Utilizing Methods and Technology from the Realms of Genetic Engineering, Neurology, And

TOEFL test, November 2009

Reading Set 1

Optogenetics

Utilizing methods and technology from the realms of genetic engineering, neurology, and optical imaging, optogenetics is a new science that uses genetic material from plants to create photosensitivity in neural tissues. Using light to trigger activity in photosensitive neurons is more precise than any existing technology and causes fewer side effects. Optogenetic research has resulted in promising advances in the quest for remedies to neurally degenerative diseases like Parkinson’s and Alzheimer’s. It also holds the potential for artificial limbs that can relay feedback like temperature or texture directly to the user’s brain.The initial light-sensitive proteins, called channelrhodopsins, are derived from Chlamydomonas, a type of algae. This genetic material, when combined with neural tissue, can use light to trigger neurons to “spike.” These spikes are electrical pulses from within the neuron that control muscle function or direct information. In an experiment at StanfordUniversity, scientists used spikes to cause a mouse to run in a circle. At YaleUniversity, spikes aimed at specific neurons caused flies to attempt to jump up and fly.

The ability to fire neurons existed before optogenetics; neurons can be caused to fire by sparking them with electrical currents. It is the addition of a promoter, a section of DNA that makes the gene affective to only one specific type of neuron, that makes the technology so singular. The promoter causes the channelrhodopsins to function in certain neurons, but to remain dormant in others. This means that only the neurons selected by the promoter will react to light, while the neural tissue in the surrounding area remains unaffected and unchanged.This composition of plant-derived channelrhodopsins and promoter is introduced into viral particles, which are injected into the brain. The modified virus inserts the mixture into a small area of neural tissue, which assimilates the botanical gene’s sensitivity to light. Minute optical fibers are then threaded into the skull to introduce flashes of light. Chlamydomas reacts strongest to blue light, so when these neurons “infected” with the algae’s gene sense blue spectrum light, they fire.But if effective control is to be attained, the ability to stop a neuron from firing is just as important as causing it to spike in the first place. Another gene taken from a bacteria and used similarly causes the neurons to stop firing when exposed to yellow light. The combined use of these two genes results in genetically modified neurons that can be switched off and on at extremely high speeds by different spectrums of light.

The product of this technology is a specific group of neurons that can be controlled very precisely through a relatively non-invasive procedure.Scientists working on optogenetic projects hope that this will soon replace the current methods of drug therapy and deep brain stimulation, which are much less precise.Drugs flood the entire brain with chemicals, often causing undesirable side effects. Deep-brain stimulation not only impacts all the tissue surrounding the target area, but also must be implanted deep within the brain through difficult and dangerous surgery. While effective, the high risks involved with deep-brain stimulation mean it is usually reserved for extreme cases in which all other options have been eliminated. Since neither of these therapies are ideal and come with multiple secondary effects, thepromise of a new, powerful and exact method is very encouraging. 

Optogenetics, providing explicit control over the function of specific neurons, means that areas of the brain that have lost their function can be re-programmed and forced to become active again. Through the use of this technology, researchers have mapped the brains of mice and discovered connections between nerves on the surface of the brain and the deep-brain nerves that Parkinson’s Disease seems to affect. These surface neurons imply that future therapies for Parkinson’s may be much easier to devise than previous means, and their side effects may be much less severe. However, this is still a new technology.The scientific community is hopeful that human testing will be as successful as experiments on various animals have led them to believe. Only then will the true extent of optogenetics’ advantages be understood.

1. The word precise in paragraph 1 is closest in meaning to

(A) special

(B) careful

(D) successful

2. The word trigger in paragraph 1 is closest in meaning to

(A) cause *

(B) shoot

(D) request

3. According to paragraph 1, which of the following is true of optogenetics?

(A) It is a well-established branch of science.

(B)It might help persons who have neurologic diseases.*

(C)It uses light-sensitive neurons that come from flowers.

(D)It uses genetic material and light to spike neurons to trigger.

4. Why does the author mention experiments on a mouse and flies?

(A)To illustrate how spikes work in the brain *

(B)To demonstrate the formation of channelrhodopsins

(C)Toargue that optogenetics is a dangerous science

(D)Toindicate two potentially dangerous side effects

5. The word singular in paragraph 2 is closest in meaning to

(A)spectacular

(B)obtuse

(C)common

(D)unusual *

6. According to paragraph 2, a promoter

(A)sparks electrical current

(B)produces different-colored lights

(C)selects specific neurons *

(D)is derived from channelrhodopsins

7. The word assimilates in paragraph 2 is closest in meaning to

(A)rejects

(B)absorbs *

(C)measures

(D)reproduces

8. The word minute in paragraph 2 is closest in meaning to

(A)sensitive

(B)tough

(C)flexible

(D)tiny *

9. Which of the following best expresses the essential information in the highlighted sentence? Incorrect choices change the meaning in important ways or leave out essential information.

