Cell and cell structure

Every creature is made up of cells. Some organisms, such as bacterial bacteria, can exist as single-celled organisms. Some organisms (including humans) are made up of countless cells working together. The human body has hundreds of millions of cells. These cells make up tissue (such as muscle tissue and skin tissue) or form organs (such as liver and lungs). The animation below shows the relationship between the organ (liver) and the cells that make up the organ. The last picture is a close-up of a single cell.

The normal functioning of the human body depends on organs such as the heart and lungs. Within the tiny cells that make up the organ, there are smaller structures, organelles. These organelles help the cells to do their job. In cancer, changes in organelles can cause serious problems for individual cells and even for the entire body. To better understand how cells work, let’s first look at some of the subcellular structures.

The organelles we will discuss play an important role in the flow of information and energy production within the cell. In addition, we also need to observe the structure that makes the cells have a certain shape and reproductive ability. The organelles and all the processes we are discussing are directly related to malignant tumors, because the structure and activity of these cells are disrupted by cancer.

The picture below shows two live mouse cells. The red is the mitochondria ( mitochondria ), the blue is the nucleus (where the bright blue part is the chromosome chromosomes). The green part near the nucleus is the golgi apparatus . The Golgi is an organelle in the cell that is responsible for “processing” and “packaging” molecules.

Stained Cells

                                                 The use of the above images has been approved by the copyright owner Molecular Probes.

The following sections detail the organelles responsible for maintaining cell function:

  • Organelle overview
  • Nucleus
  • Mitochondria
  • Ribosome
  • Cytoskeleton
  • Cell structure summary
  • Interactive games: understand the process

Organelle overview

The function of the body is divided and completed according to different organs and tissues. Gastrointestinal digestion of food, bone provides structure and strength, and the brain center is responsible for information processing and instructions to other parts of the body.

Similarly, the function of a single cell is also divided and completed by a group of organically bound biomolecules. The structures within these cells are similar to those in the body, called organelles.

The organelles are suspended in a water-based viscous liquid. This liquid is called cytosol ( the cytosol ). In the nucleus ( Nucleus cytosol (the cytosol)) other than the cytoplasm and organelles referred to as ( cytoplasm ). The cytoplasm is highly organized and the location of the organelles is effectively controlled.

Move the mouse over the screen below and you can see a brief introduction to the function of some of the organelles in the cell.



The nucleus can be seen as the “brain” of the cell. Our genetic material ( DNA ) is stored in the organelle in the form of a chromosome . The nucleus (multicore) is roughly spherical and has two layers of cell membranes. As mentioned in the previous chapter, the cell membrane consists of two layers of opposite lipids.

As shown in the animation above, there are chromosomes (chromosomes) in the nucleus. The chromosome consists of a long chain of DNA. The DNA in the chromosome is circular and highly organized. An X-  shaped chromosome in an animation  indicates that a single chromosome is replicated into two chromosomes in cell division. A single chromosome that has not been replicated includes a DNA molecule containing thousands of genes. The DNA in the chromosome, like the “planner”, directs all activities in the cell.

Some important features of our genetic makeup:

  • We have two sets of chromosomes; respectively, by both parents gametes ( gamete provided) (sperm or eggs). Normal human cells typically contain 46 chromosomes, 23 from the father, and 23 from the mother.
  • A chromosome is made up of a complex between DNA and proteins. This complex is called chromatin .
  • A gene is a secretion of DNA that contains information on the production of molecules such as proteins; it plays an important role in the development of cancer. A slight change in the nucleotidesequence of the gene may result in a change in cell behavior.

Changes in genetic material play a crucial role in the development of cancer. We will discuss how the genetic material is read and used in the next chapter.


Mitochondria (single mitochondria) is known as the “power plant” of cells. Many of the energy required for the functional activities of cells and their bodies comes from biomolecules (such as sugar and fat in food). Mitochondria Complete the final step of the food to energy conversion process. Like the nucleus, there is also a two-layer membrane wrap around the mitochondria.

Just as gasoline burns in a car engine, the energy production process is not 100% efficient. In the process, there will always be some by-products that have an adverse effect. Energy production in the mitochondria leads to the formation of certain chemicals; these chemicals can cause damage to DNA, leading to genetic mutations. These dangerous by-products are thought to play a role in genetic mutations in malignant cells.

Shown below is an illustration of mitochondria showing that the mitochondria have two separate membranes and an energy-generating inner chamber.

