Cell structure drawing without captions. The structure of the cell membrane. Significant differences between plant and animal cells

The structure of animal and plant cells

Different in structure eukaryotic cells similar. But along with the similarities between the cells of organisms different kingdoms living nature there are noticeable differences. They relate to both structural and biochemical features.

The figures show a schematic and three-dimensional image of animal and plant cells with the location of organelles and inclusions in them.

Figure 10 - Schemes of the structure of an animal cell.

The cytoplasm of a cell contains a number of tiny structures that perform various functions. These membrane-bounded cellular structures are called organelles The nucleus, mitochondria, lysosomes, chloroplasts are cellular organelles. Organelles can be separated from the cytosol by a single or double layer membrane.

Main function membrane is that various substances move through it from cell to cell. In this way, the exchange of substances between cells and intercellular substance occurs. Also, a plant cell has a rigid cell wall above a membrane. The cell walls of neighboring cells are separated by a middle plate, and to carry out metabolism in the cell walls there is a system of holes - plasmodesmata.

Figure 11 shows diagrams of the structure of a plant cell.

Figure 11 – Schemes of the structure of a plant cell

A plant cell is characterized by the presence of various plastids, a large central vacuole, which sometimes pushes the nucleus to the periphery, as well as a plasma membrane located outside cell wall consisting of cellulose. In cells higher plants in the cell center there is no centriole, found only in algae. The reserve nutrient carbohydrate in plant cells is starch.

So, main organelles of animal and plant cells:

nucleus and nucleolus; ribosomes; endoplasmic reticulum (ER), Golgi apparatus, lysosomes, vacuoles, mitochondria, plastids, cell center (centrioles)

Cytoplasm is the internal semi-liquid environment of cells, bounded by the plasma membrane, in which they are located nucleus and other organelles. The most important role of the cytoplasm is to unite all cellular structures and ensure their chemical interaction.

Various

§ inclusion(temporary formations) - containing insoluble waste metabolic processes and reserve nutrients;

§ vacuoles;

§ the thinnest tubes and filaments that form the skeleton of the cell.

The cytoplasm includes all types of organic and inorganic substances. The main substance of the cytoplasm contains a significant amount of proteins and water. The main metabolic processes take place in it, it ensures the interconnection of the nucleus and all organelles and the activity of the cell as a single integral living system. Cytoplasm is constantly moving, flowing inside a living cell, moving with it various substances, inclusions and organelles. This movement is called cyclosis.

Lesson type: combined.

Methods: verbal, visual, practical, problem-search.

Lesson Objectives

Educational: deepen students’ knowledge of the structure of eukaryotic cells, teach them to apply them in practical classes.

Developmental: improve students’ skills to work with didactic material; develop students' thinking by offering tasks for comparing prokaryotic and eukaryotic cells, plant cells and animal cells, identifying similar and distinctive features.

Equipment: poster “Structure of the cytoplasmic membrane”; task cards; handout (structure of a prokaryotic cell, a typical plant cell, structure of an animal cell).

Interdisciplinary connections: botany, zoology, human anatomy and physiology.

Lesson Plan

I. Organizational moment

Checking readiness for the lesson.
Checking the list of students.
Communicate the topic and objectives of the lesson.

II. Learning new material

Division of organisms into pro- and eukaryotes

The cells are extremely varied in shape: some are round in shape, others look like stars with many rays, others are elongated, etc. Cells also vary in size - from the smallest, difficult to distinguish in light microscope, up to perfectly visible with the naked eye (for example, fish and frog eggs).

Any unfertilized egg, including the giant fossilized dinosaur eggs that are kept in paleontological museums, was also once living cells. However, if we talk about the main elements internal structure, all cells are similar to each other.

