Zellbiologie

Oppositely charged ions (usually a metal and a non-metal) form ionic bonds in order to achieve a
stable outer shell. These bonds are very strong in the absence of water or other polar solvents.

Metals
 

• Easily lose their electrons
• End up as cations
• Empty valence

Nonmetals

• Want to gain electrons
• End up as anions
• Full valence

Two or more atoms come very close together and share one or more electrons, which defines
spatial arrangement and three-dimensional structure. Double (or triple) bonds change the geometry and inhibit
free rotation

Hydrogen Bonds: Occur between molecules with partial positive or negative charges with a differential electron
distribution between the atoms (polar molecules).

Monosaccharides: They have a general formula of (CH 2 O)n where n is between 3 and 6. They consist of 2 or
more OH groups and are called aldose if they contain an aldehyde group and ketose, if they contain a ketone
group.

• containing aldehyde group: aldose
• containing ketone group: ketose
• ring formation in aqueous solution

Isomers: Same chemical formula, different structure.

Di-/Polysaccharides: Consist of two or several monosaccharides, which are linked together. The linkage is
“produced” by a condensation reaction and destroyed by hydrolysis.

Cellulose: The major structural component of plants. It is a long polymer made of cellobiose (a disaccharide
made of two glucose molecules). Humans can’t digest cellulose because we don’t have the enzyme cellulase.

cellobiose: glucose-β-1,4-glucose

Lactose: It is made up of galactose linked to glucose. The galactose can be converted to glucose by the human
body only if the enzyme lactase is present.

lactose: galactose β 1,4 glucose