Transport Practice
Use your notes or textbook to answer the following questions.
1. Transport across the cell membrane in which substances move from high concentration to low concentration without the expenditure of energy.
2. Transport across the cell membrane that requires energy to move substances against the concentration gradient.
3. is how small nonpolar substances (like oxygen) pass through the selectively permeable cell membrane.
4. is the diffusion of water across a selectively permeable membrane.
Read each transport scenario carefully. Pay close attention to what the question is asking. Pay attention to the definitions above!
5. During respiration oxygen (O₂) passes into cells where it can be used to create cellular energy. Oxygen molecules are small enough to pass through phospholipid bilayers. If the concentration of O₂ is 42% inside the cell and 7% outside the cell. Which way will the O₂ move (into or out)?
6. What is this called (be specific)?
7. A cell with a normal concentration of 0.9% carbon dioxide is placed in a solution of 4% carbon dioxide. Carbon dioxide molecules are small, so they can diffuse through the membrane. Which way will they diffuse?
8. Carbon dioxide is a waste product that is produced in the production of cellular ATP and needs to be continually removed from cells. In reference to the previous question, what process would the cell use to maintain a low concentration (~0.9% CO₂) of carbon dioxide?
9. A cell with a normal concentration of 2% starch is placed in a solution of 28% starch. Starch molecules are too large to diffuse through the cell membrane. Which direction will the water move (into or out)?
10. What is this called (be specific)?
11. Calcium is an essential plant nutrient that plays an important role in the structure of plant cell walls and membranes, calcium (Ca²+) also serves as an obligate intracellular messenger. A certain plant cell requires a concentration of 80% calcium, it currently has only 70% calcium. The extracellular fluid contains 30% calcium, will the cell require energy to obtain enough calcium to function? Why?
12. Amoebas are animal-like aquatic protozoan. An amoeba cell that normally lives in freshwater (0.8% salt) is placed in saltwater (3.5% salt). If osmosis occurs, what will happen to the cell?
13. A Euglena (protozoan) that normally lives in saltwater (3.5% salt) is placed in freshwater (0.8% salt). If osmosis occurs, what will happen to the cell right away?
14. What will eventually happen to the cell?
15. Algae are plant-like aquatic protists. An algal cell that normally lives in saltwater (3.5% salt) is placed in a solution of 0.% salt. If osmosis occurs, what will happen to the cell?
16. What cell feature (cell part) prevents it from bursting?
17. What will happen to plant cells when providing sufficient water for growth (hypotonic solution)? What is this called (be specific)?
18. Plants require water for photosynthesis. This is what makes them autotrophs (capable of feeding themselves). During a drought the soil water concentration is lower than the concentration of water in the root cells of the plant. In which direction will osmosis occur?
19. What happens to the appearance of the plant?
20. What is this called (be specific)?
