LS1.1 Molecules of Life

LS1-1 Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.

Central Dogma of Biology DNA->RNA->Protein
- Form Dictates Function
- From Simple Instructions, complexity can arise
- Minor changes can have major impacts
- If something breaks, we know what it does.

Sickle Cell Anemia

In 1904, a 20-year old, West Indian dental student from Grenada became a patient of Dr. James Herrick. During the first 3 years of study at the Chicago College of Dental Surgery in Chicago, Illinois, the student suffered from a variety of conditions: he developed a leg ulcer, a respiratory problem that lasted more than a month, bronchitis, joint pain (especially in his knees), and pigment gallstones. A blood sample was taken by Dr. Herrick’s intern Ernest Irons. Mr. Irons noted that the student’s blood contained “many pear-shaped and elongated forms,” (shown to the right). In 1910, Dr. Herrick published the findings in Archives of Internal Medicine, without crediting his intern. Within the next 10 years several more cases were discovered. In 1922 the condition was given a name be Mr. Verne Mason, Sickle Cell Anemia. Unfortunately, the young dentist that had returned to his home in the Caribbean had already died of complications of the disease.

Consider yourself a present day doctor and the following patient arrives at your clinic. Two year old Zola and her parents have recently moved to your country from South Africa. Zola has been having many painful health problems and developmental delays. Zola had troubles healing from cuts and wounds and she also suffers from severe swelling in her fingers and toes. These symptoms are accompanied by fever, paleness, dehydration, fatigue and pneumonia like symptoms. You decide to draw some blood from Zola, it appears as shown on the right.

What questions would you have after viewing the blood in the microscope?

Image Analysis:

From the images above and below, what do you wonder about HbS?

Sickle Cell Anemia Statistics

Figure 2 from Sickle cell disease | Semantic ScholarFigure 2 | Map of the estimated numbers of births with sickle cell anaemia. Estimated numbers of births with sickle cell anaemia per 100,000 births per country in 2015. Estimates are derived from prevalence data published in REF.14. Birth data for 20152020 were extracted from the 2017 Revision of the United Nations World Population Prospects database. - "Sickle cell disease"

Standard Management of SCA Complications

Patient Reported Impact on Life

Sickle cell Disease in Saudi Arabia

Sickle Cell Anemia Questions

Individual think time

Record all the questions you have (notebook/Jamboard)
Aim for 5-10 questions

In-Class Discussion

What are some parts of this system that we need to include in an explanatory model?

Individually, develop an initial model to explain the event you just observed
Be sure your model shows a mechanism that might explain what happened?
Make sure all of your observations can be explained with your model
Go beyond labelling - Add any necessary text to support your explanation
Consider the scale at which the interactions may be occuring.

In your groups - Share your initial explanation….

Discuss your observations and explanations
Listen to how each person explains their models
Compare models - What is similar? What is different?
Generate and record questions as you share
What did people put in the “This reminds me of….” spot?

How can we begin to construct an explanation of the mechanisms causing Sickle Cell Anemia (HbS)

Additional HsB Info

Explainer: What is sickle cell disease?Gene mutations can alter an individual’s hemoglobin in ways that curl their blood cells. This can cause painful sickle cell disease.

Sickle-cell gene therapies offer hope — and challengesDoctor Erica Esrick discusses existing treatments and an ongoing clinical trial for a gene therapy to treat sickle cell disease.

The SARS-CoV-2 Virus

The coronavirus family is a big one — it includes the common cold, pneumonia, SARS, and the new coronavirus that's spreading in China.

The various strains can cause very different ailments, but they have one thing in common: an external structure that features little crown-like spikes.

-Business Insider

Coronaviruses are a group of related RNA viruses that cause diseases in mammals and birds. In humans and birds, they cause respiratory tract infections that can range from mild to lethal. Mild illnesses in humans include some cases of the common cold (which is also caused by other viruses, predominantly rhinoviruses), while more lethal varieties can cause SARS, MERS, and COVID-19. In cows and pigs they cause diarrhea, while in mice they cause hepatitis and encephalomyelitis. - Wikipedia

SARS-CoV-2 is a virus that, starting in 2020, has caused the largest global pandemic in recent history. The disease caused by this virus, COVID-19, has affected millions of people worldwide.