Mitochondria Diagram
In the figure below, the mitochondria of the murine cells are stained red. The nucleus and chromosomes (chromosomes) are blue. Note: Mitochondria are widely distributed, large in number and slightly irregular in shape. The green part near each nucleus is an organelle called the Golgi. Golgi is involved in the processing and transport of certain biomolecules such as protein proteins.

Stained Cells

The use of the image below has been agreed by the copyright owner Molecular Probes.


Containing ribosomal RNA and proteins ( Protein constituting the two complex). Ribosomes are located in the cytosol and are numerous. The ribosome is responsible for RNA interpretation and protein generation during the translation process, and we will present a more detailed description of the translation in the next chapter, Gene Function.

The following illustration shows two ribosomal subunits (large subunit and small subunit) bound to messenger RNA ( mRNA ).


The cytoskeleton is a complex and delicate framework of proteins that are interlaced in the cytoplasm. The cytoskeleton is composed of a variety of proteins. These proteins often distort the chain of growth and look like wires or steel cables that support bridges. Like these man-made wires and cables, the proteins that make up the cytoskeleton are both strong and elastic.

Actin fibers are a major fiber type composed of long chains (polymers) of actin. The figure below shows the actin fibers of the cow’s endothelial (vascular) cells. The yellow chain is the polymerized state of the protein; the red portion represents a single protein unit.

Actin fibers
Another important cytoskeletal fiber is microtubules. Microtubules are also multimers that are formed by polymerization of tubulin. The figure below shows the microtubules of cow endothelial cells.

As seen above, the cytoskeleton is widely distributed in cells.
The use of the above images has been obtained by the copyright owner Molecular Probes. 

Cytoskeleton function

The figure below shows actin fibers and microtubules of cow endothelial cells. The actin fibers are red, the microtubules are yellow, and the nucleus is blue.

Actin fibers and microtubules
Several important functions of the cytoskeleton:

  • Maintain cell structure and provide attachment scaffolds for many organelles
  • Make cells sporty
  • Ensure the normal division of cells during cell reproduction

We can observe changes in cellular Google cells in cancer cells. Malignant tumor cells often show an increase in exercise. In fact, the metastatic of cancer cells depends on the invasion of the surrounding cells by the tumor cells.

In cell proliferation ( Proliferation ) process, the key role of the cytoskeleton led to the advent of certain anticancer drugs. These anticancer drugs have the effect of inhibiting the cytoskeleton. Drugs that interfere with cytoskeletal function are Taxol® and vinblastine.

See “Cytoskeletal Inhibitors in Tumor Therapy” for more information.

The use of the above images has been obtained by the copyright owner, molecular probes.

Cell structure summary


  • An organelle is a structure that has a specific function in a cell.
  • Intracellular organelles resemble organs in the body
  • The cytosol is called the cytosol


  • Nuclear information storage of eukaryotic cells (chromosomes)
  • The nucleus is spherical and surrounded by two layers of membrane
  • The nucleus can be recognized as the “brain” of the cell


  • Mitochondria are the “power plant” of cells
  • Mitochondria convert biomolecules (such as fats and sugars) into energy
  • By-products in the production of mitochondrial energy may damage DNA and cause mutations


  • Ribosomes are made up of two complexes containing RNA and protein.
  • Ribosomes are distributed in the cytosol. Their function is to read DNA and make proteins in a process called “translation.”


  • The cytoskeleton is a complex and delicate framework of proteins that are interlaced in the cytoplasm.
  • Actin and tubulin are proteins used to make up the cytoskeletal fibers (microfilaments and microtubules, respectively)
  • The cytoskeleton has some major functions:
    • Maintain cell structure and provide attachment scaffolds for many organelles
    • Make cells sporty
    • Control mitosis in mitosis
  • Changes in cytoskeleton and increased cell movement can be observed in cancer cells
  • Many anticancer drugs inhibit cancer by interfering with cellular structural protein activities

Understand the process

The following are the topics we chose. If you can’t answer, don’t forget to review the chapter on that topic, where you will find the answer.

Understanding the process is an interactive game that tests your knowledge about cancer. How to operate:

  • Drag the correct option from the box on the right and place the options in the order of the smallest to the largest. Note: you only need to use 5 of the 6 options
  • Finish, please click the ‘Check’ button to see how much you have answered correctly.
  • Incorrect answer, please click the ‘Description’ button to review the information again.
  • To start over, click the ‘Restart’ button

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