CHO

Question 1

How are cho distributed?

Answer 1

• Carbohydrates are widely distributed in plants and animals where it
  fulfill both structural & metabolic role.

Question 2

How do plants synthetize glucose?

Answer 2

from CO2 & H2O by the process of
photosynthesis and stored it as starch or cellulose in the framework of
the plant

Question 3

What is the formula for photosynthesis?

Answer 3

• H2O+ CO2 = C6H12O6+O2
  by the help of sunlight and chlorophyll

Question 4

How can animals synthesize cho?

Answer 4

from fat and protein,
but the bulk of the animal CHO is derived ultimately from plants.

Question 5

What are carbohydrates in biochemistry?

Answer 5

The term is most common in biochemistry, where it is a synonym
of saccharide which it comes from the Greek word (sákkharon),
meaning “sugar. Carbohydrate is a large biological molecule, or
macromolecule, consisting only of carbon (C), hydrogen (H), and
oxygen (O)

Question 6

How does our body use CHO?

Answer 6

• Your body uses carbohydrates to make glucose which is the
  fuel that gives you energy and helps keep everything going.
  Your body can use glucose immediately or store it in your
  liver and muscles when it is needed.

Question 7

Where can we obtain CHO from?

Answer 7

• Fruits
• Vegetables
• Breads, cereals, and other grains
• Milk and milk products sugar-sweetened
• Foods containing added sugars (e.g., cakes, cookies)

Question 8

How can carbohydrates be defined?

Answer 8

Carbohydrates (CHO) are define as:
polyhydroxy aldehyde or ketone, or the
substances that yield them upon
hydrolysis.

Question 9

How are CHO important?

Answer 9

1-CHO is the major source of energy in most animal tissues (brain, RBCs).
2-Glucose is the most important sugar of the blood.
3- Glucose is the universal fuel of the fetus.
4- Glucose can be converted to the CHO having highly specific function e:g glycogen
for storage ribose in nucleic acids, galactose in lactose of milk, in combination with
protein in glycoprotein and proteoglycan

Question 10

What are some diseases associated with CHO?

Answer 10

DM(diabetes mellitus), galactosemia ,
glycogen storage disease, and lactose intolerance

Question 11

How are CHO classified?

Answer 11

1-Monosaccharides:
Are those sugars that cannot be hydrolyzed into simpler carbohydrates.
2-Disaccharides:
Yield two molecules of monosaccharide when hydrolyzed. examples are maltose , sucrose
&lactose.
3-Oligosaccharides:
Yield three to ten monosaccharide units on hydrolysis .
e:g maltotriose (contain three molecules of glucose) .
4-Polysaccharides:
Yield more than ten molecules of monosaccharides on hydrolysis e:g starch & dextrins.

Question 12

How are monosaccharides subdivided into?

Answer 12

A- Trioses , tetroses , pentoses , hexoses , heptoses or
octoses depending upon the number of carbon atoms
they possess.
B- Aldoses or ketoses depending upon whether aldehyde
or ketone group is present.

Question 13

What is the structure of glucose?

Answer 13

• Glucose exists as a six-carbon linear chain. Apart from this,
  glucose has different structural forms, including linear, cyclic, and
  chair conformations. Glucose is the most common sugar; a
  carbohydrate that can be used by any living organism on Earth

Question 14

What is the structure of fructose?

Answer 14

• Since fructose has a ketone functional group, the ring closure occurs at
  carbon # 2. In the case of fructose a five membered ring is formed. The -
  OH on carbon #5 is converted into the ether linkage to close the ring with
  carbon #2. This makes a 5 member ring - four carbons and one oxygen.

Question 15

What are disaccharides?

Answer 15

• Are formed by covalent bonding between an anomeric
  hydroxyl of a cyclic sugar with a hydroxyl of a second
  sugar.
  the bond is termed glycosidic bonds, the resultant
  molecules are glycosides.
• Several physiogically important disaccharides are
  sucrose, lactose, maltose, Isomaltose,

Question 16

What are glycosidic bonds?

Answer 16

Its covalent bond occur between anomeric
carbon of monosaccaride and other substance
contain OH or N

Question 17

What is a sucrose?

Answer 17

prevalent in
sugar cane and sugar
beets, is composed of
glucose and fructose
through an
α
-(1,2)b
-
glycosidic bond.

Question 18

What is lactose?

Answer 18

is found
exclusively in the milk
of mammals and
consists of galactose
and glucose in a
β
-
(1,4) glycosidic bond

Question 19

What is maltose?

Answer 19

: the major degradation product of
starch, is composed of 2 glucose
monomers in an α-(1,4) glycosidic bond.

Question 20

What do each disaccharide give and are produced by?

Answer 20

• Maltose
• Give Glucose + glucose by maltase enzyme.
• Produced during the germination of seeds and fermentation
• Sucrose
• give Glucose + fructose by sucrase enzyme(invertase) because
  the product of its hydrolysis invert optical activity from dextro
  to levorotatory.
• Refined from sugar cane and sugar beets
• Lactose
• give Glucose + galactose by lactase enzyme
• Found in milk and milk sugar

Question 21

What are oligosaccharides?

Answer 21

produce 2-10 monosaccharide units on hydrolysis
* Usually not found free but in the form of
glycoprotein and glycolipid. few e,g maltotriose
and raffinose.

Question 22

What are polysaccharides?

Answer 22

• Formed of more than 10 sugar units, classified into:
  1. Homopolysaccharides (repeated same sugar)
  include starch, glycogen and cellulose
  2. Heteropolysaccharides (repeated different sugar)
  include glucosaminoglycans, proteoglycans and
  glucoprotein.

Question 23

What are the layer of homopolysaccharides?

Answer 23

1. Inner layer called amylose ,non branching
   linked together by α 1-4 glycosidic bond .
2. outer layer a amylopectin, outer layer linked
   with other layer by α 1-6 glycosidic bond

Question 24

What is starch?

Answer 24

➢Starch is the major form of stored carbohydrate in plant cells.
➢Source: cereals, potatoes, legumes and other vegtables.
➢It consists of two layer: amylose (15-20%) and amylopectin (80-
85%)
* Its structure is identical to glycogen, except for a much lower
degree of branching (every 20-30 residues).
* Give blue color with iodine.

Question 25

What is glycogen?

Answer 25

• Source: storage form of carbohydrate in human and animals.
• It is a homopolymer of glucose in α-(1,4) linkage;
• it is highly branched, with α-(1,6) branch linkages occurring
  every 8-11 residues.
• Glycogen is primarily stored in liver and muscles.

Question 26

What is cellulose?

Answer 26

• Cellulose is a homopolymer of glucose linked by β1-4 glycosidic
  bond
• Source: leafy vegtable, fruits, wood and cotton, etc..
• Give no color with iodine.
• can not be digested by many mammals, including humans, because
  of the absence of hydrolase that attack the β linkage.
• It is an important source of fiber in the diet.