carbohydrates-lqc 8a

Question 1

formula of monosaccharide

Answer 1

CnH2nOn

Question 2

State two structural differences between a monosaccharide and a disaccharide.

Answer 2

• A monosaccharide is a single sugar unit, a disaccharide is a double sugar unit, made of two monosaccharides joined in a condensation reaction
• A monosaccharide contains NO glycosidic bonds, a disaccharide contains ONE glycosidic bond

Question 3

condensation reaction

Answer 3

• Joining of monomers or smaller molecules to make a larger molecule
• Water is removed and produced
• A bond is formed

Question 4

hydrolysis reaction

Answer 4

• Splitting/ breaking down of polymers or large molecule into smaller molecules / monomers
• Water is added
• A bond is broken

Question 5

hexose sugar

Answer 5

Six carbon sugar

Question 6

function of glucose

Answer 6

• Immediate energy source. Energy is released in the process of respiration in the cell.
• Many of these monosaccharides can be joined to form starch,
  the energy storage molecule in plants.
• Many of these monosaccharides can be joined to form glycogen, the energy storage molecule in animals.

Question 7

function of galactose

Answer 7

A component of the disaccharide lactose, which is found in milk

Question 8

function of fructose

Answer 8

Very sweet sugar which attracts animals to eat the fruit and therefore helps seed dispersal

Question 9

How does the structure of glucose relate to its function?

Answer 9

• Small – does not need to be hydrolysed, so can be quickly and easily absorbed into blood and diffuse into cells
• Soluble - polar molecule with hydrophilic OH groups on the outside – these can form hydrogen bonds with water making glucose soluble in water so it dissolves in blood for transport
• Carried to tissues eg. muscle - quickly absorbed into cells (and can be immediately used for respiration to release energy)

Question 10

glucose + glucose =

Answer 10

maltose

Question 11

glucose + fructose =

Answer 11

sucrose

Question 12

glucose + galactose =

Answer 12

lactose

Question 13

function of maltose

Answer 13

Found in germinating seeds (when starch is broken down by the enzyme amylase)

Question 14

function of sucrose

Answer 14

Used for transporting energy in plants
(transport sugar in phloem)

Question 15

function of lactose

Answer 15

Sugar in milk – for energy