The structure below is the phospholipid phosphatidylcholine.

Identify each labelled region.

Which of the following statements correctly identifies a hydrogen bond donor and a hydrogen bond acceptor in the base pair structure shown below?

The structure below is the phospholipid phosphatidylcholine.

Identify each labelled region.

GLUT1 facilitates the transport of glucose from the outside to the inside of red blood cells, down the concentration gradient of glucose.

The mechanism of GLUT1 action is shown below, along with a graph showing the relationship between the extracellular concentration of glucose and the initial velocity (rate) of glucose entry facilitated by GLUT1. Note the similarity of this graph to a Michaelis-Menten curve.

Which of the following factors is most likely to control the maximum rate of facilitated diffusion (i.e., the value of V_max) for this facilitated transport process?

[Note: You may need to draw on your understanding of Michaelis-Menten kinetics to answer this question]

The schematic diagram below shows the concentration gradients of several molecules or ions across a lipid bilayer membrane.

Gradients are represented by wedges, in which the higher concentration is at the thick end of the wedge.

Which of the following molecules or ions would you expect to readily diffuse across the membrane in the direction indicated by the red arrow?

The schematic diagram below shows the concentration gradients of several molecules or ions across a lipid bilayer membrane.

Gradients are represented by wedges, in which the higher concentration is at the thick end of the wedge.

Which of the following molecules or ions would you expect to readily diffuse across the membrane in the direction indicated by the red arrow?

GLUT1 facilitates the transport of glucose from the outside to the inside of red blood cells, down the concentration gradient of glucose.

The mechanism of GLUT1 action is shown below, along with a graph showing the relationship between the extracellular concentration of glucose and the initial velocity (rate) of glucose entry facilitated by GLUT1. Note the similarity of this graph to a Michaelis-Menten curve.

Which of the following factors is most likely to control the maximum rate of facilitated diffusion (i.e., the value of V_max) for this facilitated transport process?

[Note: You may need to draw on your understanding of Michaelis-Menten kinetics to answer this question]

A small molecule X has a higher concentration in the cytosol than in the extracellular space. A second small molecule Y has a higher concentration in the extracellular space than in the cytosol. 

Y is transported out of cells (against its concentration gradient) by binding to a transmembrane protein that hydrolyses ATP. In turn, X is transported into cells (against its concentration gradient) by binding, together with Y, to the extracellular side of a transmembrane protein and then being released into the cytosol.

The movement of X into cells is an example of:

When adrenaline (epinephrine) binds to its integral membrane receptor, this initiates an intracellular signalling cascade, which includes each of the following events (but not necessarily in this order):

1. GTP binds to the Gα subunit
2. cAMP is hydrolysed to give AMP
3. The adrenergic receptor undergoes a conformational change
4. ATP is converted to cAMP and pyrophosphate
5. GDP dissociates from the Gα subunit
6. The Gα subunit binds to adenylyl cyclase

What is the correct order of these events?

GLUT1 facilitates the transport of glucose from the outside to the inside of red blood cells, down the concentration gradient of glucose.

The mechanism of GLUT1 action is shown below, along with a graph showing the relationship between the extracellular concentration of glucose and the initial velocity (rate) of glucose entry facilitated by GLUT1. Note the similarity of this graph to a Michaelis-Menten curve.

Which of the following factors is most likely to control the maximum rate of facilitated diffusion (i.e., the value of V_max) for this facilitated transport process?

[Note: You may need to draw on your understanding of Michaelis-Menten kinetics to answer this question]