(A)The use of two genes can create genetically modified proteins that can be turned on and off like a light switch.

(B)It's easy to control neurons by the combined use of special genes that allow them to be switched on and off in reaction to light spectrums.

(C)Neurons that can combine these two genes react at high rates of speed to blue lights and yellow lights.

(D)Two combination of two genes produces special neurons that are capable of being manipulated very quickly by different-colored lights. *

10. The word this in paragraph 3 refers to

(A)procedure *

(B)group

(C)product

(D)technology

11. Look at the four squares [] that indicate where the following sentence can be added to the passage.

Deep brain stimulation is by far the most precise clinical procedure for controlling areas of the brain, but it’s still disappointingly non-specific.

Where would this sentence best fit?

Answer:

12. Complete the table below to summarize information about the threemethods of therapy described in the passage.This question is worth three points.

Optogenetics / Drug Therapy / Deep Brain Stimulation
A / C / B
D
E

(A) Precise neuron control

(B)Difficult and dangerous surgery

(C)Flood the brain with chemicals

(D) Non-invasive procedure

(E)Minimal side effects

Reading set 2

New Orleans Jazz

The city of New Orleans was made for jazz music. Today most people enjoy jazz as a mainstream form of music, art, entertainment, or a mixture of all three. But this wasn't always so. Jazz started in New Orleans as a result of the unique pressures and social climate that only this city could possess. This uniqueness of place began for New Orleans between 1713-1763, with periods of occupation by both the French and Spanish. Unlike most occupation scenarios, the native Creole population inherited knowledge of the European musical tradition from the French. In 1712, New Orleans was infused with slaves from Africa and the Caribbean. According to musical historians, the slave population—particularly from Africa— brought with it the blues notes, rhythms, and vocalizations that would become the hallmark of jazz. But jazz is also marked by the infusion of Western instruments such as the cornet, flute, and trombone.

These became prominent after 1803, when the United States acquired New Orleans from France as part of the Louisiana Purchase. The subsequent US Civil War and the backlash of the Reconstruction were among the biggest affairs to affect New Orleans, and indeed the formation of jazz. With the Civil War came new brands of music, and a new set of instruments to play them on. These new sounds were the marching band and ragtime (both are considered predecessors to jazz), and were played using trombones, other brass instruments, and pianos. After the war, large numbers of these instruments were available to the people in New Orleans for cheap prices. Ragtime settled in New Orleans for good, with bands forming on every street corner.

But jazz also formed, in large part, in response to the social changes growing in New Orleans around the late 1860s, '70s, and '80s. Reconstruction had happened, and as a result the Creoles of color (Creoles with African/Caribbean descent), who had previously lived a life of high society due to their education and breeding, found themselves living with poor African Americans who had immigrated in droves to New Orleans from 1803 on. As a result, historians believe that the two musical backgrounds began cross-pollination. The impromptu and simple blues harmony of the African-American community merged with the more classically trained sound of the Creole population. At this time, the rights and freedoms of all people of color were severely limited. Music had always played an essential part in the lives of the people of Louisiana, and now, under further oppression, musical solidarity, in the vein of the famous "Congo Square," developed. In the 1880s, Congo Square was a place where the oppressed got together every Sunday to dance and play music, and now African-American neighborhoods banded together. Being one of the few outlets for expression, it became a hotbed for the notes and rhythms of the emerging Jazz sound. By 1912, when the first self-professed jazz musicians, such as Bolden Jellyroll Morton, and others arrived on the scene, it was a good place to get noticed.

Two of the main reasons for jazz’s dissemination were its popularity and its allure of wealth. Musicians wanted to take their sound out of New Orleans. The Original Creole Orchestra was one of the first to do so. This meant good money for people who were used to playing accompaniment for vaudeville, or in bars. The Dixieland Jazz Band was the first to produce a commercial record, in 1917. Now jazz was no longer a musical tradition belonging to one group of people. It belonged to everyone who loved it, and true to its African roots, the sound changed and developed with each new artist and generation. For example, African-American artist Louis Armstrong arrived on the scene with his first album, "Hot Fives and Hot Sevens," in 1927,just a few short years after the Dixieland Jazz Band. The record made Armstrong an instant hit, and established him as one of the first jazz solo artists. His playing established a new nuance, one that would carry other artists into the jazz age of the late 1920s and 1930s.

During the '30s and '40s, jazz experienced changes that led to the creation of styles such as swing and bebop. As it had done in its past, the jazz of these decades helped individuals in times of hardship, and gave an outlet to people regardless of age, race, or gender. Its universality continues today, even while styles continue to grow and change.

