UNIT 1 (topic 1&2) carbohydrates

Question 1

define biological molecules

Answer 1

groups of chemicals that are found in living organisms

Question 2

define monomer

Answer 2

one single unit that are linked to form long chains of polymers by condensation reactions

Question 3

examples of monomers

Answer 3

monosaccharides, amino acids, nucleotides

Question 4

define a polymer

Answer 4

multiple monomers bonded together which breaks down into monomers through hydrolysis reaction

Question 5

define metabolism

Answer 5

the sum of all chemical reactions in the living organism

Question 6

define ionic bonding

Answer 6

the transfer of electrons with electrostatic attraction with the opposite charges

Question 7

define covalent bonding

Answer 7

the sharing of electrons with very strong and stable bonding

Question 8

hydrogen bonding

Answer 8

electrostatic bond between two polar molecules (partially charged)

Question 9

give an example of monosaccharides

Answer 9

glucose, fructose, galactose

Question 10

give an example of polysaccharides

Answer 10

starch, glycogen, cellulose

Question 11

what bond links monosaccharides together

Answer 11

glycosidic bond

Question 12

what monomers are used for maltose

Answer 12

glucose and glucose

Question 13

what monomers are used for sucrose

Answer 13

glucose and fructose

Question 14

what monomers are used for lactose

Answer 14

glucose and galactose

Question 15

what is the difference between alpha and beta glucose

Answer 15

Alpha- hydroxyl group is Above the first carbon
Beta- hydroxyl group Below the first carbon

Question 16

define an isomer

Answer 16

same chemical formula but different layout - glucose

Question 17

where is starch found

Answer 17

in plants as storage for excess glucose

Question 18

what are the two types of starch and what’s the differences

Answer 18

amylose - alpha 1-4 glycosidic bonds
amylopectin - alpha 1-4 and 1-6 glycosidic bonds

Question 19

properties of starch

Answer 19

• insoluble
• cannot leave the cell (usually in the chloroplasts)
• doesn’t effect water potential in the cell
• helical
• compact - lot of storage

Question 20

where is glycogen found

Answer 20

in animals as storage for glucose (energy)

Question 21

what are the benefits of the glycogen’s long branched chains

Answer 21

more access points for glucose to be released FOR RESPIRATION

Question 22

are the properties of glycogen the same as starch

Answer 22

yes

Question 23

where is cellulose found

Answer 23

in plants as structural support in the cell walls

Question 24

what are the properties of cellulose

Answer 24

• polymer of beta-glucose that are inverted every other
• creates long straight unbranched chains
• chains layer on top of each other causing strong microfibrils between the hydrogen bonds
• strong structural support

Question 25

which disaccharide is a NON-reducing sugar

Answer 25

sucrose

Question 26

why are some sugars described as reducing sugar

Answer 26

any sugar that has/ can form an aldehyde group

Question 27

explain the food test for proteins

Answer 27

• add biuret’s solution
• will go from light blue to lilac

Question 28

explain the food test for a reducing sugar

Answer 28

• add benedict’s solution
• HEAT in a water bath
• will go from light blue to a range of green to red (depending on the concentration)

Question 29

explain the food test for starch

Answer 29

• add iodine
• will go from orange to blue/ black

Question 30

explain the food test for lipids

Answer 30

• add ethanol and shake
• AND THEN, add water
• will go from clear to a white milky emulsion

Question 31

explain the food test for a non-reducing sugar

Answer 31

• carry out the benedict’s test first to check
• boil with HCL and neutralise (breaks into the two monomers)
• repeat the benedict’s test