EduNinjaThe diagram shows a section through a membrane. What are the modes of transport in the diagram?
I
II
simple diffusion
osmosis
active transport
facilitated diffusion
simple diffusion
facilitated diffusion
facilitated diffusion
active transport
Apparatus was set up as shown to collect data.
The graph shows the results after 47 minutes of data collection.
What causes the rates to differ?
I. Different concentration gradients at the start
II. Diffusion of sugar is initially greater in Y than in X
III. The systems are reaching equilibrium over time
I only
II only
I and III only
II and III only
In 2020, Peplow and co-workers obtained an image showing a GABA cell membrane protein receptor. The technique they used allowed them to take the image at a particular moment in time by treating the sample so that the protein molecules were firmer and more stable. What technique did they use to obtain this image?
Electrophoresis
Immunofluorescence
Cryogenic electron microscopy
Fluorescent dyes
State two differences in structure between plant and animal cells.
Outline how molecules move across a membrane by simple diffusion.
Explain the role of protein pumps in active transport.
The diagram shows a cell from the nervous system.
Outline how the myelin sheath and nodes of Ranvier increase the speed of an action potential along a neuron.
Compare and contrast the movement of particles across plasma membranes by simple diffusion and facilitated diffusion.
Describe the effect of neonicotinoid pesticides on synaptic transmission in insects.
Cell membranes have a fluid mosaic structure.
Outline the reason the structure is described as a mosaic.
Phospholipids are the most common molecules in cell membranes. Draw a diagram of the simplified structure of a phospholipid and label its amphipathic properties.
Explain how the rate of diffusion of oxygen into a cell is affected by the concentration of oxygen outside of the cell.
Eukaryotic cells have certain characteristics in common.
State a function for structures X and Y labelled in the cell diagram.
X :
Y:
Describe three different processes that allow molecules to pass through the lipid bilayer of a cell.
Outline one difference between the structure of prokaryotic and eukaryotic cells.
Which technique separates proteins according to size?
Treatment with restriction endonucleases
PCR
Gel electrophoresis
DNA profiling
The diagram shows red blood cells and undifferentiated tissue cells.
Diffusion of oxygen from blood cells to tissue cells is represented by arrow 3 in the diagram. What molecules are shown diffusing by arrow 1 and arrow 2?
Arrow 1
Arrow 2
carbon dioxide
urea
water
glucose
glucose
carbon dioxide
fatty acids
amino acids
Which process results in the exchange of gases across the membrane of pneumocytes?
Active transport
Simple diffusion
Facilitated diffusion
Mass flow