13. According to paragraph 1, which of the following is true of New Orleans?

(A) It is a state in the southern part of the US.

(B) Its native population is African-Americans.

(D) It had an infusion of slaves in 1763.

14. Look at the four squares [] that indicate where the following sentence could beadded to the passage.

During this time, New Orleans became home to a heterogeneous population that included African Americans (both free and slave), other Europeans, people from the Caribbean, Latin Americans, and Scandinavians.

Where would the sentence best fit?

Answer: 

15. Theword hallmark in paragraph 1 is closest in meaning to

(A) logo

(B) feature *

(D) foundation

16. The author discusses the Civil War in paragraph 2 in order to

(A) explain how Reconstruction affected New Orleans

(B) detail the intricacies of ragtime music

(D) elaborate on a point about musical instruments*

17. All of the following are mentioned in paragraph 3 EXCEPT

(A) social changes

(B) Creole Orchestra *

(D) Jellyroll Morton

18.The wordimpromptuin paragraph 3 is closest in meaning to

(A) unrehearsed *

(B) slow

(D) upbeat

19. Which of the following best expresses the essential information in the highlighted

sentence?

(A) Congo Square resulted in Louisiana's musical solidarity.

(B) Oppression developed the famous Congo Square.

(D) Music, always important, developed in the famous Congo Square.

20. The word it in paragraph 3 refers to

(A) expression

(B) Congo Square *

(D) music

21.The word dissemination in paragraph 4 is closest in meaning to

(A) importation

(B) disintegration

(D) dispersion *

22. According to paragraph 4, which jazz performer was the first to make a commercial record?

(A) The Original Creole Orchestra

(B) The Dixieland Jazz Band *

(D) Hot Fives and Hot Sevens

23.According to the author, what impact did Louis Armstrong have on jazz?

(A) He created a style that influenced artists for the next decade. *

(B) He became an instant star with the release of his first record.

(D) He introduced the northern US jazz sound to New Orleans.

24. An introductory sentence for a brief summary of the passage is provided below.Complete the summary by selecting the THREE answer choices that express important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

The social and historical conditions in New Orleans made it a perfect incubator for the birth of jazz music.

(A) The city's occupation by the French helped propagate the transfer of European musical style to the native Creoles. *

(B) After the Civil War, instruments such as the flute, trombone became cheaper and more readily available.

(C)Congo Square in the 1880s became a popular place where people gathered to make music and dance.

(D) An infusion of African and Caribbean slaves in 1712 brought some of the blues influences that would come to characterize jazz. *

(E) Jazz changed in the 1930s and '40s in response to the creation of new musical styles, such as swing and bebop.

(F) After Reconstruction, the forced mixture of Creoles and African-Americans resulted in the merger of two musical styles that birthed jazz. *

Reading set 3

Harriet Tubman

Araminta Ross, the woman who later became the famous Harriet Tubman, was born into slavery about 1820. Although she was a hard worker, she suffered much physical abuse as a slave due to her independent spirit and refusal to be cowed by her situation. Even as a young slave she displayed a great sense of compassion for her fellow slaves and a determination to help. As a teenager, she tried to intercede when an overseer wanted to punish a young slave. The overseer threw a heavy iron weight at the slave when he tried to run away from punishment, but unfortunately the weight struck Araminta instead, crushing her skull and knocking her unconscious. Though she survived her injury, she would suffer the results of dizziness and seizures for the rest of her life.

In 1844, Araminta Ross became Harriet Tubman when she married a free black man named John and took his last name, changing her first name to Harriet in honor of her mother. After spending almost thirty years in slavery, she resolved to run away when she discovered a rumor that the slaves on her plantation were going to be sold. Her husband chose not to make the journey with her, so she set off with two of her brothers, but they became frightened by the risks and turned back, leaving Harriet alone to follow the North Star to guide her toward freedom. She reached Philadelphia and found work, which allowed her to save money that she would use to help others escape. Although Harriet herself was now free, she had left behind her large family, including her parents and nine siblings. Harriet managed over several trips to bring many of her family members to freedom. Harriet had heard about something called The Underground Railroad, a system of secret guides and hiding places to help runaway slaves travel to the freedom of the northern United States and Canada. Using the network created by the Underground Railroad, Harriet continued working with the Railroad to bring other slaves north.

Although she had never been formally schooled, and was in fact illiterate, Harriet displayed a keen intellect, which helped her in her mission. She cleverly planned slave escapes for Saturdays, knowing that this would give her a time advantage, as it was illegal to put up wanted posters on Sundays. This meant the soonest there would be notification of a missing slave was Mondays, giving her time to get her charges to safety.