To writing on the topics "Cloning" and "Cosmetics"

To speaking on the topics "Cloning" and "Cosmetics"

III. Listening

Step 1. Listen to the mini-lecture (or read the transcript) and then answer the questions.

Take down as many facts and ideas as possible, noting logical connections. Watch for linking phrases and contrasts, Draw pictures of what you are listening about in your mind!

Tip: Focus on cause-and-effect, evidence vs. myth, and the professor’s stance (skeptical? cautious?).

Take down as many details and facts as possible! Draw pictures of what you read in your mind!

Click here to show/hide the transcript

Transcript (Lecture, Biology):

Professor: Today we’ll revisit the first mammal cloned from an adult cell—Dolly the sheep—and tackle a persistent claim: that Dolly was “weak” because she was cloned. To evaluate that, we need the biology and the context.

Dolly was created in 1996 by somatic cell nuclear transfer (SCNT). Researchers removed the nucleus from an unfertilized sheep egg and replaced it with a nucleus from an adult mammary-gland cell. After activation, the reconstructed egg began dividing and was implanted into a surrogate. Here is a crucial datapoint: success was extraordinarily low—hundreds of reconstructed eggs, many early losses, and one live birth, Dolly. I mention these numbers not to dramatize the achievement but to highlight how biologically demanding reprogramming is.

Why demanding? In an adult cell, gene activity is controlled by a dense pattern of chemical marks—an epigenetic landscape. SCNT has to erase and reset much of that landscape so the donated nucleus can behave like an embryo. When the reset is incomplete, development can go awry. In livestock, we’ve seen imprinting errors and a condition called “large offspring syndrome,” both linked to reprogramming glitches. So, if a clone appears unhealthy, epigenetics is a prime suspect.

Now, what about Dolly specifically? Two facts fed the “weakness” story. First, she developed arthritis at about five years of age—early for a Finn-Dorset sheep. Second, tests suggested her telomeres—the protective tips of chromosomes—were shorter than typical for her chronological age. Short telomeres can be a sign of cellular aging, so people concluded that Dolly was born “old.”

However, the evidence is less clear-cut. Arthritis can be influenced by housing, activity, genetics—factors not unique to cloning—and a single animal is a poor basis for sweeping generalizations. As for telomeres, yes, Dolly’s appeared shorter, but subsequent work on other cloned sheep from the same cell line showed normal health into later life, with no dramatic early-aging syndrome. In other words, telomere length in clones can vary and does not invariably predict frailty.

There’s also the matter of mitochondria. The egg supplies the mitochondria, which carry their own DNA. That means a clone has nuclear DNA from the donor but mitochondrial DNA from the egg donor—creating a potential nuclear–cytoplasmic mismatch. Some researchers have speculated that certain pairings might stress metabolism, but evidence remains mixed.

So why did Dolly die at six? She was euthanized due to progressive lung disease consistent with ovine pulmonary adenocarcinoma, a contagious condition caused by a retrovirus. That diagnosis points more to an infectious exposure than to a built-in weakness of cloning. It’s tragic, but not a smoking gun for “clones are fragile.”

To sum up: SCNT is inefficient and biologically risky, primarily because epigenetic reprogramming is hard. Those risks can produce abnormalities. But Dolly’s case—arthritis, short telomeres, viral lung disease—doesn’t prove that cloning necessarily yields weak animals. The fair conclusion is nuanced: early clones faced elevated developmental risks, yet individual outcomes reflect a blend of reprogramming quality, husbandry, infection control, and plain chance.

Questions:

1. What is the professor’s main point about Dolly’s so-called “weakness”?

A. It definitively proves cloning makes animals fragile.
B. The evidence is mixed; Dolly’s issues do not by themselves prove clones are inherently weak.
C. Dolly’s problems were caused only by mitochondrial DNA.
D. Dolly was healthier than most non-cloned sheep.

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2. According to the lecture, what condition led to Dolly’s euthanasia?

A. Prion disease (scrapie)
B. Progressive lung disease consistent with ovine pulmonary adenocarcinoma
C. Heart failure
D. Chronic kidney disease

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3. What piece of evidence initially suggested accelerated aging in Dolly?

A. Elevated mitochondrial mutation rates
B. Shorter telomeres than expected for her age
C. Abnormally high birth weight
D. Lack of immune response to vaccines

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4. Why does the professor emphasize that many reconstructed eggs were needed to obtain one live birth?

