1.2 Carbohydrates

Question 1

what is a carbohydrate made up of?

Answer 1

carbon molecules + water molecules

Question 2

what is a sequence of carbon atoms called and why is it important

Answer 2

a backbone, other atoms can attach allowing a number of different types and sizes of molecule, all carbon based

Question 3

what is an organic molecule

Answer 3

carbon containing molecules

Question 4

3 examples of monomers

Answer 4

monosaccharides, amino acids, nucleotide

Question 5

2 examples of polymers

Answer 5

carbohydrates, proteins

Question 6

what are most polymers based on

Answer 6

CHON

Question 7

what is the basic monomer in carbohydrates

Answer 7

a sugar, (saccharides)

Question 8

3 examples of a monosaccharide

Answer 8

glucose
galactose
fructose

Question 9

are monosaccharides soluble or insoluble

Answer 9

soluble

Question 10

general formula of a monosaccharide

Answer 10

CH20N

Question 11

what are the two isomers of glucose

Answer 11

alpha glucose

beta glucose

Question 12

what are reducing sugars

Answer 12

ALL monosaccharides

SOME disaccharides

Question 13

what is reduction

Answer 13

the chemical reaction involving gain of electrons / hydrogen

Question 14

how do reducing sugars reduce

Answer 14

by donating electrons to another case

Question 15

describe the benedicts test

Answer 15

• add 2cm^3 of food sample to a test tube, if the sample isn’t in liquid form, grind it in water
• add an EQUAL amount of benedicts solution
• HEAT the mixture in gently boiling water for 5 minutes
• is a reducing sugar is present the solution will be ORANGE/BROWN

Question 16

is benedictus solution acidic, neutral or alkaline?

Answer 16

alkaline

Question 17

what happens when a reducing sugar is heating with benedicts solution

Answer 17

benefits solution forms an INSOLUBLE RED precipitate, COPPER (1) OXIDE

Question 18

what actually is benedicts reagent (in chemicals)

Answer 18

COPPER (111) SULFATE

Question 19

what is glucose useful for in cellular respiration

Answer 19

the energy released from glucose helps to make ATP (adenosine triophosphate)

Question 20

what is an isomer

Answer 20

isomers have the same molecular formula but in different molecular arrangements of atoms in space

Question 21

glucose + glucose =

Answer 21

maltose

Question 22

glucose + fructose =

Answer 22

sucrose

Question 23

glucose + galactose =

Answer 23

lactose

Question 24

use of sucrose

Answer 24

common table sugar

Question 25

where is lactose found

Answer 25

in milk, lactose intolerance is where the body is unable to digest lactose

Question 26

polysaccharides are made out of what type of BONDS

Answer 26

glycosidic

Question 27

4 examples of polysaccharides

Answer 27

starch, glycogen, cellulose, chitin

Question 28

3 examples of disaccharides

Answer 28

maltose, sucrose, lactose

Question 29

what colour is benedicts solution to begin with, and what colour does it turn if a reducing sugar is PRESENT

Answer 29

begin- clear/blue

present- orange/brown

Question 30

what do these colour solution mean about benedicts test?
blue solution 
yellow/green precipitate 
orange/red precipitate
brick red precipitate

Answer 30

blue solution: no reducing sugar
yellow/green precipitate: traces of reducing sugars
orange/brown precipitate: moderate amount of reducing sugars present
brick red precipitate: large amount of reducing sugars present

Question 31

how do you test for NON reducing sugars

Answer 31

• boil in dilute HCL (to hydrolyse the non-reducing sugar)
• neutralise the solution by adding sodium hydrogen carbonate
• repeat benedicts test

Question 32

why do you add HCL in testing for NON reducing sugars

Answer 32

to hydrolyse the non reducing sugar

Question 33

is sucrose a reducing or non-reducing sugar

Answer 33

sucrose is a non rescuing sugar

Question 34

glucose + _ = lactose

Answer 34

galactose