biological molecules (carbs + water) DIRT

Question 1

state a fact about polysaccharides of glucose

Answer 1

glycogen has a high proportion of 1-6 glycosidic bonds to produce a highly branched molecule for a rapid release of alpha glucose

Question 2

which ion is required for the hydrolysis of starch by an enzyme

Answer 2

Cl- (chlorine -ve)

Question 3

describe the molecular structure of glucose

Answer 3

• contains hydrogen
• contains oxygen
• contains a hydroxyl group

Question 4

why does ice produce a good habitat for organisms

Answer 4

• extremely high specific heat capacity meaning it requires large amounts of energy to increase its temperature, making it a constant environment
• when water freezes the structure changes, making ice less dense allowing ice to float on the surface insulating the water below meaning organisms can survive during extremely cold conditions
• water is a polar molecule allows it to act as a solvent so many solutes can freely dissolve into it providing essential compounds and molecules for aquatic life’s metabolic processes
• molecules of water have cohesive properties due to its hydrogen bonds, making it move as one mass. There is stronger cohesion between water molecules than there is between water and the air. This creates surface tension allowing small insects to inhabit the surface

Question 5

what makes glucose soluble

Question 6

how is cellulose synthesised

Answer 6

• Cellulose is a polysaccharide found in plants
• It consists of long chains of β-glucose joined together by 1,4 glycosidic bonds
  β-glucose is an isomer of α-glucose, so in order to form the 1,4 glycosidic bonds consecutive β-glucose molecules must be rotated 180° to each other
• Due to the inversion of the β-glucose molecules, many hydrogen bonds form between the long chains giving cellulose its strength

Question 7

what is the covalent bond called that forms in the synthesis of maltose

Answer 7

alpha (1-4 glycosidic bond)

Question 8

describe the structure of cellulose? how is it similar to chitin?

Answer 8

• It consists of long chains of β-glucose joined together by 1,4 glycosidic bonds

-β-glucose is an isomer of α-glucose, so in order to form the 1,4 glycosidic bonds consecutive β-glucose molecules must be rotated 180° to each other

• Chitin has the same structure as cellulose except that it is composed of N-acetylglucosamine, an amide derivative of D-glucose, in place of D-glucose in cellulose

Question 9

roles of hydrogen ions

Answer 9

• The concentration of H+ in a solution determines the pH - The more H+ ions present, the lower the pH (the more acidic the solution)
• The concentration of H+ is therefore very important for enzyme-controlled reactions, which are all affected by pH

Question 10

roles of sodium ions

Answer 10

• Na+ is required for the transport of glucose and amino acids across cell-surface membranes (e.g. in the small intestine)
• Na+ is also required for the transmission of nerve impulses

Question 11

what is the name of the monomer in maltose

Answer 11

alpha glucose

Question 12

how do the branches of glycogen make it a good energy storage molecule in animals?

Answer 12

• allows for quick and efficient storage and release of glucose
• glycogen can be broken down rapidly when energy is needed, providing a quick source of energy for the body