Name: Khoo Ying Ying Matric number: MS2613108648 Practicum: H1T1B Lecturer: Mdm Marzian binti MD DeliMOLECULES OF LIFE PROTEIN MOLECULES OF LIFE PROTEIN
1.State the main types of molecules of life. water carbohydrate lipid Protein DNA and RNA molecules
2.Describe the three main classes of carbohydrates based on their structure and characteristics [15 marks].1.Fibrous proteins (known as scleroproteins) Characterized by their elongated, strand-like, or sheet-like shapes, formed from long, repetitive amino acid chains that intertwine into rods or wires. function as : structural components within cells and tissues, providing support, strength, and elasticity. Insoluble due to arrangement of hydrophobic amino acids. Examples: Collagen(found in connective tissue etc) and Keratin (primary component of hair,nails and etc)
2.Globular proteins (known as spheroproteins) polypeptide chains that are tightly folded into compact, spherical, or globe-like shapes. Soluble in water due to their unique, highly folded three-dimensional structure. Functions: metabolic reactions, transport, regulation, and defense mechanisms. Examples: Myoglobin and Enzymes.2.Describe the three main classes of carbohydrates based on their structure and characteristics [15 marks].
3.Conjugated proteins Proteins(apoprotein) with non-protein material (prosthetic group)within their structure. These types of proteins are attached by covalent bonds or weak interactions Examples:Glycoprotein and Lipoprotein.2.Describe the three main classes of carbohydrates based on their structure and characteristics [15 marks].
3.All types of muscle cells consist of filaments containing the proteins actin and myosin. Differentiate the three types of muscle cells in terms of their structure [5 marks].Three types of muscle cells are skeletal muscle cells,cardiac muscle cells and smooth muscle cells.
Skeletal muscle cells Cardiac muscle cells Smooth muscle cells Long,cylindrical and unbranched fibres. Short,cylindrical and branched fibres. Small,spindle-shaped cells that are thick in the middle and tapered at both ends Multinucleated 1-2 central nuclei 1 central nucleus3.All types of muscle cells consist of filaments containing the proteins actin and myosin. Differentiate the three types of muscle cells in terms of their structure [5 marks].
4.A girl with curly hair would like to make her hair straight using a hair straightener known as a flat iron. Explain how this can be done in relation to the structure of the hair protein [10 marks].Hair is primarily made of a fibrous protein called keratin.Keratin is composed of long chains of amino acids which organised into an a-helix structure.These chains are arranged parallel to each other which will form the hair fibre.The shape of an individual’s is maintained by two main types of cross-linkages which are hydrogen bonds and disulfide bonds.
When a flat iron is applied to the hair,it caused reversible denaturation process to happen.The heat from the flat iron is applied to break the hydrogen bonds in the keratin protein chains, As the hydrogen bonds break,the mechanical pulling force of the flat iron streches the curled a-helices out into an extended,temporary B-pleated sheet-like arrangement. As the hair cools down in its newly stretched, straight position, new hydrogen bonds reform between the parallel polypeptide chains. These new bonds temporarily lock the keratin chains into a straight alignment.
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