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ATI TEAS 7 Science Course

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  1. Introduction

    Free ATI TEAS Science Diagnostic Test
    1 Quiz
  2. Human Anatomy and Physiology
    General Anatomy and Physiology
    15m|
    3 Lessons
    |
    1 Quiz
  3. Cardiovascular System
    30m|
    9 Lessons
    |
    1 Quiz
  4. Respiratory System
    17m|
    4 Lessons
    |
    1 Quiz
  5. Gastrointestinal System
    8m|
    2 Lessons
    |
    1 Quiz
  6. Neuromuscular System
    43m|
    10 Lessons
    |
    1 Quiz
  7. Reproductive System
    8m|
    2 Lessons
    |
    1 Quiz
  8. Integumentary System
    11m|
    2 Lessons
    |
    1 Quiz
  9. Endocrine System
    11m|
    3 Lessons
    |
    1 Quiz
  10. Genitourinary System
    16m|
    4 Lessons
    |
    1 Quiz
  11. Immune System
    13m|
    4 Lessons
    |
    1 Quiz
  12. Skeletal System
    26m|
    6 Lessons
    |
    1 Quiz
  13. Life and Physical Sciences
    Apply Concepts of Mendel's Laws of Inheritance
    1 Quiz
  14. Describe the Relationship Between Genetic Material and the Structure of Proteins
    3 Lessons
    |
    2 Quizzes
  15. Describe Cell Structure, Function, and Organization
    9 Lessons
  16. Describe the Structure and Function of the Basic Macromolecules in a Biological System
    1 Lesson
    |
    1 Quiz
  17. Describe the Role of Microorganisms in Disease
    2 Lessons
  18. Chemistry
    Explain Physical Properties and Changes of Matter
    11 Lessons
    |
    1 Quiz
  19. Recognize Basic Atomic Structure
    36m|
    10 Lessons
    |
    1 Quiz
  20. Describe Chemical Reactions
    1 Quiz
  21. Understand Properties of Solutions
  22. Scientific Reasoning
    Use Basic Scientific Measurements and Measurement Tools
    1 Quiz
  23. Apply Logic and Evidence to a Scientific Explanation
    1 Quiz
  24. Predict Relationships Among Events, Objects, and Processes
    1 Quiz
  25. Apply the Scientific Method to Interpret a Scientific Investigation
    1 Quiz
  26. Timed Practice Test Simulations
    ATI TEAS Science Practice Tests
    5h 15m|
    5 Quizzes
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Learning Goals

By the end of this lesson, you will be able to:

  • Explain the basic structure of lysosomes
  • Explain the basic functions of lysosomes

Key Vocabulary

Lysosome– a type of cellular organelle found in eukaryotic cells. It is a spherical, membrane-bound structure that contains a variety of hydrolases, which are enzymes that break down and digest cellular waste and damaged materials.

Cellular homeostasis– refers to the maintenance of a stable and balanced internal environment within a cell. This internal environment includes factors such as the concentration of ions and nutrients, pH, and the presence of waste products.

Phagosome – a double-membrane structure formed during the process of autophagy, which is a cellular degradation and recycling process.

Apoptosis – also known as programmed cell death, is a process by which cells naturally self-destruct in a controlled and regulated manner.

Lysosomes

Lysosomes are like the recycling centers of our cells. They play a very important role in keeping our cells healthy and functioning properly.

Think of our cells as tiny cities. Just like how cities need to get rid of their waste, our cells need to get rid of old and damaged materials too. That’s where lysosomes come in! They contain special enzymes, called hydrolases, that break down and recycle old or damaged materials in our cells, just like how recycling centers break down and reuse waste.

As the β€œdigestive system” of the cell, lysosomes contain a variety of hydrolases. Hydrolases are enzymes that break down complex molecules into smaller components, and they require a certain pH in order to function effectively. Lysosomes have an acidic environment with a pH of around 5.0. The low pH of the lysosome provides the optimal environment for these enzymes to work and digest the contents within the lysosome, including cellular waste, damaged organelles, and bacteria.

When vesicles, called phagosomes, containing cellular waste or damaged materials are delivered to the lysosome, the acidic environment within the lysosome activates the hydrolases and the contents of the vesicles are digested and recycled.

NurseHub Note: The pH of the lysosome is maintained by a proton pump, which actively pumps hydrogen ions into the lysosome to keep the pH low. This proton pump is regulated by a variety of factors, including the availability of energy within the cell and the needs of the cell for the degradation of specific materials.

By breaking down and digesting cellular waste, lysosomes help to prevent the buildup of harmful materials within the cell. This allows the cell to maintain a stable internal environment, supporting its normal functions and overall health.

The Golgi apparatus and lysosomes work together to ensure that cellular waste is processed and eliminated efficiently, maintaining cellular homeostasis. Cellular homeostasis (when the inside environment of the cell is stable and balanced) is essential to the proper functioning and health of the cell.

There are two types of processes that cells can use to prepare materials that are targeted for digestion – endocytosis and autophagy. Endocytosis is the process by which the cell takes in materials and substances from outside the cell, and then processes and digests them within the lysosome. Autophagy is the process by which cells degrade and recycle their own cellular components, also facilitated by the lysosome.

Autophagosomes

An autophagosome is a double-membraned vesicle that is formed during the process of autophagy.

Autophagy is a cellular process in which the cell identifies and engulfs its own damaged or unnecessary parts, such as proteins or organelles into a double-membraned vesicle known as an autophagosome. The autophagosome then fuses with a lysosome, which digests and recycles the contents of that vesicle.

Autophagy plays an important role in cellular homeostasis by making sure that damaged and unnecessary cell parts are removed and recycled. This prevents any build-up of cellular waste and allows the cell to continue functioning properly. It is also involved in a variety of physiological processes, such as an organism’s growth and development, immunity, and cellular stress responses.

Lysosomal damage can lead to apoptosis, which is programmed cell death. When lysosomes are damaged they can become dysfunctional and fail to effectively digest and recycle cellular components. This can lead to the accumulation of cellular waste and damaged materials, causing cellular stress and potentially triggering apoptosis. In some cases, lysosomal damage can also trigger the release of lysosomal contents into the cytoplasm, where they can activate apoptotic pathways and lead to cell death.

NurseHub Note: Gaucher disease is a lysosomal storage disease caused by a deficiency of the enzyme glucocerebrosidase, which is involved in the breakdown of a specific type of fat molecule. As a result, this fat accumulates within the lysosome, causing cellular damage and leading to symptoms such as enlarged liver and spleen, anemia, and low platelet count.

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