Name
THE CELL MEMBRANE STRUCTURE
1. What did Singer and Nicholson discover?
Cell membrane
2. What does fluid mosaic mean? Description of the cell membrane that has many different
components (mosaic), but still maintains a flexible (fluid) feature.
3. Draw a simplified version of the cell membrane. Include and label the following parts – phopholipid,
protein, cholesterol, carbohydrate chains, glycolipid, glycoprotein, cytoskeleton
4. Name and describe the four types of proteins in the cell membrane. Enzymes, marker(recognition),
transport, receptor
5. What type of protein determines blood type? antigen
6. What type of protein does glucagon connect with on liver cells? Receptor protein
7. What type of proteins are an antigens and antibodies? Marker (recognition) proteins
8. Why is mixing blood types dangerous? Cells will agglutinate and clump together, blocking blood flow
and cells could rupture. (Know the difference in antibodies & antigens for the blood types)
9. ** What is the main job of the cell membrane? Maintain homeostasis
10. ** Describe selective permeability. Allowing certain substances in/out of a cell and preventing
others.
State other characteristics/structures of the membrane that help it do its job.
See fluid mosaic model and parts/functions
THE CELL MEMBRANE FUNCTION
11. What is Brownian motion? Random motion of molecules
Name
12. What are 2 factors that determine what can pass through the membrane and where? Size and
charge
13. List three molecules that can go directly through the bilayer. CO2, O2, H2O (sort of)
14. List three molecules that must pass through a membrane protein. Na+/K+/Glucose
15. List 2 characteristics of passive transport.
No energy/highlow concentration
16. What are three passive transport processes? Diffusion/osmosis/facilitated diffusion
17. What is concentration? Amount of substance in a given area
18. What is a concentration gradient? The difference in the concentration of an area (there will be a
high and a low)
19. Describe dynamic equilibrium. When there is no more concentration gradient
20. What two important gases will pass through the cell membrane by diffusion? CO2 and O2
21. What is the protein in red blood cells that transport oxygen and carbon dioxide? Hemoglobin
22. What is osmosis? Diffusion of water across a membrane
23. If a cell is placed in a hypertonic solution it ______plasmolysis__________________. If it is
placed in a hypotonic solution it _______gains osmostic pressure___________________. If in an
isotonic solution it ___________remains unchanged_______________________.
24. What is osmotic pressure and how is it related to turgor pressure?____it is the pressure inside an
animal cells in a hypotonic environment (like turgor pressure in plant cells___________
25. A slightly shrunken plant cell is scientifically referred to as ____flaccid__________________. A
plant cell that has lost MOST of its water is called
__________wilts___________________________. A plant in a hypotonic solution is really full of
water and is called _________turgor pressure_______________________.
26. Animal cells that have burst are called ________lysed (cytolysis________________. Animal cells
that are shrunken are called ______crenated (plasmolysis)________________.
27. Describe one adaptation of organisms such as protists to a hypotonic environment. Contractile
vacuole
28. How is facilitated diffusion different from regular diffusion? Requires a protein to get substance
across the membrane
29. What three substances may pass through the membrane by facilitated diffusion? Glucose, amino
acids, and ions
Name
30. What are two characteristics of active transport? Require energy (ATP), movement from low to high
concentration
31. What is the difference between active transport and facilitated diffusion? Active requires
energy/Facilitated does not
32. What is the similarity between active transport and facilitated diffusion? Both require protein in
membrane
33. What is the difference between endocytosis and exocytosis? Endo= substance enters cell; Exo=
substance exits the cell
34. Give an example of endocytosis: when a cell takes in a bacterium or virus in order to destroy it
35. Give an example of exocytosis: Protein synthesis when protein is packaged and released from the cell