Review #1 Q’s ANSWER KEY
1. The cell membrane is a phospholipid bilayer which has a FLUID consistency and it has lots of integral proteins embedded in it giving it a SCATTERED PATTERN (mosaic) appearance.
2. Integral proteins are embedded in the CM and held in place by the CM, peripheral are not embedded but are held in place to the inside by cytoskeleton filaments.
3. A glycoprotein is a protein with a glycol-chain protruding from it. A glycolipid is a phospholipid with a glycol-chain protruding from it.
4. The GLYCOCALYX gives the cell a unique fingerprint for identification.
5. You gotta love C.R.E.R.C !
C. CHANNEL
R. – RECOGNITION
E – ENZYMATIC
R- RECEPTOR
C- CARRIER
6. Cholesterol molecules help firm up the CM, making it less fluid in texture.
G-2
1. Selectively permeable, means that it will let molecules and other substances get in and out based on need rather than just on the size of the molecule.
2. Passive transport like diffusion, osmosis and facilitated transport –require no ATP (energy) and go with the concentration gradient.
Active Transport like endocytosis, and exocytosis and active carrier transport require ATP.
3. Diffusion and Osmosis and Facilitated Transport are all classified as methods of PASSIVE TRANSPORT.
4. Facilitated transport requires a carrier protein.
5. CO2, O2, H2O (through aquaporin protein channels), Glycerol, and Alcohol all easily diffuse across the cell membrane.
G-3
1. According to the law of diffusion, molecules like to spread out from an area of higher concentration to an area of lower concentration. Down their concentration gradient
2. In gases, there is more kinetic energy in the particles
3. Solvent – the more abundant material that does the dissolving.
Solute – The less abundant material that gets dissolved into the solvent.
4. A difference between an area of higher concentration and an area of lower concentration.
HIGH à à low
5. Mostly through protein channels called aquaporins, but some also scoot between the phospholipids. It is small enough and its polarity is weak enough to do so.
6. Osmosis is the diffusion of water from High conc. to an area of low conc. across a membrane.
7. Osmosis is water and across a membrane, Diffusion is anything and it doesn’t have to be across a membrane. They both are passive transport and follow their concentration gradient.
8. Osmotic Pressure
9. Solutions can be ISOTONIC, HYPOTONIC or HYPERTONIC
10. When an animal cell is placed into a hypotonic solution, it has more solutes inside the cell than outside the cell. The solutes suck water into the cell and the cell swells often causing LYSIS
When an animal cell is placed into a Hypertonic solution, the solution has a higher concentration of solutes. The solutes suck water out of the cell, causing the cell to shrivel. This is called CRENATION
11. When a plant cell is placed into a HYPOTONIC solution. The plant cell has more solutes inside the cell. These solutes suck water into the cell. The plant cell swells and turgor pressure builds up against its cell wall. It becomes TURGID.
When a plant cell is placed into a HYPERTONIC solution, the solution has more solutes. These solutes suck water out of the cell and the cell wilts to undergo PLASMOLYIS.
PRACTICE QUIZ KEY:
1. WATER – osmosis
2. C – As water moves from side B àA, the solutes on side B, automatically become more concentrated.
- C – Many of that particular solute will migrate over from Side A à B but the other solute is stuck where it is plus water cannot move to balance it out
3. C
4. C
5. B
6. C
7. D
8. B
9. D
10. B
11. A