Directions: Use the information provided and your knowledge of Life Science to answer the following questions. Show all work where necessary.
Directions: Use the information provided and your knowledge of Life Science to answer the following questions. Show all work where necessary.
Yeast are unicellular organisms that reproduce by budding, a process where a new cell forms from the surface of an existing one. Each yeast cell performs all life functions - it takes in nutrients, grows, reproduces, and responds to its environment - even though it is made of only one cell.
Scientists use yeast as a model to study how single cells grow and divide. When yeast are given sugar and warmth, they multiply rapidly through cell division, which can be observed under a microscope or by measuring the increase in cell density in a culture.
Researchers at the Massachusetts Institute of Technology Microbial Systems Lab tracked yeast population growth over several hours, counting cells with a hemocytometer.
Table 1.
Time (hours) | Average Cell Count (cells/mL x | Percent Budding Cells (%) |
|---|---|---|
0 | 1.2 | 3 |
1 | 2.5 | 12 |
2 | 5 | 20 |
3 | 9.8 | 28 |
4 | 18.5 | 32 |
5 | 24 | 29 |
The increase in both cell count and percent of budding cells over time shows that yeast are made of individual, self-replicating cells. Each cell performs the functions necessary for life. Because yeast can live and reproduce independently as one cell, they provide direct evidence that living things can be made of just a single cell.
Graph of Information - Figure 1.
Graph of Information - Figure 2.
Using the information from the reading, table, and figures, explain how yeast demonstrate that living things can be made of only one cell.
Claim:
Evidence:
Reasoning:
How does the yeast cell count change between hours 0 and 4, and what does this pattern show about how yeast grow and divide?
Compare the trend in percent budding cells from hour 1 to hour 4. Based on the data, what does the change in budding percentage tell you about the activity of the yeast population?
Which statement best describes why yeast are useful for studying cellular processes?
Based on Table 1, what is the best explanation for why cell numbers increase as hours pass?
Explain how the yeast data supports the idea that cells are the basic unit of structure and function in living things.