Biochemistry Flashcards
What is an aqueous solution?
All solutions where water is a solvent
How is water a polar molecule?
The covalent bonds between the oxygen and the two hydrogens bond in a way so that the hydrogens are not as far apart from each other as possible. The hydrogens are relatively close together and this causes the side with the hydrogens to obtain a positive charge. The opposite side (with the oxygen) will then result in becoming negatively charged
What is cohesion?
-Molecules of the same type are attracted to each other
-The positive side of one oxygen molecule is attracted to the negative side of another oxygen molecule (this is a hydrogen bond)
EXAMPLES:
-water droplets
-surface tension (insects)
-able to move as a water “column” in vascular tissues of plants
What is adhesion?
Attraction between two unlike molecules. Hydrogen bonds cause water molecules to be attracted to cellulose molecules
What is one example of cohesion and adhesion working together?
The column of water in plants.
The column is pulled up by cohesion and adhesion keeps the water from falling down again
How are water’s thermal properties important?
- Water has a high specific heat meaning that water can absorb or give off a lot of heat without changing it’s temperature too much this causes the temperature to be quite stable
- Another property is high heat of vaporization, water absorbs a lot of heat when it evaporates, good for cooling mechanism
What kind of molecules can water dissolve?
Water is a good solvent for other polar molecules including carbohydrates, proteins and nucleic acids (DNA and RNA)
List some properties of water
-Polar molecule
-Able to form hydrogen bonds
^Cohesion
^Adhesion
-Good solvent
-High specific heat
-High evaporation temperature
-Good for transport
What is a different name for polar molecules (referring to as to whether or not the substance can be dissolved in water)?
Hydrophilic
Give an example of a hydrophilic substance
Carbohydrates
Give an example of a hydrophobic substance
Long chains of hydrocarbons => fatty acids in triglyceride lipids and phospholipids
What are the monomers of carbohydrates?
Monosaccharides
How do monosaccharides form larger sugars?
Two glucose molecules undergo a condensation reaction resulting in a water molecule and a maltose molecule where the glucose molecules have joined by a 1-4 glycosidic bond
What are some examples of carbohydrates?
Monosaccharides: -glucose -fructose -galactose Disaccharides: -maltose -sucrose -lactose Polysaccharides: -cellulose -starch -glycogen
Why do plants need cellulose?
- Major component of cell wall
- Rigidity/support to stems, leaves