EduNinjaThe drawings are from two original papers that proposed a structure of the cell membrane.
For what reason is the Singer-Nicolson model considered a better representation of the cell membrane than the Davson-Danielli model?
It has extrinsic proteins.
It shows how the phospholipid bilayer is arranged.
It helps in the understanding of the fluidity of the cell membrane.
It shows how oxygen can diffuse into the cell.
In 1925, Gorter and Grendel carried out an experiment to study the structure of cell membranes in different mammals. The total surface area of red blood cells was measured in a sample and compared to the surface area formed by a single layer of lipid extracted from cell membranes and floated on water.
Which diagram best illustrates Gorter and Grendel's conclusion drawn from this experiment?
The cell membrane model proposed by Davson-Danielli was a phospholipid bilayer sandwiched between two layers of globular protein. Which evidence led to the acceptance of the Singer-Nicolson model?
The orientation of the hydrophilic phospholipid heads towards the proteins
The formation of a hydrophobic region on the surface of the membrane
The placement of integral and peripheral proteins in the membrane
The interactions due to amphipathic properties of phospholipids
The diagram shows the fluid mosaic model of cell membranes. Which labelled regions are hydrophilic?
I and II
I and III
II and IV
III and IV
The Davson-Danielli model of membrane structure proposed that membranes were composed of a phospholipid bilayer that lies between two layers of globular proteins, as shown in this diagram.
Exterior
What evidence supported this model?
An electron micrograph that showed two dark lines with a lighter band in between
Freeze-fracture electron microscopy
Evidence that all membranes are identical
The hydrophobic regions of protein would be in contact with water
The diagram shows the Davson-Danielli model of the cell membrane.
How does this model relate to the fluid mosaic model?
Both models include a phospholipid bilayer sandwiched between two layers of protein.
The Davson-Danielli model does not include integral proteins, whereas the fluid mosaic model does.
The fluid mosaic model shows proteins sandwiched between two layers of phospholipid.
The Davson-Danielli model includes a phospholipid bilayer, whereas the fluid mosaic model does not.
What part of the plasma membrane is fluid, allowing the movement of proteins in accordance with the fluid mosaic model?
In 1925, Gorter and Grendel carried out an experiment to study the structure of cell membranes in different mammals. The total surface area of red blood cells was measured in a sample and compared to the surface area formed by a single layer of lipid extracted from cell membranes and floated on water.
| Source of red blood cell samples | Total surface area of single layer of extracted lipid on water / arbitrary units | Total surface area of membrane on red blood cells / arbitrary units |
|---|---|---|
| Dog | 62.0 | 31.0 |
| Goat | 6.8 | 3.4 |
| Rabbit | 9.8 | 4.9 |
Which diagram best illustrates Gorter and Grendel's conclusion drawn from this experiment?
The electron micrograph shows the surface membrane of an animal cell.
What are the parts of the cell membrane indicated in the diagram?
1
2
3
4
phospholipid
glycoprotein
integral protein
hydrophobic layer
hydrophilic layer
carbohydrate
cholesterol
phospholipid
phospholipid
peripheral protein
glycoprotein
cholesterol
hydrophobic layer
carbohydrate
integral protein
phospholipid