All Subjects



AP Bio



Unit 2

2.2 Cell Structure and Function

2 min readjune 8, 2020



As with most biological processes, the structure of all of the organelles listed above contribute to the function of that organelle. A few examples are below:



The inner foldings of the mitochondria membrane, referred to as cristae, are essential to the increased surface area of the inner membrane. This increased surface area allows for much more space for the Electron Transport Chain (ETC), an essential part of cellular respiration. The matrix, used as the site of the Krebs cycle, is right next door and can therefore transfer its products easily to the ETC. 


Similarly, the stacked thylakoid membranes of the chloroplast allow for an increase in surface area necessary for the ETC of the light-dependent reactions of photosynthesis. These membranes are also lined with photosystems and chlorophyll, increasing the amount of energy that the plant can get from light. Similarly, the proximity of the stroma to the thylakoids allows for the sharing of products between the Calvin Cycle (which happens in the stroma) and the light-dependent reactions (more on all of this in Unit 3!).

Plasma Membrane

The plasma membrane, discussed more below, is specifically designed to be semi-permeable. This means that some molecules are able to travel through without any problem, while others need specific proteins in order to help them across. The plasma membrane allows for the creation of a concentration gradient, an essential part of many biological processes.


The plasma membrane that contains the lysosome is incredibly important. If the hydrolytic enzymes inside of the lysosome were to burst, all of the cell's organelles may burst as well, and the cell would die. In order to prevent this, the membrane is specially designed to keep these enzymes in. The lysosome will bind with other vesicles that contain contents necessary for digestion when needed.
🎥 Watch: AP Biology - Cell Structure & Function


Was this guide helpful?

🔍 Are you ready for college apps?
Take this quiz and find out!
Start Quiz
FREE AP bio Survival Pack + Cram Chart PDF
Sign up now for instant access to 2 amazing downloads to help you get a 5
Browse Study Guides By Unit
Big Reviews: Finals & Exam Prep
Free Response Questions (FRQ)
General Review
Multiple Choice Questions (MCQ)
Unit 1: Chemistry of Life
Unit 3: Cellular Energetics
Unit 4: Cell Communication and Cell Cycle
Unit 5: Heredity
Unit 6: Gene Expression and Regulation
Unit 7: Natural Selection
Unit 8: Ecology
Join us on Discord
Thousands of students are studying with us for the AP Biology exam.
join now
💪🏽 Are you ready for the AP Bio exam?
Take this quiz for a progress check on what you’ve learned this year and get a personalized study plan to grab that 5!
Hours Logo
Studying with Hours = the ultimate focus mode
Start a free study session
📱 Stressed or struggling and need to talk to someone?
Talk to a trained counselor for free. It's 100% anonymous.
Text FIVEABLE to 741741 to get started.
© 2021 Fiveable, Inc.