BISC 113 Chapter Notes - Chapter 4, 5, 6, 16, 7, 15, 17: Character Displacement, Oogenesis, Canadian Cancer Society
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BISC 113 - Biology in Everyday Life
Chapter Study Questions
Chapter 4 Study Questions
1. Congratulations! You have just been hired by the United Nations to manage a global malaria
control program. With the knowledge that you gained from viewing the three videos above,
make a list of the three top projects you would fund. For each of the projects you have listed,
write a short explanation of why you decided to fund that project.
4.1 What is sickle cell disease?
1. What is the function of hemoglobin in your body?"
Hemoglobin is the protein that carries oxygen in red blood cells.
2. Sickle cell disease is the result of defective Hemoglobin proteins (HbS rather than the
normal HbA). What causes HbS to appear in a person?"
Inheritance of one normal gene and an altered one, or two altered genes, that direct the
synthesis or production of HbS protein means a person will be a carrier or infected with
sickle cell disease.
3. A person can be a “carrier” of sickle cell but not have the disease. How is this possible?"
Only people who inherit genes that encode for HbS protein from both parents will suffer from
sickle cell disease. Thus, if only one altered HbS gene is inherited, the person is a carrier of
the gene without the effects of the full blown disease (“recessive”).
4. Why do some groups of people in Africa have a relatively high percentage of individuals with
sickle cell disease?"
Malaria is most common in Africa. Having sickle cell disease presents a resistance to and
protection from malaria, which is an example of human evolution.
4.2 Could molecular medicine prevent sickle cell disease?
1. In electrophoresis which type of molecules will move the farthest from the well?"
The small fragments migrate ﬁrst and will gradually move the furthest away from the well,
while longer fragments will move last and remain closer to the well.
2. Why do molecules move through the gel in electrophoresis?"
One end of the chamber is positively charged, which will cause negatively charged
molecules to move towards the opposite end up the electrophoresis chamber.
4.3 Where is our genetic information stored?
1. If pangenesis was how inheritance worked, and you crossed a white ﬂower with a red ﬂower,
what colour would the offspring be?"
The offspring would be pink because the two colour traits of white and red would blend.
4.5 How did Mendel discover the rules of inheritance?
1. The presence of horns on Hereford cattle is controlled by a single gene. The hornless
condition (H) is dominant over the horned (h) condition. A hornless cow was crossed
repeatedly with the same horned bull. The following results were obtained in the offspring:
-8 hornless calves
-7 horned calves
A. What are the alleles of the parents?"
Hh + Hh8
2. In human beings, brown eyes are dominant over blue eyes. Suppose a blue-eyed man
marries a brown-eyed woman whose father was blue-eyed. What proportion of their children
would you predict should have blue eyes?"
Bb + bb → Bb, Bb, bb, bb"
The proportion would be 50% brown and 50% blue eyes.
3. If a brown-eyed man marries a blue-eyed woman and they have 10 brown-eyed children,
can you be certain that the man is pure-breeding for eye colour?"
Yes because that would require two dominant alleles (for brown eyes) from the father that
would cause the allele for blue eyes be unexpressed within each child.
4. A brown-eyed man whose father was blue-eyed and whose mother was brown-eyed married
a blue-eyed woman whose father and mother were both brown-eyed. The couple has a
blue-eyed son. For which of the individuals can you be sure of their genotypes? What
genotypes are possible for the others?"
Father = Bb/Mother = bb/Son = bb"
You can be sure of the parents’ genotypes because of the gene expression in their son. You
can also be sure that both the mother’s parents carried a gene for blue eyes (Bb + Bb)
because even though they each had brown eyes, their daughter had blue eyes. However, it
is difﬁcult to be sure of the father’s parents’ genotypes because the grandfather may have
had either two blue eyed genes, or one brown and one blue for the son to have had brown
eyes. Likewise, the mother may have had either two dominant brown eyed alleles or one
brown and one blue for the son to have had blue eyes.
4.6 What are genes made of?
1. Given the following strand of DNA write the nucleotide sequence for the complementary
strand: A T C C G C C T A G G T"
A T G G C G G A T C C A
4.8 What processes must DNA accomplish?
A. It must replicate itself (process of replication).
B. It must be able to change, or mutate, which you learned in the evolution chapter is
essential for variation (process of mutation – these errors occur at a very low rate (1 in a
billion bases) during the process of replication).
C. It must produce the proteins responsible for physical changes (process of protein
1. Why is it easy for a DNA molecule split down the middle to reform in an exact replica of
Due to its double-helix structure, it is easy for DNA to separate the base pairings from one
another and “unzip” itself.
2. Given the following small piece of DNA, which is part of a longer strand, ﬁll in the correct
nucleotides for the mRNA and the amino acids in the protein. DNA: C C A A T A A G G C G
C A T T"
mRNA: G G U U A U U C C G C G U A A"
Amino acid sequence (read mRNA codon) _______ ______ _______ ______ _______
3. In a protein, when one amino acid is replaced by another, the protein often can’t do its job.
What changes about the protein?"
The difference is often responsible for meaningful changes in the structure of the protein.
The shape of the protein will be altered, changing its function.
4. Mutations are not always random, natural events. Certain things can cause DNA damage.
One of these things is UV radiation.
4.9 Why is protein structure so important?
1. Tay Sachs disease is the result of abnormal genes, much like sickle cell, and both can be
identiﬁed with genetic screening. As a result of screening programs, Tay Sachs is now very
rare in North America, but sickle cell is not. What’s different between these cases?
A. Tay Sachs is worse, so people pay more attention to positive results if they are
B. The Tay Sachs screening program started with good education and cultural
sensitivity toward participants so people are more willing to be tested.
C. The sickle cell screening program started with good education and cultural sensitivity
but health insurance didn’t cover the tests.
D. Sickle cell alleles are much more common to start with, so it’s been more difﬁcult to
eradicate the disease.
E. Sickle cell disease doesn’t show up until much later in life than Tay Sachs."
2. If you investigate and map out the family history of a particular trait, what have you
A pedigree analysis
Chapter Five Study Questions