Membranes and Chemical transport
One of the main functions of the cell membrane is to control the movement of chemicals into and out of the cell.
A)Web site name: Florida State College at Jacksonville
Web URL:
Read “Membranes”
1).What are two molecules that can freely move across the cell membrane? ______
2).In diffusion particles move from areas of ______concentration to areas of ______concentration.
3).If the temperature of a solution increased, would you expect the rate of diffusion to increase or decrease? ______
4).Give an example of a chemical that moves into cells by facilitated diffusion: ______
5).Is external energy required for facilitated diffusion? ______
6).What is “osmosis”? ______
7).What is the clinical importance of osmosis? ______
8).Why can too much water kill you? ______
______
9).What is meant by :
a) Hypertonic ______
b) Isotonic ______
c) Hypotonic ______
10).What happens to a plant cell in a hypotonic solution? ______
11).What happens to an animal cell in a hypotonic solution? ______
12).What happens to a plant cell in a hypertonic solution? ______
B)Web site name: Estrella Mountain Community College
Web URL:
Read “Transport in and out of cells”
13).What is “water potential?” ______
14).In which direction (into or out of the cell) is the net flow of the following chemicals :
a)carbon dioxide ______
b)oxygen ______
15).What are two examples of semi-permeable membranes apart from the cell membrane? ______
16).What problem does Paramecium have? ______
17).How does Paramecium overcome this problem? ______
18).What is “active transport”? ______
19).Look at the diagram of active transport. Are the two transported ions moving in the same direction, or in different directions, through the “symport”? ______
20).Which ion is kept at high concentrations inside nerve cells? ______
21).What is the difference between exocytosis and endocytosis ? ______
22).What is “phagocytosis”? ______
______
23).How does insulin enter animal cells? ______
C)Web site name: Cells Alive
Web URL:
24).What is the function of blood plasma? ______
______
25). What are three specialized cells that are among the red cells?
______
Click on the bottom of the page, or “Anatomy of a Splinter” at the top.
26).How do white cells know there is damage to control?
______
27). What is “diapedesis”? ______
Click on “Chemotaxis”
28).Which cells are the body’s first line of defense against bacteria? ______
Click on the Play icon to view the video.
29).Roughly how many cells are moving across the screen? ______
Click on “Phagocytosis”
30).What does “Phagocyte” mean? ______
Click on the Play icon to see the video.
31). How many yeast (Candida) cells are being digested? ______
32).Do you think the sound on the movie is the real sound the cell makes? ____
Membranes are important because they control which chemicals can enter or leave the cell. Cancer researchers are trying to develop better ways of killing cancer cells while leaving regular body cells alone.
D)Web site name: Science Daily
Web URL:
Read “Tumors feel the deadly sting of nanobees”
33).Which toxin is the focus of this study? ______
34).How does this protein kill cells? ______
35).How many injections of these nanoparticles were given over several days? ______
36).How much was the size of melanoma decreased compared to untreated controls? ______%
37).Why does the drug concentrate in tumor cells and not regular cells? ______
38).What problem is caused by directly injecting mellitin into the bloodstream? ______
39). Why is the size of nanoparticles (six millionth of an inch) so important?
______
______
E)Website name: Science Daily
Web site URL:
Read “Broad-spectrum antiviral”
40). What is the limitation of antibiotics?
______
41). What is the problem with current “broad-spectrum” antivirals?
______
42). List four viruses that this new antiviral compound can stop:
______
43). How many molecules were screened before they found “LJ001”?
______
44). Which specific virus was originally blocked by LJ001? ______
45).Explain how the antiviral compound prevents cells from being infected by
the virus.
______
46). Why does LJ001 not cause ill effects on cell membranes, but it does
permanently affect viruses?
______