EduNinjaFig. 1.1 is a diagram showing part of a cell surface membrane of an animal cell.
Fig. 1.1
State the approximate thickness of the membrane as shown by the line G-H.
Complete Table 1.1 to show:
- the names and functions of the components of the cell surface membrane
- the letters of the labels in Fig. 1.1 that identify each component.
Table 1.1
Fig. 1.1 is a diagram representing part of the phospholipid bilayer of a cell surface membrane.
Fig. 1.1
Cholesterol is an important lipid component of many cell surface membranes. Fig. 1.2 shows the structure of a cholesterol molecule.
Fig. 1.2
Using the information in Fig. 1.2, explain the orientation (positioning) of cholesterol molecules in the phospholipid bilayer, as shown in Fig. 1.1.
State one role of cholesterol in phospholipid bilayers.
Prostaglandins are small lipids produced in many tissues of the body. One role of prostaglandins is to cause inflammation at the site of an injury or infection. Inflammation is the normal first response of the immune system to injury or infection.
Cyclooxygenase (COX) is an enzyme that catalyses one of the steps in the reaction pathway for the formation of prostaglandins from phospholipids. The reaction pathway occurs in the smooth endoplasmic reticulum (SER) of cells. Part of the reaction pathway is shown in Fig. 1.3.
Fig. 1.3
Prostaglandins are examples of cell-signalling molecules.
Outline the process of cell signalling that leads to a response by the cells involved in inflammation.
Fig. 1.1 is an electron micrograph of part of a eukaryotic cell.
Fig. 1.1
×47000
Many of the cell structures in Fig. 1.1 are surrounded by membranes.
Membranes are approximately 6 nm to 7 nm wide.
Describe the fluid mosaic model of membrane structure.
There is space below for a diagram.
The inner membrane of the mitochondrial envelope is much less permeable than the outer membrane.
Suggest one way in which the structure of the inner membrane of the mitochondrion may differ from that of the outer membrane to produce a less permeable inner membrane.
The Golgi body, rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER) form part of the internal membrane system of a cell. The membranes have a fluid mosaic structure.
Fig. 1.1 is a transmission electron micrograph of one area of a liver cell showing a region with RER and a region with SER. Mitochondria are also visible in the image.
Fig. 1.1
One function of a Golgi body is to package molecules into Golgi vesicles.
Some Golgi vesicles contain glycoproteins or glycolipids to be added to the cell surface membrane.
Outline the role of glycolipids in the cell surface membrane.
Fig. 1.1 shows five biological molecules.
Fig. 1.1
State the letter of the molecule that forms part of the cell surface membranes of eukaryotic cells.
Fig. 1.1 is an electron micrograph of part of a eukaryotic cell.
Fig. 1.1
The inner and outer membranes of the mitochondrion have a fluid mosaic structure similar to other cell membranes. They are both approximately 6 to 7 nanometres ( nm ) thick.
Outline the fluid mosaic model of membrane structure.
There is space below for a diagram.
The inner and outer membranes of the mitochondrion differ in the detail of their membrane components. The inner membrane is also much less permeable than the outer membrane.
Suggest one way in which the structure of the inner membrane may differ from that of the outer membrane to produce a less permeable inner membrane.
A diagram of a chromosome from a dividing cell is shown in Fig. 1.1.
Fig. 1.1
The control of the cell cycle can be affected by extracellular chemical messengers that bind to proteins and glycoproteins in the cell surface membrane. The overall mechanism is known as cell signalling.
State the term used to describe the proteins and glycoproteins that function in this way.
State two components of a cell surface membrane other than phospholipid molecules and describe their function.
component 1
function
component 2
function
The cell surface membrane has a fluid mosaic structure.
Describe what is meant by the term fluid mosaic.
In 1934, the biologists Davson and Danielli published their suggestion for the structure of the cell surface membrane, as shown in Fig. 1.1.
They suggested that the membrane was a phospholipid bilayer with a layer of hydrophilic protein on both surfaces.
Fig 1.1
State one way in which the Davson-Danielli structure is similar to the fluid mosaic structure and one way in which it differs from the fluid mosaic model.
similarity
difference
Fig. 1.1 is a diagram of a transverse section through a vein.
Fig. 1.1
Explain how the following structural features of a capillary are related to its function.
The capillary wall is composed of a single layer of squamous epithelial cells.