Q.No.1
Define blochemistry. What is its importance? What are organic and inorganic compounds?
Answer:
BIOCHEMISTRY:
Biochemistry is a branch of biology, which deals with the study of chemical components and the chemical processes in living organisms.
Importance:
A basic knowledge of Biochemistry is essential for understanding anatomy and physiology, because all of the structures of an organism result from biochemical reactions.
For example:
photosynthesis, respiration, digestion, muscle contraction can all be described in biochemical terms.
All living things are made of certain chemical compounds, which are generally classified as organic and inorganic. Organic Compounds: Those containing carbon (other than carbonates) are called organic compounds. For example, most important organic compounds in living organisms are carbohydrates, proteins, lipids and nucleic acids. Inorganic Compounds: Compounds, which are without carbon, are called inorganic compounds. For example, water, carbon dioxide, acids, bases, and salts. Typically an animal and a bacterial cell consist of chemicals as shown in the following Table.
Q.No.2
Define the following:
Metabolism
Coordinated Metabolism
Catabolism
Anabolism
Metabolism:
All the chemical reactions taking place within a cell are collectively called metabolism. Metabolic processes are characterized as anabolism and catabolism
Anabolism:
Those reactions in which simpler substances are combined to form complex substances are called anabolic reactions. Anabolic reactions need Answer: energy
Catabolism:
Energy is released by the break down of complex molecules into simpler ones, such reactions are called catabolic reactions. Anabolic and catabolic reactions go hand in hand in the living cells.
Coordinated Metabolism:
Complex molecules are broken down and the resulting smaller molecules are reused to form new complex molecules Interconversions of carbohydrates, proteins, and lipids that occur continuously in living cells are examples of co-ordinated catabolic and anabolic activities.
Q.No 3:
What is covalent bond: write a note on importance of carbon in biology.
COVALENT BOND:
Covalent bonds result when two or more atoms complete their electron shells by sharing electrons. When an electron pair is shared between two atoms, a single covalent bond results. An example is the bond between two hydrogen atoms to form a hydrogen molecule. Covalent bond stores large amount of energy.
IMPORTANCE OF CARBON:
Carbon occupies the central position in the skeleton of life. covalent bonds.
1. Carbon is the basic element of organic compounds. Due to its unique properties carbon occupy the central position in the skeleton of life.
2. Carbon is tetravalent. It can react with many other known elements forming covalent bonds.
3. Carbon combines commonly with H, O, N, P and S. Combinations with these and other elements contribute to the large variety of organic compounds.
4. Carbon and hydrogen bond (C-H bond) is the potential source of chemical energy for cellular activities.
5. Carbon-oxygen association in glucosidic linkages provides stability to the complex carbohydrate molecules.
6. Carbon combines with nitrogen in amino acid linkages to form peptide bonds and forms proteins, which are very important due to their diversity in structure and functions.
7. Large organic molecules (macromolecules) such as cellulose, fats, proteins, etc, are generally insoluble in water, hence they form structures of cells. They also serve as storage for smaller molecules like glucose, which in turn are responsible for providing energy to the body.
8. Small molecules, such as glucose, amino acids, fatty acids etc, serve either as a source of energy, or as subunits to build macromolecules.
9. Some small molecules are so unstable that they are immediately broken down to release energy e.g ATP Such substances serve as the immediate source of energy for cellular metabolism.
Q.No.4
Write a note on importance of water in living organisms.
Answer:
IMPORTANCE OF WATER:
Water is the medium of life. It is the most abundant compound in all organisms. Its amount varies from 65 to 89%. Human tissues contain about 20 per cent water in bone cells and 85 per cent in brain cells.
1. Solvent properties:
Due to its polarity, water is an excellent solvent for polar substances. Ionic substances when dissolved in water, dissociate into positive and negative ions. Non-ionic substances, having charged groups in their molecules, are dispersed in water. When in solution, ions and molecules move randomly and are in a more favourable state to react with other molecules and ions. It is because of this property of water that almost all reactions in cells occur in aqueous media. Non-polar organic molecules, such as fats, are insoluble in water and help to maintain membranes, which make compartments in the cell.
2. Heat capacity:
Water has great ability of absorbing heat. The specific heat capacity of water the number of calories required to raise the temperature of 1g of water from 15 to 16C is 1.0. This is because much of the energy is used to break hydrogen bonds. Water thus works as temperature stabilizer.
3. Heat of vaporization:
Water absorbs much heat as it changes from liquid to gas. Heat of vaporization is expressed as calories absorbed per gram vaporized. The specific heat of vaporization of water is 574 Kcal/kg, which plays an important role in the regulation of heat produced by oxidation. It also provides cooling effect to plants when water is transpired, or to animals when water is respired. Evaporation of only two ml out of one liter of water lowers the temperature of the remaining 998 ml by IC.
4. Ionization of water:
5. Protection:
Water is effective lubricant that provides protection against damage resulting from friction. For example, tears protect the surface of eye from the rubbing of eyelids. trauma. Water also forms a fluid cushion around organs that helps to protect them from.
6. Reagent reactions:
Water acts as a reagent in many processes such as photosynthesis and hydrolysis
7. Turgidity:
Water provides turgidity to the cells.
Pre-medical ist year biology notes.
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