test for carbohydrates

Question 1

reduction

Answer 1

gain of electrons

Question 2

what biomolecules are reducing sugars

Answer 2

all mononsaccharides and some diasaccharides

Question 3

give 2 examples of disaccharide reducing sugars

Answer 3

maltose and lactose

Question 4

reducing sugar

Answer 4

can donate electons/ reduce another molecule/ chemical

Question 5

chemical used

Answer 5

Benedict’s reagent

Question 6

procedure (RS)

Answer 6

place sample in boiling tube
add equal vol of Benedict’s reagent
heat mixture gently in boiling water bah for 5 min

Question 7

suggest what you could do if the sample is not a liquid

Answer 7

grind it up/ blend in water

Question 8

what do reducing sugars react with

Answer 8

copper ions in Benedict’s reagent

Question 9

green

Answer 9

low conc of reducing sugar

Question 10

yellow/amber/orange

Answer 10

medium conc of reducing sugar

Question 11

red

Answer 11

high conc of reducing sugar

Question 12

positive result for reducing sugar

Answer 12

brick red ppt

Question 13

what makes the test qualitative

Answer 13

the more r.sugar present and the less Cu2+ ions left in solution.
colour seen depens on conc of r.sugar

Question 14

what is the most common non-reducing sugar

Answer 14

sucrose

Question 15

procedure (NRS)

Answer 15

sucrose first boiled w/HCl

add NaHCO3

Question 16

why is sodium hydrocarbonate added

Answer 16

to neutralise solution

Question 17

why does adding HCl to sucrose give a positive result

Answer 17

hydrolyse sucrose to glucose and fructose- monodisaccharides, r.sugars

Question 18

what is the iodine test use to detect

Answer 18

presence of starch

Question 19

colour change for iodine test

Answer 19

yellow/brown to blue/black

Question 20

iodine test procedure

Answer 20

add few drops of I2 in KI sol

mix w/sample

Question 21

what do reagent strips test

Answer 21

presence of reducing sugars

Question 22

what do reducing test strips usually test for

Answer 22

glucose

Question 23

advantage of test strips testing for r.sugars

Answer 23

with use of a colour-coded chart, the conc of the sugar can be determined

Question 24

what diease can test strips test for

Answer 24

diabetes

Question 25

state a quantitative method to determine conc

Answer 25

colorimetry

Question 26

colorimter

Answer 26

piece of equip used to quantit meas absobance/ transmission of light by a coloured solution

Question 27

the more conc the sample in the colorimeter is

Answer 27

the more light it will absorb and the less light it will transmit

Question 28

what can colorimeters be used to calculate

Answer 28

conc of reducing sugar present