Lecture 2 Flashcards
What is an atom?
Smallest unit of matter to take part in chemical reactions
What is an element?
Composed of one type of atom
Ex. C, H, O
What is a molecule?
When two or more atoms join together
Ex. O2, H2O, C6H12O6
What is the structure of atoms?
Centred local nucleus that contains protons and neutrons
Electrons exist outside of the nucleus called orbitals
What charge does the nucleus carry?
A net positive charge
Why is the nucleus considered stable?
Nuclear contents do not participate in chemical reactions
What is an ion?
When an atom has an overall positive/ negative charge it is no linger neutral
Examples of molecule vs anion vs ion
O2
O2-
Ca2+
What is the goal of every atom?
To achieve chemical stability by filling their outermost shell with electrons
How many electrons makes a full shell?
8
What are the 3 types of chemical bonds in living systems?
Covalent, ionic and hydrogen bonds
What are the characteristics of covalent bonds?
Very strong
Sharing outer electron
What are the characteristics of ionic bonds?
Attracted to ions of opposite charge ( + to - / - to + ) which holds atoms together
Gives electron away
Weaker than covalent bonds
Ex. Na wants to give electron away to Cl but is still pulled into Cl strong negative pull
What are the characteristics of hydrogen bonds?
Connects H2O and H2O molecules ( or DNA)
Very weak
Some are polar molecules and some are not
H2O causes partial charges (polar) due to the greater O attraction to the electron
What atom do organic compounds contain?
Carbon. Inorganic do not contain carbon
How much of water composes the weight of a cell?
60 - 80%
75%*
What characteristics does water have when mixed with other materials?
It is a polar solvent
Successfully breaks apart ions by surrounding negative ion with the partial positive H2O region/ positive ion with partial negative H2O region to make a solution
Can make 4 hydrogen bonds with other water molecules
Temperature buffer with strong hydrogen bonds
H2O -> H + OH easy split important for chemical reactions
What are the 4 major classes of organic compounds in living things?
Carbohydrates
Proteins
Lipids
Nucleic acids
Characteristics of carbohydrates
Sugar
Easily accessible energy source
3 major groups of carbs
What elements do carbohydrates contain?
C, H, O
What are the 3 major groups of carbohydrates?
Monosaccharides - one sugar group (glucose, fructose, galactose)
Disaccharides - two monosaccharides together (glucose + fructose = sucrose)
Polysaccharides - hundreds monosaccharides together too large to be water soluble (starch, cellulose)
Characteristics of lipids
Contains fats, complex, lipids and steroids
Essential structure and function of membranes
Energy storage (takes time to get)
Non polar and hydrophobic
3 types of fats
What are the 3 fats?
Monoglycerides - glycerol + one fatty acid
Diglycerides - glycerol + 2 fatty acid
Triglycerides - glycerol + 3 fatty acid
What are the types of fatty acid?
Saturated - no double bonds, popular with hydrogens
Unsaturated - at least 1 double bond, less hydrogen bond popular
