|What are the main components of a cell? ||Nucleus
|What are the parts of the nucleus? ||Nucleolus: center of synthesis of ribosomal RNA
Nuclear Membrane: porous, double; between 2 membranes: perinuclear cisternae
Chromatin: DNA; 2 components: Euchromatin, Heterochromatin
Nucleoplasm (Karyoplasm): has macromolecules & nuclear particl|
|What are cell organelles? ||Organelles are specialized parts of living substance within cells.|
|Cell organelles are classified into _______ and ________. ||Membranous and nonmembranous|
|List the membranous organelles. ||Golgi Apparatus - Endosomes - Plasma Membrane - Peroxisomes - Lysosomes - Mitochondria - Endoplasmic Reticulum|
|List the non-membranous organelles. ||Cytosomes - Centrioles - Ribosomes|
|Describe the cell membrane’s appearance under the electron and light microscopes. ||Light microscope: not visible
Electron microscope: trilaminar appearance|
|Describe the molecular structure of the cell membrane. ||Lipids: polar heads, nonpolar bodies
Proteins: (60%-70%) Peripheral & Integral
Carbohydrates (glycolipids + glycoproteins = glycocalyx = cell coat)
|What are the functions of the cell membrane? ||Exchange of materials.
Protection and cell recognition|
|What are the properties of the mitochondria? ||The inner membrane is highly folded (cristae) and the outer membrane is smooth.
They can divide by binary division.
The mitochondrial lumen is filled with matrix, which contains mitochondrial granules.|
|What are the functions of the mitochondria? ||It is the powerhouse of the cell.
It contains enzymes of the Kreb’s cycle.
*Describe the structure of the SER?
It is formed of anastomotic network of tubules and vesicles.
Its lumen is continued with the lumen of RER.|
|What is the function of the SER? ||Steroid and lipid synthesis
Detoxification of drugs.
It may be involved in glycogen synthesis.
Form sarcoplasmic reticulum in skeletal muscle.|
|Describe the structure of the RER? ||It is formed of anastomotic network of tubules and vesicles.
The outer membranes of these saccules are richly studied with ribosomes.
The cells rich in (RER) stains deeply with basic dye (basophilia) i.e. blue color.|
|What is the function of the RER? ||Protein synthesis and modification|
|Describe the structure of the Golgi apparatus. ||Stack of parallel flattened cisternae or sacs, each cisternae has 2 faces:
-Cis Golgi or forming face (convex) towards nucleus.
-Trans Golgi or mature face (concave)towards plasmalemma.
|What is the function of the Golgi apparatus? ||It is concerned with secretory activity of the cell.
Modification and sorting of proteins manufactured on RER.
Has a role in membrane biosynthesis. |
|Describe the structure of the lysosomes. ||They have different sizes and shapes.
They have hydrolytic enzymes.|
|What is the function of lysosomes? ||Digestion of macromolecules, microorganisms, cellular debris and excessive organelles|
|What are the types of lysosomes? || 1- Primary lysosomes: recently formed and don`t contain digested material.
2- Secondary lysosomes: phagosome - auto phagic vacuole - pinocytotic vesicle
3- Residual body: lysosome that digested materials.|
|What are peroxisomes? ||They contain oxidative enzymes that are responsible for break down of H2O2 (Hydrogen peroxide), which is a toxic substance.|
|What are endosomes? ||They are system of tubules and vesicles
They prepare contents for the destruction by lysosomes|
|What are the types of cytoskeleton? ||-Microtubules formed of tubulin
-Filaments = microfilaments.
Thick filaments: (Myosin) - Intermediate filaments: (Tonofilaments) - Thin filament: (Actin)|
|What is the function of the cytoskeleton? ||Shape and movement of the cell, cilia, flagella
Transport of vesicles and chromosomes|
|What is the function of the centriole? ||It is involved in cell division.|
|What are the types of ribosomes? ||Attached and free ribosomes|
|Describe the structure of attached ribosomes. ||They are granules consist of 2 subunits: large and small.
They are attached to (RER) by their large subunit.|
|What is the function of attached ribosomes? ||Attached ribosomes are responsible for protein secretion to outside the cells (proteins for export).|
|Describe the structure of free ribosomes. ||They are granules consist of 2 subunits: large and small.|
|What is the function of free ribosomes? ||Free ribosomes are responsible for protein synthesis inside the cells.|
|What are cell inclusions? ||These are the non- living structures of the cell|
|What are the types of cell inclusions? ||Pigments: Melanin - Lipofuscin - Haemosidrin
Lipid = Fat droplets.
Glycogen : stored in liver cell and muscle.|
|Give examples of specializations of the cell. ||Apical : Microvili, cilia, cell coat
Lateral: Junctional couplex (Gap junction)
Basal: Basement membrane (hemidesmosomes).|