40 Questions
What is the primary function of lipids in the cell?
Energy storage and release
Which type of lipid is characterized by a long hydrocarbon tail terminating with a carboxyl group?
Fatty acid
What is the main difference between saturated and unsaturated fatty acids?
Presence of carbon-carbon double bonds
Which of the following types of lipids is NOT mentioned in the chapter?
Glycoproteins
What is the purpose of the polar end of amphipathic membrane lipids?
To interact with water
What is the effect of cis-double bonds on the hydrocarbon chain of fatty acids?
Causes a 'kink' or 'bend' in the structure of the hydrophobic tail, reducing Van der Waal's and hydrophobic interactions
What is the physical state of stearate (C18:0) at 25°C?
Solid
What is the characteristic of fatty acids that are rich in 'trans-fat'?
They are solid at 25°C
What is the difference between saturated and unsaturated fatty acids in terms of their hydrophobic tails?
Saturated fatty acids have a more linear hydrophobic tail
What is the classification of fatty acids based on the presence of double bonds?
Saturated fatty acids have no double bonds, while unsaturated fatty acids have one or more
What is the characteristic of unsaturated fatty acids?
They have one or more double bonds between carbons.
What is the function of phospholipids in cells?
They form plasma membranes of cells.
What is the general structure of triglycerides?
One glycerol molecule linked to three fatty acids.
What is the characteristic of phospholipids in water?
They aggregate to form a lipid bilayer.
What is the difference between cis and trans configurations in unsaturated fatty acids?
Cis has chemical groups on the same side of the double bond.
What happens to the membrane's structure when heat is applied?
The membrane becomes more disordered
What is the characteristic difference between animal and plant membranes?
Plant membranes have a higher percentage of unsaturated fatty acids
What is the primary force driving the formation of lipid bilayers?
Hydrophobic interaction
What is the characteristic of membranes with a higher percentage of unsaturated fatty acids?
They are more fluid
What is the characteristic of prokaryotic membranes?
They are the most fluid
What is the function of kinks in the tails of phospholipids?
To keep the plasma membrane fluid across a range of temperatures
What is a characteristic of waxes?
They are solid at room temperature
What is the structure of steroids?
Four fused carbon rings
What is the function of cholesterol in the cell membrane?
To maintain membrane fluidity and structure
What is a characteristic of triglycerides?
They are amphipathic
What is the function of cholesterol in biological membranes?
To decrease the fluidity of membranes
What is the characteristic of proteins in the fluid mosaic model of biological membranes?
They are embedded in the membrane and can move laterally
What type of proteins are bound to the membrane by electrostatic interactions and can be removed by raising the ionic strength?
Peripheral proteins
What is the term for the structure of biological membranes, composed of a lipid bilayer with proteins, glycolipids, and steroids embedded in it?
Fluid mosaic model
Which of the following is NOT a function of membrane proteins?
Synthesize new membrane lipids
What is the primary function of HDL cholesterol in the body?
To absorb cholesterol in the blood and carry it back to the liver
What is the term given to LDL cholesterol?
Bad cholesterol
What happens to cholesterol when it is carried back to the liver by HDL?
It is flushed from the body
What is the characteristic of lipids that makes them difficult to dissolve in water?
Their low solubility in water
What is the term given to the structures formed by lipids in aqueous environments?
All of the above
What is the purpose of lipid bilayers in biological systems?
To form biological membranes
What is the result of high levels of HDL cholesterol in the body?
A decreased risk of heart disease and stroke
What is the term given to the lipoprotein that carries cholesterol from the liver to the body's tissues?
LDL
What is the effect of high levels of LDL cholesterol in the body?
An increased risk of heart disease and stroke
What is the role of lipids in the body?
All of the above
Test your understanding of lipids and membrane proteins, including their functions, structures, and classifications. Learn about the importance of lipids as energy sources, energy storage, and cell membrane components. Explore the characteristics of amphipathic membrane lipids and their roles in insulation and protection.
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