Biology 2201 Cell Organelles Question Sheet (2)

 

1.      Muscle cells tend to have more mitochondria than other body cells, explain why this is so?

 

Muscles cells use more energy than other body cells to make us move. Mitochondria provide cells with usable energy.

Highest Energy needs =Highest Number of Mitochondria.

 

2.      Why is the cell membrane essential to a cell’s functioning, and why is it important that it is selectively permeable.

 

The Cell Membrane is the package for all cell types. It keeps a cell together as a structure, that is why it is essential.  Selectively permeable means to let some substances through and not others and to control the amounts. If the cell membrane didn’t allow things such as oxygen through to the cells the cells would “suffocate”.  If the cell membrane didn’t control what moves in and out of the cell then things the cell wants to store or keep out would move freely.

 

3.      Most animals are consumers that are capable of locomotion; while most plants are stationary producers, explain how the structure of the cells of these organisms contributes to their functions.

 

Plant cells have chloroplasts so they can get energy from the sun.  Plants grow where there is available light so they don’t need to move to feed. Plant Cells have a cell wall that helps them keep a constant shape.  This means it would be very hard for them to move like animals.

 

Animals ca’tn use sunlight, their cells lack chloroplasts.  Thus animals must move around to gather and catch food.  Animal cells don’t have a cell so the cells can easily change shape and move around.

 

4.      The pancreas is an organ that secretes large amounts of a protein called insulin. What specializations might you expect to see in the cells of this organ?

 

Insulin is a protein.  Proteins are made by ribosomes, so pancreas cells should have lots of ribosomes.  Proteins that are for use outside of the cell are made in the ER so there should be lots of ER.  Insulin must be packaged and moved out of the cell so pancreas cells should have lots of vesicles(packages/ taxis)  and golgi apparatus (packing plant.

 

5.      Cells are described as having a "division of labor". What is meant by this statement and give examples of how it is evident in cells.

 

Division of labor means that each different type of  part has a different job without repeating jobs.  In a cell each different type of structure performs a different task. For example mitochondria provide the cell with usable energy by making ATP, ribosomes make proteins etc.

 

6.      List all the organelles in a cell that are essential to the life functions of a cell.

 

All organelles perform necessary functions for a cell there are no “useless”organelles.

 

7.      Describe the difference between cilia and flagella, in terms of both structure and function (page 30)

 

Cilia – shorter, move in a wave like fashion, can move the cell around and direct

the movement of particles outside the cell (ex. Cilia line our respiratory

system and direct dust away from our lungs)

 

        Flagella – same structure as cilia, longer than cilia, move in whip-like fashion

                        use only to move a cell around

 

            See the site below for an animation

http://programs.northlandcollege.edu/biology/Biology1111/animations/flagellum.swf

 

8.      Cells in plant leaves tend to have far more chloroplasts than the cells in other parts of the plant. Explain this observation.

 

Chloroplasts are the structures in plant cells that use light and other substances to produce sugars (energy).  All plant cells have plastids.  Only plastids exposed to light become Chloroplasts.  Leaves get more sun than other plant parts.  That’s why leaf cells have more chloroplasts than cells in other plant parts such as the roots.

 

 

9.      What organ in the body, would you expect to contain cells that have numerous peroxisomes? Explain.

 

Peroxisomes rid the cell of toxic substances like hydrogen peroxide and alcohol. The liver rids the body of toxic substances.  Thus you would expect liver cells to have lots of peroxisomes.

 

10.  List the cell parts that play an important role in the production, refinement, and transport of proteins.

 

-- on ER (make proteins for use outside the cell)

·        ER – changes proteins made by ribosomes on the ER and packages them in

    vesicles

·        Golgi Apparatus – absorbs vesicles from the ER, activates the proteins in them

                                       and repackages them in vesicles.

·        Vesicles – packages that contain proteins and move them around and out of a

                         cell

 

 

 

11.    List the cell parts that are found only in animal cells and those found only in plant cells.

 

Only in Plants à cell wall and chloroplasts

 

Only in Animals à Lysosomes and Centrosomes