Edexcel A (SNAB) A Level Biology:复习笔记3.1.3 Prokaryotic Cells
Prokaryotic Cells: Structure
- Animal and plant cells are types of eukaryotic cells, whereas bacteria are a type of prokaryote
- Prokaryotic cells are much smaller than eukaryotic cells
- They also differ from eukaryotic cells in having
- A cytoplasm that lacks membrane-bound organelles
- Ribosomes that are smaller (70 S) than those found in eukaryotic cells (80 S)
- No nucleus, instead having a single circular bacterial chromosome that is free in the cytoplasm and is not associated with proteins
- A cell wall that contains the glycoprotein murein
- Murein is sometimes known as peptidoglycan
- In addition, many prokaryotic cells also have the following structures
- Loops of DNA known as plasmids
- Capsules
- Flagella (singular flagellum)
- Pili (singular pilus)
- A cell membrane that contains folds known as mesosomes
Additional Prokaryotic Structures Table
Bacteria are prokaryotic cells
Prokaryotes vs eukaryotes
- There are a number of important structural and physiological differences between prokaryotic and eukaryotic cells
- These differences affect their metabolic processes and how they reproduce
Comparison of Prokaryotic and Eukaryotic Cells Table
Exam Tip
You will need to know all the differences between prokaryotic and eukaryotic cells; remember that not all of the structures mentioned here are present in all prokaryotic cells
Remember that size is not a structural feature so if you are asked for a structural difference between a prokaryotic and eukaryotic cell don't include size in your answer.
转载自savemyexams
国际竞赛真题资料-点击免费领取！
美高学分项目重磅来袭！立即了解
AMC8备考管家服务全新上线！
