Read the following passage.
A. Every cell copies the genetic information in its DNA into messenger RNA, or mRNA. This molecule carries the instructions for a protein from the nucleus to the watery interior of the cell, where the protein-making machinery reads them. During the 1980s, scientists introduced efficient methods for making mRNA without growing cells, a process called in vitro transcription. Ideas for using mRNA in vaccines and treatments followed, but there were obstacles. Lab-made mRNA was unstable and hard to deliver, and it triggered inflammation. Early enthusiasm for using it in patients was therefore limited.
B. The Hungarian biochemist Katalin Karikó kept working on mRNA as a treatment. In the early 1990s, as an assistant professor at the University of Pennsylvania, she had trouble persuading research funders that her project mattered. There she began working with the immunologist Drew Weissman. They found that immune cells called dendritic cells treated lab-made mRNA as foreign, while mRNA from mammal cells did not cause the same reaction. The difference lay in the bases, the chemical letters of RNA, which are often modified in mammal cells. When modified bases were used, the inflammation almost disappeared. They published this in 2005, and in studies from 2008 and 2010 they showed that modified mRNA also greatly increased protein production.
C. By 2010, several companies were developing the method, and vaccines against the Zika virus and MERS were pursued. After the COVID-19 pandemic began in early 2020, two vaccines made from modified mRNA were developed at record speed. Each carried the code for the virus's surface protein, packed in lipid nanoparticles, tiny spheres that protect the mRNA. Inside the body, the mRNA directs cells to make that protein, and the immune system learns to treat it as foreign. Reported protection was around 95 per cent, and both vaccines had been approved by December 2020.
D. Researchers hope the same speed and flexibility will lead to vaccines against other infectious diseases and to cancer treatments. Clinical trials have tested mRNA treatment vaccines in people with several cancers, including pancreatic and colorectal cancer and melanoma. Some are personalized: each is designed from the molecular features of one patient's tumour, which takes 1 to 2 months after tissue samples are collected. In one early trial for head and neck cancer, 2 of the first 10 patients had all signs of their tumours disappear. Cancer researchers are testing both modified and unmodified mRNA in these experimental vaccines, and more research is needed to understand the relative advantages of each.
E. Not given in any of the above paragraphs.
Decide which paragraph, A to D, has the information given in each statement below. Select E if the information is not given in any of the paragraphs.
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Correct Answer: C
Why this is correct: Look at Paragraph C. Each of the two pandemic vaccines carried the code for the virus's surface protein. A code works like a recipe. A surface protein sits on the outside of the virus.
Passage Reference: Each carried the code for the virus's surface protein, packed in lipid nanoparticles, tiny spheres that protect the mRNA.
Tips: Paragraph A also talks about instructions for a protein. Look for the protein that belongs to the virus.
Why the other options are wrong:
- A: In Paragraph A, mRNA carries protein instructions inside our own cells. No virus or vaccine is named.
- B: Paragraph B describes lab work on inflammation and protein output. It does not say what the pandemic vaccines contained.
- D: Paragraph D is about hopes for cancer treatments built from tumours. No virus protein is mentioned.
- E: The text covers this. Paragraph C describes the code for the virus's surface protein.
Correct Answer: E
Passage Reference: In the early 1990s, as an assistant professor at the University of Pennsylvania, she had trouble persuading research funders that her project mattered.
Why this is correct: Look at Paragraph B. In the early 1990s, Karikó worked at the University of Pennsylvania as an assistant professor. She had trouble persuading research funders. But it never says who paid for her experiments.
Tips: Trouble finding funders is not the same as being paid by someone. Check who actually paid.
Why the other options are wrong:
- A: Paragraph A describes early lab methods and problems. It names no person and no source of money.
- B: Her university and her funding trouble are both in Paragraph B. Who paid for the work is missing.
- C: Paragraph C mentions companies working on the method by 2010. It does not cover the money for her early experiments.
- D: Paragraph D talks about cancer trials today. Karikó and costs are not mentioned.
Correct Answer: D
Passage Reference: Some are personalized: each is designed from the molecular features of one patient's tumour, which takes 1 to 2 months after tissue samples are collected.
Why this is correct: Look at Paragraph D. Some vaccines are personalized, each designed from one patient's tumour. This takes 1 to 2 months after tissue samples are collected. One to two months is several weeks.
Tips: Paragraph C also talks about speed. Look for a vaccine made for just one person.
Why the other options are wrong:
- A: Paragraph A explains how mRNA is made in the lab. It gives no time for making a vaccine for one patient.
- B: Paragraph B covers experiments with modified bases. It mentions no single patient.
- C: In Paragraph C, the pandemic vaccines were made at record speed. They were for everyone, not for one sick person.
- E: The text gives this time. The 1 to 2 months for a one-patient vaccine is in Paragraph D.
