1 cell organelles continuous……... 2 the cytoskeleton الهيكل الخلوى pages 126 - 131 a...
TRANSCRIPT
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Cell OrganellesCell Organelles
Continuous……..Continuous……..
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The Cytoskeleton الهيكلالخلوى
Pages 126 - 131
A network of fibres االلياف من that provide structural شبكةsupport تدعيم to the cell extending throughout تمتدthe cytoplasmخالل
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Cytoskeleton
Page 126 - 131
Responsible for cell motilityحركة , and
separation of chromosome during cell division انفصال
اثناء الكروموسوماتالخلوي .االنقسام
(Tubulin protein)
Support cell motility and
transport materials within the cell نقل
الخلية داخل .المواد
(Actin protein)
Support the cell shape and fixing
position of organelles.
(Fibrous protein)
MicrofilamentsIntermediate
filamentsMicrotubules
Thick Thin Middleسميكة رفيعة متوسطة
أنيبيبات دقيقة
دقيقة ألياف ألياف متوسطة
4Page 127
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• The cytoskeleton is dynamicمتحرك , dismantling يتفككin one part and reassembling يتجمعin another to change cell shape الخلية شكل . يغير
Functions of the cytoskeleton
1. The cytoskeleton provides mechanical supportدعم and maintains shape of the cell الخلية شكل على . يحافظ
2. The cytoskeleton also plays a major role اساسي دور in cell يلعبmotility الخلية مع by interacting حركة البروتين motor proteins االتصال.الحركى
3. Interactions of motor proteins and the cytoskeleton circulates تدور materials الموادwithin the cell.
4. Motor molecules also carry organelles العضيات to variousتحملdestinations العمل .by the cytoskeleton أماكن
Fig. 7.21a, Page 126
The Cytoskeleton الخلوى الهيكل
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MicrotubuleMicrotubule
Motor Protein
Organelle
P
Energy
Microtubules functions as tracks قضيب that guide motor proteins carrying organelles to their destination المكان.المستهدفe.g. They move chromosomes during cell division
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Fig. 7.22, Page 128
المركزي Centrosomeالجسم
• In animal cells, the centrosome has a pair of centrioles السنتريوالت من each with 9 triplets of ,زوجmicrotubules
• أنيبيبات ثالثة من مكون منها كل مجموعات ) تسعة 9 + 0 pattern) arranged in a ring دائريا .مKرتبة
• During cell division the Centrioles replicate تتضاعف.
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• Microtubules are the central structural supports both cilia األهداب and flagella األسواط.– Both can move unicellular and small multicellular organisms by
propelling الماء .water outside the organism دفع
Fig. 7.23, Page 129
Cilia and Flagella
• Cilia usually occur in large numbers on the cell surface.
• Flagella usually occur in just one or a few per cell.
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cilia
flagellum
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Fig. 7.24
Both cilia and flagella have the same ultrastructure الدقيق .التركيبBoth have a core مركز of microtubules surrounded by ب محاطة
the plasma membrane. 9-doublets (9 + 2 pattern) أنيبيبتان من مكون منها كل مجموعات of تسعة
microtubules arrangedمرتبة aroundحول a pair زوج at the
centerالمركز.
The outer doublets are
also connected by motor
proteins.The structure of cilium
and flagellum is identical
to that of centriole.
Cilia and flagella are formed
of arms of a motor protein
(dynein الداينين بروتين ).
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7- Cell membrane
Fig. 7.6, Page 113, and Fig. 7.29 Page 133
• The plasma
membrane
functions as a
selective barrier
إختيارى that حاجز
allows passage
of oxygen,
nutrients, and
wastes for the
whole volume of
the cell.
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Cell membrane
Composed of lipids (phospholipids) and proteins
Lipid layer contains hydrophilic and hydrophobic regions
Phospholipid
Hydrophilic م<حبللماء
Hydrophobic للماء كاره
Proteins
Carbohydrate chains
Fig. 7.6 Page 113, and Fig. 7.29 Page 138
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Term Prokaryotes EukaryotesSize 1-10 µm in diameter 10-100 µm in diameter
Cell wall Existed In plant cell (not animal cell)
nucleusNo nuclear envelope but Nucleoid
True nucleus exists with nuclear envelope
DNAAs fibre in the nucleoid region (plasmids in some cases)
As Chromatin (DNA and
protein)
Specialized Organells Most of them are absent All are existed
Cell division By Binary Fission Meiotic and/or Mitotic
Comparison between Prokaryotes and Eukaryotes