Lecture (1)

Lecture (1)

1. Levels of structural complexity

   • 1- chemical level 2- cellular level 3- tissue level 4- organ level 5- system level 6- organismal level

2. The shape of a cell serves its function

   • For example : - sperm cell - smooth muscle cell - nerve cell - RBC - Epithelial cell

3. Cell-cell communication

   • Cell (1) : send signal in a shape of hormone. Cell (2) : a- receive the signal via receptors on the plasma membrane. b- send it inside. c- translate it via biochemical machinery.

4. Typical structure of a cell

   • The Nucleus
     • -
   • The cytoplasm
     • Organelles
       • Endoplasmic Reticulum
         • Rough ER
           • - Ribosomes-attached (Protein synthesis) and ER for processing and sorting . - synthesize phospholipids .
         • Smooth ER
           • - Extend from rough ER. - synthesize fatty acids and steroids. - contain enzymes that detoxify drugs. - store Ca ion that triggers contraction in muscle cells .
       • Mitochondria
         • - The power house. - Has its own DNA (from mother )
       • Golgi complex
         • Proteins are : 1- Modified. 2- Sorted. 3- Packed.
       • Ribosomes
         • Protein synthesis 1- free (used in cytosol). 2- attached to ER (secretion outside the cell).
       • Lysosomes
         • - Form from Golgi complex. - Hydrolytic enzymes. - Carry out : 1- autophagy. 2- autolysis. 3- extracellular digestion.
     • The cytosol
       • - 55% of cell volume. - site of chemical reaction. - contains dissolved particles .
   • The cell membrane
     • Introduction
     • Arrangement of membrane proteins (Structurally)
       • Integral Proteins
       • Peripheral Proteins
     • Functions of membrane proteins (Functionally)
       • 1- Ion channel (Integral) 2- Carrier/Transporters (Integral) 3- Receptor (Integral) 4- Enzyme (Integral and peripheral) 5- Linker (Integral and peripheral) 6- Cell identity marker (glycoprotein)

5. The cytoskeleton

   • The Microfilaments
   • Intermediate filaments
   • The Microtubules

6. Cell junction

   • e- Hemidesmosomes
   • d- Desmosomes
   • c- Adherens junction
   • b- Gap junction
   • a- Tight junction

7. Cellular communication