Textbook Homework 3/25/2013

Textbook Page 25 - (1-18)


1. What life processes do cells perform?

     - Intake of nutrients

     - Waste removal

     - Growth

     - Reproduction

     - Movement

2. List the 5 organelles that are common to plant and animal cells. What are their functions?

     - Cell membrane: Forms a protective barrier around the cell.
     - Nucleus: Controls all the activities in a cell, including growth and reproduction.

     - Cytoplasm: Fills the cell and surrounds the organelles.
     - Vacuoles and Vesicles: Stores nutrients, wastes, and other substances used by the cell.
     - Mitochondria: Supplies energy.
     - Lysosomes: Where digestion takes place.     
     - Golgi Apparatus: Modifies, sorts, and packages proteins for delivery throughout the cell or 
outside of the  cell.       
     - Cytoskeleton: Helps maintain the cell's shape.

     - Endoplasmic Reticulum: Makes proteins (rough), fats and oils (smooth). 

3. What are the 3 differences between plant & animal cells?

     1. Plant cells contain a special chemical compound called chlorophyll - a pigment that makes  photosynthesis possible.

     2. Animal cells have centrioles, which are paired structures that are involved in cell division. Unlike plant cells, which do not have centrioles.
     3. Plant cells have a large central vacuole. Vacuoles in animal cells tend to be much smaller.

4. Why can the granum and thylakoid structures be described as “solar collectors”?

     - They operate like solar panels and collect light energy from the sun, which is then used for the process of photosynthesis to produce carbohydrates in the chloroplast.

5. Prepare a table that summarizes the organelles and structures found in plant and animal cells.

Organelles Found in Both                                                                                 Description
     - Cell membrane:                                         Forms a protective barrier around the cell
     - Cytoplasm:                                                  Fills the cell and surrounds the organelles
     - Nucleus:          Controls all the activities in a cell, including growth and reproduction
     - Vacuoles and Vesicles: Store nutrients, wastes, and other substances used by the cell
     - Mitochondria:                                                                                        Supplies energy
     - Lysosomes:                                                                     Where digestion takes place
     - Golgi Apparatus: Modifies, sorts, and packages proteins for delivery throughout the cell or outside of the cell
     - Endoplasmic Reticulum:                  Makes proteins (rough), fats and oils (smooth)
     - Cytoskeleton:                                                               Helps maintain the cell's shape

Found In Plants

     - Chlorophyll:                                                                                     

     - Cell Wall:                                                              Gives durability & provides strength

Found In Animals

     - Centrioles:

6. Explain how fluorescence microscopy works.

     - Cells may be difficult to observe due to their colour or transparency and thus, fluorescent substances are added to the cells rendering them easier to see.

7. Name two types of electron microscopes that are used by cell biologists.

     - Transmission electron microscope (TEM)

     - Scanning electron microscope (SEM)

8. What is the name of the image created by an electron microscope? 

     - Electron micrograph.

9. Explain why the cell can be considered to be the “building block” of life.

     - Every living organism is made up of cells.

10. Explain the importance of contrast in microscopy.

     - Adjusting contrast allows for visibility of the different parts and layers of the cell.

11.  What two things can you do to create contrast when you use a compound light microscope to study a specimen?

     1. Change the objective lens.

     2. Adjust course adjustment knob and fine adjustment knob.

12. Explain why a cell biologist would choose to use an electron microscope rather than a light microscope. When would a light microscope be preferred?

     - A cell biologist would choose an electron microscopes when they would like to see parts of the cell in much greater detail and resolution which requires much higher magnification. A light microscope would be preferred when the required image is not as detailed or magnified and/or if there aren't sufficient funds for an electron microscope.

13. What details of a microscope would you need to know to determine the total magnification of the system?

     - In order to determine the total magnification of the system you must know the magnification of the objective lens you are using, plus the magnification power of the eyepiece.

14. Explain why you would expect the cells of a desert plant, such as a cactus, to have thickened cell walls?

     - For more protection due to harsh environmental conditions - sand storms.

15.  - I would expect to see more mitochondria from the cells from the athlete opposed to the elderly individual, because the athlete is younger and in overall better health than the elderly individual.

16. Explain how a microscope may be used to assess human health.

     - A microscope may be used to assess human health by examining a sampling of the individual's cells to determine their condition, because after all, cell's make up life.

17. Write a short paragraph that compares and contrasts plant and animal cells.

     - In an animal cell the proteins and sugars are converted into energy, whereas in a plant cell, the process of photosynthesis occurs - harvesting energy from light.

18. How has the development of technology aided our understanding of cells?

     - The evolution of technology has rendered us capable of seeing more- in greater detail- and allowing us to understand and observe the functionality of cells, broadening our general understanding.