Chapters 2,3,4 Flashcards
Essential elements
Elements needed to makntain life (large amts)
What makes up 96% livong matter
Oxygen, Nitrogen, Carbon, Hyrdrogen
Carbon is used to build…
Carbohydrates, proteins, lipids, and nucleic acids
Also used in sotrage xompounds and cell formation
Nitrogen is ised in building of…
Building proteim and nucleic acids
Phosphorus is used in building of…
Nucleic acids and some lipids
Trace elements
Element required by organism in small amts
Ex of trace elements
Iron, iodine
Atom
Smallest unit of matter that still retains the properties of an element
When is an atom unstable and very reactive?
When its valence she’ll has unpaired electrons
Valence number
Number unpaired electrons in outer shell, tells how many bonds can be formed
Chemical bonds
Formed when valence electrons from different atoms interact to form molecules
Electronegativity
Attraction of an atom for the electrons of a covalent bond
Double covalent bond
Sharing two pairs of electrons
Ionic bond
Type of bond resulting from attraction between oppositely charged ions
Ion
Atom that has gained or lost an electron
Weak ionic bond
In presence of water ionic bond is easily disrupted
Hydrogen bond
Interaction between a hydrogen atom of one molecule and a very electronegative atom of another molecule
Van der Waals interaction
Weak attractions between molecules that occur when molecules are in close proximity, attracted by charge differences
When does van der waals occur
When electrons are not symetrixally distributed in a molecule
Hydrophobic interaction
Weak chemical bomd formed when molecules that do not mix w water congregate to exclude water
Characteristics of water
- Polar
- Oxygen has slight negative charge
- Hydrogen has slight positive charge
- Hydrogen bonds form between molecules
What do properties of water result from
Polarity amd hydrogen bonding
Cohesion
Bonding together of like molecules to hold a substance together- water moves up plant against gravity
Adhesion
Clinging of one substance to anoher