Correct Answer: C
Passage Reference: Reported protection was around 95 per cent, and both vaccines had been approved by December 2020.
Why this is correct: Put two dates in Paragraph C together. The COVID-19 pandemic began in early 2020. Both vaccines had been approved by December 2020. That is the same year.
Tips: Find when the pandemic began and when approval came. Both dates are in one paragraph.
Why the other options are wrong:
- A: Paragraph A deals with the 1980s and the early problems of lab-made mRNA. No approval is mentioned.
- B: Paragraph B gives dates of studies from 2005 to 2010. None of them is a vaccine approval date.
- D: Paragraph D describes cancer vaccines that are still in trials. It reports no approval.
- E: Paragraph C gives the December 2020 approval, so this is not missing from the text.
Correct Answer: E
Passage Reference: Reported protection was around 95 per cent, and both vaccines had been approved by December 2020.
Why this is correct: Paragraph C gives protection of around 95 per cent for the two vaccines. That is one figure for everyone. No results are given by age, so older and younger adults are never compared.
Tips: One overall figure does not tell you about different age groups.
Why the other options are wrong:
- A: Paragraph A covers lab methods from the 1980s. No COVID-19 vaccine exists yet in it.
- B: Paragraph B describes lab results on inflammation. It does not say how well any vaccine protected people.
- C: The 95 per cent figure sits in Paragraph C. That single number has no split into age groups.
- D: Paragraph D is about cancer trials. It gives no COVID-19 results for any age.
Correct Answer: A
Passage Reference: Early enthusiasm for using it in patients was therefore limited.
Why this is correct: Read the end of Paragraph A. Lab-made mRNA was unstable, hard to deliver, and it triggered inflammation. Early enthusiasm for using it in patients was therefore limited. Inflammation counts as an unwanted effect in the body.
Tips: Paragraph B also mentions inflammation. Look for the paragraph that links it to low interest.
Why the other options are wrong:
- B: Paragraph B explains how Karikó and Weissman almost removed the inflammation. It does not describe the early lack of interest.
- C: Paragraph C tells of companies taking up the method by 2010. That shows interest, not doubt.
- D: Paragraph D describes hope for cancer treatments. It does not talk about early doubts.
- E: The text does say this. The limited early enthusiasm closes Paragraph A.
Correct Answer: E
Passage Reference: In one early trial for head and neck cancer, 2 of the first 10 patients had all signs of their tumours disappear.
Why this is correct: Paragraph D reports one early trial for head and neck cancer. In it, 2 of the first 10 patients had all signs of their tumours disappear. The paragraph stops there. It never says the vaccine was approved later.
Tips: Paragraph C is the one that mentions approval. Check which vaccines it is about.
Why the other options are wrong:
- A: Paragraph A tells the history of lab-made mRNA. No cancer trial appears.
- B: Paragraph B covers experiments from 2005 to 2010. It has no trial with cancer patients.
- C: Paragraph C reports approvals, but only for the two pandemic vaccines. A cancer vaccine is not included.
- D: Paragraph D stops at the first results of the head and neck trial. Approval is not mentioned.
Correct Answer: D
Passage Reference: Cancer researchers are testing both modified and unmodified mRNA in these experimental vaccines, and more research is needed to understand the relative advantages of each.
Why this is correct: The last lines of Paragraph D say cancer researchers are testing both modified and unmodified mRNA. More research is needed to understand the advantages of each. So nobody knows yet which works better.
Tips: Paragraph B also discusses modified mRNA. Find where the choice is still open.
Why the other options are wrong:
- A: Paragraph A explains why early mRNA caused problems. Modified and unmodified forms are not compared there.
- B: Paragraph B shows modified mRNA cutting inflammation in the lab. It raises no doubt about which form is better.
- C: Paragraph C tells you the pandemic vaccines used modified mRNA. It says nothing about cancer treatments.
- E: The text covers this. The open question about the two forms ends Paragraph D.
Correct Answer: B
Passage Reference: They published this in 2005, and in studies from 2008 and 2010 they showed that modified mRNA also greatly increased protein production.
Why this is correct: The clue is at the end of Paragraph B. In studies from 2008 and 2010, modified mRNA greatly increased protein production. Modified means the bases, the letters of RNA, were changed.
Tips: Paragraph D also mentions modified mRNA. Look for a result about how much protein was made.
Why the other options are wrong:
- A: Paragraph A explains that cells read mRNA to make proteins. It reports no change that raised the amount.
- C: In Paragraph C, cells make the virus protein from the vaccine. It does not compare amounts from modified and plain mRNA.
- D: Paragraph D names modified mRNA as one option in cancer vaccines. It gives no result on protein output.
- E: This result is in the text. The rise in protein production is in Paragraph B.
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