### nucleon | proton:

Energetic proton
* More energetic protons can penetrate the shielding, but their flux and cross section are much lower.
* can arrive anywhere from a few minutes after the soft X-rays to hours later.

Free proton
* are emitted directly from atomic nuclei in some rare types of radioactive decay.
* tend to repel one another.

Solar proton
* can penetrate into the Earth's magnetosphere near the magnetic poles.
* passing through humans ionize molecules along their tracks.
* pose a significant risk to inadequately shielded crewmembers.

### nucleophilic:

Organometallic compound
* Most organometallic compounds are soluble in hydrocarbon oils.
* are nucleophilic
  - usually strong bases

Nucleotide
* All nucleotides are either purines or pyrimidines
  - have a common structure
  - share the sugar-phosphate backbone
* Some nucleotides consist of sugar
  - find in cytoplasm
* also have either a pyrimidine or purine base, attached to the pentose sugar
  - serve as nucleic acid monomers
* are a major constituent of the non-protein fraction of breast milk
  - abundant in the cell's nucleus
  - arranged in two long strands that form a spiral called a double helix
  - carriers of activated intermediates in many biosynthetic processes
  - combined phosphate, sugar, and base
  - energy rich molecules because they contain nucleosides
  - ester
  - hard to make
  - important for several reasons
  - joined together by covalent
  - linked to one another to form a strand
  - nucleoside phosphates
  - organic molecules
  - part of codons
* are the basic unit of the DNA molecule
  - basis for nucleic acids
* are the building blocks of DNA
  - nucleic acid polymers
  - monomers that make nucleic acids
  - rungs of the ladder of the DNA double helix
  - units which, when linked sugar to phosphate, make up one side of a DNA ladder
  - very small, only a few dozen atoms apiece
* belonging to chromatin are an example.
* can also serve as short-term carriers of energy
  - join to each other by phosphodiester bonds
* contain organic bases.
* form the basic structural unit of nucleic acids.
* have a nitrogenous base backbone
  - many functions in the cell
  - metabolic functions in cells
  - phosphate, sugar, and a nitrogen base
  - several carbons
* is ester
* only require two phosphorylations.

### nucleotide:

Uracil
* Some uracil replaces thymine.
* lacks the methyl group of thymine.

Nullity
* is acts
  - the beginning of the universe
* restores a couple to the status of never having been married.

### numbers game:

Mail order
* Mail Order is nothing more or less than selling a product or service via advertising by direct mail
  - numbers game
* is only a process by which products are advertised and delivered to consumers
  - order

### numerals:

Arabic numeral
* All Arabic numerals precede all Roman numerals.
* are numerals
  - preferable to Roman numerals
  - to be used for volume, part, and section numbers
* begin with the text itself.
* indicate divisions in sub-headings
  - fretting-hand fingering
* represent intensities at specific locations.

### numerals:

Roman numeral
* Roman Numerals Look up the conversions between American numerals and Roman numerals
  - use a base numbering system with letters
* appear to be a refinement of the tally method still in use today.
* can be cardinal or ordinal according to their position.
* identify digits.
* indicate a chord's fret location
  - the order of members of the individual families
* refer to cranial nerves
  - generations
* refer to the issue number, Arabic, to page number
  - nymph stage
  - volume numbers, while arabic numerals refer to pages
* reflect Mercalli scale of earthquake intensity.
* represent subgroups and Arabic numerals denote series.

Numerous compound
* Most numerous compounds have properties.
* Some numerous compounds affect fate
  - find in fish
* undergo free radical oxidation reactions on exposure to the oxygen in air.