Passage #2 DIRECTIONS: Choose the best answer for each question.

 The DNA Trail  [A] Everybody loves a good story, and when it’s finished, this may be the greatest one ever told. It begins in Africa with a group of people, perhaps just a few hundred, surviving by hunting animals and gathering fruits, vegetables, and nuts. It ends about 200,000 years later with their seven billion descendants spread across the Earth.  [B] In between is an exciting tale of survival, movement, isolation, and conquest, most of it occurring before recorded history. Who were those first modern people in Africa? What routes did they take when they left their home continent to expand into Europe and Asia? When and how did humans reach the Americas? For decades, the only proof was found in a small number of scattered bones and artifacts that our ancestors had left behind. In the past 20 years, however, DNA technologies have allowed scientists to find a record of ancient human migrations in the DNA of living people.  Tracing Ancestry in DNA  [C] “Every drop of human blood contains a history book written in the language of our genes,” says population geneticist Spencer Wells. The human genetic code, or genome, is 99.9 percent identical throughout the world. The bulk of our DNA is the same. However, the remainder is responsible for our individual differences—in eye color or disease risk, for example. On very rare occasions, a small change—called a mutation—can occur. This can then be passed down to all of that person’s descendants. Generations later, finding that same mutation in two people’s DNA indicates that they share the same ancestor. By comparing mutations in many different populations, scientists can trace their ancestral connections.  [D] These ancient mutations are easiest to track in two places. One is in DNA that is passed from mother to child (called mitochondrial DNA, or mtDNA). The other is in DNA that travels from father to son (known as the Y chromosome, the part of DNA that determines a child will be a boy). By comparing the mtDNA and Y chromosomes of people from various populations, geneticists can get a rough idea of where and when those groups separated in the great migrations around the planet.  Out of Africa  [E] In the mid-1980s, a study compared mtDNA from people around the world. It found that people of African descent had twice as many genetic differences from each other than did others. Because mutations seem to occur at a steady rate over time, scientists concluded that modern humans must have lived in Africa at least twice as long as anywhere else. They now calculate that all living humans maternally descend from a single woman who lived roughly 150,000 years ago in Africa, a “mitochondrial Eve.” If geneticists are right, all of humanity is linked to Eve through an unbroken chain of mothers. This Eve was soon joined by “Y-chromosome Adam,” the possible genetic father of us all, also from Africa. DNA studies have confirmed that all the people on Earth can trace their ancestry to ancient Africans.  [F] What seems certain is that at a remarkably recent date— probably between 50,000 and 70,000 years ago—one small group of people, the ancestors of modern humans outside of Africa, left Africa for western Asia. They either migrated around the wider northern end of the Red Sea, or across its narrow southern opening.  [G] Once in Asia, genetic evidence suggests, the population split. One group stayed temporarily in the Middle East, while the other began a journey that would last tens of thousands of years. Moving a little farther with each new generation, they followed the coast around the Arabian Peninsula, India, and Southeast Asia, all the way to Australia. “The movement was probably imperceptible,” says Spencer Wells. “It was less of a journey and probably more like walking a little farther down the beach to get away from the crowd.”  [H] Archeological evidence of this 13,000-kilometer migration from Africa to Australia has almost completely vanished. However, genetic traces of the group that made the trip do exist. They have been found in the DNA of indigenous peoples in Malaysia, in Papua New Guinea, and in the DNA of nearly all Australian aborigines. Modern discoveries of 45,000-year-old bodies in Australia, buried at a site called Lake Mungo, provide physical evidence for the theories as well. [I] People in the rest of Asia and Europe share different but equally ancient mtDNA and Y-chromosome mutations. These mutations show that most are descendants of the group that stayed in the Middle East for thousands of years before moving on. Perhaps about 40,000 years ago, modern humans first advanced into Europe.  Peopling the Americas  [J] About the same time as modern humans pushed into Europe, some of the same group that had paused in the Middle East spread east into Central Asia. They eventually reached as far as Siberia, the Korean peninsula, and Japan. Here begins one of the last chapters in the human story—the peopling of the Americas. Most scientists believe that today’s Native Americans descend from ancient Asians who crossed from Siberia to Alaska in the last ice age. At that time, low sea levels would have exposed a land bridge between the continents. Perhaps they—only a few hundred people—were traveling along the coast, moving from one piece of land to the next, between a freezing ocean and a wall of ice. “A coastal route would have been the easiest way in,” says Wells. “But it still would have been a hell of a trip.” Once across, they followed the immense herds of animals into the mainland. They spread to the tip of South America in as little as a thousand years.  [K] Genetic researchers can only tell us the basic outlines of a story of human migration that is more complex than any ever written. Many details of the movements of our ancestors and their countless individual lives can only be imagined. But thanks to genetic researchers, themselves descendants of mtDNA Eve and Y-chromosome Adam, we have begun to unlock important secrets about the origins and movements of our ancient ancestors.   In the last line of paragraph G, what does the author demonstrate by including the analogy of people walking on the beach?

Use this zoom link to ask questions during the exam.  Please wait in the waiting room and then leave promptly once your questions are answered so we can let the next student in. Join URL: https://uwmadison.zoom.us/j/95419925314?pwd=Vtl7VQZM8Cng4ewzk4AQUXhQ67YfoZ.1  

A 62-year-old female presents to the emergency department following an MVA where she experienced renal trauma. Which of the following is not typical of an adequate functioning RAAS system?

A patient’s urinalysis came back with a result of glycosuria indicating a possible diagnosis of diabetes. What bedside glucose would appropriately demonstrate this finding?

A bacterial toxin was found to cause fever, vomiting and diarrhea.  Upon structural elucidation this toxin was found to be a single-subunit protein that leads to a massive increase in cytokines, which results in toxic shock syndrome. This toxin could be produced by:

Pick TWO of the FOUR mechanisms of spread of antibiotic resistance (spontaneous mutation, transformation, transduction or conjugation). For each: Antibiotic resistance mechanism 1: Clearly describe the meaning of the term in relation to antibiotic resistance (2 points) Indicate whether this is a method of vertical or horizontal gene transfer (1 points) Antibiotic resistance mechanism 2: Clearly describe the meaning of the term in relation to antibiotic resistance (2 points) Indicate whether this is a method of vertical or horizontal gene transfer (1 points)  

What causes ADH to be released?

A bacterial polycistronic operon with three (3) genes would have how many of the following?   A) PROMOTERS  __________ B) ACTIVATOR BINDING SITES  __________ C) OPERATORS  __________ D) TERMINATORS __________ E) PROTEIN PRODUCTS __________  

ANTIMICROBIALS and ANTIMICROBIAL RESISTANCE