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Cells PRE-LAB QUESTIONS 1. What are the functional requirements of life? The functional requirements of life are movement, responsiveness, metabolism, reproduction, and excretion. 2. Using Table 1, identify the major similarities and differences between prokaryotic and eukaryotic cells. Some similarities between prokaryotic and eukaryotic cells are that they both have cytoplasm and ribosomes as well as they both carry out the functional requirements for life. Some differences between prokaryotic and eukaryotic cells are that eukaryotic cells have a nucleus unlike a prokaryotic cell. And prokaryotic cells are less complex than eukaryotic. 3. Where is DNA housed in a prokaryotic cell? Where is it housed in a eukaryotic cell? In a prokaryotic cell, DNA is housed in the nucleoid region. And in a eukaryotic cell DNA is housed in the nucleus. 4. Compare and contrast the role of secretory vesicles, the lysosome, and the peroxisome. The role of secretory vesicles is that they aid in exocytosis by ensuring the transported cargo in vesicle goes where it is supposed to. The lysosome is responsible for digesting macromolecules and to aid in the response against foreign bacteria. The role of the peroxisome is to oxidate certain enzymes and break down fatty acids. 5. Identify three structures that provide support and protection in a eukaryotic cell. The three structures that provide support in a eukaryotic cell are the cytoplasm, cell membrane, and the cytoskeleton.

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Cells EXPERIMENT 1: CELL STRUCTURE AND FUNCTION Post-Lab Questions 1. Identify A and B in the slide image below.

Onion root tip, 1000x.

A: chromosomes_________

B: nucleus______________

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Cells 6. What components of the eukaryotic cell were visible in the onion root tip? Which components were not? Why do you think some components were more visible than others? The components that were visible in the slide were the chromosomes, nucleus, cell wall, and occasionally the cytoplasm. Some components that were not visible were ribosomes, chloroplasts, and the endoplasmic reticulum. I think this is because the dark color in the cells comes from DNA when it is clustered together (which would explain why the nucleus shows up in every cell). And ribosomes are much smaller than the nucleus, so I would likely need a more advanced microscope to see them. 7. In this experiment, you observed onion root tip cells. What structure could be observed in these cells that would not be observed in a human cell? In a human cell, some structures that could be observed are lysosomes and centrosomes. 8. Would an animal cell be able to survive without mitochondria? Why or why not? No, animal cells would not survive. They get all their energy from anaerobic respiration which must occur by the mitochondria.

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Cells EXPERIMENT 2: EXPLORING CELL SIZE Data Tables Table 2: Surface Area and Volume in Relation to Cell Size Radius (µm)

Surface Area (µm2)

Volume (µm3)

Surface Area:Volume Ratio

Time to Center of the Cell (s)

15

2827.43

14137.17

0.199 = 0.2

0.075

30

11309.73

113097.33

0.099 = 0.1

0.15

45

25446.9

381703.51

0.066 = 0.07

0.225

60

45238.93

904778.68

0.049 = 0.05

0.3

75

70685.83

1767145.87

0.039 = 0.04

0.375

90

101787.6

3053628.06

0.033

0.45

105

138544.24

4849048.26

0.029 = 0.03

0.525

120

180955.74

7238229.47

0.025 = 0.03

0.6

135

229022.10

10305994.7

0.022

0.675

150

282743.34

14137166.94

0.019 = 0.02

0.75

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Cells Post-Lab Questions 0.12

0.1

SA:V Rato µm

0.08

0.06

0.04

0.02

0 0.15

0.23

0.3

0.38

0.45

0.53

0.6

0.68

Time to Center of Cell (s)

1. Create a graph of the time to the center of the cell as a function of the surface area:volume ratio.

2. How did the surface area affect diffusion to the center of the cell? What about volume? What about the surface area-to-volume ratio? The surface area of the cell affected the diffusion rate to the center of the cell by association to the volume. When surface area increases, so does volume. With more space in the cell, it took longer for the diffusion to occur. The SA:V ratio also became smaller as the two values increased.

9. How does this experiment demonstrate the need for cells to maintain a smaller size? By having a smaller cell size, cells do not have to exert as much (if any) energy to diffuse materials. This way, they can use that energy to do other things and overall be more efficient. ©eScience Labs, 2016

0.75

Cells

©eScience Labs, 2016

Cells

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