monomers, polymers + carbohydrates

Question 1

what are monomers

Answer 1

small, repeating molecules from which larger molecules/polymers are made

Question 2

what is a polymer

Answer 2

molecule made up of many identical monomers

Question 3

condensation reaction

Answer 3

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

Question 4

hydrolysis reaction

Answer 4

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

Question 5

give examples of polymers and the monomers from which they are made

Answer 5

Question 6

what are monosaccharides and give 3 common examples

Answer 6

-monomers from which larger carbohydrates are made
-e.g. glucose, fructose and galactose

Question 7

structure of α-glucose

Answer 7

Question 8

describe the difference between the structure of α-glucose and β-glucose

Answer 8

they are isomers
-OH group is below carbon 1 in alpha glucose but above carbon 1 in beta glucose

Question 9

what are isomers

Answer 9

same molecular formula but differently arranged atoms

Question 10

what are disaccharides and how are they formed

Answer 10

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

Question 11

list 3 common disaccharides and the monosaccharides from which they are made

Answer 11

maltose= glucose + glucose
sucrose= glucose + fructose
lactose= glucose + galactose

Question 12

what are polysaccharides and how are they formed

Answer 12

polysaccharides are many monosaccharides joined together with glycosidic bonds
-formed by many condensation reactions, releasing water molecules

Question 13

describe the basic function and structure of starch

Answer 13

function- energy store in plant cells
structure- polysaccharide of alpha glucose
-amylose contains 1-4 glycosidic bonds and is unbranched
-amylopectin contains 1-4 and 1-6 glycosidic bonds and is branched

Question 14

describe the basic structure and function of glycogen

Answer 14

function- energy storage in animal cells
structure- polysaccharide made of alpha glucose, containing 1-4 and 1-6 glycosidic bonds causing it to be a branched structure

Question 15

explain how the structure of starch (amylose) relates to its function

Answer 15

(amylose)
-helical so is compact for storage in the cell
-large, insoluble polysaccharide molecule so cannot leave the cell/cross the cell surface membrane
-insoluble in water, therefore the water potential of the cell is not affected (no osmotic effect)

Question 16

explain how the structure of glycogen (+ amylopectin) relates to its function

Answer 16

-branched structure so more compact, allowing more molecules to fit in a small area
-branched, meaning more ends are available for faster hydrolysis which releases glucose for respiration to make ATP for energy release
-large, insoluble polysaccharide molecule meaning it cant leave the cell/cross the cell surface membrane
-insoluble in water, therefore water potential of the cell is unaffected (no osmotic effect)

Question 17

describe the basic function and structure of cellulose

Answer 17

function- provides strength and structural support to plant/algal cell walls
structure- polysaccharide of beta glucose, contains 1-4 glycosidic bonds forming straight, unbranched chains that are linked in by hydrogen bonds forming microfibrils

Question 18

explain how the structure of cellulose relates to its function

Answer 18

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

Question 19

examples of reducing sugars

Answer 19

monosaccharides, maltose, lactose

Question 20

describe the test for reducing sugars

Answer 20

1. add benedicts solution (blue) to sample
   -heat in a boiling water bath
   -positive result= green/yellow/orange/red precipitate

Question 21

example of non reducing sugar

Answer 21

sucrose

Question 22

describe the test for non reducing sugars

Answer 22

-do benedicts test and stays blue/negative
-heat in a boiling water bath with acid (to hydrolyse into reducing sugars)
-neutralise with alkali
-heat in a boiling water bath with benedicts solution
-positive result= green/yellow/orange/red precipitate

Question 23

suggest a method to measure the quantity of sugar in a solution

Answer 23

-carry out benedicts test, then filter and dry precipitate
-find mass/weight

Question 24

describe the biochemical test for starch

Answer 24

-add iodine dissolved in potassium iodine (orange/brown) and shake/stir
-positive result= blue-black