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爱德思国际 A-Level · 生物 · 单元 2 · WBI12 细胞、发育、生物多样性 · 16 分钟
全部 (9)
核心定义 (3)
常考原理 (3)
常见误区 (3)
第 1 张
★★
干细胞有什么能力？
Define a stem cell.
核心定义
A stem cell is an undifferentiated cell that can divide and can differentiate into specialised cells.
干细胞尚未特化，能够分裂，并且能够分化成特化细胞。
第 2 张
★★
胚胎干细胞和成体干细胞，能形成的细胞种类有什么不同？
Explain the difference between the range of cell types formed by embryonic stem cells and by adult stem cells.
核心定义
Embryonic stem cells can become a wide range of cell types. Adult stem cells are more limited.
胚胎干细胞可以成为体内多种细胞。成体干细胞更受限制，只能形成较少种类的细胞。
第 3 张
★
细胞分化是什么？
Define differentiation.
核心定义
Differentiation is the process by which a cell becomes specialised in structure and function. Some genes are expressed and others are switched off.
分化是细胞变成具有特定结构和功能的特化细胞。某些基因被表达，另一些被关闭。细胞核里的遗传物质通常并不改变。
第 4 张
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全能和多能应怎样说才稳妥？
Explain the difference between totipotent and pluripotent cells without overstating it.
常考原理
Totipotent cells of the early embryo can give rise to every cell type. Embryonic stem cells are described as able to become a wide range of cell types. Adult stem cells are more limited and should not be described as able to become every cell type.
很早的胚胎细胞如果是全能的，可以分化成各种细胞。胚胎干细胞通常说成能成为广泛的细胞类型。不要把成体干细胞也说成能成为任何细胞。
第 5 张
★
为什么分化后的细胞功能不同，DNA 却通常相同？
Explain how cells with the same genes can have different functions.
常考原理
Different genes are expressed in different cells. The proteins that are made determine the structure and function of the cell.
不同细胞表达的基因不同。被表达的基因决定细胞制造哪些蛋白质，从而决定结构和功能。
第 6 张
★
干细胞在医学上可能用来做什么？
State one medical use of stem cells.
常考原理
Stem cells may be used to produce specialised cells that replace damaged tissue. The source of the stem cell limits the range of cell types that can be formed.
干细胞可用来产生特化细胞，以替换受损组织。使用前要说明细胞来源，以及它能形成的细胞范围是有限还是较广。
第 7 张
★★
成体干细胞写成和胚胎干细胞一样，可以成为任何细胞，对吗？
Explain the error in saying that adult stem cells can become any cell type, just as embryonic stem cells can.
常见误区
The same unlimited range does not score. Embryonic stem cells can become a wide range of cell types. Adult stem cells are more limited.
把两者说成范围相同不得分。得分的是：胚胎干细胞可以成为广泛的细胞类型，成体干细胞更受限制。
第 8 张
★
分化写成细胞里的 DNA 被换成另一种 DNA，对吗？
Explain the error in saying that differentiation replaces the DNA with a different set of genes.
常见误区
Replacing the DNA does not score. The genes stay the same. Differentiation switches some genes on and others off, so the cell becomes specialised.
换成另一套 DNA 不得分。得分的是：遗传物质通常不变，只是有的基因表达、有的基因关闭，细胞因而特化。
第 9 张
★★
干细胞写成已经完全特化、不能再分裂，错在哪？
Explain the error in defining a stem cell as a fully specialised cell that can no longer divide.
常见误区
A fully specialised cell that cannot divide does not score. A stem cell can divide and can differentiate.
已经特化并且不能分裂，这不是干细胞。得分的是：干细胞能分裂，也能分化。
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