Kulsoom pirjan

sucrose

Sub topics

1.. carbohydrates 8.. Regulation of sucrose

2.. Chemical groups of carboydrates 9.. Degradation of sucrose.

3.. Importance of carbohydrates

4.. Sucrose introduction

5.. Carbohydrates biosynthesis

6.. Synthesis of sucrose

• Carbohydrates are one of the main types of

nutrients. They are the most important source of

energy for your body. Your digestive system

changes carbohydrates into glucose (blood

sugar). Your body uses this sugar for energy for

your cells, tissues and organs.

• A carbohydrate is a biological molecule

consisting of carbon (C), hydrogen (H) and

oxygen (O) atoms, usually with a hydrogen:

oxygen atom ratio of 2:1 (as in water).

• carbohydrate, with the empirical formula

Cm(H2O)n (where m could be different from n).

• The term is most common in biochemistry, where

it is a synonym of saccharide, a group that

includes sugars, starch, and cellulose.

• Carbohydrates are technically hydrates of

carbon.

• Monosaccharides are the simplest carbohydrates

in that they cannot be hydrolyzed to smaller

carbo-hydrates.

• Monosaccharides are important fuel molecules

as well as building blocks for nucleic acids.

• Two joined monosaccharides are called a

disaccharide and these are the simplest

polysaccharides.

• I .e sucrose , lactose and maltose

• A chain of two or more monosaccharides. The

chain may be branched (molecule is like a tree

with branches and twigs) or unbranched

(molecule is a straight line with no twigs).

Polysaccharide molecule chains may be made

up of hundreds or thousands of

monosaccharides.

• Polysaccharides are polymers. A simple

compound is a monomer,

• Carbohydrates are initially synthesized in plants from a

complex series of reactions involving photosynthesis.

• Store energy in the form of starch (photosynthesis in plants)

or glycogen (in animals and humans).

• Provide energy through metabolism pathways and cycles.

• Supply carbon for synthesis of other compounds.

• Form structural components in cells and tissues

• Sucrose is a common, naturally occurring

carbohydrate found in many plants and plant

parts. Saccharose is an obsolete name for

sugars in general, especially sucrose.

• Molar mass: 342.2965 g/mol

• Formula: C12H22O11

• Density: 1.59 g/cm³

• Melting point: 186 °C

• Soluble in: Properties of water

• The molecule is a disaccharide combination of

the monosaccharides glucose and fructose with

the formula C12H22O11.

• Sucrose commonly called table sugar.

• Sucrose is often extracted and refined from

either cane or beet sugar for human

consumption.

• Modern industrial sugar refinement processes

often involves bleaching and crystallization also,

producing a white, odorless, crystalline powder

with a sweet taste of pure sucrose, devoid of

vitamins and minerals. This refined form of

sucrose is commonly referred to as table sugar

or just sugar

• About 175 million metric tons of sucrose sugar

were produced worldwide in 2013.

• In Nature, sucrose is present in many plants, and

in particular their roots, fruits and nectars,

because it serves as a way to store energy,

primarily from photosynthesis.

• Plants and photosynthetic micro organisms, can

synthesize carbohydrates from CO2 and water,

reducing CO2 at the expense of the energy and

reducing power furnished by the ATP and

NADPH that are generated by the light-

dependent reactions of photosynthesis .

• Green plants contain in their chloroplasts unique

enzymatic machinery that catalyzes the conversion

of CO2 to simple (reduced) organic compounds, a

process called CO2 assimilation. This process has

also been called CO2 fixation or carbon fixation

• but we reserve these terms for the specific reaction

in which CO2 is incorporated (fixed) into a three-

carbon organic compound, the triose phosphate 3-

phosphoglycerate

• Most of the triose phosphate generated by CO2 fixation

in plants is converted to sucrose or starch.

• In the course of evolution, sucrose may have been

selected as the transport form of carbon because of its

unusual linkage between the anomeric C-1 of glucose

and the anomeric C-2 of fructose.

• It is a carbon fixation pathway present in some

plants also known as CAM photosynthesis .

• These plants fix carbon dioxide( CO2) during the

night storing it as the 4 – carbon acid malate.

• Triose phosphates produced by the Calvin cycle

in bright sunlight, as we have noted, may be

stored temporarily in the chloroplast as starch, or

converted to sucrose and exported to non-

photosynthetic parts of the plant, or both. The

balance between the two processes is tightly

regulated, and both must be coordinated with the

rate of carbon fixation.

• Five-sixths of the triose phosphate formed in the

Calvin cycle must be recycled to ribulose 1,5-

bisphosphate, if more than one-sixth of the triose

phosphate is drawn out of the cycle to make

sucrose and starch, the cycle will slow or stop.

• Regulation of sucrose also responsible for the

gene expressions .

• Sucrose is the world’s most abundant disaccharide, it is only produced by photosynthetic organisms and serves a role as a transportable carbohydrate and sometimes as a storage compound. The reactions in plant tissues leading to degradation of sucrose to hexose monophosphates .

• Plant tissues contain distinct invertases located in the vacuole, cell wall (acid invertases) cytosol, mitochondria, nucleus, and cholorplast which hydrolyse sucrose to glucose and fructose in an irreversible reaction.

• The first step is cleavage of the glycosidic bond

by either invertase (Equation 1) or sucrose

synthase (Equation 2)

• Sucrose + H2O→D-Glucose + D-Fructose(1)

• Sucrose + UDP→UDP-Glucose + D-Fructose(2)