Carbohydrates

Question 1

what are monomers

Answer 1

-smaller, repeating molecules / units from which larger molecules / polymers are made

Question 2

what are polymers

Answer 2

-molecules made from many (a large number) identical / similar monomer molecules

Question 3

what happens in a condensation reaction

Answer 3

• 2 molecules join together
• forming a chemical bond
• releasing a water molecule

Question 4

what happens in a hydrolysis reaction

Answer 4

• 2 molecules separated
• breaking a chemical bond
• using a water molecule

Question 5

examples of monomers

Answer 5

-nucleotides
-monosaccharides eg glucose
-amino acid

Question 6

example of polymers

Answer 6

-polynucleotides (dna/rna)
-polysaccharides (starch)
-polypeptides (protein)

Question 7

what are monosaccharides

Answer 7

• monomers from which larger carbohydrates are made
• glucose, fructose, galactose

Question 8

describe the structure of alpha glucose

Answer 8

-on the right,
-H on the top and OH on the bottom

Question 9

describe the difference between the structure of alpha glucose and beta glucose

Answer 9

• isomers - same molecular formula but differently arranged atoms
  -OH group is below carbon 1 in α-glucose but above carbon 1 in β-glucose

Question 10

what are disaccharides and how are they formed

Answer 10

• two monosaccharides joined together with a glycosidic bond
• formed by a condensation reaction, releasing a water molecule

Question 11

list 3 common disaccharides

Answer 11

-maltose
-sucrose
-lactose

Question 12

monosaccharides that make up maltose

Answer 12

glucose + glucose

Question 13

monosaccharides that make up sucrose

Answer 13

glucose + fructose

Question 14

monosaccharides that make up lactose

Answer 14

glucose + galactose

Question 15

what are polysaccharides and how are they formed

Answer 15

• many monosaccharides joined together with glycosidic bonds
• formed by many condensation reactions, releasing many water molecules

Question 16

function of starch

Answer 16

-energy store in plant cells

Question 17

structure of starch

Answer 17

• polysaccharide of α-glucose
• some has 1,4-glycosidic bonds so is unbranched (amylose)
• some has 1,4- and 1,6 glycosidic bonds so is branched (amylopectin)

Question 18

function of glycogen

Answer 18

-energy store in
animal cells

Question 19

structure of glycogen

Answer 19

-polysaccharide made of α-glucose
-1,4- and 1,6-glycosidic bonds → branched

Question 20

explain how the structure of starch relates to its function

Answer 20

• helical → compact for storage in cell
• large, insoluble polysaccharide molecule → can’t leave cell / cross cell membrane
• insoluble in water → water potential of cell not affected (no osmotic effect)

Question 21

explain how the structure of glycogen relates to its function

Answer 21

• branched → compact / fit more molecules in small area
• branched → more ends for faster hydrolysis → release glucose for respiration to
  make ATP for energy release
• large, insoluble polysaccharide molecule → can’t leave cell / cross cell membrane
• insoluble in water → water potential of cell not affected (no osmotic effect)

Question 22

describe the function of cellulose

Answer 22

• provides strength and structural support to plant / algal cell walls

Question 23

describe the structure of cellulose

Answer 23

• polysaccharide of β-glucose
• 1,4-glycosidic bonds so forms straight, unbranched chains
• chains linked in parallel by hydrogen bonds, forming microfibrils

Question 24

explain how the structure of cellulose relates to its function

Answer 24

• every other β-glucose molecule is inverted in a
  long, straight, unbranched chain
• many hydrogen bonds link parallel strands
  (crosslinks) to form microfibrils (strong fibres)
• hydrogen bonds are strong in high numbers
• so provides strength to plant cell walls