- Created by: mxllyxsmithhh
- Created on: 06-11-19 14:13
Properties of water
- Water is a dipolar molecule
- Hydrogen bonds form between the oxygen of one water molecule and the hydrogen of another.
-The slightly negatively charged oxygen and slightly positively charged hydrogen are joined by the hydrogen bonds.
- Water molecules therefore tend to be attracted to each other by hydrogen bonds and this attraction is called Cohesion.
-Cohesion is responsible for surface tension which helps organisms in following ways:
1. Enables aquatic insects to walk on water e.g. Skaters
2. It aids capillarity in the xylem vessel
-Surface tension occurs when water molecules are attracted to each other but not attracted to different molecules, surfaces or air.
-Water requires lots of energy to break the hydrogen bonds. This is why water has such high melting and boiling points.
- Contain carbon, hydrogen and oxygen
-They are largest group of organic componds in living organisms
-Groups of carbohydrates
Monosaccharides- simple sugars
Disaccharides- double sugars
Polysaccharides- complex sugars
- General formula of (CH2O)n.
-Glucose is the most common monosaccharide and there are two forms we need to know: Alpha glucose and Beta glucose
- They are isomers so they have same chemical formula but different properties
-Hexoses - C6H12O6
-They are single units
-They are soluble in water
-They lack glycosidic bonds
- Two monosaccharides joined by condensation reaction where water is given out.
-The monosaccharide are joined by covalent bonds called glycosidic bonds
-The general formula is (C5H10O5)n
Maltose - Alpha glucose + Alpha glucose
Sucrose - Alpha glucose + Fructose
Lactose - Alpha glucose + Galactose
- Condensation reaction join together (H2O released)
-Hydrolysis reactions split apart (H2O issued)