Cellular Level of Organization
Lecture 2
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Topics:
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4.
RESEARCH METHODS IN CYTOLOGY
Cell. Membrane organelles
Cell. REMEMBRANCE ORGANELLES
Nucleus, chromosome
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Topic: RESEARCH METHODS
IN CYTOLOGY
QUESTIONS
1.
What studies Cytology.
2.
The idea that organisms are made up of cells.
3.
Research methods used in Cytology.
4.
Cell fractionation.
5.
Autoradiography.
6.
Determination of the duration of some stages of the cell
cycle by radio.
RESEARCH METHODS
IN CYTOLOGY
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What studies Cytology (I)
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1.
2.
3.
4.
5.
Cytology - the science of the cell.
From among other biological Sciences, it stood out almost 100 years
ago.
For the first time generalized information about the structure of
cells were collected in the book Zh.-B. Karnua «Сell Biology",
published in 1884.
Modern Cytology studies:
structure of cells, their functioning as elementary living systems;
the functions of individual cell components;
the process of reproduction of cells and their reparations;
adaptation to environmental conditions and many other processes
that allow to judge the properties and functions common to all
cells.
Cytology also considers the features of the structure of specialized
cells.
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IN CYTOLOGY
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What studies Cytology (II)
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Cytology is closely related to
Biochemistry
Biophysics
Molecular biology
Genetics
The discipline "Cytology" refers to the fundamental sections of
biology, because it explores and describes the only unit of all life on
Earth – the cell.
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IN CYTOLOGY
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Cell theory
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In the XVII century. Robert Hooke, a physicist and biologist,
characterized by great ingenuity, created a microscope. He
called small units cells.
in 1839, Matthias Schleiden (Germany) and Theodor Schwann
(Germany) independently formulated the cell theory
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The main positions of the cell
theory (I)
• The cell is the basis of structural and functional organization of
plants and animals;
• Plant and animal cells are similar in structure and develop
similarly (by dividing the original cell);
• Cells in all organisms have a membrane structure;
• The nucleus of a cell represents its main regulatory organoid;
• Cellular structure of living organisms is the evidence of the
unity of their origin
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The main positions of the cell
theory (II)
Additions were made to the cell theory in
the period of 1855-1859
Rudolf Virchow (Germany):
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Cells arise only from cells through
reproduction. This point of the cell
theory excludes the possibility of cell
formation from the non-cellular
material;
The cell is a unit of pathology..
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Research methods in Cytology
1. Ordinary light microscopy, which has not lost its role.
2. Polarizing microscopy.
3. Ultraviolet microscopy.
4. Fluorescence microscopy.
5. Phase-contrast microscopy.
6. Electron microscopy
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IN CYTOLOGY
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Modern research methods
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The most useful in modern times were:
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1) Electron microscopy;
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2) Fractionation of cells by which biochemists can identify a
relatively pure fraction of cells contain certain organelles, and to
study, thus separate they are interested in metabolic reactions;
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3) radioautography, which made it possible to directly study the
individual metabolic reactions occurring in organelles.
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IN CYTOLOGY
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Fractionation method
The method allows:
to separate different organelles of the cell in a relatively
pure form;
determine the chemical composition of organelles and
enzymes contained in them;
on the basis of the data obtained to draw conclusions
about the functions of organelles in the cell.
to determine the chemical composition and enzymatic
activity of the selected organelles.
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IN CYTOLOGY
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The stages of
fractionation of the cell
Cell fractionation by centrifugation
Repeated centrifugation at progressively higher speeds
will fractionate homogenates of cells into their
components. In general, the smaller the subcellular
component, the greater is the centrifugal force required to
sediment it.
