The document discusses important biological molecules and concepts in biochemistry. It begins by defining biochemistry and describing the four fundamental kinds of biological molecules: carbohydrates, proteins, lipids, and nucleic acids. It then addresses questions about the polarity of water, why water is a universal solvent, the importance of hydrogen bonding, how water can absorb large amounts of heat with little temperature change, and how this protects living things. It concludes by discussing how the high heat of vaporization of water allows animals to efficiently release excess body heat.

1. BIOLOGICAL
MOLECULES
Important
Conceptual
Questions
Conceptual
questions
Ch2

2. 1. How would you describe biochemistry?
◉ Biochemistry is the branch of Biology that deals with the
biological molecules or biomolecules.
◉ It also deals with various chemical reactions(metabolism) of
living beings.
◉ Biochemistry helps Biologist to understand anatomy,
physiology, Pharmacology, biotechnology, Bioinformatics

3. 2. What are the four fundamental kinds of biological
molecules? Explain
The four fundamental kinds of biological molecules are carbohydrates,
proteins, lipids and nucleic acid.
1. carbohydrates are present in the inclusions of the cells and provide fuel
for the metabolic activities of the cell.
2. Proteins are present in the membranes, ribosome, cytoskeleton and
enzymes of the cell.

4. 3. Lipids are present on the membranes of Golgi Complex and inclusion of the
cell, which provide a reserve energy source, shape, protect and insulate the
cell.
4. Nucleic acid DNA is present in the chromosome. it controls the cell activity.
The nucleic acid RNA is present in the nucleoplasm and cytoplasm. it
transmits genetic information and take part in the protein synthesis.

5. 3. Why is the covalent bond in water is Polar?
In case of water, the sharing of electrons between oxygen and hydrogen
is not completely equal so, the covalent bond is Polar.
◉ A polar covalent bond is a chemical bond in which shared electrons are pulled
closer to the more electronegative atoms making it partially negative and the
other atom partially positive.
◉ Thus, in water the O atom actually has slightly negative charge and the each H
atom has slightly positive.
◉ Because of its polar covalent bonds, water is a polar molecule that is it has a
slightly negative pole and two slightly positive ones.

6. 4. Why water is regarded as universal solvent?
This is the polarity of water molecules that make it an excellent or
universal solvent for polar substances.
◉ Ionic compounds can be easily dissolved in water, non polar
substances having charge groups in their molecules can also be
dissolved in water.

7. ◉ Such compounds when dissolved in water, dissociates into
positive and negative ions and are in more favourable state
to react with other molecules and ions.
◉ This is the reason why all chemical reactions in living
beings occur in aqueous medium.

8. 5. What is the importance of hydrogen bonding?
◉ Because of hydrogen bonding water is a liquid at temperatures suitable
for life.
◉ The high Cohesion and adhesion force of water is due to the presence of
hydrogen bonds in water which in turns make water as transport
medium.
◉ it is important for the determination of the structure of various
substances like proteins.

9. 6. Why very large amount of heat can increase very little
temperature in water?
water has relatively a very high heat capacity than any other
substance due to its hydrogen bonding, because much of
the heat absorbed by water is utilised in the breakdown of
hydrogen bonding therefore it does not manifest itself to
raise the temperature of water.

10. ◉ Hence, very large amount of heat can increase very little
temperature in water due to its high heat capacity.
◉ Water works as temperature stabilizer or regulator for organism
in the hot environment and hence protects the living material
against certain thermal changes.

11. 7. How water protects living things against certain thermal
change
◉ Very large amount of heat can increase very little temperature in
water due to its high heat capacity.
◉ Water works as temperature stabilizer or regulator for organism in
the hot environment and hence protects the living material
against certain thermal changes.

12. 8. What is the importance of high heat of vaporization of
water to animals?
◉ This is high heat of vaporization of water that gives animals
an efficient way to release excess body heat in a hot
environment
◉ When an animal sweats, body heat is used to vaporize the
Sweat thus cooling the animal.
◉ Due to this property of water, evaporation of only 2ml out of
1 l of water lowers the temperature of the remaining 998 ml
water by 1 ć.