To first dive into your question, here are some vocabulary terms that I will be using and will be helpful to you as well.
- Homozygous dominant (BB): <em>Is not affected by cystic fibrosis</em>.
- Homozygous recessive (bb):<em> Is affected by cystic fibrosis</em>.
- Heterozygous (Bb):<em> A carrier for cystic fibrosis</em>.
- Phenotype (Ex: Having cystic fibrosis): <em>The appearance of an allele pair</em>.
- Genotype (Ex: bb): <em>The genetic makeup of an allele pair</em>.
We know that if both of the parents are phenotypically normal, there is no way that they can be homozygous recessive (bb), or have cystic fibrosis. We also know that since they have a child with this disease, they can't be homozygous dominant (BB) either. This means that <u>both parents have to be carriers (Bb)</u> in order for them to have a child with cystic fibrosis.
Below I have attached a Punnett square with both of the heterozygous parents.
<em>Each child they have will have a </em><u><em>1/4</em></u><em> or </em><u><em>25%</em></u><em> chance of having cystic fibrosis.</em>
In the winter, cold, dry air masses tend to dominate the central and eastern United States as cold winds blow from the northwestern Canadian prairies. In summer, the warm southern winds blow moist, hot air into the eastern and central US, leading to days of high humidity and sultry conditions. In spring and fall, moving low and high pressure areas pull alternating warm and cold air masses across a given area, leading to a lot of variability in day-to-day weather.
Enzymes can be divided into two groups, intracellular and extracellular enzymes.
Enzymes formed and retained in the cell are known as intracellular enzymes. They are found in the cytoplasm, organelles and the nucleus of the cell. Examples of such enzymes are DNA polymerase, RNA polymerase and ATP synthetase.
Extracellular enzymes are produced in the cell then packed and secreted from the cell. This kind of enzymes catalyze reactions outside the cell. Most digestive enzymes are extracellular enzymes . Examples of such are amylase, zymase and cellulase