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Chapter 9 biomolecules -biology


01
 
DEFINITION
Biomicromolecules and biomacromolecules
  • Biomicromolecules are small sized simple chemical that have low molecular weight, higher solubility and simple conformation.
  • They may be organic or inorganic and include water, gases, minerals, sugars, amino acids and nucleotides.
  • Biomacromolecules are large sized complex chemicals that have high molecular weight, low solubility and complex configuration.
  • They belong to carbohydrates, lipids, proteins and nucleic acid.
02
 
DEFINITION
Glycosidic bond
  • A glycosidic bond or glycosidic linkage is a type of covalent bond that joins a carbohydrate (sugar) molecule to another group, which may or may not be another carbohydrate.
03
 
DEFINITION
Types of polysaccharides
Depending upon the composition, polysaccharides are of two types. They are
  • Homopolysaccharides (fructan, xylan)
  • Heteropolysaccharides (agar, arabanoxylans)
04
 
DEFINITION
Cellulose and glycogen
  • Cellulose makes cell walls in plants. It is unused in our body but it contributes in providing roughage for proper functioning of gut.
  • Glycogen is the form in which carbohydrates are stored in animals.
05
 
DEFINITION
Starch
  • Starch is a white, tasteless, insoluble carbohydrate.
  • Chief source of carbohydrates are potatoes, rice, wheat, maize, barley and bread.
  • Starch is a polysaccharide, having chemical formula as .
  • There are two other insoluble polysaccharides of carbohydrate. They are cellulose and glycogen.
  • Cellulose makes cell wall in plants. The undigested cellulose act as roughage. It stimulates muscle contraction, prevents constipation and helps in removal of cholesterol. Source of roughage are vegetables, fruits, corn, half crushed wheat (dalia) etc.
  • Glycogen is the form in which the carbohydrate is stored in animal livers.
06
 
DEFINITION
Proteins
  • Proteins are large chemical molecules containing carbon, hydrogen, oxygen and nitrogen and sometimes sulphur and phosphorus.
  • They are needed for growth and repair in the body.
  • Protein rich food include egg, cheese, beans, nuts, peas, fish etc.
  • Severe deficiency of protein causes Kwashiorkor and Marasmus.
07
 
DEFINITION
Nucleic acid
  • Nucleic acids are biopolymers, or large biomolecules, essential for all known forms of life. 
  • Nucleic acids, which include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid), are made from monomers known as nucleotides.
08
 
DEFINITION
Nucleic acids
  • Nucleic acids are biopolymers, or large biomolecules, essential for all known forms of life. Nucleic acids include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). 
09
 
DEFINITION
Anabolism
Metabolism is the sum total of all the activities present in the cell. It is mainly of two types anabolism and catabolism. Anabolism is a synthesis of complex molecules from simpler one. Photosynthesis also includes anabolic reaction, glucose is synthesised from simpler raw materials like carbon dioxide and water.
10
 
DEFINITION
Example of anabolism
Anabolism is a synthesis of complex molecules from simpler one. Example formation of protein from simpler amino acids which helps in the construction of cellular membranes. Photosynthesis also includes anabolic reaction, glucose is synthesised from simpler raw materials like carbon dioxide and water.
11
 
DEFINITION
Catabolism
Catabolism
It is a process where the complex organic substances are broken down into simpler substances and energy is released.This energy released is used to drive the intercellular reaction. For example, cellular respiration and digestion.
12
 
DEFINITION
Examples of catabolism
Catabolism is the breakdown of complex substances to simpler one. Like during respiration complex food particles are digested broken down into simpler one which is further assimilated.
13
 
DEFINITION
Classification of enzymes
The main features of the classification proposed by enzyme commission are as follows:
  • All enzymes are divided into six major classes, viz. oxidoreductases, transferases, hydrolases, lyases, ismoerases and ligases.
  • Each major class of enzyme is divided into sub-classes and sub sub-classes on the basis of the nature of the individual transformations involved.
  • Each enzyme has a systematic code number (E.C).
14
 
DEFINITION
Effect of enzyme concentration on enzyme action
  • Increasing enzyme concentration will increase the rate of reaction, as more enzymes will be colliding with substrate molecules.
15
 
DEFINITION
Enzyme action by lowering activation energy
  • The graph above shows how the activation energy is lowered in the presence of an enzyme (blue line) that is doing the catalysis, exempflified with the carbon anhydrase reaction. 
  • The transition state is usually the most unstable part of the reaction since it is the one with the highest free energy. The difference between the transition state and the reactants is the Gibbs free energy of activation, commonly known as activation energy.
  • Enzymes (blue line) change the formation of the transition state by lowering the energy and stabilizing the highly energetic unstable transition state. This allows the reaction rate to increase, but also the back reaction occurs more easily.
16
 
DEFINITION
Co-factor
A non-protein chemical compound that is required for the activity of an enzyme e.g., zinc ion, copper ion, potassium ion etc.
17
 
DEFINITION
Co-enzyme
  • Co-enzymes are the helper organic molecule required for the activity of enzymes.
  • They cannot by themselves catalyze a reaction but helps other enzymes to do so.

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