BIO FLIPBOOK: MOLECULES OF LIFE & CELL STRUCTURES AND FUNCTIONSBIOLOGY 1 (SB015) ASSIGNMENT 2026/2027Name: Goh Yu Fei Matric number: MS2613108490 Practicum: H1T1B Nama guru: Madam Marzian
Main Types of Molecules of Life Water Carbohydrate LIPID Protein DNA & RNA Molecules
Three Main Types of LipidsTriglycerides Phospholipids Steroids Lipids are not soluble in water but soluble in nonpolar oraganic solvents
1.Triglycerides Also known as triacylglycerol! Consists of 1 glycerol and 3 fatty acids Glycerol and fatty acids are joined by ester linkage Glycerol is a type of alcohol that contain 3 carbon atoms (C) and 3 hydroxyl groups (-OH)
1. TriglyceridesFatty Acids Formation of triglyceride Breakdown of triglyceride Formed through condensation reaction Formed through hydrolysis reaction 3 water molecules are removed 3 water molecules are added Hydroxyl group (OH) from carboxyl end of fatty acid and hydrogen from the hydroxyl group of glycerol are removed Hydroxyl (OH) reacts with the carboxyl end and hydrogen react with the hydroxyl groupConsist of a long linear hydrocarbon chain (R)and a carboxyl group (-COOH)Carboxyl groupLong hydrocarbon chain Unsaturated SaturatedThe hydrocarbon chain is non-polar & hydrophobic (cause triglyceride to be insoluble in water)Hydrocarbon chain usually consists of even number of carbons
2.PhospholipidsTwo fatty acid chain which usually one saturated and one unsaturated, attached to a glycerol backbone.Contains a phosphate group often linked to an organic molecule such as cholinePhospholipid is selectively permeable that allow small nonpolar molecules to pass. Fluidity & flexibility The mix of saturated and unsaturated fatty acids ensures membranes are not rigid but dynamic.DO YOU KNOW? Lecithin is also a type of phospholipid a type of lipid molecule that is the main building block of all cell membranes that made up of Glycerol backbone (One 3-Carbon alcohol molecule) Fatty acids (Two hydrophobic hydrocarbon tails) Phosphate group (One hydrophilic polar head) a type of lipid molecule that is the main building block of all cell membranes that made up of Glycerol backbone (One 3-Carbon alcohol molecule) Fatty acids (Two hydrophobic hydrocarbon tails) Phosphate group (One hydrophilic polar head) Component of cell membrane Contain nutrient choline found in egg yolk, peanut, milk, soya bean.
3.SteroidsCholesterol Steroids hormone Vitamin D Testosterone Aldosterone Progesterone Stabilizes membrane fluidity Low density lipoprotein (LDL) & High density lipoprotein (HDL) Lipids synthesized from cholesterol in the adrenal cortex, testes, ovaries, and placenta. Increases Calcium Absorption Maintains Healthy Bones and Teeth Precursor for sex hormone made up of carbon and hydrogen atoms structured into four distinct, fused rings
Structure of Plasma Membrane Carbohydrate chain/oligosaccharides -Found on the external surface of the plasma membrane -Function as cell identity markers and recognition Glycoprotein: Carbohydrate chain attaches to protein Glycolipid: Carbohydrate chain attaches to phospholipid Protein Channel: Only allow certain ions or molecules can pass through Phospholipid -Hydrophilic head facing outwards and attracted to the aqueous surrounding -Hydrophobic tails of phospholipid facing inwards Glycoprotein functions in cell recognition, cell adhesion, receptor activity, and cell communication Cholesterol Found between phospholipids Function to increase flexibility and stabilises the membrane structure by regulating the fluidity of the membrane Alpha-helix protein hydrophobic amino acids interact with the membrane lipids, allowing the protein to remain embedded in the membrane. Filament of Cytoskeleton protein fibers in the cytoplasm that maintain cell shape, provide support, facilitate movement, and assist in intracellular transport and cell division. Peripheral protein/Extrinsic Protein Attached to the outer and inner surfaces of the membrane. Glycolipid lipid molecule with attached carbohydrate chains. It functions in cell recognition, cell adhesion, cell communication, and membrane stability. Integral Protein/Intrinsic Protein Partially embedded or fully embedded: transmembrane protein. Surface protein Protein on the surface membrane
How the different types of lipid in the plasma membrane causes and regulate membrane fluidityPhospholipidsPhospholipids and proteins can move laterally (can move side to side) Cholesterol At high temperature Cholesterol reduce membrane fluidity by preventing free movement of phospholipid molecules At low temperatures: Cholesterol prevent close packing of phospholipids by inserting between phospholipid molecules to slow down solidification Glycolipids Help stabilize the membrane structure. Reduce excessive movement of phospholipids. Contribute to membrane organization. Unsaturated phospholipids have one or more double bonds in their fatty acid tails that introduce kinds, or bends, in the well- ordered structure of the membrane Increase membrane fluidity Saturated phospholipids Lack of double bond between the carbon atoms decrease the membrane fluidity by making the membrane more rigid