Prokaryotes (from lat. pro- before, earlier, instead of and Greek. karyon– nucleus) are organisms whose cells do not have a membrane-bound nucleus, i.e. all bacteria, including archaebacteria and cyanobacteria. Total number There are about 6000 species of prokaryotes. All the genetic information of a prokaryotic cell (genophore) is contained in a single circular DNA molecule. Mitochondria and chloroplasts are absent, and the functions of respiration or photosynthesis, which provide the cell with energy, are performed by the plasma membrane (Fig. 1). Prokaryotes reproduce without a pronounced sexual process by dividing in two. Prokaryotes are capable of carrying out a number of specific physiological processes: fix molecular nitrogen, carry out lactic acid fermentation, decompose wood, oxidize sulfur and iron.

After an introductory conversation, students review the structure of a prokaryotic cell, comparing the main structural features with the types of eukaryotic cells (Fig. 1).

Eukaryotes - This higher organisms having a clearly defined nucleus, which is separated from the cytoplasm by a membrane (karyomembrane). Eukaryotes include all higher animals and plants, as well as unicellular and multicellular algae, fungi and protozoa. Nuclear DNA in eukaryotes is contained in chromosomes. Eukaryotes have cellular organelles, limited by membranes.

Differences between eukaryotes and prokaryotes

– Eukaryotes have a real nucleus: the genetic apparatus of the eukaryotic cell is protected by a membrane similar to the membrane of the cell itself.
– Organelles included in the cytoplasm are surrounded by a membrane.

Structure of plant and animal cells

The cell of any organism is a system. It consists of three interconnected parts: shell, nucleus and cytoplasm.

When studying botany, zoology and human anatomy, you have already become familiar with the structure various types cells. Let's briefly review this material.

Exercise 1. Based on Figure 2, determine which organisms and tissue types the cells numbered 1–12 correspond to. What determines their shape?

Structure and functions of organelles of plant and animal cells

Using Figures 3 and 4 and using the Biological encyclopedic dictionary and textbook, students fill out a table comparing animal and plant cells.

Table. Structure and functions of organelles of plant and animal cells

conclusions

1. The cell wall, plastids and central vacuole are unique to plant cells.
2. Lysosomes, centrioles, microvilli are present mainly only in the cells of animal organisms.
3. All other organelles are characteristic of both plant and animal cells.

Cell membrane structure

The cell membrane is located outside the cell, delimiting the latter from the outer or internal environment body. Its basis is the plasmalemma (cell membrane) and the carbohydrate-protein component.

Functions of the cell membrane:

– maintains the shape of the cell and gives mechanical strength to the cell and the body as a whole;
- protects the cell from mechanical damage and the entry of harmful compounds into it;
– carries out recognition of molecular signals;
– regulates the metabolism between the cell and the environment;
– carries out intercellular interaction in a multicellular organism.

Cell wall function:

– represents an external frame – a protective shell;
– ensures the transport of substances (water, salts, and molecules of many organic substances pass through the cell wall).

The outer layer of animal cells, unlike the cell walls of plants, is very thin and elastic. It is not visible under a light microscope and consists of a variety of polysaccharides and proteins. Surface layer animal cells are called glycocalyx, performs the function of direct connection of animal cells with the external environment, with all the substances surrounding it, but does not play a supporting role.

Under the glycocalyx of the animal cell and the cell wall of the plant cell there is a plasma membrane bordering directly on the cytoplasm. The plasma membrane consists of proteins and lipids. They are arranged in an orderly manner due to various chemical interactions with each other. Lipid molecules in the plasma membrane are arranged in two rows and form a continuous lipid bilayer. Protein molecules do not form a continuous layer; they are located in the lipid layer, plunging into it to different depths. Molecules of proteins and lipids are mobile.

Functions of the plasma membrane:

– forms a barrier that separates the internal contents of the cell from external environment;
– provides transport of substances;
– provides communication between cells in the tissues of multicellular organisms.

