Concepts Flashcards
1
Q
the four elements that account for about 96 percent of the weight of a living cell.
A
oxygen, carbon hydrogen, and nitrogen
2
Q
contains two or more atoms linked through covalent bonds
A
molecules
3
Q
in a covalent bond two atoms share a pair of
A
electrons
4
Q
water molecules associate with each other through weak attractions known as
A
hydrogen bonds
5
Q
A chemical reaction occurs when…
A
bonds between atoms are formed or broken
6
Q
An acid
A
releases hydrogen ions
7
Q
A base
A
accepts hydrogen ions
8
Q
the four main classes of molecules that are common to all living organisms are…
A
carbohydrate, proteins, lipids and nucleic acids.
9
Q
life on earth is based on
A
carbon
