Biochemistry/Organic Flashcards
What makes water dipolar?
The electrons collect in the oxygen molecule, giving it a delta negative charge. The hydrogen is delta positively charge and is attracted to the oxygen. Due to both positively and negatively charged areas, water is dipolar.
What bonds are present between water molecules and what causes them to form?
All water molecules attract to each other to form hydrogen bonds. This is a result of the uneven distribution of charge, causing the adjacent molecules to become attracted to each other.
What is the difference between hydrophilic and hydrophobic molecules?
Polar substances which disassociae in water are said to be hydrophilic. Non- polar substances are repelled by water and group together in its presence, making them hydrophobic.
What are the thermal properties of water?
Individual hydrogen bonds are weak however collectively they make water very stable.
What relevance does a high specific heat capacity in water have to life?
Water is able to provide a constant temperature within aquatic environments, providing a stable environment for enzymes to work within organisms.
Why is the latent heat of vaporisation in water high?
This is very high in water due to the hydrogen bonding within the molecules. These bonds require a lot of energy o overcome and break apart.
Why does the density of water lead to the formation of surface ice?
Each molecule in ice is hydrogen bonded to 4 neighbours in a 3D crystal. This makes ice less dense than the water, causing it to float - due to the hydrogen bonds in solid ice being slightly further apart than they would be in liquid state.
What relevance does the density of water have to do with the survival of organisms?
Surface ice acts as an insulator, allowing aquatic organisms to live and move in the water below. The temperature gradient causes the circulation of nutriens.
What is the difference between condensation and hydrolysis reactions?
Condensation reactions link monomers together, releasing water. A hydrolysis reaction breaks up polymers into monomers, water is required for this reaction.
What are monosaccharides and what are examples of them?
Monosaccharides are simple sugar molecules. Examples of these include glucose, fructose and galactose.
What are some properties of monosaccharides?
They are soluble in water - this is because they contain many hydroxyl groups, which form hydrogen bonds with water molecules (hydrophillic).
They can be chemically join to form larger carbohydrates such as disaccharides and polysaccharides.
How are disaccharides formed?
They are formed by condensation reactions, producing water molecules when made. The hydrogen and hydroxyl groups form together, forming a 1,4 glycosidic bond. Adding water breaks this bond, converting it back into a monosaccharide through hydrolysis.
How is sucrose made?
Glucose + fructose
How is lactose made?
Glucose + galactose
How is maltose made?
Alpha glucose + alpha glucose
