Download The Cell Organelles

Lecture 3: The
Cell
The Cell Theory
 In 1838, the German botanist Matthias Schleiden concluded that all plants
were composed of cells
 In 1839, Theodor Schwann concluded the same thing for animals
 In 1855, Rudolf Virchow noted that all cells come from other cells
The cell theory states that:
1) all living organisms are made of one or more cells,
2) cells are the basic units of structure and function, and
3) cells come only from pre-existing cells.
A cell is the smallest unit that can carry on all of the processes of life
Types of cells
‫بدائية النواة‬
‫حقيقية النواة‬
Prokaryotes
Eukaryotes
Bacteria and Archaea
All Protists, Fungi,
Plants and Animals
Prokaryotic and eukaryotic cells
A) Similarities
‫أوجه‬
‫التشابه‬
 All cells are surrounded by a plasma membrane ‫غشاء بالزمى‬.
 The semi-fluid substance ‫ المادة النصف سائلة‬within the cell is called
“cytosol”, ‫ السيتوبالزم‬containing the cell organelles ‫ ِعضيات الخلية‬.
 All cells contain chromosomes which have genes in the form of
DNA.
 All cells have tiny organelles ‫ عضيات صغيرة‬called “Ribosomes” that
make proteins.
Prokaryotic and eukaryotic cells
B) Differences ‫أوجه اإلختالف‬
 A major difference ‫ الفرق األساسي‬between prokaryotic and eukaryotic
cells is the location of chromosomes ‫موضع الصبغيات‬
 In an eukaryotic cell, chromosomes are contained in a true nucleus
(‫ )النواة‬with nuclear membrane ‫غشاء نووي‬.
 In a prokaryotic cell, the DNA is concentrated in the nucleoid (‫)شـبه نواة‬
without a nuclear membrane separating it from the rest of the cell.
 In prokaryotic cell, DNA is a single strand (‫ )أحادى الشريط‬or double strand
(‫)ثنائي الشريط‬, but in eukaryotic cell, DNA is double strand.
Comparison between Prokaryotes and Eukaryotes
Term
Prokaryotes
Eukaryotes
Size
1-10 µm in diameter
10-100 µm in diameter
Cell wall
Existed
In plant cell (not animal
cell)
nucleus
No nuclear membrane but
Nucleoid
True nucleus exists with
nuclear membrane
DNA
As fibre in the nucleoid
region (plasmids in some
cases)
As Chromatin (DNA and
protein)
Specialize
Most of them are absent
organells
All are existed
Cell
division
Meiotic and/or Mitotic
By binary fission
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Types of
Prokaryotes
Prokaryotes
Bacteria
Archaea
Exist in most environments
Exist in extreme
environments ‫البيئات القاسية‬
(hot and salty)
They are differing in some other structural, biochemical and
physiological characteristics ‫صفات‬
Bacteria
‫شبه نواة‬
‫الريبوزومات‬
‫غشاء بالزمى‬
‫الجدار الخلوى‬
‫الكبسولة‬
‫األسواط‬
The prokaryotic cell is much simpler in structure, lacking a nucleus and
the other membrane-enclosed organelles of the eukaryotic cell.
Prokaryotic Cell
Plasma
membrane
Ribosomes
Nucleoid
Cell Wall
Cytoplasm
(Cytosol)
Capsule
Eukaryot
es
 An eukaryotic cell has internal membranes, which partition
‫ تـُقـَســم‬the cell into compartments ‫أجزاء مستقلة‬.
 These membranes also participate in metabolism as many
enzymes are built into membranes.
 The general structure of a biological membrane is a double
layer ‫ ثنائي الطبقات‬of phospholipids and diverse proteins ‫بروتينات‬
‫متنوعة‬.
 Each type of membrane has a unique combination ‫تركيب مـُمـَيـٍز‬
of lipids and proteins for its specific functions.
 For example, those in the membranes of mitochondria
function in cellular respiration.
Eukaryot
es
Eu: True
Karyon: Nucleus
Animal Cell
Plant Cell
Compare between Animal and Plant cell?
What are the functions of cell organelles ?
‫الشبكة اإلندوبالزمية‬
‫الكروماتين‬
‫نوية‬
‫النواة‬
‫الغالف النووى‬
‫ناعمه‬
‫خشنه‬
‫سوط حركى‬
‫جسم مركزى‬
‫ريبوسوم‬
‫حهاز جولـﭽـي‬
‫حلمات دقيقة‬
‫غشاء بالزمي‬
‫ميتوكوندريا‬
‫جسم ُمحلل‬
‫الهيكل الخلوى‬
‫فجوة مركزية‬
‫بالستيدة خضراء‬
‫الجدار الخلوى‬
‫ثقوب بينية‬
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