Entry of substances into the cell

The surface of the cell is not continuous. In the cytoplasmic membrane there are numerous tiny holes - pores, through which, with or without the help of special proteins, ions and small molecules can penetrate into the cell. In addition, some ions and small molecules can enter the cell directly through the membrane. The entry of the most important ions and molecules into the cell is not passive diffusion, but active transport, requiring energy expenditure. The transport of substances is selective. Selective permeability of the cell membrane is called semi-permeability.

By phagocytosis Large molecules of organic substances, such as proteins, polysaccharides, food particles, and bacteria enter the cell. Phagocytosis occurs with the participation of the plasma membrane. At the point where the surface of the cell comes into contact with a particle of any dense substance, the membrane bends, forms a depression and surrounds the particle, which is immersed inside the cell in a “membrane capsule”. A digestive vacuole is formed, and organic substances entering the cell are digested in it.

Amoebas, ciliates, and leukocytes of animals and humans feed by phagocytosis. Leukocytes absorb bacteria, as well as a variety of solid particles that accidentally enter the body, thus protecting it from pathogenic bacteria. The cell wall of plants, bacteria and blue-green algae prevents phagocytosis, and therefore this route of entry of substances into the cell is not realized in them.

Drops of liquid containing various substances in a dissolved and suspended state also penetrate into the cell through the plasma membrane. This phenomenon was called pinocytosis. The process of fluid absorption is similar to phagocytosis. A drop of liquid is immersed in the cytoplasm in a “membrane package”. Organic substances that enter the cell along with water begin to be digested under the influence of enzymes contained in the cytoplasm. Pinocytosis is widespread in nature and is carried out by cells of all animals.

III. Reinforcing the material learned

What two large groups are all organisms divided into based on the structure of their nucleus?
Which organelles are characteristic only of plant cells?
Which organelles are unique to animal cells?
How does the structure of the cell membrane of plants and animals differ?
What are the two ways substances enter a cell?
What is the significance of phagocytosis for animals?

1. Let's define the concepts.

A cell is the structural unit of all living things.
An organelle is a specialized cell structure that performs specific functions.

2. Let us refute the statement that the nucleus is an essential component of all cells of organisms.
The nucleus is the center of all nucleated cells. However, there are organisms that do not have a nucleus - bacteria. Such organisms are called prokaryotes.

3. Let's fill out the table.

4. Let's supplement the sentences.
The internal environment of the cell is the cytoplasm. It contains the nucleus and numerous organelles. It connects organelles to each other, ensures movement various substances and is the environment in which various processes take place. The membrane serves as the outer framework of the cell, gives it a certain shape and size, performs protective and support functions, and participates in the transport of substances into the cell.

5. Let’s label the cell organelles, indicated by numbers in the figure.

1 – chloroplast
2 – cell wall
3 – cytoplasmic membrane
4 – lysosome
5 – vacuole
6 – Golgi apparatus
7 – EPS
8 – core

6. Let's fill out the table.

7. Let us designate the organelles in the outline of an animal cell.

8. Let's complete the tasks.
1) Let us designate the organelles of the cytoplasm:
a) core
c) chloroplasts
d) ribosomes
e) mitochondria
e) vacuoles

2) Let us denote the structures located in the core:
b) nucleolus

9. Let's find out the role of chromosomes in the cell.
Store hereditary information.

10. Insert the missing letters.
Endoplasmic reticulum, cytoplasm, mitochondria, ribosome, chloroplast, vacuole, chlorophyll, pinocytosis, phaocytosis.

Laboratory work
"Structure of a plant cell"

4. Let's sketch a group of plant cells.

5. Let’s draw one cell of the Elodea leaf and label its parts.

Laboratory work
"Structure of an animal cell"

2. Let's sketch a group of animal tissue cells.

3. Let's draw one cell and label its parts.

4. Let us denote the distinctive and common features animal cell with Elodea leaf cell.
The similarities are that there is a cytoplasmic membrane, cytoplasm and nucleus.

Differences: an elodea cell has chloroplasts, a cell wall and a vacuole, while an animal cell has lysosomes and mitochondria.

