9) Structure and functions of carbohydrates.

Carbohydrates are organic compounds made up of C, H, O atoms. Carbohydrates provides the primary energy source for all organisms. They participate in the structure of the plasma membrane and cell wall. They are categorized into 3 groups:

• Monosaccharides. These are the simplest of all saccharides and can’t be hydrolysed. They are categorized according to the number of carbons within their structure.

• Triose sugars: these sugars have 3 carbon atoms.

• Pentose sugars: these sugars have 5 carbon atoms.

• Hexose sugars: these sugars have 6 carbon atoms.

• Disaccharides. 2 monosaccharide covalently linked.

• Maltose: Maltose is a sugar composed of two glucose molecules. It is found in the endosperm of barley.

• Sucrose: It is formed from the bonding of a glucose and a fructose monosaccharide unit. It is known as table sugar. It is found in sugar cane.

• Lactose: It is formed from the bonding of a glucose and galactose monosaccharide unit.It is found in mil of mammals.

• Polysaccharides. These molecules are formed by chains of monosaccharides.

• Starch: Starches are glucose polymers in which glucopyranose units are bonded by alpha-linkages. It is made up of a mixture of amylose and amylopectin 

• Glycogen: Glycogen is a multibranched polysaccharide that serves as a form of energy storage in animals and fungi.

• Cellulose: Cellulose is a linear polysaccharide polymer with many glucose monosaccharide units.

• Chitin: Chitin is a polysaccharide found in the outer skeleton of insects, crabs, shrimps, and lobsters and in the internal structures of other invertebrates.

Functions of carbohydrates:

1. Production of energy.

2. Carbohydrate rich foods in their natural state are low in calories and high in fiber. 

3. Carbohydrates are also important for the correct working of our brain, heart and nervous, digestive and immune systems. 

4. Fibre, which is also a form of carbohydrate, is essential for the elimination of waste materials and toxins from the body and helps to keep the intestines disease-free and clean.

5. Structural material of plant cell walls.

6. Source of carbon in metabolic processes.

7. Structural elements of cells and tissues.

10) Structure and function of lipids.

Lipids are biological molecules that are insoluble in water, but are soluble in non-polar solvents, meaning that they are non-polar molecules. Lipids are made up of C, H, O atoms but some lipids contain P and S atoms.

Structure of Lipids

Every Lipid has a different structure. But they all have a large number of carbon hydrogen bonds. The length of the chain which is generally linear is less than the chain length of proteins. In other words the molecular mass of lipids is in between amino acids and proteins.

Functions of lipids:

1. They are secondary source of energy for organisms. They release twice the energy produced by proteins and carbohydrates.

2. They participate in the structure of cell membrane.

3. They help joint movement and gives organisms good appereance.

4. They are found in the structure of some hormones and works as shemical messengers.

5. They also release metabolic water which is of vital importance for hibernating animals since it is their only source of water.

6. They protect our organs

7. It regulates fluid balance.

8. Stores energy for future use.

11) Structure and function of nucleic acid.

Nucleic acids are the master molecules of cells since they play such vital roles in the continuation of all life processes.

Nucleic acid are the largest known organic molecule. Nucleic acid molecules are enormous, complex polymers made up of monomers. Nucleic acids allow organisms to transfer genetic information from one generation to the next. There are two types of nucleic acids: deoxyribonucleic acid, better known as DNA and ribonucleic acid, better known as RNA.

FUNCTIONS OF NUCLEIC ACIDS:

They have 2 main functions:

1. Regulation of all metabolic activities within the cell.

2. Maintenance of genetic continuity between generations.

3. The carry information from genes in the cell nucleus to certain structures in the cytoplasm that direct major biochemical processes.

4. Nucleic acids are the genetic material for all living cells.

5. Nucleic acids determine the phenotype of an organism.

STRUCTURE OF NUCLEIC ACIDS:

Nucleic acids are composed of long chains of repeating units called nucleotides. DNA molecules are the largest of the naturally occurring organic molecules.

Each monomer is a nucleotide. Each nucleotide is composed of a sugar molecule containing five carbon atoms, a phosphate group, and a molecule containing nitrogen which will be referred to as nitrogenous base. In cells DNA is the nucleic acid that functions as the original blueprint for the synthesis of proteins.