30 Questions
Which of the following is NOT a feature of all biological membranes?
Ability to change composition
What is the role of cholesterol in the cell membrane?
To act as a 'fluidity buffer'
What is the function of the extracellular matrix in cell physiology?
To provide structural support
What determines the structure and flexibility of the lipid bilayer?
Temperature
What are vesicles?
Liquid-filled compartments enclosed by a lipid bilayer
What was the result of the first demonstrations of lipid molecule diffusion within lipid bilayers?
Recognition of the fluidity of biological membranes
Which type of membranes are commonly used as model membranes in experimental studies?
Liposomes
What is the purpose of using black membranes?
To measure the permeability properties of synthetic membranes
What is the process called when phospholipids move from one leaflet of the lipid bilayer to the other?
Flip-flop
Which type of proteins catalyze the flip-flop movement of phospholipids?
Flippases
What is the main factor that determines the fluidity of a lipid bilayer?
Phospholipid content (FA length and saturation)
How is the lipid bilayer stabilized?
By hydrophobic interactions between lipids' fatty acid chains
Which protein gives tissues their elasticity, such as skin, blood vessels, and lungs?
Elastin
Which protein is a multifunctional adhesive glycoprotein that plays a role in tissue repair, cell attachment, and motility?
Fibronectin
Which protein is the primary organizer of the sheet structure of the basal lamina?
Laminin
Which type of proteins facilitate cell adhesion and mediate cellular signals in various types of cells?
Integrins
How many distinct genes in the human genome code for different collagen chains?
42
Which component of all epithelia is thin, flexible, and tough?
Basal lamina
Which state is the lipid bilayer in at low temperatures?
Paracrystalline state
What effect do unsaturated fatty acids have on the melting point of the lipid bilayer?
Decrease the melting point
What effect does a shorter hydrocarbon chain in membrane phospholipids have on the fluidity of the membrane?
Increases fluidity
What is the role of cholesterol in the plasma membrane?
Decreases fluidity
What effect does an increase in saturated fatty acids content have on the melting point of the lipid bilayer?
Increase the melting point
What effect does an increase in unsaturated fatty acids content have on the melting point of the lipid bilayer?
Decrease the melting point
Proteoglycans are formed by the combination of glycosaminoglycans (GAGs) and what other component?
Fibrous proteins
Which type of tissue has collagen fibers and bone mineral in its extracellular matrix?
Bone tissue
Which cells produce and secrete the extracellular matrix in connective tissue?
Fibroblasts
What is the main function of the extracellular matrix in biology?
Structural and biochemical support to surrounding cells
Where are basement membranes/basal lamina found in animal tissues?
On the basal side of epithelial and endothelial tissues
What are the major classes of macromolecules found in the extracellular matrix?
Glycosaminoglycans, fibrous proteins, and non-collagen fibrous proteins
Test your knowledge on the influence of temperature and fatty acids on cell membrane fluidity. Learn about the different states of the lipid bilayer and how cis-double bonds affect the packing of hydrocarbon chains in membrane phospholipids.
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