Objects of living nature have cellular structure similar for all types. However, each kingdom has its own characteristics. This article will help you find out in more detail what the structure of an animal cell is, in which we will tell you not only about the features, but also introduce you to the functions of organelles.

A complex animal organism consists of a large number of tissues. The shape and purpose of the cell depends on the type of tissue it is part of. Despite their diversity, we can identify general properties in cellular structure:

• membrane consists of two layers that separate the contents from the external environment. Its structure is elastic, so cells can have a variety of shapes;
• cytoplasm located inside the cell membrane. It is a viscous liquid that is constantly moving;

Due to the movement of the cytoplasm, various chemical processes and metabolism occur inside the cell.

• core - It has big sizes, compared to plants. Located in the center, inside it there is nuclear juice, a nucleolus and chromosomes;
• mitochondria consist of many folds - cristae;
• endoplasmic reticulum has many channels through which nutrients enter the Golgi apparatus;
• a complex of tubules called Golgi apparatus , accumulates nutrients;
• lysosomes regulate the amount of carbon and other nutrients;
• ribosomes located around the endoplasmic reticulum. Their presence makes the network rough; the smooth surface of the ER indicates the absence of ribosomes;
• centrioles - special microtubules that are absent in plants.

Rice. 1. The structure of an animal cell.

Scientists have recently discovered the presence of centrioles. Because they can only be seen and studied using an electron microscope.

Functions of cell organelles

Each organelle performs certain functions, and their joint work constitutes a single cohesive organism. For example:

• cell membrane ensures the transport of substances into and out of the cell;
• Inside the nucleus there is a genetic code that is passed on from generation to generation. Exactly core regulates the functioning of other cell organelles;
• The energy stations of the body are mitochondria . It is here that the substance ATP is formed, the breakdown of which releases a large number of energy.

Rice. 2. The structure of mitochondria

• on the walls Golgi apparatus fats and carbohydrates are synthesized, which are necessary for building the membranes of other organelles;
• lysosomes break down unnecessary fats and carbohydrates, as well as harmful substances;
• ribosomes synthesize protein;
• cell center (centrioles) play an important role in the formation of the spindle during cell mitosis.

Rice. 3. Centrioles.

Unlike a plant cell, an animal cell does not have vacuoles. However, temporary small vacuoles may form that contain substances to be removed from the body.

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What have we learned?

The structure of an animal cell, which is studied in biology lessons in grades 7-9, is no different from the structure of other living cells. A feature of an animal cell is the presence of a cell center, the so-called centrioles, which participate in the formation of the spindle during mitosis. Unlike plant organism there are no vacuoles, plastids or cellulose cell wall. The cell membrane is quite elastic, which makes it possible for cells to acquire various shapes and sizes.

Test on the topic

Evaluation of the report

Average rating: 4.2. Total ratings received: 271.

According to their structure, the cells of all living organisms can be divided into two large sections: non-nuclear and nuclear organisms.

In order to compare the structure of plant and animal cells, it should be said that both of these structures belong to the superkingdom of eukaryotes, which means they contain a membrane membrane, a morphologically shaped nucleus and organelles for various purposes.

Features of the structure of a plant cell:

Features of the structure of an animal cell:

Brief comparison of plant and animal cells

What follows from this

1. The fundamental similarity in the structural features and molecular composition of plant and animal cells indicates the relationship and unity of their origin, most likely from single-celled organisms. aquatic organisms.
2. Both species contain many elements of the Periodic Table, which mainly exist in the form of complex compounds of inorganic and organic nature.
3. However, what is different is that in the process of evolution these two types of cells have moved far away from each other, because from various adverse effects external environment they have absolutely different ways protection and also have different feeding methods from each other.
4. plant cell mainly differs from animals in its strong shell, consisting of cellulose; special organelles - chloroplasts with chlorophyll molecules in their composition, with the help of which we carry out photosynthesis; and well-developed vacuoles with a supply of nutrients.