CELL A cell is an elementary unit of a living system. Specific functions in a cell are distributed between
organelles - intracellular structures. Despite the variety of forms, cells of different types
have striking similarities in their main structural features.
A cell is an elementary living system consisting of three main structural
elements - shell, cytoplasm and nucleus. Cytoplasm and nucleus form protoplasm.
Almost all tissues of multicellular organisms are composed of cells. On the other hand, slime molds consist
from a cell mass undivided by septa with many nuclei.
Cell
Small organisms may consist of only hundreds of cells. Human organismincludes 1014 cells. The smallest cell currently known has the size
0.2 microns, the largest - an unfertilized Epyornis egg - weighs about 3.5 kg.
On the left is exterminated
several centuries ago
epiornis.
On the right is his egg, found
in Madagascar
Typical sizes of plant and animal cells range from 5 to 20 microns. Wherein
There is usually no direct relationship between the size of organisms and the size of their cells.
In order to maintain the required concentration of substances, the cell must
be physically separated from one's surroundings. At the same time, vital activity
the body involves intensive metabolism between cells. The role of the barrier
The plasma membrane plays between cells. Internal structure cells long
time was a mystery to scientists; it was believed that the membrane limits protoplasm -
some kind of liquid in which everything happens biochemical processes. Thanks to
electron microscopy managed to reveal the secret of protoplasm, and it is now known that
inside the cell there is a cytoplasm in which various organelles are present, and
genetic material in the form of DNA, collected primarily in the nucleus (in eukaryotes).
The structure of a plant cell.
There are plastids;Autotrophic type of nutrition;
ATP synthesis occurs in
chloroplasts and mitochondria;
There is cellulose
cell wall;
Large vacuoles;
The cell center is only
the lower ones.
The structure of an animal cell
There are no plastids;Heterotrophic type of nutrition;
ATP synthesis occurs in
mitochondria;
Cellulose cell wall
absent;
Vacuoles are small;
Everyone has a cell center
cells.
Differences in the structure of plant and animal cells.
plant cellThere are plastids;
Autotrophic type
nutrition;
ATP synthesis occurs
in chloroplasts and
mitochondria;
There is cellulose
cell wall;
Large vacuoles;
Cell center only
among the lower ones.
animal cell
There are no plastids;
Heterotrophic type
nutrition;
ATP synthesis occurs
in mitochondria;
Cellulose cell
the wall is missing;
Vacuoles are small;
There is a cell center
all cells.
Common features characteristic of animal and plant cells
Fundamental unity of structure(surface cell apparatus,
cytoplasm, nucleus.)
Similarities in the flow of many chemicals
processes in the cytoplasm and nucleus.
Unity of transmission principle
hereditary information during division
cells.
Similar membrane structure.
Unity chemical composition.
Distinctive characteristics of plant and animal cells
CONCLUSION:
1.2.
Fundamental similarity of structure and
chemical composition of plant cells and
animals indicates their commonality
origin, probably from unicellular
aquatic organisms.
Animals and plants have moved far away
from each other in the process of evolution they have different
food types, various ways protection
from the adverse effects of external
environment. All this was reflected in their structure
cells.
Colorless, thick, viscous formation. Cytoplasm is the internal environment in which all other parts of the cell are located. Various biochemical processes take place in it to ensure the life of the cell. It constantly moves throughout the entire volume of the cell. Cytoplasm
A vacuole is a reservoir that contains cell sap, accumulates reserve nutrients and waste products that cells do not need. Cell sap is a liquid with sugars and mineral salts dissolved in it. As the size of the vacuole increases, the size of the cell also increases; it grows. Vacuole
Comparison of plant and animal cells Plant cell 1. 1. Strong cell wall made of cellulose 2. 2. Presence of plastids and vacuoles 3. 3. Absence cell center 4. 4. Mineral salts are in the form of crystals (inclusions) Animal cell 1. 1. The cell wall is fragile Absence of plastids and vacuoles 3. 3. Presence of a cell center 4. 4. Mineral salts are dissolved in the cytoplasm Similarities: 1. the main parts of cells – membrane, cytoplasm, nucleus 2. Similar composition of organelles (ER, Golgi apparatus, lysosomes, ribosomes, mitochondria)
Comparison of plant and fungal cells Plant cell 1. 1. Cell wall made of cellulose 2. 2. Presence of plastids 3. 3. Presence of vacuoles, the function of which is the accumulation of nutrients and harmful substances (starch), regulation, water flow into the cell One nucleus in the cell Urea is not formed Fungal cell 1. 1.Cell wall made of chitin 2. 2.Lack of plastids 3. 3.Reserve products are deposited in the form of glycogen or fat, starch is never formed Nuclei are very small, one or two, and sometimes more During metabolism urea is formed Similarities: 1. main parts of cells - membrane, cytoplasm, nucleus 2. Well-defined cell wall 3. Presence of ribosomes
Structure and function of animal and plant cells
Slide 2: The cell is the smallest structure of the entire plant and animal world - the most mysterious phenomenon of nature. Even at its own level, the cell is extremely complex and contains many structures that perform specific functions. In the body, a collection of certain cells forms tissues, tissues form organs, and those form organ systems
Slide 3: Plant and Animal cells
Slide 4
A plant cell differs from an animal cell in the following structural features: 1) A plant cell has a cell wall (shell). The cell wall is located outside the plasma membrane (cytoplasmic membrane) and is formed due to the activity of cell organelles: the endoplasmic reticulum and the Golgi apparatus. The basis of the cell wall is cellulose (fiber). The existence of hard cell membranes in plants determines another feature of plant organisms - their immobility, while in animals there are few forms that lead an attached lifestyle. 2) Plants have special organelles in their cells - plastids. 3) In a plant cell there are vacuoles bounded by a membrane - the tonoplast. Plants have a poorly developed waste excretion system, so substances that the cell does not need accumulate in vacuoles. In addition, a number of accumulated substances determine the osmotic properties of the cell. 4) There are no centrioles (cell center) in a plant cell. There are exceptions to all rules: lower plants cells can represent a whole independent organism. Cells that have lost their living contents during development can participate in the conduction of water, etc. Therefore, in botany the term “cell” is used to refer to both living and dead cells.
