Biochem Q2

• Cells are surrounded by a membrane that confines their contents called Cell Membrane. It comprises 80% of lipid materials and it gives the cells their individuality as it separates it from the environment
• 3 common types of cell membranes are Phospholipids, Sphingoglycolipids and Cholesterol
• Phospholipids is the most abundant type of membrane lipid and it contains one or more fatty acid and a phosphate group
• Phospholipids is a barrier to protect the cells against environmental insults and for skin perspiration.
• phosphate group removes unneeded materials in the cell
• complex C18 amino alcohol is called sphingosine
• Glycerol-based phospholipids are called Glycerophospholipids and Sphingosine-base phospholipids are called Sphingophospholipids
• Sphingoglycolipids are the most abundant in cell membranes and are used as structural components for the cell
• Sphingoglycolipid contains both fatty acid and a carbohydrate attached to a sphingosine molecule and It also undergoes saponification reactions.
• Sphingoglycolipid occurs primarily in the brain (7% dry mass) and also present in the myelin sheath of nerves
• Cerebrosides are the simplest form of sphingoglycolipids while Gangliosides are the complex sphingoglycolipids.
• Sphingoglycolipids modulate the behavior of cellular proteins and receptors and also participate in signal transduction
• Cholesterol is a steroid and the most abundant lipid in the body. it is the only membrane lipid without fatty residue & Glycerol. it is biosynthesized in the liver and intestine in 800-1000mg every day.
• Cholesterol helps make new cell membranes, and hormones, aids production of vitamin D, and is needed for cell membrane fluidity.
• Lipoproteins is a combination of cholesterol and protein. There are two types which are Low-density Lipoproteins (LDLs) and high-density Lipoproteins (HDLS).
• Low-density Lipoproteins (LDLS) carry cholesterol from the liver to various tissues and if it carries too much it may increase blood cholesterol levels leading to blood clotting and heart attack
• High-density Lipoproteins (HDLS) carry excess cholesterol from tissue back to the liver and reduces blood cholesterol levels. However, if it carries too small it is bad cholesterol.
• Atherosclerosis is a cardiovascular disease due to high cholesterol levels. Due to the build-up of plaque which is composed of cholesterol in the arteries, It blocks the flow of blood leading to a heart attack.
• Glycerophospholipids is the dominant lipid in cell membrane. It provides Stability, Fluidity, and permeability in the cell membrane.
• PHOSPHATIDYLCHOLINES also known as lecithins are waxy solids from colloidal suspensions in water. it is made in the liver but it does not reach the tissues and are not essential nutrients.
• Phosphatidylcholines regulates the physical properties of mebranes and is important in blood clotting.
• Sphingophospholipids are structural components in cellular membranes and helps stabilize membrane layer.
• Cell Membrane also known as Plasma Membrane
• Plasma membrane separate cell's cytoplasm (aqueous interior fluid) of a cell from a aqueous sorroundings
• Plasma Membrane controls movement in and out of the cell
• Lipid Bilayer is 2 layer-thick structure of phospholipids and glycolipids. where the non-polar tails are in the middle while the polar tails are on the outside.
• Polar (Hydrophilic) water-loving meanwhile Non-polar (Hydrophobic) does not attract water.