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Questions and Answers
What is the primary function of the cell membrane?
What is the primary function of the cell membrane?
- To provide structure and support to the cell
- To regulate the movement of substances in and out of the cell (correct)
- To facilitate cell division
- To store genetic material
Why is the cell membrane often referred to as the plasma membrane?
Why is the cell membrane often referred to as the plasma membrane?
- Because it is the outer limiting membrane of the cell (correct)
- Because it is a barrier to all molecules
- Because it has a plasma-like appearance under a microscope
- Because it is composed entirely of lipids
Which statement accurately describes the visibility of the cell membrane using a light microscope?
Which statement accurately describes the visibility of the cell membrane using a light microscope?
- It can be seen with special staining techniques
- It is clearly visible due to its thickness
- It is not visible because it is too thin (correct)
- It appears as a single thick line
What alternative name is commonly used for the cell membrane?
What alternative name is commonly used for the cell membrane?
What characteristic of the cell membrane allows it to control cellular interactions?
What characteristic of the cell membrane allows it to control cellular interactions?
What percentage of the content is made up of proteins?
What percentage of the content is made up of proteins?
Which type of membrane proteins are categorized as intrinsic proteins?
Which type of membrane proteins are categorized as intrinsic proteins?
What molecules primarily compose the lipid content?
What molecules primarily compose the lipid content?
Which of the following statements is true regarding the composition?
Which of the following statements is true regarding the composition?
What percentage of the total composition is made up of lipids and proteins combined?
What percentage of the total composition is made up of lipids and proteins combined?
What is one primary function of the cell coat?
What is one primary function of the cell coat?
Which component is NOT part of the cell coat?
Which component is NOT part of the cell coat?
How does the cell coat aid in the exchange of materials?
How does the cell coat aid in the exchange of materials?
Which of the following best describes the role of proteins in the cell coat?
Which of the following best describes the role of proteins in the cell coat?
What is a characteristic feature of the cell membrane's function related to material exchange?
What is a characteristic feature of the cell membrane's function related to material exchange?
What process describes the movement of substances from inside a cell to the extracellular fluid?
What process describes the movement of substances from inside a cell to the extracellular fluid?
Which of the following accurately describes exocytosis?
Which of the following accurately describes exocytosis?
What happens to the vesicle during exocytosis?
What happens to the vesicle during exocytosis?
Which type of substances are typically involved in the process of exocytosis?
Which type of substances are typically involved in the process of exocytosis?
In which scenario would exocytosis most likely occur?
In which scenario would exocytosis most likely occur?
What is the thickness range of the layer mentioned?
What is the thickness range of the layer mentioned?
What effect does PAS stain have on the cell structure?
What effect does PAS stain have on the cell structure?
What distinguishes the trilaminar appearance of the layer?
What distinguishes the trilaminar appearance of the layer?
What microscopy method is typically insufficient for resolving details of this layer?
What microscopy method is typically insufficient for resolving details of this layer?
Under what conditions can the layer's details be observed with light microscopy?
Under what conditions can the layer's details be observed with light microscopy?
Study Notes
Cell membrane (plasmalemma or plasma membrane)
- The outermost layer of the cell
- Not visible under a light microscope (LM) due to its thinness (8-10 nm)
- May be visible with oblique sections or when stained with PAS stain, which stains carbohydrates of the cell coat
- Appears as a trilaminar structure under an electron microscope (EM) with an outer and inner dark layer separated by a middle light layer
- Comprised of lipids (30%) and proteins (60%)
- Lipid layer contains phospholipids and cholesterol
- Proteins can be either intrinsic (integral) or extrinsic (peripheral)
- It is covered by a cell coat, which consists of proteins and carbohydrates
Functions of the cell membrane
- Protects the cell
- Regulates the exchange of materials between the cell and its environment
- Exocytosis is a process by which cellular contents are extruded into the extracellular fluid via membranous vesicles
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Description
This quiz explores the structure and functions of the cell membrane, also known as the plasmalemma or plasma membrane. Learn about its composition, visibility under different microscopes, and key roles in cellular regulation and protection.