Typical values for the various centrifugation steps referred
to in the figure are:
low speed
1000 times gravity for 10 minutes
medium speed
20,000 times gravity for 20 minutes
high speed
80,000 times gravity for 1 hour
very high
speed
150,000 times gravity for 3 hours
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Topic: Cell. Membrane
organelles
Questions:
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General outline of the cell structure
Features of the structure of
prokaryotic cells
Comparison of plant and animal
cells
Characteristic of membranes
Lysosomes
Golgi apparatus
Endoplasmic reticulum
Mitochondria
Plastids
Vacuole
Metabolic cycle in a cell
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General outline of the cell structure
Golgi apparatus
Lysosomes
Cytoplasm
Chloroplast
Cell wall
Cytoplasmic membrane
Mitochondrion
Nucleus
Rough endoplasmic
reticulum
Smooth endoplasmic
reticulum
Vacuole
Ribosomes
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Cell
SHELL
PROTOPLASM
(cell wall + cytoplasmic membrane in plants
(the contents of the cell)
or cytoplasmic membrane in animals)
CYTOPLASM
KARYOPLASM
(all other contents of the cell)
(nucleus substance)
CYTOSOL
ORGANOIDS
SPARE NUTRIENTS
(soluble part
of cytoplasm)
(structurally and functionally
isolated parts of the cytoplasm)
(organic and inorganic)
MEMBRANOUS
Non-MEMBRANE
Lysosomes, Golgi apparatus,
endoplasmic reticulum,
mitochondria, plastids
Cell center, ribosomes microtubules,
microfilaments, cilia, flagella
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Comparison of plant and animal cells:
Animal cell
Plant cell
TYPE OF NUTRITION
AUTOTROPHIC
(synthesis of organic substances
from inorganic)
HETEROTROPHIC
(synthesis of organic substances
only from organic
Cell wall
PLASTIDS
(the organelles responsible for
autotrophic type of nutrition)
VACUOLE
in lower animals
performs a digestive
function
ATP synthesis
mitochondria,
mitochondria
chloroplasts
CELLULAR CENTRE
only in lower animals
starch
SPARE CARBOHYDRATES
glycogen
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Biological membrane
Protein molecules immersed in lipid bilayer
Shell or part of
the cell shell
they are part of the cell membrane
organoids (the principle of
compartmentalization)
in EUKARYOTES)
GLYCOCALYX
INTEGRAL PROTEINS
form a hydrophilic
channel - pore
transported through the
membrane of certain
substances (are carriers)
they are part of the
membrane cell
formations
in PROKARYOTES
recognition of external signals
adhesion of cells in the tissue
immune response
protein
lipid
lipid
7-21 нм
protein
PERIPHERAL PROTEINS
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Topic: Membrane organelles
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Hypotheses of increasing the
number of mitochondria in a cell:
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Mitochondria are formed from precursors
(promitochondria)
Mitochondria are formed from other
membrane organelles of the cell
The increase in the number of
mitochondria in the cell occurs as a result
of the division of the mitochondria
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Topic: CELL.
REMEMBRANCE ORGANELLES
Questions :
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Cell wall
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Microtubules
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Microfilament
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Cell center
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Ribosomes
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IN CYTOLOGY
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Topic: Nucleus.
CHROMOSOME
Questions:
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Structure and functions of the nuclear
apparatus of the cell
Definition of chromosome
Structure and function of chromosomes
Types of chromosomes
Chromosomes of "tube brushes" type
Polytene chromosomes
B-chromosomes
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The chromosome is a
Chromosome
permanent component of the
nucleus, characterized by a special
structure, personality, function
and ability to reproduce itself,
which ensures the continuity and
transmission of hereditary
information from one generation
of living organisms to another.
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The term "chromosome" was
proposed in 1888 by Valldaura.
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Functions of chromosomes
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1. Information - contains DNA, which contains qualitatively different
genes that make up the genome of the cell.
2. Transcription – the reading of the information contained therein in the
course of gene expression.
3. Structural and organizational - provides extremely accurate
reproduction of chromosomes during replication and identity of child
chromosomes diverging to the poles.
4. Segregation - provides distribution of chromosomes along the poles in
different spores or gametes in meiosis.
5. Recombination - provides a significant part of the combinative
variability - recombination of linked genes.
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Karyotype
Karyotype - chromosomal complex species with its own characteristics:
- the number and size of chromosomes;
- their morphology;
- the presence of under a light microscope parts of the structure,
constrictions, satellites,
- shoulder ratio, alternation of EU-and heterochromatin.
The most important property of the karyotype is the presence of pairs of
homologous chromosomes.
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The generally accepted parts
of modern cell theory include:
 All known living things are made up of one or more cells
 All living cells arise from pre-existing cells by division.
 The cell is the fundamental unit of structure and function in all
living organisms.
 The activity of an organism depends on the total activity of
independent cells.
 Energy flow (metabolism and biochemistry) occurs within cells.
 Cells contain DNA which is found specifically in the chromosome
and RNA found in the cell nucleus and cytoplasm.
 All cells are basically the same in chemical composition in
organisms of similar species.
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Thank you for attention!!!
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