cell wall

IPA/ˈsel ˌwɔːl/
IPA/ˈsel ˌwɔːl/

cell wall — noun

1. a stiff outer layer around a plant cell, made mostly of a tough material called

1.名詞A2
釋義

a stiff outer layer around a plant cell, made mostly of a tough material called cellulose, that gives the cell its shape and protects it from damage

例句

Under a microscope, the onion cells showed a clear, thick cell wall around each one.

describes appearance: clear, thick

Gabriel cut an apple slice and saw its cells held together by their cell walls.

用法筆記

Only plant cells (not animal cells) have a cell wall. This is a key difference students learn in basic biology.

常見錯誤

Animal cells also have a cell wall.
Only plant cells have a cell wall; animal cells have only a cell membrane.
💡Animal cells lack the stiff outer cell wall.

2. a firm, non-living layer outside the cell membranes of various one-celled and ma

2.名詞B1
釋義

a firm, non-living layer outside the cell membranes of various one-celled and many-celled organisms such as plants, algae, fungi, and bacteria — it gives the cell structural support and stops it from bursting when water enters

例句

Bacteria have a tough cell wall that protects them from drying out in harsh conditions.

broadens to bacteria

Dr. Sumin studied how the cell wall of yeast changes shape during bread making.

用法筆記

This sense covers all organisms with cell walls (plants, bacteria, fungi, and algae). The cell wall is non-living and fully permeable, unlike the cell membrane, which is living and selectively permeable.

常見錯誤

The cell wall controls what enters the cell.
The cell membrane controls what enters the cell; the cell wall only provides strength.
💡Students often confuse the functions of cell wall and cell membrane.