Chromosomes and the cell cycle · 染色体与细胞周期
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| chromosome/ˈkrəʊməsəʊm/ | 染色体 | rǎn sè tǐ |
| histone/ˈhɪstəʊn/ | 组蛋白 | zǔ dàn bái |
| replication/ˌreplɪˈkeɪʃn/ | 复制 | fù zhì |
| sister chromatid/ˈsɪstə ˈkrəʊmətɪd/ | 姐妹染色单体 | jiě mèi rǎn sè dān tǐ |
| centromere/ˈsentrəʊmə/ | 着丝粒 | zhe sī lì |
| telomere/ˈteləʊmə/ | 端粒 | duān lì |
| interphase/ˌɪntəˈfeɪz/ | 间期 | jiān qī |
| mitosis/maɪˈtəʊsɪs/ | 有丝分裂 | yǒu sī fēn liè |
| cytokinesis/ˌsaɪtəkəˈniːsɪs/ | 胞质分裂 | bāo zhì fēn liè |
How one cell becomes two
- Your DNA is huge — to fit in the nucleus it is wound up into chromosomes 染色体.
- Before a cell divides, all of that DNA must be copied perfectly.
- The whole repeating life of a cell is the cell cycle.
一个细胞如何变成两个
- 你的 DNA 很庞大——为了塞进细胞核,它被卷成 染色体(chromosomes)。
- 在一个细胞分裂之前,所有那些 DNA 都必须被完美地 复制。
- 一个细胞整个重复的生命是 细胞周期(cell cycle)。
A chromosome is: · 一条染色体是:
Chromosomes are DNA wound tightly around histone proteins, packing a huge length into the nucleus. · 染色体是紧紧缠绕在组蛋白周围的 DNA,把巨大的长度塞进细胞核。
A replicated chromosome
- A chromosome is one long DNA molecule wound tightly around proteins called histones 组蛋白.
- After the DNA is copied (replication 复制), the chromosome is two identical sister chromatids 姐妹染色单体 joined at the centromere 着丝粒.
- The tips are capped by telomeres 端粒, which protect the ends.
一条复制好的染色体
- 一条 染色体 是一个长 DNA 分子,紧紧缠绕在叫 组蛋白(histones) 的蛋白质周围。
- DNA 被复制(复制(replication))之后,染色体是两条相同的 姐妹染色单体(sister chromatids),在 着丝粒(centromere) 处连接。
- 末端被 端粒(telomeres) 封顶,它们保护两端。
After replication, a chromosome is two identical sister ______ joined at the centromere. · 复制后,一条染色体是在着丝粒处连接的两条相同的姐妹 ______。
Replication makes an identical copy; the two sister chromatids stay joined at the centromere until anaphase. · 复制制造一个相同的副本;两条姐妹染色单体在着丝粒处保持连接,直到后期。
The cell cycle
- Interphase 间期 — the longest part: grow (G₁), copy DNA (S phase), grow and prepare to divide (G₂).
- Mitosis 有丝分裂 — the nucleus divides into two identical nuclei.
- Cytokinesis 胞质分裂 — the rest of the cell splits into two daughter cells.
细胞周期
- 间期(interphase)——最长的部分:生长(G₁)、复制 DNA(S 期)、生长并准备分裂(G₂)。
- 有丝分裂(mitosis)——细胞核分裂成两个相同的核。
- 胞质分裂(cytokinesis)——细胞的其余部分分裂成两个子细胞。
The cell cycle · 细胞周期
Step around the cycle. Most of it is interphase (grow, copy DNA, grow); mitosis and cytokinesis are short, then it repeats. · 绕着这个循环走。它的大部分是间期(生长、复制 DNA、生长);有丝分裂和胞质分裂很短,然后它重复。
Match each phase of the cell cycle to what happens. · 把细胞周期的每个阶段与发生的事配对。
G₁ → S → G₂ make up interphase; then mitosis divides the nucleus and cytokinesis splits the cell. · G₁ → S → G₂ 构成间期;然后有丝分裂分裂细胞核,胞质分裂分裂细胞。
Put the cell cycle in order, starting from G₁. · 把细胞周期按顺序排列,从 G₁ 开始。
Interphase (G₁ → S → G₂) is the longest part; mitosis and cytokinesis finish the cycle. · 间期(G₁ → S → G₂)是最长的部分;有丝分裂和胞质分裂完成这个循环。
During which phase of interphase is the DNA copied? · 在间期的哪个阶段 DNA 被复制?
DNA replication happens in the S (synthesis) phase, between G₁ and G₂. · DNA 复制发生在 S(合成)期,在 G₁ 和 G₂ 之间。
Telomeres and the ends
- When DNA is copied, the machinery cannot reach the very end, so a little is lost each time.
- Telomeres are short repeats that carry no genes — they are shortened instead, so no important genes are lost.
端粒和末端
- 当 DNA 被复制时,机器 无法到达最末端,所以每次都丢失一点。
- 端粒 是 不带基因 的短重复序列——它们被缩短而代替,所以没有重要的基因丢失。
Interphase (G₁, S, G₂) is the longest part of the cell cycle. · 间期(G₁、S、G₂)是细胞周期最长的部分。
Interphase takes up most of the cycle; mitosis and cytokinesis are comparatively short. · 间期占据这个循环的大部分;有丝分裂和胞质分裂相对较短。
Why does shortening telomeres protect a cell's genes? · 为什么缩短端粒保护一个细胞的基因?
The ends cannot be fully copied, so a little is lost; because telomeres hold no genes, the loss is harmless. · 末端不能被完全复制,所以丢失一点;因为端粒不含基因,这个丢失是无害的。
You've got it
- chromosome = DNA wound on histones; after replication → two sister chromatids joined at the centromere
- cell cycle: interphase (G₁ → S = copy DNA → G₂) → mitosis → cytokinesis
- interphase is the longest part
- telomeres cap the ends, carry no genes, and protect against losing DNA in copying
你掌握了
- 染色体 = 缠在 组蛋白 上的 DNA;复制 后 → 在 着丝粒 处连接的两条 姐妹染色单体
- 细胞周期:间期(G₁ → S = 复制 DNA → G₂)→ 有丝分裂 → 胞质分裂
- 间期是 最长的 部分
- 端粒 封住末端、不带基因,并防止在复制中丢失 DNA