OCR A Level Biology:复习笔记2.1.6 Eukaryotic Cells Under the Microscope

• There are some features or structures that can help to identify whether a cell shown in an image is a plant cell or animal cell
  • Structures found only in animal cells: centrioles and microvilli
  • Structures found only in plant cells: the cellulose cell wall, large permanent vacuoles and chloroplasts

   

The ultrastructure of an animal cell shows a densely packed cell – the ER and RER and ribosomes form extensive networks throughout the cell in reality.

Plant cells have a larger, more regular structure in comparison to animal cells.

• Describing and interpreting photomicrographs, electron micrographs and drawings of typical animal/plant cells is an important skill
• The organelles and structures within cells have a characteristic shape and size which can be helpful when having to identify and label them in an exam

TEM electron micrograph of an animal cell showing key features. Notice the lack of a cell wall.

TEM electron micrograph of a plant cell showing key features. Notice the presence of a cell wall and vacuole.

• More detailed structures can be seen and identified in electron micrographs compared to photomicrographs
• This is because electron microscopes have greater maximum magnification and resolution than light (optical) microscopes

Mucus producing goblet cells (found in the lining of trachea, bronchi and larger bronchioles) are shown in a photomicrograph

Details of the structures inside the goblet cell can be seen in an electron micrograph