بنيه الخليه

1. Cell Structure and Function
‫الرحيم‬‫الرحمن‬‫هللا‬‫بسم‬
DR.MOTAZ A.A. NUGGEDALLA

2. Types Of cells
 Prokaryotes include bacteria & lack a
nucleus or membrane-bound
structures called organelles.
 Eukaryotes include most other cells &
have a nucleus and membrane-bound
organelles (plants, & animals)

3. Eukaryotic Cell
 Contain 3 basic cell
structures:
• Cell Membrane
• Cytoplasm with
organelles
• Nucleus

4. Representative Eukaryotic Cell

5. General Cell structure:
 3 principal parts:
 Plasma (cell) membrane.
 Cytoplasm & organelles.
 Nucleus.

6. Plasma (cell) membrane

7. Plasma membrane:
 Surrounds, holds cell together & gives its form.
 10 nanometer thick.
 Separates cell’s internal structures from
extracellular environment.
 Is selectively permeable, & controls passage of
materials into & out of cell.
 Participates in intracellular communication.

8. Plasma (Cell) Membrane
 Composed of:
 Double layer of
phospholipids
(hydrophobic/
hydrophilic parts).
 Proteins span, or
partially span the
membrane.
 Negatively
charged
carbohydrates
attach to the outer
surface.

9. Plasma Membrane (continued)

10. General composition of cell membrane
 Proteins ……………………. 55%
 Lipids ……………………….. 41%
- Phospholipids … 25%
- Cholesterol ……. 12% Lipids
- Glycolipids …….. 4%
 Carbohydrates …………… 3%

11. Cytoplasm & Organelles

12. Cytoplasm, Organelles, Nucleoli (continued)

13. Cytoplasm
 The aqueous content of a
cell (fluid, jellylike
substance), that lies
between cell membrane
& nucleus in which
organelles are suspended.
 Serves as matrix
substance in which
chemical reactions occur.

14. components of cytoplasm
 Interconnected filaments
& fibers
 Fluid = cytosol
 Organelles
 storage substances

15. Cytoskeleton
 Filaments & fibers
 Made of 3 fiber types
 Microfilaments
 Microtubules
 Intermediate
filaments
 3 functions:
 mechanical support
 anchor organelles
 help move
substances

16. EM show cytoskeleton _ A = actin, IF = intermediate filament, MT = microtubule

17. Organelles
 Subcellular structures within the cytoplasm that
perform specific functions.

18. Endoplasmic Reticulum
 Helps move substances within cells
 Network of interconnected
membranes
 Two types
 Rough endoplasmic reticulum
 Smooth endoplasmic reticulum

19. Rough Endoplasmic Reticulum
 Ribosomes attached to surface
 Manufacture protiens
 Not all ribosomes attached to rough ER
 May modify proteins from ribosomes

20. Smooth Endoplasmic Reticulum
 No attached ribosomes
 Has enzymes that help build molecules
 Carbohydrates
 Lipids

21.  It is composed of two
subunits: smaller
(lighter) & larger
(darker) subunits. The
space between the two
subunits
accommodates a
molecule of transfer
RNA, needed to bring
amino acids to the
growing polypeptide
chain.
Ribosome

22. Golgi Apparatus
 Involved in synthesis of cell membrane
 Packaging & shipping station of cell

23. Golgi Apparatus Function
1. Molecules come in vesicles
2. Vesicles fuse with Golgi
membrane
3. Molecules may be modified by
Golgi

24. Golgi Apparatus Function
(Continued)
4. Molecules pinched-off in separate vesicle
5. Vesicle leaves Golgi apparatus
6. Vesicles may combine with plasma
membrane to secrete contents

25. Animation from: http://www.franklincollege.edu/bioweb/A&Pfiles/week04.html
See a Golgi movie

26. Lysosomes
 Contain digestive enzymes
 Functions
 Aid in cell renewal
 Break down old cell parts
 Digests invaders

27. LYSOSOMES
Image modified from: http://www.people.virginia.edu/~rjh9u/lysosome.html
See
lysosomes
in action:

28.  The structure of
a mitochondria.
The outer
mitochondrial
membrane &
the infoldings
of the inner
membrane. The
fluid in the
center is the
matrix.
Mitochondria

29. Mitochondria
 Break down fuel molecules (cellular
respiration)
 Glucose
 Fatty acids
 Release energy
 ATP

30. Centrioles
 Pairs of microtubular structures
 Play a role in cell division

31. Cilia & Flagella
 Provide motility
 Cilia
 Short
 Used to move
substances outside
human cells
 Flagella
 Whip-like extensions
 Found on sperm cells
 Basal bodies like
centrioles

32. Cytoplasmic Organelles: Structure & Function
Function
Structure
Component
Agranular (smooth) ER metabolizes nonpolar
compounds & stores Ca2+ in striated muscle
cells; granular (rough) ER assists in protein
synthesis
System of
interconnected
membrane-forming
canals & tubules
Endoplasmic
reticulum
Synthesize proteins
Granular particles
composed of protein &
RNA
Ribosomes
Synthesizes carbohydrates & packages
molecules for secretion. Secretes lipids &
glycoproteins
Cluster of flattened
membranous sacs
Golgi complex
Release energy from food molecules &
transform energy into usable ATP
Membranous sacs w
folded inner partitions
Mitochondria
Digest foreign molecules & damaged
organelles
Membranous sacs
Lysosomes

33. Nucleus

34. NUCLEUS
THE “BRAIN”
IT CONTROLS ALL CELL
ACTIVITIES

36. Definition
 It is rounded or elongated organelle
present in all mammalian cells except
the red blood cell.
 It plays an important role in heredity, cell
division and controlling all cellular
functions.

37. General characteristics
 Number: usually one, two may present in some
liver cells and many nuclei are present in the
skeletal muscle cells.
 Size: is variable.
 Shape: is variable; rounded, oval, flattened,…
 Position: may be central, eccentric or peripheral in
position.

38. Structure of the nucleus
 Nuclear membrane.
 Nuclear sap and
matrix.
 Nucleolus.

39. The nuclear membrane
 Surround the
nucleus and
disappear during
cell division.
 Nuclear pores: they
are the openings in
the nuclear
membrane.

40. The nuclear sap and matrix
 It is a colloidal clear solution, which is formed of:
Nucleoproteins, enzymes, and some minerals.
 According to the amount of the sap nuclei are:
 Open face type.
 Condensed (closed) type.
 Functions: a medium for the ribonucleic acids
interaction.

41. The nucleolus
 It is a basophilic mass formed of RNA & DNA.
 It disappear during cell division.
 Nucleolus size depend on the cell activities.
Functions of nucleolus:
1. Controls the cell functions.
2. Store the genetic informations.
3. Regulates the cell division.
4. Forms the Ribosomal RNA.