The document discusses the history and principles of cell theory. It describes how early microscopists like Hooke, Levenguk, and Purkinje made early observations of cells. In 1839, Schwann and Schleiden formulated the first principles of cell theory: (1) all living things are made of cells and (2) animal and plant cells have similar structure and composition. Later, Virchow added that cells only arise from preexisting cells. The modern cell theory includes four principles: (1) cells are the basic unit of life, (2) cells have similar composition and function, (3) new cells arise from existing cells, and (4) cell specialization leads to tissue and organ formation

1. The main principles of the Cell
theory. Prokaryotes and eukaryotes
Biology/topic 2-3

2. The first steps in study of cells
he history of the discovery and study of cells
connected with the invention and an
improvement of the microscope. Cell was
opened in 1665 by Robert Hooke, who described
the cell walls of cork. Levenguk first observed
the single-celled organisms. Purkinje described
the internal contents of the cell - the protoplasm.
R.Broun opened the nucleus.

4. In 1839 zoologist T. Schwann used the data
(information) of botanist M. Schleiden
formulated the basic position of the Cell
theory:
1. All living organisms are composed of cells;
2. Cells of animals and plant similar in structure
and chemical composition.
3. German Virchow added to the Cell theory
position: Each cell is formed by division of the
mother cell.

5. Modern cell theory includes the
following statements:
• 1) The cell - the smallest structural and functional
unit of life.
• 2) The cells of all living organisms are similar in
structure and chemical composition, metabolic
processes and the most important manifestations of
life.
• 3) The new cells are formed by the division of the
mother cell.
• 4) The cells of multicellular organisms are
specialized by function and form tissues, which
make up the organs.

6. • The study of cells is important for the
development of science and medicine in
particular. So, in many diseases are affected
cells, and knowledge of the mechanisms of cell
division, of metabolic processes in the cell will
allow to develop new methods of treatment of
these diseases.

7. Live
organisms
Prokaryotes
Eukaryotes

8. Cells without nucleus
pro - "before“
Karyon - "nut or kernel"
Prokaryotes - is organisms, cells of which do not
have a nucleus, they lack a membrane-bound
nucleus (karyon). They include bacteria and
cyanobacterias.

9. Cells without nucleus
pro - "before“
Karyon - "nut or kernel"

11. Cells with nucleus
eu - “true“
Karyon - "nut or kernel"

12. Eukaryotes - are organisms whose cells have a
nucleus, demarcated from the cytoplasm by
nuclear membrane. Eukaryotes include all
animals, plants and fungi.
A typical animal cell
A typical animal cell

13. Similarities and differences of
prokaryotes and eukaryotes cells
Features
Nucleus
Nucleoid
DNA molecule
Мosaic structure of DNA
Ribosomes
Мembranous organelles
Cytocentrum
Мezosomy
Cell size
Cell division
Prokaryotes
Eukaryotes

15. Similarities and differences of
prokaryotes and eukaryotes cells
Features
Prokaryotes
Eukaryotes
Nucleus
-
+
Nucleoid
+
-
forms a ring
divided into fragments
Мosaic structure of DNA
-
+
Ribosomes
+
+
Мembranous organelles
-
+
Cytocentrum
-
+
Мezosomy
+
-
small (0,2-10 мкм)
big (10-100 мкм)
direct binary division
mitosis, meiosis
DNA molecule
Cell size
Cell division

16. The main features of prokaryotes:
1) no nucleus; instead nucleus is
nucleoid (equivalent of nucleus)
devoid of the nuclear membrane
and consisting of a DNA molecule
in the form of a ring;
2) there are no organelles with the
membrane structure;
3) have mezosomy (invagination
of plasma membrane) that
function as membrane organelles;
4) characteristically by simple
binary division.

17. The main features of eukaryotes:
1) DNA-associated with proteins - histone
and forms the chromatin which at the
division of cells is transformed into
chromosomes;
2) DNA have a mosaic structure (between
the genes are uninformative areas –
spacers; in genes are exons - informative
sites and introns - non-informative sites);
3) have all cytoplasmic organelles with the
membrane and non-membrane structure;
4) eukaryotic cells divide by mitosis,
meiosis.

18. Recap quiz:
What are Prokaryotes?
What are Eukaryotes?
What kind of Prokaryotes do you know?
What kind of Eukaryotes do you know?
Who first did enter the term “nucleus”?
Who did formulate the cell theory ?
What is Homeostasis?
What statements does Modern cell theory
include?
 What is the difference between the Prokaryot
and Eukaryot cells?
 What is the similarity between the Prokaryot
and Eukaryot cells?









19. Home task:
• Learn definitions which you wrote on the lesson

20. • https://www.facebook.com/groups/267369803416703/
• kiolk@tut.by
• Skype: tyteishi