跟读练习: Viruses: Components & Shapes - Microbiology Acellular Pre-Nursing, Pre-Med | @LevelUpRN - 通过视频学习英语口语
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Hi, I'm Kathy with Level Up RN.
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In this video, I'm going to begin my coverage of topics from the Acellular Infectious Agents section of our Microbiology Flashcard deck.
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Specifically, I'll be talking about viruses, including key characteristics of viruses, virus components, and virus shapes.
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I've included a quiz at the end of the video to test your knowledge on some of the key facts
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I'll be covering, so definitely stay tuned for that.
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And if you have our Level Up RN microbiology flashcards, go ahead and pull out your flashcards on viruses
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so you can follow along with me
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and pay close attention to the bold red text on the back of the cards
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because those are the things that you are likely to get tested on in your micro class.
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Viruses are acellular pathogens.
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This means that they are not composed of cells and do not contain cells.
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Viruses require a host cell in order to survive.
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They basically hijack the host cell's machinery to reproduce, synthesize viral proteins, and assemble virus components.
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This makes them obligate intracellular parasites.
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Viruses come in a variety of sizes, but in general, they are very small, usually between 20 and 900 nanometers in length.
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Each virus has a host range, which is the range of species and cell types that the virus can infect.
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So for example, a bacteriophage is a virus that only infects bacterial cells.
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They do not infect human cells.
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A virulent phage is a bacteriophage that infects a bacterial cell and causes the cell to lice or burst,
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which results in cell death.
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Whereas a temperate phage integrates its genetic material into the host cell's chromosome,
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and that genetic material is replicated when the host cell replicates.
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So in the next video, in this video playlist, we will go into detail about the different ways that a bacteriophage can replicate.
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Of note, when you see the term virion, that is referring to a virus particle that is outside the host cell.
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So it's basically the extracellular form of a virus that is capable of infecting a new host.
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Let's now talk about the different components that make up a virus.
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So each virus will contain genetic material.
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This may be DNA or RNA, but not both.
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And then in addition to the DNA or RNA, each virus will have a capsid,
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which is a protein coat that surrounds and protects the genetic material.
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The capsid is made up of capsimeres, which are protein subunits that interlock to form the capsid.
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Many viruses also have an envelope, which is a phospholipid membrane that surrounds the virus.
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This envelope is derived from the host cell when the virus pinches off from the host cell during a process called budding.
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A virus that lacks an envelope is referred to as a non -enveloped virus or a naked virus.
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Some viruses also have spikes, which are protein structures that extend outward and away from the virus.
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These spikes allow the virus to more effectively attach to the host cell, enter the cell, and cause infection.
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So viruses that have spikes tend to be more virulent.
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An example of a virus that has spikes is the coronavirus, which causes COVID -19.
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Now let's talk about key virus shapes, which include a helical shape, a polyhedral shape, and a complex shape.
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A virus with a helical shape has a cylindrical
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or rod -shaped capsid with the viral nucleic acid poiled up inside the capsid.
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An example of a virus with a helical shape is the tobacco mosaic virus.
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A virus with a polyhedral shape has a nucleic acid surrounded by a multi -sided capsid.
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An example of a virus with a polyhedral shape is the adenovirus.
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An icosahedron is a polyhedron with 20 equilateral triangular sides,
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which makes the virus appear spherical in shape.
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An example of a virus with an icosahedral shape is the poliovirus.
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And of note, helical viruses and polyhedral viruses may also have an envelope.
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Lastly, some viruses will have a complex shape, which includes features of both helical and polyhedral viruses.
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The most common example of a virus with a complex shape is a bacteriophage.
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So as you can see in the image, the head of the bacteriophage has a polyhedral shape,
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whereas the tail of the bacteriophage has a helical shape.
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All right, it's quiz time, and I have five questions for you.
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Question number one, what do you call the protein coat that surrounds and protects the nucleic acid of a virus?
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The answer is the capsid.
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Number two, what do you call the protein subunits that make up a capsid?
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The answer is capsomeres.
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Number three, what is a naked virus?
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The answer is a virus that lacks an envelope.
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Number four, what viral shape is shown here?
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The answer is helical.
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And number five, what do you call a complete virus particle outside the host cell?
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The answer is a virion.
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All right, that's it for this video.
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I hope you found it to be helpful.
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If so, be sure to hit that like button.
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Take care and good luck with studying!
