8. cystic fibrosis is a recessive disease. a couple (jack and jill) is worried about having a child that has
cystic fibrosis because the man had a brother with the deadly disease. because they want to have
children, they sought the advice of a genetic counselor. during the course of the interview, the
counselor determines that jack's parents were not affected with cystic fibrosis, yet his brother had
it. what is immediately known about the genotypes of the man's parents? is the genotype of jack
immediately known? under what circumstances could jack and jill have a child with cystic fibrosis?
assume that neither jack nor jill has cystic fibrosis

Question 1.

Cystic fibrosis is an autosomal dominant disease caused by a mutation in the CFTR gene located in chromosome 7.

From the information obtained, we can conclude that Jack's parents are both carriers of cystic fibrosis, that is, they are heterozygotes (that is, they both have one healthy allele and one mutated allele). Jack's brother has the disease (he is a sick homozygote) so each of his parents has necessarily given him a mutated allele.

Question 2.

With the information we have, we can not accurately predict Jack's genotype.

Jack can not have two mutated allele, since he does not express the disease, but there remain two valid possibilities: either he is a heterozygous carrier of the disease (one of his parents transmitted him the disease) either is a healthy subject, that is, both of his alleles are normal.

Question 3.

For this couple to have sick children, both parents would have to be carriers of the disease so that each one of them would transmit a mutated allele.

So Jack would have the disease carrier (heterozygote) as well as Jill. An investigation (genetic counseling) in Jill's family is also needed to see if cystic fibrosis is spread in her family or not.

water is a polar molecule. a chemical bond is a force of attraction between atoms or ions. bonds form when atoms share or transfer valence electrons. atoms form chemical bonds to achieve a full outer energy level, which is the most stable arrangement of electrons. so, false

explanation:

in h2o molecule, two water molecules are bonded by a hydrogen bond but the bond between two h - o bonds within a water molecule are covalent. the greater the electronegativity difference, the more ionic the bond is. bonds that are partly ionic are called polar covalent bonds. nonpolar covalent bonds, with equal sharing of the bond electrons, arise when the electronegativities of the two atoms are equal.