CHO Flashcards
How are cho distributed?
- Carbohydrates are widely distributed in plants and animals where it
fulfill both structural & metabolic role.
How do plants synthetize glucose?
from CO2 & H2O by the process of
photosynthesis and stored it as starch or cellulose in the framework of
the plant
What is the formula for photosynthesis?
- H2O+ CO2 = C6H12O6+O2
by the help of sunlight and chlorophyll
How can animals synthesize cho?
from fat and protein,
but the bulk of the animal CHO is derived ultimately from plants.
What are carbohydrates in biochemistry?
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)
How does our body use CHO?
- 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.
Where can we obtain CHO from?
- Fruits
- Vegetables
- Breads, cereals, and other grains
- Milk and milk products sugar-sweetened
- Foods containing added sugars (e.g., cakes, cookies)
How can carbohydrates be defined?
Carbohydrates (CHO) are define as:
polyhydroxy aldehyde or ketone, or the
substances that yield them upon
hydrolysis.
How are CHO important?
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
What are some diseases associated with CHO?
DM(diabetes mellitus), galactosemia ,
glycogen storage disease, and lactose intolerance
How are CHO classified?
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.
How are monosaccharides subdivided into?
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.
What is the structure of glucose?
- 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
What is the structure of fructose?
- 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.
What are disaccharides?
- 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,
What are glycosidic bonds?
Its covalent bond occur between anomeric
carbon of monosaccaride and other substance
contain OH or N
What is a sucrose?
prevalent in
sugar cane and sugar
beets, is composed of
glucose and fructose
through an
α
-(1,2)b
-
glycosidic bond.
What is lactose?
is found
exclusively in the milk
of mammals and
consists of galactose
and glucose in a
β
-
(1,4) glycosidic bond
What is maltose?
: the major degradation product of
starch, is composed of 2 glucose
monomers in an α-(1,4) glycosidic bond.
What do each disaccharide give and are produced by?
- 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
What are oligosaccharides?
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.
What are polysaccharides?
- 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.
What are the layer of homopolysaccharides?
- Inner layer called amylose ,non branching
linked together by α 1-4 glycosidic bond . - outer layer a amylopectin, outer layer linked
with other layer by α 1-6 glycosidic bond
What is starch?
➢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.
What is glycogen?
- 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.
What is cellulose?
- 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.
