CARBOHYDRATES

Question 1

occur in all plants and animals and are essential to life.

Answer 1

Carbohydrates

Question 2

Through ______, plants convert atmospheric carbon dioxide to carbohydrates, mainly cellulose, starch, and sugars.

Answer 2

photosynthesis

Question 3

is the building block of rigid cell walls and woody tissues in plants, whereas starch is the
chief storage form of carbohydrates for later use as a food or energy source.

Answer 3

Cellulose

Question 4

Two other sugars,________, are
components of the genetic materials RNA and DNA.

Answer 4

ribose and 2-deoxyribose

Question 5

True or False

Other carbohydrates are important components of coenzymes, antibiotics, cartilage, the shells of crustaceans, bacterial cell walls, and mammalian cell
membranes

Answer 5

True

Question 6

Almost __ of dry plant material is
produced by photosynthesis

Answer 6

75%

Question 7

Most of the matter in plants, except
_____, are carbohydrate material

Answer 7

water

Question 8

____are the major source of carbohydrates and average of human
diet contains 2/3 of carbohydrates

Answer 8

Plant products

Question 9

What is the recommended carbohydrates percentage

Answer 9

60%

Question 10

The word carbohydrate arose because
molecular formulas of these compounds
can be expressed as _____.

Answer 10

hydrates of carbon

Question 11

____, for example, has the molecular
formula C6H12O6, which might be
written as C6(H2O)6.

Answer 11

Glucose

Question 12

We can now define carbohydrates more
precisely in terms of their ___.

Answer 12

organic
structures

Question 13

Carbohydrates are polyhydroxyaldehydes,
polyhydroxyketones, or substances that
give such compounds on ____.

Answer 13

hydrolysis

Question 14

The chemistry of carbohydrates is mainly the combined chemistry of two functional groups:

Answer 14

the hydroxyl group & the carbonyl group.

Question 15

Carbohydrates are usually classified according to their structure as
monosaccharides, oligosaccharides, or
polysaccharides.

The term saccharide comes from Latin ____ and refers to the sweet taste of some simple carbohydrates.

Answer 15

saccharum

Question 16

The three classes of carbohydrates are related to each other through ___

Answer 16

hydrolysis

Question 17

Functional groups of monosaccharides

Answer 17

Aldose
Ketose

Question 18

Example of aldose

Answer 18

Glucose

Question 19

Example of ketose

Answer 19

Fructose

Question 20

Categories in the oligosaccharide

Answer 20

Disaccharide
Trisaccharide
Tetrasaccharide

Question 21

Example of disaccharide

Answer 21

Maltose
Lactose
Sucrose

Question 22

Example of trisaccharide

Answer 22

Raffinose

Question 23

Example of tetrasaccharide

Answer 23

Stachyose

Question 24

Categories of polysaccharide

Answer 24

Homopolysaccharide
Hetropolysaccharide

Question 25

Examples of Homopolysaccharide

Answer 25

Starch Dextrin Glycogen Cellulose Insulin

Question 26

Examples of Hetropolysaccharide

Answer 26

Hyaluronic acid Heparin Chondroitin Sulfate Dermatan sulfate Keratan sulfate

Question 27

These are crystalline compounds, soluble in water, sweet to taste, and needs digestion in order to be absorbed into the blood stream

Answer 27

Monosaccharides

Question 28

(or simple sugars, as they are sometimes called) are carbohydrates that cannot be hydrolyzed to simpler compounds.

Answer 28

Monosaccharides

Question 29

These are crystalline, water-soluble, sweet to tase, and must be digested to monosaccharides before they can be absorbed and used for energy

Answer 29

DISACCHARIDES

Question 30

These are not water soluble and are not crystalline. They form colloidal suspensions instead of solutions. They are not sweet and must be digested before being absorbed

Answer 30

POLYSACCHARIDES

Question 31

contain many monosaccharide units— sometimes hundreds or even thousands. Usually, but not always, the units are identical.

Answer 31

Polysaccharides

Question 32

Two of the most important polysaccharides, _____, contain linked units of the same monosaccharide, glucose

Answer 32

starch and cellulose

Question 33

(from the Greek oligos, few) contain at least two and generally no more than a few linked monosaccharide units.

Answer 33

OLIGOSACCHARIDES

Question 34

general test for carbohydrates this test is given by almost all of the carbohydrates

Answer 34

MOLISCH’S TEST

Question 35

In this test, concentrated sulfuric acid converts the given carbohydrate into furfural or its derivatives, which react with α-naphthol to form a purple coloured product.

Answer 35

MOLISCH’S TEST

Question 36

The appearance of purple or violet ring confirms the ____.

Answer 36

presence of carbohydrate

Question 37

This test is given by reducing sugars. To the aqueous solution of carbohydrate ___ solution is added and heated in water bath.

Answer 37

Fehling’s Test

Question 38

Fehling’s test The formation of red precipitate confirms the presence of ____.

Answer 38

reducing sugars

Question 39

The copper ions present in fehling’s solution in +3 state is reduced to +2 oxidation state and in alkaline medium it is precipitated as ___.

Answer 39

red cuprous oxide

Question 40

Fehling’s test The appearance of ____ confirms the presence of carbohydrates.

Answer 40

red precipitate

Question 41

This test is given by reducing sugars. In an alkaline medium, sodium carbonate converts glucose to enediol and this enediol reduces cupric to cuprous forming ____.

Answer 41

BENEDICT’S TEST Na2CO3 -> Glucose -> enediol —cuprous hydroxide

Question 42

BENEDICT’S TEST This solution is kept in ____ and on boiling, red precipitate of cuprous oxide is formed.

Answer 42

sodium citrate

Question 43

This test is given by reducing sugars. Carbohydrates react with Tollens reagent and forms a silver mirror on the inner walls of the test tube. This confirms the presence of reducing sugars. Silver ions are reduced to ___

Answer 43

TOLLEN’S TEST metallic silver

Question 44

TOLLEN’S TEST The appearance of ____ confirms the presence of reducing sugars.

Answer 44

silver mirror

Question 45

This test is only given by starch.

Answer 45

IODINE TEST

Question 46

Starch reacts with iodine solution forms complex ___ colour solution. On heating, the ___ colour disappears and on cooling the ___ colour reappears. Note: The appearance of ___ colour solution confirms the presence of starch

Answer 46

blue

Question 47

Most monosaccharides have a sweet taste ( ____is sweetest; 73% sweeter than sucrose) - they are solids at room temp - they are extremely soluble in water

Answer 47

fructose