Slide 5: Common characteristics of plant and animal cells
Unity structural systems– cytoplasm and nucleus. The similarity of metabolic and energy processes. Unity of the principle of hereditary code. Universal membrane structure. Unity of chemical composition. Similarities in the process of cell division.
Last presentation slide: Structure and functions of animal and plant cells: Table: Distinctive features of plant and animal cells
Characteristics Plant cell Animal cell Plastids Chloroplasts, chromoplasts, leucoplasts Absent Method of nutrition Autotrophic (phototrophic, chemotrophic). Heterotrophic (saprotrophic, chemotrophic). ATP synthesis in chloroplasts, mitochondria. In mitochondria. ATP breakdown in chloroplasts and all parts of the cell where energy is required. In chloroplasts and all parts of the cell where energy is required. Cellular center in lower plants. In all cells. Cellulose cell wall Located on the outside of the cell membrane. Absent. Inclusion Reserve nutrients in the form of grains of starch, protein, drops of oil; in vacuoles with cell sap; salt crystals. Spare nutrients in the form of grains and drops (proteins, fats, carbohydrate glycogen); end products of metabolism, salt crystals; pigments. Vacuoles Large cavities filled with cell sap - aqueous solution various substances, which are spare or final products. Osmotic reservoirs of the cell. Contractile, digestive, excretory vacuoles. Usually small. Table: Features plant and animal cells
The cell of any organism is an integral living system. It consists of three inextricably linked parts: the membrane, the cytoplasm and the nucleus.
General plan of the structure of an animal cell
Composition of an animal cell
1.Outer cell membrane
2. Cytoplasm
3. Centrioles
5. Nucleolus
6. Smooth endoplasmic reticulum
7. Golgi apparatus
8. Mitochondria
9. Ribosomes
10. Cytoskeleton
11. Lysosomes
12. Microhairs
Features of the structure of an animal cell
On the surface of many animal cells, for example various epithelia, there are very small thin outgrowths of the cytoplasm covered with a plasma membrane - microvilli. Largest quantity microvilli is located on the surface of intestinal cells.
animal cell
The structure of an animal cell
It is contained in every cell of the animal body. Often there may be two or even more nuclei in a cell.
Features of the structure of an animal cell
The cell membrane has a complex structure. It consists of an outer layer and a plasma membrane. Animal and plant cells differ in the structure of their outer layer.
The outer layer of the surface of animal cells is very thin and elastic. Consists of a variety of polysaccharides and proteins. The surface layer of animal cells is called the glycocalyx.
The structure of the animal cell membrane
Features of the structure of an animal cell
Each cell is separated from the environment by a plasma membrane, 7-10 nanometers thick. But unlike plant cells, animal cells do not have a protective layer - a cellulose cell wall, which is secreted by the outer surface of the plant cell membrane.
The structure of the animal cell membrane
1. Plasma membrane
Features of the structure of an animal cell
1.Cell center
In animal cells, near the nucleus there is an organelle called the cell center. The main part of the cell center consists of two small bodies - centrioles, located in a small area of densified cytoplasm.
Centrioles
Cell center
Features of the structure of an animal cell
1. Cellular inclusions
Present in the form of grains and drops (proteins, fats, carbohydrates, glycogen); end products of metabolism, salt crystals, pigments.
Inclusions
Composition of an animal cell
1.Mitochondria
unicellular and multicellular animal organisms. They can be spherical, rod-shaped or filamentous, and are also covered with a membrane.
Features of the structure of an animal cell
There are no vacuoles or plastids in the cytoplasm of an animal cell. The presence of these two organelles and the cell membrane distinguishes a plant cell from an animal cell. Otherwise they are very similar.
An animal cell does not have a dense cell wall. It lacks vacuoles, characteristic of plants and some fungi, and plastids. As a backup energetic substance The polysaccharide glycogen usually accumulates.