1.4 – Membrane transport

1.The salt concentration inside an animal cell is 1.8 %. The salt concentration in the surrounding medium becomes 5 %. What will be the likely response?    

2. Dialysis membrane was set up to model digestion and absorption in the small intestine. What is a limitation of this model?

3. The salt concentration inside the Paramecium is 1.8 %. The salt concentration in the surrounding medium suddenly drops to 0.2 %. What will be the likely response? [Source: Adapted from www.biology-resources.com. Copyright 2004–2017 D G Mackean & Ian Mackean. All rights reserved.]  

4. Cladograms can be created by comparing DNA or protein sequences. The cladogram on the left is based on DNA sequences and the cladogram on the right is based on comparing protein sequences.   What is the reason that cladograms based on DNA sequences are more reliable predictors of the phylogenetic relationship of species than cladograms based on protein sequences?

5. The bacterium Neisseria gonorrhoeae causes infections related to the human reproductive system. The graph shows the percentage of samples in which this bacterium showed resistance to six antibiotics over a period of ten years. What is a possible explanation for the total percentage resistance being larger than 100% in 2010?

6. The giant marine alga Halicystis ovalis is able to move sodium ions from vacuoles to the surrounding seawater through active transport. Which condition or feature is required for this mode of transport?

7. The diagram is a model of one type of movement across a membrane. What is this type of movement?

8. What is osmosis?

9. Which movement occurs by osmosis?  

10. Which process contributes to growth of a multicellular body?

11.What features of a cell favour efficient removal of waste products?

12. Which process requires channel proteins?

13. What feature of cell membranes allows endocytosis to occur?

14. Why do crop plants dry out when a field is irrigated with water contaminated by sea water?

15. What do diffusion and osmosis have in common?  

16. Which pair of features is correct for both diffusion and osmosis?

17. What route is used to export proteins from the cell?

18. Cells in the adrenal gland produce the hormone epinephrine and store it in vesicles. To release epinephrine these vesicles are carried to the plasma membrane and fuse with it. What process is occurring?

19. What is the difference between simple diffusion and facilitated diffusion?

20. Which of the following is not a function performed by a membrane protein?