cell structure

1. CELLS,
STRUCTURE
AND
FUNCTION
BY
Assist lecturer : Asawer Kareem

2. INTRODUCTION
• All living things are
made up of cells. Cells are
the smallest units that can
be alive. During the 1950’s
scientists developed the
concept that life on earth
is classified into six
kingdoms and each have
their own characteristic
kind of cell.

3. What was the cell ??
• Every thing we know about
cells we call “ cell theory”.
• 1. All living things are composed
of cells.
• 2. Cells are the basic unit of
structure and function in living
things.
• 3. New cells are produced from
existing cells
Virchow

4. Number of Cells
• Although ALL living things are made of cells,
organisms may be:
• Unicellular – composed of one cell
• Multicellular- composed of many cells.

5. Size of Cells

6. The basic types of cells with
STRUCTURAL differences.
Eukaryotes
Animal Plant
Bacteria
Prokaryotes

8. Prokaryotic
• No nucleus
• Few internal structures
• have simple ribosomes
• Smaller & simpler than
eukaryotic cells
• Ex. Bacteria

9. Eukaryotic
• Have a membrane bound
nucleus, control center that
holds DNA (genetic
material)
• Contain organelles
surrounded by membranes
(small organs)
• Most living organisms
• Larger & more complex
than prokaryotic cells

10. Prokaryotic Cell Eukaryotic Cell
• The Cell Wall
• The Plasma Membrane
• The Cytoplasm
• The Genetic Material
• The Ribosomes
• The Cell Wall
• The Plasma Membrane
• The Nucleus
• The Nuclear Membrane
• The Nucleolus
• The Mitochondria
• The Chloroplast
• The Endoplasmic Reticulum
• The Ribosomes
• The Golgi Bodies
• The Lysosomes
• The Vacuoles
• The Cytoplasm
• The Chromosomes

11. Two Main Types of Eukaryotic Cells
11
Plant Cell Animal Cell

13. Similarities between plant cells
and animal cells
Both have a cell membrane
surrounding the cytoplasm
Both have a nucleus
Both contain mitochondria

14. 14
Differences between plant cells
and animal cells
Relatively
smaller in size
Irregular shape
No cell wall
Relatively larger
in size
Regular shape
Cell wall present

15. 15
Animal cells Plant cells
Vacuole small or
absent
Glycogen as food
storage
Nucleus at the
center
Large central
vacuole
Starch as food
storage
Nucleus near cell
wall
Differences between Plant
Cells and Animal Cells

16. 16
Different kinds of animal cells
white blood cell
red blood cell
cheek cells
sperm
nerve cell
muscle cell
Amoeba
Paramecium

17. Cell wall
Nonliving layer
Gives structure
and shape to plant
and bacterial cells

18. Cell membrane
Surrounding the Cell
Lies immediately against the cell
wall in plant cells
Made of protein and phospholipids
Selectively permeable

19. Cytoplasm of a Cell
Jelly-like substance Between the cell
surface membrane and the nucleus
Contains enzymes and organelles as:
• Mitochondria ,Ribosomes,
Chloroplasts (only in plant cells) , Cell
vacuoles etc.…

20. Nucleus
• Surrounded by a membrane
called the nuclear envelope
• Contains one or more nucleoli
• Contains chromatin
• Functions of the nucleus:
• 1. Controls cell activities such as;
cell growth and the repair of
worn-out parts
• 2. Essential for cell division

21. Nucleolus
• Cell may have 1 to 3
nucleoli Inside nucleus
• Disappears when cell
divides
• Makes ribosomes that
make proteins

22. Smooth & Rough Endoplasmic
Reticulum
Smooth ER: no
ribosomes; makes
lipids
Rough ER: has
ribosomes ; making
proteins

23. Mitochondria
• Rod shape Site of Cellular respiration
• Aerobic respiration occurs in the mitochondria
Energy production
• Energy used to perform cell activities such as
growth and reproduction

24. Cell Differentiation
The process by which cells develop to carry out
specific functions.

25. 25
Levels of Organization
CELLS (muscle cells , nerve cells)
TISSUES (muscle, epithelium)
ORGANS (heart, lungs, stomach)
SYSTEMS (circulatory system)
ORGANISM (human)

26. Living Levels
Cell Tissue Organs System Organism

27. Thank you