Aman with cystic fibrosis of the pancreas wishes to marry a young woman whose family has never had an individual born with the disorder. cystic fibrosis is an inborn error of metabolism, a recessive condition, in which an enzyme necessary for fat digestion is lacking. could this couple have a child with cystic fibrosis? write all of the possible genotypes for the genotypes for the man, the woman, and the children that they may have should they marry.

Cystic fibrosis is a recessive condition; meaning if a dominant condition takes over it will not be seen in the offspring. The man genotype with cystic fibrosis can only be this: cc (when c is equal to the cystic fibrosis and C is equal to not having one). The woman with no history of cystic fibrosis can possibly have either of these two genotypes: Cc or CC.

To see their offspring’s possible genotype, we’ll use a punnett square let’s start with Cc:

                C             c

c              Cc           cc

c              Cc           cc            There is a 50 % chance of the child having cystic fibrosis.

To see their offsprings possible genotype with CC:

                C             C

c              Cc           Cc

c              Cc           Cc           There is no chance that the child will have cystic fibrosis.

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!

the correct answer is d