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CAS BI 203 Study Guide - Quiz Guide: Protein Folding, Chromosome, The Molecules

Course Code
CAS BI 203
Francis Monette
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September 25, 2017
Cell Biology: Discussion Notes (Week #3)
From Cow Juice to a Billion Dollar Drug, With Some Breakthroughs in Between
Part I Introduction
1. What is diabetes? What are the different types of diabetes seen in humans?
Diabetes is a disease in which the body is unable to properly use and store glucose (a form of
sugar). Glucose backs up in the bloodstream causing one's blood glucose, or blood sugar,
to rise too high. There are two major types of diabetes: Type 1 (juvenile-onset or insulin-
dependent) diabetes and Type II (adult-onset or non-insulin dependent) diabetes. There is
also gestational diabetes (a form of high blood sugar) that affects pregnant woman.
2. What is insulin? Where is it produced? What is its physiological role? How does it carry out
this function?
Insulin is a hormone made in the pancreas, a gland located behind your stomach, that plays a
key role in the regulation of blood glucose levels. It allows glucose (sugar) to get into the
cells of our body that need glucose for energy. After you eat, your blood sugar (glucose)
rises. This rise in glucose triggers your pancreas to release insulin into the bloodstream.
Insulin travels through the blood to your body's cells. It tells the cells to open up and let the
glucose in. Once inside, the cells convert glucose into energy or store it to use later.
3. Which types of diabetes require insulin injections? How are other types of diabetes
Actually, all types of diabetes (type 1, type 2 and gestational) can require insulin injections.
With type 1 diabetes, a person's beta cells stop producing insulin (or enough insulin), so this
means that in order to survive, insulin injections are necessary. In the case of type 2 diabetes,
a combination of meal planning, weight loss, physical activity and oral medication may work
well for a while to control blood glucose. But over time, at least 40% of these folks will need
to go on insulin. And with gestational diabetes, insulin may be needed if blood glucose goals
can't be met with meal planning and exercise alone.
Part II The Discovery of Insulin
1. Why was bovine insulin used as the source of insulin? Why not other animals? Consider pragmatic
as well as biochemical reasons in your answer.
Bovine insulin was used as the source of insulin because it showed that it worked in cows
and dogs. Other animals were not used because both cows and dogs because of financial
circumstances; they were the easiest to obtain.
2. What are the major drawbacks of using insulin purified from animals?
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September 25, 2017
There is a slight structural difference of 1-3 amino acids between the animal insulin and
human insulin. When his animal insulin was administered by a diabetic patient he developed
antibodies against the animal insulin thereby causing allergic reactions. Another
disadvantage was large number of animals were to be sacrificed for extracting the insulin
from their pancreas. For example: To obtain 5 kgs of pancreatic juice about 75 pigs have to
be killed to get insulin for treating only a single diabetic patient just for one year.
3. How could you make human insulin in a lab? Give at least two methods.
Scientists build the human insulin gene in the laboratory using Recombinant DNA. They make a
loop of bacterial DNA known as a plasma and insert the human insulin gene into the plasmid.
Researchers then return the plasmid to the bacteria and put the recombinant bacteria in large
fermentation tanks. There, the recombinant bacteria use the gene to begin producing the human
insulin. Scientists harvest the insulin from the bacteria and purify the substance for use as a
medicine for people. Also, Scientists could purify insulin from pigs, which only differed from
human insulin by a single amino acid. Then they could chemically treat the porcine insulin to
change that single amino acid to the human amino acid, thereby producing human insulin. The
insulin can also last longer to affect someone than human insulin would.
Part III Chemical Synthesis of Human Insulin Close, but no Cigar
1. What are some of the criteria a pharmaceutical company would want to meet if it is
producing a drug for sale to consumers?
- Safe for users (Sterile)
- Quick time to effect
- Been FDA approved
- Specificity
- Standardized Dose
- Bulk Production
2. How do cells make proteins? Give a general overview of the process.
Cell make proteins based on a process called protein synthesis. During protein synthesis, the
cell uses information from a gene on a chromosome to produce a specific protein. First, the
mRNA enters the cytoplasm. DNA unzips between its base pairs. Then one of the strands of
DNA directs the production of a strand of mRNA. To form the RNA strand, RNA bases pair
up with the DNA bases. The mRNA leaves the nucleus and enters the cytoplasm. Then,
ribosomes attach to mRNA in the cytoplasm. On the ribosome, the mRNA provides the code
for the protein that will be made. After, tRNA attaches to mRNA. The molecules of tRNA
and their amino acids attach to the mRNA. The bases on the tRNA "read" the message and
pair with bases on mRNA. In the fourth step, amino acids join in the ribosome. Transfer
molecules attach one at a time to the ribosome and continues to read the message. The amino
acids are linked together and form a growing chain. The order of the amino acids is
determined by the order of the three-base codes on the mRNA. Lastly, the protein chain
forms. When the ribosome continues to move along the mRNA adding amino acids, the
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