ISC 11>Content>Unit-4>Biomolecules

Scope of syllabus

Biomolecules: 

• Carbohydrates- General classification and functions of monosaccharides (glucose, galactose and fructose), disaccharides (Maltose, lactose and sucrose), Polysaccharides (Glycogen, starch, cellulose)
• Proteins-Structure and functions, level of proteins (simple (keratins, collagen) and conjugated (chromoprotein, glycoprotein, phosphoprotein, metalloprotein, lipoprotein and nucleoprotein);
• Lipids – classification, structure and functions of fats and oils.
  
• Nucleotides and nucleic acids – structure and functions of DNA, types of RNA. Differences between DNA and RNA

Class presentation 

---

---

Biomolecules
The molecules occurring in living organisms are called biological molecules.

---

Basics of biochemistry

A. Common elements

• Oxygen (O), carbon (C), hydrogen (H), and nitrogen (N) make up 96% of most living organisms.
• Trace elements are elements that are necessary, but present in very small quantities.(1% of the body weight)

1. Sulphur: an important element in some amino acids.
   
2. Calcium: used during nerve impulses 
3. Iron: found in hemoglobin (oxygen transport protein)
4. Sodium: needed for a nerve impulse 
5. Phosphorus: in cell membrane structures and DNA
   

---

2. Chemical bonding

• Molecules are made of two or more atoms bonded together through electron interactions.
• A substance made of atoms of different elements is a compound.
• Attractive forces (chemical bonds) hold atoms together in molecules.

---

3.  Polarity:  Electrons in a covalent bond may be equally or unequally shared between the atoms

Non-polar covalent bond: 
atoms share electrons evenly

Polar covalent bond: atoms share electrons unequally, so there is a slight difference in charge between the two poles of the bond

---

4. Carbon

Why Is Carbon So Important?

• Carbon atoms are versatile and can form up to four bonds (single, double, or triple) and rings..
• Functional groups in organic molecules confer chemical reactivity and other characteristics.
• Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules
  

---

5. Condensation and hydrolysis
Condensation: A chemical reaction in which two molecules combines to form single molecule, with the loss of a small molecule (Water)
Hydrolysis: A reaction in which water is used to split a substance into smaller particles.

---

---

Cellular pool

Cellular pool :  Collection of different types of biomolecules, compounds and ions present in a cell is called the cellular pool.
 It has two phases: the aqueous and the non-aqueous phase.
A) Aqueous pool: molecules are dissolved in water and form molecular or colloidal solutions.

•  Molecular solution- clear and transparent and uniformly dispersed called crystalloids.
• Colloidal solution- cloudy and translucent called colloids.

B) Non aqueous phase-organic molecules forming cell wall, cell membrane and other cell organelles.

---

Micromolecules and macromolecules

---

---

Carbohydrates            Lipids               Proteins               Nucleic acids