What makes phospholipid membranes good at keeping some molecules out, and allowing others to freely pass?

a. They are positively charged.
b. They are completely hydrophobic.
c. They are completely hydrophilic.
d. They have both hydrophilic and hydrophobic regions.


Answer: d. They have both hydrophilic and hydrophobic regions.

Biology & Microbiology

You might also like to view...

The visible indentation that forms on the exterior of a dividing animal cell is called the ________

a. cleavage furrow b. gray crescent c. contractile ring d. cell plate

Biology & Microbiology

The Hardy-Weinberg law can be used to calculate allele and genotype frequencies without genetic testing

a. True b. False

Biology & Microbiology

Which of the following is the correct path sperm travel on their way out of the male?

A) Epididymis ? urethra ? vas deferens ? seminiferous tubules B) Seminiferous tubules ? epididymis ? vas deferens ? urethra C) Urethra ? vas deferens ? seminiferous tubules ? epididymis D) Epididymis ? seminiferous tubules ? vas deferens ? urethra E) Seminiferous tubules ? vas deferens ? urethra ? epididymis

Biology & Microbiology

Which of the following species is credited with the first knowledge of fire and cooking meat?

a) Homo habilis b) Homo erectus c) Cro-Magnon d) Australpithecus afarensis e) Homo sapiens

Biology & Microbiology