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Questions and Answers
Which of the following is a feature of all biological membranes?
Which of the following is a feature of all biological membranes?
What is the role of cholesterol in the cell membrane?
What is the role of cholesterol in the cell membrane?
What determines the structure and flexibility of the lipid bilayer?
What determines the structure and flexibility of the lipid bilayer?
Which type of membrane is commonly used to measure the permeability properties of synthetic membranes?
Which type of membrane is commonly used to measure the permeability properties of synthetic membranes?
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What is the process called when phospholipids move from one leaflet of the lipid bilayer to the other?
What is the process called when phospholipids move from one leaflet of the lipid bilayer to the other?
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Which factor does NOT affect the fluidity of a lipid bilayer?
Which factor does NOT affect the fluidity of a lipid bilayer?
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What is the change of a lipid bilayer from a liquid state to a two-dimensional rigid crystalline state called?
What is the change of a lipid bilayer from a liquid state to a two-dimensional rigid crystalline state called?
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Which protein is responsible for giving tissues their elasticity, such as the skin, blood vessels, and lungs?
Which protein is responsible for giving tissues their elasticity, such as the skin, blood vessels, and lungs?
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What type of bond joins the molecules of elastin together to generate a cross-linked network?
What type of bond joins the molecules of elastin together to generate a cross-linked network?
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Which protein plays an important role in tissue repair, cell attachment, and motility, as well as embryogenesis?
Which protein plays an important role in tissue repair, cell attachment, and motility, as well as embryogenesis?
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What is the primary organizer of the sheet structure of the basal lamina?
What is the primary organizer of the sheet structure of the basal lamina?
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Where are cells contained in a complex and intricate network of macromolecules known as the extracellular matrix (ECM)?
Where are cells contained in a complex and intricate network of macromolecules known as the extracellular matrix (ECM)?
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What are the common functions of the extracellular matrix (ECM)?
What are the common functions of the extracellular matrix (ECM)?
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Which type of connective tissue consists of collagen fibers and bone mineral?
Which type of connective tissue consists of collagen fibers and bone mineral?
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Which cells produce and secrete the extracellular matrix (ECM) in connective tissue, specifically collagen fibers?
Which cells produce and secrete the extracellular matrix (ECM) in connective tissue, specifically collagen fibers?
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Which of the following is true about the fluidity of the lipid bilayer at low temperatures?
Which of the following is true about the fluidity of the lipid bilayer at low temperatures?
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What effect do unsaturated fatty acids have on the melting point of the lipid bilayer?
What effect do unsaturated fatty acids have on the melting point of the lipid bilayer?
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How does the presence of cholesterol in the lipid bilayer affect membrane fluidity?
How does the presence of cholesterol in the lipid bilayer affect membrane fluidity?
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What is the role of cis-double bonds in hydrocarbon chains of membrane phospholipids?
What is the role of cis-double bonds in hydrocarbon chains of membrane phospholipids?
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Study Notes
Biological Membranes
- All biological membranes have a feature of fluidity, which is the ability to change shape and move in response to changes in temperature and other environmental factors.
Role of Cholesterol
- Cholesterol is present in the cell membrane and plays a crucial role in maintaining membrane fluidity by reducing the mobility of phospholipids at high temperatures and increasing their mobility at low temperatures.
Lipid Bilayer Structure
- The structure and flexibility of the lipid bilayer are determined by the properties of phospholipids, such as the length of their hydrocarbon chains and the presence of unsaturated fatty acids.
- The lipid bilayer is commonly measured using the black lipid membrane, which is a type of artificial membrane.
Phospholipid Movement
- Phospholipids can move from one leaflet of the lipid bilayer to the other through a process called flip-flop.
Factors Affecting Fluidity
- The fluidity of a lipid bilayer is affected by temperature, with higher temperatures increasing fluidity and lower temperatures decreasing it.
- The presence of unsaturated fatty acids and cholesterol also affects membrane fluidity.
- The length of the hydrocarbon chains of phospholipids does not affect the fluidity of the lipid bilayer.
Lipid Bilayer Phase Transition
- The change of a lipid bilayer from a liquid state to a two-dimensional rigid crystalline state is called a phase transition.
Elastin and Its Role
- Elastin is a protein responsible for giving tissues their elasticity, such as the skin, blood vessels, and lungs.
- The molecules of elastin are joined together by desmosine cross-links, which generate a cross-linked network.
Fibronectin and Its Role
- Fibronectin is a protein that plays an important role in tissue repair, cell attachment, and motility, as well as embryogenesis.
Basal Lamina and Extracellular Matrix
- The primary organizer of the sheet structure of the basal lamina is laminin.
- Cells are contained in a complex and intricate network of macromolecules known as the extracellular matrix (ECM), which is composed of collagen, elastin, and other proteins.
- The common functions of the ECM include providing mechanical support, regulating cell behavior, and facilitating cell-cell communication.
Connective Tissue
- Bone tissue is a type of connective tissue that consists of collagen fibers and bone mineral.
- Fibroblasts are the cells that produce and secrete the ECM in connective tissue, specifically collagen fibers.
Lipid Bilayer Fluidity
- At low temperatures, the lipid bilayer is more rigid and less fluid due to the increased ordering of the phospholipid tails.
- Unsaturated fatty acids decrease the melting point of the lipid bilayer, making it more fluid.
- Cholesterol increases the fluidity of the lipid bilayer by reducing the mobility of phospholipids at high temperatures and increasing their mobility at low temperatures.
- Cis-double bonds in hydrocarbon chains of membrane phospholipids increase the fluidity of the lipid bilayer by introducing kinks in the chain, making it more flexible.
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Description
Test your knowledge on the influence of temperature and fatty acids on cell membrane fluidity. Learn about the effects of low and high temperatures on lipid movement and the state of the lipid bilayer. Explore how the presence of cis-double bonds in membrane phospholipids affects the packing of hydrocarbon chains.
