Lon selectivity in voltage gated channels depends on the hydration status of the ion. what is the basis of k+ selectivity in voltage gated k+ channels?
a. k+ is repelled by positive charges in the channel pore
b. a k+ ion that is not hydrated is stabilized at the outside of the pore and then loses a neutron to allow it to pass through the pore
c. voltage gated k+ channels are not actually selective to k+ as they also readily pass na+
d. a k+ ion hydrated by a single water molecule is the perfect size to be stabilized at the pore and pass through after shedding its water molecule

fertilization, pictured in figure 24.23a is the process in which gametes (an egg and sperm) fuse to form a zygote. the egg and sperm each contain one set of chromosomes. to ensure that the offspring has only one complete diploid set of chromosomes, only one sperm must fuse with one egg. in mammals, the egg is protected by a layer of extracellular matrix consisting mainly of glycoproteins called the zona pellucida. when a sperm binds to the zona pellucida, a series of biochemical events, called the acrosomal reactions, take place. in placental mammals, the acrosome contains digestive enzymes that initiate the degradation of the glycoprotein matrix protecting the egg and allowing the sperm plasma membrane to fuse with the egg plasma membrane, as illustrated in figure 24.23b. the fusion of these two membranes creates an opening through which the sperm nucleus is transferred into the ovum. the nuclear membranes of the egg and sperm break down and the two haploid genomes condense to form a diploid genome.

explanation:

explanation:

b,bacteria convert nitrates

into nitrogen gas.

d,plants and animals take in

and use nitrogen compounds.

e,bacteria break down waste    

products and return nitrogen  

to the soil.

a,bacteria convert atmospheric

nitrogen to ammonia.

c,bacteria convert ammonia

to nitrites and nitrates.

maybe because its impossible for balloons to lift a whole entire house.