A. To demonstrate SCNT’s low efficiency and biological difficulty
B. To argue that cloning is financially impossible
C. To show that egg donors are easy to find
D. To prove Dolly’s telomeres were short

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5. What can be inferred about Dolly’s arthritis?

A. It conclusively proves clones age faster.
B. It may have had non-cloning causes, so it’s insufficient to generalize about all clones.
C. It resulted from telomeres lengthening too quickly.
D. It was caused by mitochondrial DNA alone.

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6. Which mechanism does the professor identify as a likely source of developmental problems in clones?

A. Incomplete epigenetic reprogramming of the donor nucleus
B. Complete absence of mitochondrial DNA
C. Lack of chromosomes in the egg cell
D. Overproduction of antibodies

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7. How does the professor organize the discussion, and what attitude does she convey?

A. She contrasts popular claims with biological evidence, conveying cautious skepticism about the “clones are weak” claim.
B. She narrates Dolly’s life chronologically to celebrate cloning.
C. She lists financial costs and argues cloning should be banned.
D. She focuses on ethics while avoiding scientific details.

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8. Why does the professor bring up mitochondrial DNA from the egg donor?

A. To show that mitochondria cause viral diseases
B. To suggest a possible nuclear–cytoplasmic mismatch that might affect clone health
C. To argue that SCNT never resets the nucleus properly
D. To explain why Dolly’s arthritis was inevitable

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II. Reading

1. Fill in the missing letters in the paragraph

(Questions 1-10)

2. Read in Daily Life

Read the following Invoice and answer questions on it

There will be 5 questions only. These 10 ones are for better practice.

1. Step 1. Read the text below

Read the passage carefully, taking down as many facts and ideas as possible, noting logical connections. Watch for linking phrases and contrasts at the beginning and end of paragraphs

Reading + Test Time — 18 minutes

Start Timer

During the actual exam, you won't see the questions in advance! So take down as many notes as possible. Try to formulate an answer to the question 'What is the passage mainly about?', as it is highly likely to be in the test. Also pay attention to what phenomena and things the author mentions and why.

Paragraph 1
In everyday conversation, cloning is often imagined as producing a carbon-copy of an entire organism. Biologists, however, use the term more broadly to describe making genetically identical copies at different scales—genes, cells, tissues, and, in rare cases, whole organisms. This umbrella meaning matters because the word gathers together methods that differ sharply in technical steps, aims, and ethical implications.

Paragraph 2
One of the earliest approaches to organismal cloning is embryo splitting, sometimes called twinning. In this procedure, an early embryo at the stage of only a few cells is mechanically divided so that each half can continue developing on its own. The result is analogous to naturally occurring identical twins: two embryos with the same nuclear DNA, both derived from a single fertilized egg. The method does not involve replacing DNA or re-engineering cells; it simply separates developmental potential that was already present. Because it relies on a fertilized egg, embryo splitting is best viewed as a refinement of assisted reproduction rather than a radical departure from it.

Paragraph 3
More technically demanding is somatic cell nuclear transfer (SCNT), the technique that produced the sheep Dolly in the 1990s. SCNT begins with an unfertilized egg cell from which the nucleus—containing almost all the cell’s DNA—has been removed. The emptied egg then receives a nucleus from a somatic (body) cell taken from an animal that one hopes to clone. If the reconstructed egg is coaxed to begin dividing, it forms an embryo carrying the donor’s nuclear genome. Unlike embryo splitting, SCNT uses DNA from a mature cell that has long since committed to a specialized identity. Reverting that nucleus to an embryonic state is biologically formidable because the pattern of chemical marks that control gene activity—the epigenetic landscape—must be widely reset. Failures in this reprogramming help explain why SCNT remains inefficient, with many embryos failing to implant or develop normally.

Paragraph 4
A third path, sometimes mentioned alongside cloning but distinct in goal, is the generation of induced pluripotent stem cells (iPSCs). Here, researchers reprogram an adult cell back to a flexible, embryonic-like state by altering the expression of a handful of regulatory genes. iPSCs can be expanded into many kinds of tissues genetically matched to the donor. Unlike SCNT, the aim is not to produce an embryo for reproduction but to generate patient-specific cells for research or potential therapy. For that reason, iPSC work is often described as a “cloning” of cellular potential rather than an attempt at making a copy of an entire organism.

