BAGHDAD COLLEGE OF MEDICINE CELL BIOLOGY - Prof. Dr Zuhair Radhi Zahid E. Mail : zuhair_zahid @yahoo . com.

BAGHDAD COLLEGE OF MEDICINE
       CELL BIOLOGY

Prof. Dr Zuhair Radhi Zahid
 E. Mail : zuhair_zahid @yahoo . com.

Objective :
 1. Describe structure , ultrastructure , and
function of plasma
     membrane.
  2. Describe membrane models.
  3. Evaluate biomedical significance of plasma
membrane.
  4. Define cellular aging.
  5. Give examples on clinical relevance related to
cellular aging.
  6. Describe cellular activity and give examples.
  7. Evaluate clinical relevance.

Summary:
    PLASMA MEMBRANE:
   1. The plasma membrane (PM) is a trilaminar
    structure
   2. The (PM) is symmetrical and / or asemytrical
   3. At least five types of functional proteins are
    present in the (PM)
   4. Receptors and reception are of great biomedical
    significance
   5. Structural proteins are of three types
   6. Clinical relevance to (PM) is also considered

   CELLULAR ACTIVITY:
   1. Growth, cell division, muscle contraction, release,
    synthesis are certain examples on cellular activity
   2. Cellular energy (ATP) is required to perform such
    activity
   3. Neuromuscular junctions (Synapse) ,
    neuroglandular synapse, neurovascular synapse are
    considered

    4. Muscular atrophy is an example on
    neuromuscular injury

   CELLULAR AGING
   1. In elderly , normal aging as affected by several factors, these
    are hormonal, environmental …..etc.
   2. Cellular aging may be induced by certain factors as for
    example genetical pollution and malnutrition
   3. Alzheimer , Parkinson's diseases are common at elderly

   NOTE: A brief account on macromolecules is also considered
    during this course with special reference to DNA molecule

Details: Plasma membrane

The trilaminar structure of plasma
membrane, models, transport of
molecules, reception , recognition and
other functions of plasma membrane are
to be studied.
Other topics, for example, cellular aging,
cellular activity , nanotechnology and
synthetic biology are to be considered by
students.

Symmetry and asymmetry of the plasma
  membrane:
1.The presence or absence of carbohydrate
  chains project externally forming the
  glycocalyx (a muco-
Polysaccharide) giving the impression
  whether it is symmetrical or
  asymmetrical.
2.The arrangement of three types of
  structural proteins ( alpha, beta, and
  globular) within the external and internal
  layers of the plasma membrane
  determine whether the plasma membrane
  is symmetrical or asymmetrical.

According to their function, proteins in the
  plasma membrane are classified into :
1.Channel proteins : allows a particulsr
  molecule or ion to cross the plasma
  membrane freely ;CYSTIC
2.FIBROSIS , an inherited disorder, is caused by
  a faulty chloride channel.
3.Carrier protein : Selectively interacts with a
  specific    molecule or ion so that can cross
  the plasma membrane.
The inability of some persons to use energy for
  sodium-potassium transport has been
  suggested as the cause of their obesity.

4.Cell recognition protein :
  The MHC ( major histo-Compatibility
  complex ) . Glycoproteins are different
  for each person, so organ transplants are
  difficult to achieve. Cells with foreign
  glycoproteins are attacked by blood cells
  responsible for immunity.
 5.Receptor protein: is shaped in such a
  way that a specific molecule can bind to
  it. Pigmies are short,
  Not because they don’t produce enough
  growth hormone, but because their
  plasma membrane
Growth hormone receptors are faulty and
  cannot interact with growth hormone.

6.Enzymatic protein : Catalyzes a specific reaction.
      The membrane protein adenylate cyclase,
involved in ATP metabolism. Cholera bacteria release
a toxin that interferes with the proper functioning of
adenylate cyclase; Sodium ions and water leave
intestinal cells and the individual dies from severe
diarrhea.

The second function of the
 receptor is initiating a biological
 response. The mechanism of
 interaction between the signal
 and the receptor involves a
 conformational change, this of
 great biomedical
Significance such as in the
 immune system, drug receptor
 interaction and fertilization (
 cell-cell interaction.

CELLULAR ACTIVITY
   1. To study examples such as :-
       a. Growth
       b. Cell division
       c. Release of secretion
       d. Transport of molecules
       e. Contractions of muscles ( neuromuscular junction )
       f. Synthesis
   2. Control of cellular activity
      a. Negative feed back mechanisim as between glucagon
          and insulin
      b. Energy requirements
   CLINICAL RELEVANTS:
   1. Muscular atrophy due to neural degeneration
   2. Diabetes

Cellular aging : Studies on the cellular aging
  proposed several theories. The genetic apparatus
  of the cell has been examined for clues to
  sequences, since altered flow of information at
  any point in the sequence from DNA to RNA to
  protein synthesis and degradation could be
  involved.
A decline in the hormonal system can affect many
  different organs in the body. The immune system
 too; no longer performs as it once did, and this can
  affect the body as a whole. Today, elderly were
  not as aware they were younger of the importance
  of, for example, diet and exercise
To general health, iy is possible, then that much of
  what we attribute to aging is instead due to years
  of poor health habits

One school has focused upon the role of the
 CNS
, notably, dopamine, nor epinephrine, and
 serotonin. These neurotransmitters have
 come under
 special study in part because of known
 alterations in certain age related neurological
 diseases (e.g. Parkinson and Alzheimer).
Recent technologies :
 1. Nanotechnology : Two of the 21st century’s
 technologies      are     biotechnology    and
 nanotechnology. The latter is new area of
 science that involves working with materials
 and devices that are the nano-scale ( one
 nanometer is billionth of a meter).

References :
  1.Watson J D, Crick F H C : Molecular
    Structure of nucleic acids. Structure
    For DNA . Nature 1953; 171 : 737-738.
  2.Zuhair R Zahid : Synthetic biolology :
    Science of the unthinkable. J Fac Med
    Baghdad 2011; 53(4); 406-407.
  3.Zuhair R Zahid : Man made stem cells.
    J Fac Med Baghdad 2013; 55(1); 83-85.
  4.Bruce Alberts, D Bray, J Lewis, M Raff, K
     Roberts J D Watson : Molecular Biology
     of the cell . Third Ed.(1994). Garland
     publishing Inc. New York and London.
5.en.wikipedia.org/wiki/macromolecule.
6.www.annualreviews.org./doi/abs/10.
                  1146/annurev.biophys.