Biology 2.1.2

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  • Created by: LivviR123
  • Created on: 25-10-16 14:03

CARBOHYDRATES- carbon, hydrogen, oxygen (usually in the ratio Cx(H2O)x

LIPIDS- carbon, hydrogen, oxygen

PROTEINS- carbon, oxygen, hydrogen, nitrogen and sulfur

NUCLEIC ACIDS- carbon, hydrogen, oxygen, nitrogen and phosphorus

Biological molecules are often polymers, polymers are long chain molecules made from monomers in a repeating pattern. In carbs, the monomers are sugars (saccharides) and in proteins the monomers are amino acids

Water

  • Polar molecules- regions of positivity and regions of negativity
  • Polar molecules interact with eachother as the positive and negative regions attract each other and form hydrogen bonds, hydrogen bonds are weak, but occur in large numbers
  • Relatively high boiling point as the hydrogen bonding means it takes more nergy to break the water molecules apart
  • Ice is less dense than water because the hydrogen bonds fix slightly further apart than the average distance in liquid state, producing a giant, open and rigid structure with every oxygen at the centre of a tetrahedral arrangement of hydrogen aroms.
  • Water is cohesive, it moves as one mass because the molecules are attracted to one another
  • Water is adhesive and attracted to other molecules
  • Solvent- because it is polar. Many of the solutes in an organism can be dissolved, the cytosol of prokaryotes and eukaryotes is mainly water. Many solutes are also polar molecules, amino acids, proteins and nucleic acids. Water acts as a medium for chemical reactions and also helps transport dissolved compounds in and out of cells.
  • Capillary action- the process by which water can rise up a narrow tube against the fore of gravity
  • Coolant- helps buffer changesduring chemical reactions in prokaryotic and eukaryotic cells because of the large amount of energy needed to overcome hydrogen bodning- important bc enzymes are usually only active within a certain range.
  • Stable- does not become gaseous or change temp easily, providing a constant environment. Ice forms an insulating layer which keeps temps stable in colder months.
  • Surface tension is strong enough to support small insects such as pond skaters.

Carbohydrates- molecules that only contain carbon, hydrogen and oxygen (Cx(H2O)y. Also known as saccharides/sugars. Single sugar is monosccharide e.g. glucose, fructose and ribose, two monosaccharides make a disaccharide and more than two is a polysaccharide e.g. glycogen, cellulose and starch.

Glucose C6H12O6- a hexose monosaccharide, there are two variates alpha (OH bottom) and beta (OH top). Glucose molecules are polar and soluble in water due to the hydrogen bonds that form between the hydroxyl groups and water molecules, as it is soluble, it can be dissolved in the cytosol of the cell. 

Condensation reaction: reaction between two molecules resulting in the formation of a larger molecule and the release of a water molecule.

When a condensation reaction occurs betweem two alpha glucose molecules (the hydorxul groups interact), two hydrogen atoms and one oxygen atom is removed from the glucose monomers and join to make a new molecules, a glycosidic (type of covalent) bond forms between carbons 1 and 4

  • Fructose + galactose -> sucrose
  • Galactose +glucose -> lactose
  • glucose + glucose -> maltose
  • Ribose is…

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