Paragraph 5
Cloning’s conceptual boundaries become clearer when we look at organisms that reproduce asexually in nature. Many plants, some invertebrates, and a few vertebrates can generate near-identical offspring from cuttings, budding, or parthenogenesis. In agriculture and horticulture, humans harness this clonal capacity through vegetative propagation and micropropagation, producing uniform crops or disease-free stock. These examples remind us that cloning is not solely a laboratory invention; it also names a spectrum of strategies by which life repeats successful genetic combinations.

Paragraph 6
Despite their shared label, these methods diverge in their ethical and practical profiles. Embryo splitting stays closest to conventional reproduction, yet it raises questions about the number and disposition of embryos. SCNT carries the scientific promise of copying genotypes valuable for conservation or agriculture, but its low success rates and risks of abnormal development make it controversial, especially in mammals. iPSC technology sidesteps the creation of embryos, thereby avoiding some objections, but it introduces others—such as how to regulate embryo-like structures that iPSCs can form under certain conditions. Across all methods, debates concentrate on welfare considerations, the moral status of early developmental stages, and whether the benefits justify the risks.

Paragraph 7
Because language shapes policy, it is important to distinguish the techniques rather than treat them as interchangeable. When “cloning” is used without qualification, the public may assume that any laboratory work aims to produce a copy of a person or animal. In practice, most contemporary research focuses on cellular models and tissues that never approach reproduction. Clear terminology helps reconcile scientific goals with social expectations and legal rules.

 

Questions:

1. According to paragraph 2, what is a defining feature of embryo splitting? [Detail]

A. It replaces the nucleus of an egg with DNA from a somatic cell.
B. It divides an early embryo so that each portion can develop separately.
C. It alters gene expression using regulatory factors.
D. It creates embryos without using fertilized eggs.

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2. The word “analogous” in paragraph 2 is closest in meaning to: [Vocabulary]

A. predetermined
B. identical
C. comparable
D. experimental

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3. Which of the following is NOT mentioned as a difficulty associated with SCNT? [Negative Factual]

A. Reprogramming the donor nucleus to an embryonic state
B. Low efficiency leading to developmental failures
C. The impossibility of obtaining suitable egg cells
D. Abnormal development in mammalian embryos

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4. In paragraph 3, the phrase “epigenetic landscape” refers to: [Detail]

A. the exact DNA sequence found in mitochondria
B. the pattern of chemical marks that regulate gene activity
C. the physical arrangement of chromosomes within the nucleus
D. the geographic distribution of donor animals

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5. What is the primary goal of iPSC technology as described in paragraph 4? [Detail]

A. To create embryos for reproductive purposes
B. To generate patient-matched tissues for research or therapy
C. To increase the number of fertilized eggs available
D. To enhance natural asexual reproduction in plants

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6. Why does the author discuss asexual reproduction in plants and some animals in paragraph 5? [Purpose]

A. To argue that laboratory cloning is unnecessary
B. To demonstrate that cloning exists along a natural continuum
C. To show that parthenogenesis is the most efficient cloning method
D. To claim that plant cloning presents greater ethical challenges

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7. Which of the following best describes the organization of paragraph 6? [Rhetorical Purpose]

A. Presenting a chronological history of cloning methods
B. Listing practical applications without addressing ethics
C. Comparing multiple cloning approaches in terms of ethical and practical issues
D. Arguing that only SCNT should be permitted

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8. The word “interchangeable” in paragraph 7 is closest in meaning to: [Vocabulary]

A. indistinguishable
B. inexpensive
C. reversible
D. interchangeable (no change)

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9. In the paragraph below, indicate where the following sentence best fits.
This widespread assumption can distort public debate and complicate regulation. [Sentence Insertion]

Because language shapes policy, it is important to distinguish the techniques rather than treat them as interchangeable. (A) When “cloning” is used without qualification, the public may assume that any laboratory work aims to produce a copy of a person or animal. (B) In practice, most contemporary research focuses on cellular models and tissues that never approach reproduction. (C) Clear terminology helps reconcile scientific goals with social expectations and legal rules. (D)

A. Option A
B. Option B
C. Option C
D. Option D

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10. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by dragging the letters of the three answer choices that express the most important ideas into the box. [Summary]

Cloning encompasses multiple methods with distinct goals, challenges, and ethical profiles.

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Total Questions: 0

Incorrect Answers: 0

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To writing on the topics "Cloning" and "Cosmetics"

To speaking on the topics "Cloning" and "Cosmetics"