GENES The gene is a nucleic acid sequence that is necessary for function of gene product. Gene may be a protein coding gene whose transcribed RNA is translated into proteins or RNA only genes. Protein coding genes may be solitary or families or tandem repeats NON –CODING SEQUENCE The non coding sequence are genes that do not encode the protein. The amount of non-coding sequence in DNA of organism varies among species. Eg-Human genome -98% non-coding genes Prokaryotes -10% non-coding genes Types of Non coding sequences The non coding sequences can be in the form of following Introns Anti leader and Anti trailer sequence Promoter sequence Enhancers Pseudogenes Gene fragments Telomeres Non-coding functional RNA Cis-Trans regulatory elements INTRONS Introns are non-coding sequence that transcribed into RNA But precursor mRNA removed by splicing during processing. The eukaryotic genome has large amount of introns...
Monosaccharide involves glyceraldehyde and dihydroxyacetone found as intermediate in glycolysis.Erythrose found in HMP shunt intermediates.Ribose found in DNA .glucose in blood and fructose in fruit and honey .
Oligosaccharides has 2 to 10 sugar glucose units linked by glycosidic linkage.
Disaccharides has 2 monosaccharide .It is classified into 2 as reducing and non-reducing sugar.
Maltose:
It is also called malt sugar.It is found in sprouting barely and other cereal grains.
Physical property:
White crystalline,melting point as 160-165 degree,soluble in water and dextrorotatory.
Chemical property
It answers Benedict's ,fehlings reaction as it's reducing sugar.
Hydrolysis
It is hydrolysed by enzyme maltase and form 2 glucose units in SI.
Structure:
Maltose is link to glucose molecule as by alpha 1to 4 linkage.
LACTOSE:
It is milk sugar as 6-8 percent in human milk and 4-8 percent in cows milk.
Physical properties:
It is white crystalline,melting point 200 degree Celsius,dextrorotatory,exhibit mutarotation,less soluble in water.
Chemical reaction :
It answers Benedict's, Fehling's test
Hydrolysis:
The enzyme lactase in SI break to glucose and galactose .
Some are lactose intolerance due to lack of enzyme lactase. They cause sign like diarrhoea,cramps in stomach.
Structure:
It has beta -D galactose link with alpha -D glucose by beta 1 to 4 linkage.
NON REDUCING SUGAR:
SUCROSE:
It is also called cane sugar or table sugar.
Physical property:
White crystalline,when heated it melt to form caramel , Dextrorotatory,lack murarotation.
Chemical property:
It doesn't reduce Benedict's and feelings reagent as they lack ,doesn't react with phenylhydrazone .
Hydrolysis:
It hydrolysed by enzyme sucrase or invertase to yield equimolar mixture of glucose and fructose is also called as invert sugar as it's sweetest sugar of carbohydrate.
Structure:
Glucose and fructose linked together by alpha 1 to 2 linkage.
TRISACCHARIDES:
1.RAFFINOSE:
It is found in beans,cabbage,sprouts.
Chemical properties:
It is nonreducing sugar.Thus doesn't answer Benedict's and Fehling test.
Hydrolysis:
It is not digested in SI thus pass to large intestine forming indigestion.
Structure:
It is liked by alpha -D galactose and sucrose by 1 to 6 linkage.
STACHYOSE:
It is found in beans and soyabeans.
Chemical property:
It is nonreducing sugar due to lack of answering to Benedict's and feelings test .
Hydrolysis
It is not hydrolysed due to lack of enzyme cause passing to large intestine lead to fermentation and indigestion.
Structure:
It is linked by alpha -D galactose to raffinose by 1 to 6 linkage.
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