proteins: building blocks, enzymes
- Nucleic Acids: DNA, RNA
Monosaccharides
Simple sugars; primary choice to make cellular energy (ATP)
Polysaccharides
Carbohydrates that cells make to store energy in the form of a carbohydrate; glycogen in animals, cellulose in plants; chitin, cellulose, and peptidoglycan are complex carbohydrate molecules that cells use as building blocks of cell walls
Triglycerides
Fat molecules that cells construct to store energy
Saturated Fat
Fatty acid that contains no double bonds
Unsaturated Fat
Fatty acid with one or more double bonds