Diffusion is one form of passive transport that doesn't require the expenditure of cellular energy. A molecule can diffuse passively through the cell membrane if it's lipid-soluble, uncharged, and very small, or if a carrier molecule can assist it. ... The assisted process is known as facilitated diffusion.
Got this off google but still hope it helps :)
Answer:
B) All DNA molecules will migrate up the gel toward the positive electrode.
Explanation:
Because the DNA has a negative charge - regardless the size-, all DNA molecules will migrate towards the positive electrode, at the top of the gel. This is due to the Coulomb's physic law "force of the interaction between the charges is attractive if the charges have opposite signs".
Instead of migrate down the gel , the DNA will do migrate up the gel (opposite direction).
Trisomy 21, as illustrated by the karyotype, is caused by nondisjunction. This occurs when chromosomes do not separate properly during meiosis.
Answer is D) nondisjunction
