Practise IB Biology HL B2.1 with membrane diagrams and data questions covering selective permeability, transport mechanisms, fluidity, vesicles and ion pumps.
111 questions in this syllabus scope, with question parts counted together.
117 papers analysed · Tagging incomplete
The diagram shows the original drawing of the cell membrane made in 1972 by Singer and Nicolson.
Label with the letter H part of a phospholipid molecule that is hydrophilic.
Glucose is absorbed through protein channels in the plasma membrane of epithelium cells in the small intestine. Which characteristics of glucose prevent its diffusion through the phospholipid bilayer?
It is non-polar and therefore hydrophobic.
Its hydrogen bonds link with amino acids in the protein channel.
It is polar and therefore hydrophilic.
Its covalent bonds interact with the phospholipids.
Which process results in the exchange of gases across the membrane of pneumocytes?
Active transport
Simple diffusion
Facilitated diffusion
Mass flow
How is facilitated diffusion in axons similar to active transport?
They both require the energy of ATP.
They both move substances against a concentration gradient.
They both use sodium-potassium pumps.
They are both carried out by proteins embedded in the axon membrane.
In the early 1990s, investigations involving egg cells from the African clawed frog (Xenopus laevis) led to the discovery of membrane channel proteins called aquaporins.
In one investigation, scientists injected 10 frog egg cells with a solution containing mRNA encoding for an aquaporin, and another 10 frog egg cells with distilled water (control cells). All the frog egg cells were then incubated in a hypotonic solution. The volume of the frog egg cells was then measured during a period of five minutes.
The graph shows the mean results of the investigation.
State the direction of net movement of water across the plasma membrane of all the frog egg cells between 0 and 3 minutes.
Explain the reasons for the different results obtained for the frog egg cells with aquaporin mRNA and the control frog egg cells.
By which process do potassium ions move through potassium channels in axons?
Active transport
Exocytosis
Facilitated diffusion
Simple diffusion
A cell was placed into a solution containing a dye. After two hours the concentration of the dye inside the cell was higher than in the solution. This was repeated in the presence of a substance that inhibits ATP. In this case the dye did not enter the cell. What is the probable mechanism by which the dye entered the cell?
Active transport
Simple diffusion
Osmosis
Facilitated diffusion
The diagram shows a cell from the nervous system.
Compare and contrast the movement of particles across plasma membranes by simple diffusion and facilitated diffusion.
The 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.
Which changes would take place in the plasma membrane composition to maintain fluidity at very low temperatures?
Unsaturated fatty acids
Saturated fatty acids
Proteins
increase
increase
decrease
no change
increase
decrease
increase
decrease
no change
decrease
no change
increase
What is a function of cholesterol in the cell membrane?
To regulate fluidity
To store energy
To provide a channel for transport
To hold adjacent cells together
Describe the process of endocytosis.
The table shows two types of gated ion channels in neurons. How are they gated?
Nicotinic acetylcholine
receptors
Potassium channels
voltage
neurotransmitter
neurotransmitter
voltage
voltage
voltage
neurotransmitter
neurotransmitter
The table shows concentrations of potassium ions and sodium ions inside and outside human cells.
What explains these concentrations?
Potassium ions diffuse in and sodium ions diffuse out.
Sodium ions diffuse in and potassium ions diffuse out.
Active transport pumps sodium ions in and potassium ions out.
Active transport pumps sodium ions out and potassium ions in.
Explain the mechanisms used by the ileum to absorb and transport food.
No public sample questions are available for this syllabus point yet.
The diagram shows the original drawing of the cell membrane made in 1972 by Singer and Nicolson.
Label with the letter H part of a phospholipid molecule that is hydrophilic.
Distinguish between this model of the cell membrane and the Davson-Danielli model.
Explain the role of molecules such as M in sodium-potassium pumps.
