Bio 11 – Virtual Cell Assignment.
Answer Key.
Go to the following site: www.virtualcell.com
I. Click on the "Virtual Cell Tour" and answer the following questions: Some answers
will come from the virtual text book .
1. Describe the process in which proteins are packaged by the golgi body.
Once the proteins are produced by the RER they pass into the sack like
parts of the Golgi bodies & are then pinched off into little blobs that drift
into the cytoplasm
2. Describe the structure of lysosomes. Lysosomes consist of a single membrane
surrounding strong, digestive enzymes.
3. What are the functions of lysosomes. The enzymes inside lysosomes digest
bacteria and other foreign bodies. They also cause autolysis which is a way
of getting rid of old or damaged cells.
4. What is autolysis? When a lysosome releases its strong digestive enzymes
all at once, it will destroy the cell .( cell suicide)
5. Describe the outer and inner structure of mitochondria. Mitochondria are rod
shaped and have a double membrane. The inside membrane has many inner
folds called cristae.
6. Why is the inner membrane of mitochondria ruffled? This ruffling increases the
surface area ( this is where enzymes attach for cellular respiration.)
7. Where might have mitochondria originated from? Why? It is thought that the
mitochondrion evolved from symbiotic bacteria that took up residence inside
the first eukaryotic cells. This is suspected because mitochondria produce
their own DNA and can make some of their own protein.
8. Describe the arrangement of microtubules that compose the centrioles. (Hint: look
carefully at the image) There are 9 groups of 3 protein fibers arranged in a
circular pattern for each centriole.
9. Describe the outer membrane of the nucleus. The nuclear membrane has many
pores. The nuclear membrane is continuous with the E.R
10. Describe the inner contents of the nucleus. The inner contents of the nucleus
contain thick ropy strands called chromatin. The large solid spot is the
nucleolus.
11. Describe the appearance of the nucleolus. The nucleolus is a dense knot of
chromatin which manufactures ribosomes.
12. Describe the appearance of the endoplasmic reticulum. It is a folded system of
membranes that loop back and forth giving it a very large surface area.
13. What makes rough ER "rough"? RER is rough because ribosomes are
attached to it.
14. What is the function of the chloroplasts.? What do they look like? Chloroplasts
are the site of photosynthesis and they are green cylinder like bodies.
15. In the cell membranes – what are the blue and yellow structures called? What are the
pink structures? Blue and yellow are the phospholipids and the pink structures
represent the protein molecules.
16. What do marker proteins in the cell membrane do? Marker proteins identify
the cell to other cells.
17.
In the cell membrane there are channel proteins. Are they involved with active or
passive transport? They are involved with passive transport since the cell uses
no energy – it is diffusion which causes particles to move through the
channel proteins.
18. Observe the animation of endocytosis. What is the example shown on the web site of
endocytosis? In this animation an ameba engulfs a food particle.
19. Find the animation of a contractile vacuole. Why must single celled pond organisms
(protozoa) have these types of vacuoles? Protozoa must constantly excrete the
water that enters through their membranes to combat the effects of
osmosis.
20. Find plastids and then look up leucoplasts and amyloplasts. What function do they
serve? Give an example. Leucoplasts (colorless plastids) usually store food
molecules such as starch being stored in potato cells.