35 Questions
What is another name for the cell membrane?
Plasma membrane
What is the function of the cell plasma membrane?
Regulates transportation of molecules and filters what goes in & out of cell
Which of the following is a major class of membrane lipids?
Phospholipids
What is the characteristic of lipids that makes them amphiphilic?
They have one end that is soluble in water and an ending that is soluble in fat
Which membrane differentiation is responsible for increasing absorption area and contains actin filaments?
Microvillus
What type of junction connects cells through actin filaments and selectively permits molecules?
Tight junctions (zonula occludens)
Which structure provides physical support to the cells as a thin extracellular matrix layer in the basal regions of the epithelial cells?
Basal lamina
What type of membrane differentiation is composed of 9 double and 2 single microtubules made of α and β tubulins?
Cilia
Which type of junction links one cell to another through intermediate filaments and provides tissue integrity against damage and abrasion?
Desmosomes (macula adherens)
What is the function of gap junctions?
Intercellular connection through adapters
Which membrane differentiation helps carry secretory molecules in epithelial cells and transports foreign substances?
Cilia
Which type of junction links cells to the matrix through intermediate filaments and provides integrity?
Hemidesmosomes
Which type of transport across cell membranes requires cell energy?
Active transport
What is the process where vesicles release large molecules from the cell by fusing with the plasma membrane?
Exocytosis
What type of molecules are important markers in the immune system for cell differentiation between self and non-self cells?
Glycoproteins
What determines the direction of water movement and the state of the cell in different concentrations of NaCl solutions?
Osmosis
In which type of solution is there no net movement of water across the cell membrane?
Isotonic solution
What type of transport involves the diffusion of water across a semipermeable membrane from high to low water potential?
Osmosis
Which proteins facilitate the movement of materials across the cell membrane in processes like facilitated diffusion?
Carrier proteins
What is the process where cells engulf and internalize solid particles?
Phagocytosis
What is the term for the movement of molecules from high to low concentration without requiring cell energy?
Simple diffusion
Which type of molecules are important for cell membrane permeability and are semipermeable for small and non-polar molecules?
Phospholipids
What type of transport moves materials against the concentration gradient and requires cell energy?
Active transport
What structures on the cell membrane serve specific functions and differentiate on apical, lateral, and basal surfaces?
Microvilli
What is the main function of cholesterol in cell membranes?
Regulating fluidity and stability
What is the role of carbohydrates found on the outside surface of cells?
Forming glycoproteins or glycolipids for cell recognition
What is the primary reason for the fluidity of lipid membranes?
Lateral movement of phospholipids
What is the significance of membrane proteins in therapeutic interventions and drug development?
Over 50% of modern medicinal drugs target membrane proteins
What is the arrangement of phospholipids in the cell membrane according to the fluid mosaic model?
Forming bilayers with hydrophobic tails inside and hydrophilic heads outside
What is the role of integral membrane proteins in cell membranes?
Acting as receptors, channels, carriers, or agents in electron transfer
What is the structure of phospholipids in cell membranes?
Polar hydrophilic head with a phosphate group and nonpolar hydrophobic tails
What is the term used to describe the membrane structure as fluid due to freely moving phospholipids and proteins?
Fluid mosaic model
What is the function of peripheral membrane proteins in cell membranes?
Provide support and signaling
What is the role of carbohydrates on the outside surface of cells in cell recognition?
Forming glycoproteins or glycolipids for cell recognition
What technique was used to develop the fluid mosaic model of membrane structure?
Freeze fracture studies
Study Notes
Cell Membrane Structure and Components
- Phospholipids with a phosphate group are called phospholipids and are crucial structural components of cell membranes.
- Phospholipids have a polar hydrophilic head with a phosphate group and nonpolar hydrophobic tails made of carbon and hydrogen.
- Phospholipids form bilayers with hydrophobic tails protected inside and hydrophilic heads outside, constituting the basic membrane structure.
- Cholesterol, a type of sterol, is an essential component of cell membranes, regulating fluidity and stability, and preventing ion passage.
- The fluid mosaic model describes the membrane structure as fluid due to freely moving phospholipids and proteins, forming a mosaic pattern.
- Membrane proteins, integral or peripheral, are crucial for various functions such as signaling, transport, enzymatic activities, and cell adhesion.
- Proteins in the membrane can be fixed or floating, with hydrophobic and hydrophilic portions ensuring their integration and stability.
- Integral membrane proteins act as receptors, channels, carriers, or agents in electron transfer, while peripheral proteins provide support and signaling.
- Carbohydrates, found on the outside surface of cells, form glycoproteins or glycolipids and serve as cellular markers for cell recognition.
- The fluidity of lipid membranes is essential for lateral movement, rotational dynamics, and flip-flop mediated by various enzymes.
- The fluid mosaic model was developed using freeze fracture studies, revealing the scattered pattern of proteins and the mobility of phospholipids.
- Over 50% of modern medicinal drugs target membrane proteins, demonstrating their significance in therapeutic interventions and drug development.
Test your knowledge of cell membrane structure and components with this quiz. Explore the role of phospholipids, cholesterol, membrane proteins, and carbohydrates in maintaining membrane integrity and functionality. Gain insights into the fluid mosaic model and its implications for drug development.
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