chapter 1- bio molecules

Question 1

monosaccharide

Answer 1

monomers from which larger carbohydrates are made

Question 2

examples of monosaccharides

Answer 2

-glucose
-galactose
-fructose

Question 3

reducing sugars test

Answer 3

-add 2cm3 of liquid food sample to test tube
-add equal volume of Benedicts reagent
-heat in water bath for 5 mins
-brick red if positive

Question 4

disaccharide

Answer 4

pairs of monosaccharides

Question 5

disaccharide pairs

Answer 5

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

Question 6

bonding between monosaccharides

Answer 6

a condensation reaction occurs to form a glycosidic bond

Question 7

non reducing sugar test

Answer 7

-add 2cm3 of liquid food sample to test tube with equal parts Benedicts reagent
-heat in waterbacth for 5 mins
-add 2cm3 of food sample to 2cm3 of dilute hydrochloric acid
-add sodium hydrocarbonate to neutralize
-heat with 2cm3 of Benedicts reagent
-positive = brick red

Question 8

polysaccharides

Answer 8

polymers formed by combining together many monosaccharides in condensation reactions

Question 9

examples of polysaccharides

Answer 9

-cellulose
-starch

Question 10

test for starch

Answer 10

–2cm3 of food in test tube
-2 drops of iodine+ shake
-blue black = positive

Question 11

starch

Answer 11

made up of chains of alpha glucose monosaccharides-linked by glycosidic bonds

Question 12

starch properties

Answer 12

-insoluble so doesn’t affect water potential
- compact so a lot can be stores in a small space
-highly branched so more enzyme reactions

Question 13

glycogen

Answer 13

found in animals and bacteria- major carbohydrate store

Question 14

glycogen properties

Answer 14

-insoluble so doesn’t diffuse out of cells
-more highly branched than starch
-compact so lots can be stored in a small space

Question 15

cellulose

Answer 15

-made of b glucose
-straight unbranched chains
-hydrogen bonds form cross linkages across the chains

Question 16

cellulose properties

Answer 16

-long,straight unbranched chains
-cross linked adds strength
-grouped to form microfibrils which provides more strength

Question 17

characteristics of lipids

Answer 17

-insoluble in water
-contain carbon,hydrogen,oxygen

Question 18

role of lipids

Answer 18

-source of energy
-insulation
-waterproofing

Question 19

triglycerides

Answer 19

-3 fatty acids, 1 glycerol
-each fatty acid forms an ester bond with glycerol in condensation reactio

Question 20

triglyceride properties

Answer 20

-low mass:energy
-lots of energy can be stored in small volumes
-insoluble in water

Question 21

emulsion test for lipids

Answer 21

-2cm3 of sample add 5cm3 of ethanol
-shake
-add 5cm3 water
-shake
milky white=positive

Question 22

amino acid

Answer 22

basic monomer units which combine to make up a polymer called a polypeptide

Question 23

structure of amino acid

Answer 23

-h-h-o-h
-n-c-c
-h-r-o

Question 24

primary structure

Answer 24

many amino acids join by polypeptide bonds

Question 25

secondary structure

Answer 25

hydrogen bonds from between the polypeptides forming a helices and b pleated Sheets

Question 26

tertiary structure

Answer 26

-disulfide bridges-very. strong
-ionic bonds-easily broken by changes in ph
-hydrogen bonds-easily broken

Question 27

quaternary structure

Answer 27

combination of different polypeptide chains

Question 28

biuret test for proteins

Answer 28

• add equal volume of sodium hydroxide to food
  -add drops of very dilute copper sulfate solution
  -purple=positive