Cell Membrane Structure Flashcards
What is the structure of a phospholipid?
A phospholipid has a hydrophilic head and a hydrophobic tail.
Since phospholipids have hydrophilic and hydrophobic parts, what are they called?
Amphipathic
Are phospholipid tails saturated or unsaturated?
They can be both.
What type of phospholipid tails are straight?
Saturated phospholipid tails.
What type of phospholipid tails are bent?
Unsaturated phospholipid tails.
Why are unsaturated phospholipid tails bent?
The presence of a double bond.
Does the straightness of phospholipid tails change based on fluid content?
Yes, the more fluid there is, the more bent they are.
What is the primary molecule of the cell membrane?
Phospholipids.
How are phospholipids synthesized?
Through the endoplasmic reticulum.
How are phospholipids transported?
They are transported as vesicles to the cell membrane.
Who proposed the idea of a phospholipid bilayer?
Gorter and Grendel in 1925.
What does the fluidity of the cell membrane allow for?
It allows for materials to move through the cell membrane via endo and exocytosis.
Who discovered membranes are made of lipids?
Overton (1899)
Who discovered membranes are a lipid bilayer made of phospholipids that have a hydrophilic head and a hydrophobic tail?
Gorter and Grendel (1925)
Who discovered the membrane includes globular protein molecules attached to each side of the lipid bilayer?
Davson and Danielli (1935)
Who discovered the membrane is a fluid bilayer of lipids with embedded proteins?
Singer and Nicolson (1972)
What model of the cell membrane do we use today?
The mosaic model.
What are integral proteins?
Proteins that span the entire membrane and are permanently attached.
What are peripheral proteins?
Proteins that are not attached permanently and that attach to the surface, or sometimes integral proteins.
What molecule moderates the fluidity of the cell membrane in eukaryotes?
Cholesterol, by making the membrane more fluid at lower temperatures and vice versa.
What is the structure of cholesterol?
Hydroxyl, hydrocarbon rings, and a hydrocarbon tail.
Is cholesterol amphipathic?
Yes, it has both hydrophilic and hydrophobic parts.
Where is cholesterol in the cell membrane model?
It is between the phospholipids, with the head of cholesterol near the head of the phospholipid and the tail of the cholesterol between the phospholipid tails.
