The correct answer is: A) The polarity of membrane phospholipids
Factors that affect membrane permeability are
1. Chemicals :
Some of the organic solvents such as chloroform and ethanol can dissolve the membrane and thus, destroy the selective permeability of the membrane.
2. Temperature :
Too high temperatures denature the protein that are in the structure of the membrane destroying its selective permeability. On the other hand, too low temperature slows down molecule movements and the permeability decreases.
3. Cholesterol:
Increases the permeability by reducing the barrier formed by phospholipids’ heads
4. The saturation of hydrocarbon tails in membrane phospholipids:
Saturated fatty acids decrease permeability of the membrane because they get very close together, which makes it harder for the molecules to pass through.
Answer:
B) The conclusion is not valid; there were fewer bacteria cultures on the soap plates
Explanation:
In a recent experiment, anti-bacterial hand sanitizer was compared to hand soap. Students washed their hands using the sanitizer or soap and warm water for two minutes; then they dried their hands with a paper towel. The standard of comparison was rubbing hands vigorously for 2 minutes in warm water, without any soap or sanitizer, and then drying with a paper towel. The sanitizer advertisement claimed to kill bacteria more effectively than any soap. After washing, hands were swabbed and then the swab applied to a culture plate and incubated. Finally, the bacterial cultures were counted and recorded in the data table. Students concluded that the hand sanitizer was most effective in killing bacteria. How would you respond to the students' conclusion?
Hand Washing Test Hand Washing Test
Treatment Bacterial cultures (#/plate)
Warm water 24
Hand sanitizer 28
Soap A 12
Soap B 13
The above table should have been included before the question. From the table we can conclude that
B) The conclusion is not valid; there were fewer bacteria cultures on the soap plates
Which also means that the sanitizer is not as effective as warm water. it is the least effective solution to kill bacterial.
Answer:
RR, Rw, Rw, ww
Explanation:
Rw
R
w
RR, Rw, Rw, ww
The phenotypes would be 1 Red, 2 Roan, and 1 white, assuming the colors of roan are white and red and red is dominant white is recessive, hope that helps!
