Question

LABORATORY 5: WORKSHEET NAME: SECTION: DATE INSTRUCTOR LEARNING CHECK EXERCISES 1. When you view your specimen, it is difficult to see because it looks too dark. What part of the microscope might you adjust to correct this? light condensor 2. When you view your specimen it is slightly out of focus, what part of the scope might you adjust to correct this? Fine adjustment Knob. 3. Explain the effect of an increase in magnification on the field of view, and the working distance. 4. The field of view of a microscope with a 10x ocular and a 4x objective is 10mm. What is will be the field of view with a 20x objective? 5. What do the different sized cubes represent? What cellular structure determines the surface area of the cell? 6. Summarize what happens to the rate of diffusion as the cell size increases. 7. How do you know that diffusion is occurring in experiment 5? 8. Based on your observations in lab today, what differences did you note between the eukaryotic cells visualized compared to the prokaryotic cells? Microscopy and Cells: Warhet

Answer 1

QUESTION 1: condenser gathers the light from the illuminator and focuses on the specimen viewed.

QUESTION 2: fine adjustment knob fine tunes the focus and helps to see the specimen more detailed

QUESTION 3: Both field of view and working distance are inversely proportional to the magnification of the objective lens i.e with the increase in magnification, both the field of view and working distance will decrease.

QUESTION 4: Field of view = field number /magnification number

Given, eyepiece = 10x ocular

FOV (for 4x magnification ) = 10mm

Field number / ( 4 X 10) = 10

Field number = 10 X 40

= 400

Now, FOV ( for 20x magnification) = 400 / (20 X 10)

= 2 mm

QUESTION 6: When the cell size increases , volume of the cell increases faster than the surface area of the cell ( volume is cubed , surface area is squared). When there is less surface area and more volume, the process of diffusion takes longer and its effectiveness also decreases.

QUESTION 8: the main difference between the eukaryotic and prokaryotic cells is the presence of true nucleus. In Eukaryotic cell, nucleus is present while prokaryotic lacks one.

In Eukaryotic cells, we can find organelles within the cytoplasm but in prokaryotic cells, other organelles like ribosomes too so small to see under the microscope with regular light.