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本课的词汇与口语要点
这节口语课以视频“Viruses: Components & Shapes - Microbiology Acellular Pre-Nursing, Pre-Med”为素材。 视频中反复出现的词有：virus, shape, cell, viruses, host。 这段视频共有 17 个句子、891 个单词可供跟读。 讲话部分时长为 6:43。 说话人语速平稳，每分钟约 133 个词，很适合跟读。 只有 69% 的单词属于英语最常用的 3,000 词，词汇难度较高。 全部 17 个句子中有 5 个是问句，适合练习疑问语调和简短回答。
视频中的重点词汇
视频中 15 个值得学习的单词，附发音和释义：
| 单词 | 发音 | 释义 |
|---|---|---|
| virus 名词 | /ˈvaɪ.ɹəs/ | 病毒 |
| envelope 名词 | /ˈɛnvə(ˌ)loʊp/ | 信封 |
| surround 动词 | /səˈɹaʊnd/ | 包圍 /包围, 圍繞 /围绕 |
| acid 名词 | /ˈæsɪd/ | 酸 |
| component 名词 | /kəmˈpoʊ.nənt/ | 元件, 部件 |
| refer 动词 | /ɹɪˈfɜː/ | 談到 /谈到 |
| helpful 形容词 | /ˈhɛlp.fl̩/ | 有幫助 /有帮助 |
| naked 形容词 | /ˈneɪkɪd/ | 赤裸, 裸 |
| whereas | /(h)wɛɹˈæz/ | 然而 |
| coat 名词 | /ˈkoʊ̯t/ | 外衣, 大衣 |
| particle 名词 | /ˈpɑɹtək(ə)l/ | 粒子 |
| quiz 名词 | /kwɪz/ | 測驗 /测验, 競猜 /竞猜 |
| bacterial 形容词 | [bækˈtɪəɹiəɫ] | 微生物的 |
| topic 名词 | /ˈtɑpɪk/ | 主題 /主题, 話題 /话题 |
| deck 名词 | /ˈdɛk/ | 甲板 |
视频中出现的短语动词
| 单词 | 发音 | 释义 |
|---|---|---|
| make up 动词 | /ˌmeɪk ˈʌp/ | 組成 /组成 |
| go ahead 动词 | /ˌɡoʊ əˈhɛd/ | 請便 /请便 |
视频中的语法
说话人最常用的结构，并附上视频中的原话：
| 结构 | 视频中的用法 |
|---|---|
| 被动语态 be + 过去分词 — 强调发生了什么，而不是谁做的 | are not composed · is replicated · is made |
| 定语从句 who / which + 从句 — 补充说明人或事物 | range, which is · capsimeres, which are · envelope, which is |
需要注意的发音
说话人用了 5 次缩略和弱读形式，例如 I'll, I'm, I've。请按听到的简短形式来说。
- “th” 音: pathogen /ˈpæθəd͡ʒn̩/, synthesize /ˈsɪnθəsaɪz/
- “sh” 和 “zh” 音: infection /ɪnˈfɛkʃən/, machinery /məˈʃiːnəɹi/, infectious /ɪnˈfɛk.ʃəs/, flashcard /ˈflæʃˌkɑɹd/
- 长单词——注意重音位置: machinery /məˈʃiːnəɹi/, characteristic /ˌkæɹ(ə)ktəˈɹɪstɪk/, bacteriophage /bækˈtɪəɹ.ɪəʊˌfeɪd͡ʒ/, microbiology /ˌmʌɪkrə(ʊ)bʌɪˈɒlədʒi/, adenovirus /əˈdɛnəʊˌvaɪɹəs/
中文母语者容易读错的音：
- /v/ — 不要读成 /w/，上齿轻触下唇: virus /ˈvaɪ.ɹəs/, envelope /ˈɛnvə(ˌ)loʊp/, viral /ˈvaɪɹəl/, invite /ɪnˈvaɪt/, microwave /ˈmaɪkɹoʊˌweɪv/
- 词尾辅音 — 要读清楚，后面不要加元音: virus /ˈvaɪ.ɹəs/, envelope /ˈɛnvə(ˌ)loʊp/, genetic /d͡ʒəˈnɛt.ɪk/, spike /spaɪk/, surround /səˈɹaʊnd/
- /r/ 和 /l/ 的区别: viral /ˈvaɪɹəl/, replicate /ˈɹɛplɪkeɪt/, particle /ˈpɑɹtək(ə)l/, bacterial [bækˈtɪəɹiəɫ], flashcard /ˈflæʃˌkɑɹd/
如何用这段视频练习
- 先完整听一遍视频，不要开口，记下不认识的单词。
- 用正常速度逐句跟读，每句重复到你的节奏与说话人一致为止。
- 录下自己的声音并与原声对比，特别注意 virus, envelope, surround 这类单词。
什么是跟读法？
跟读法 (Shadowing) 是一种有科学依据的语言学习技巧，最初开发用于专业口译员的培训，并由多语言者Alexander Arguelles博士普及。这个方法简单而强大：您在听英语母语原声的同时立即大声重复——就像是一个延迟1-2秒紧跟说话者的影子。与被动听力或语法练习不同，跟读法强迫您的大脑和口腔肌肉同时处理并模仿真实的讲话模式。研究表明它能显着提高发音准确性，语调，节奏，连读，听力理解和口语流利度——使其成为雅思口语备考和真实英语交流最有效的方法之一。