1a-Structure of cell membrane-Part1- Lipids and Proteins

Dr. Eman Nabil introduces the histology course, emphasizing the importance of understanding the reasons behind phenomena, using a series of books titled 'Let Me Why'. She highlights that understanding reasons aids in retention of knowledge and mentions a child's natural inclination to ask 'why'.

Dr. Eman uses KitKat chocolates in her lectures as an incentive for students to answer questions. She introduces histology as the study of tissues and cells using microscopes, emphasizing the precision of human creation and the importance of understanding it.

The lecture explains that cells are the functional and structural units of the body, and how cells form tissues, organs, and systems. She introduces the light microscope and electron microscope as tools for studying histology, focusing on their differences in magnification capabilities.

The light microscope is explained as having a magnification limit of 1500 times, suitable for viewing stained cell samples. For more detailed cell structure, the electron microscope, which uses electrons for imaging, can magnify up to a million times, providing black-and-white images.

Dr. Eman explains the structure of cells, comparing it to the human body with a protective membrane, internal organelles, and energy storage. The cell membrane is compared to skin, and organelles to human organs, providing specific cellular functions.

The cell membrane's appearance under a microscope is discussed, noting that its thinness often makes it challenging to view with a light microscope. The electron microscope reveals it as a trilaminar structure, aiding in understanding its composition and function.

The composition of the cell membrane is broken down into lipids, proteins, and carbohydrates. Phospholipids are introduced as key components, having hydrophilic heads and hydrophobic tails due to their chemical structure, influencing their arrangement in the membrane.

Cholesterol is discussed as a component of the membrane, essential for maintaining its stability and fluidity across different temperatures. This prevents the membrane from becoming too rigid or too fluid, which ensures proper cellular function.

Integral membrane proteins are detailed, emphasizing their roles as channels, receptors, and enzymes. Their functions include facilitating active and passive transport across the membrane, serving as receptors for signals, and catalyzing biochemical reactions.