C3, C4 and CAM Plant Photosynthesis & Photorespiration

C3 Photosynthesis, C4 Photosynthesis and CAM Photosynthesis are all related, but have some critical differences. This video compares and contrasts them, and explains how C4 and CAM photosynthesis help plants to avoid the wasteful process of photorespiration. It also covers C3 C4 and CAM leaf anatomy, example plants, key cells, and the ideal temperature range for each plant type. Finally, the video covers practical applications for using this information in your research or business in order to optimize crop yield.

C3 Photosynthesis (considered the standard) is highly efficient, so long as an ample supply of CO2 is available. However, the C3 Calvin Cycle uses an enzyme known as RuBisCO, which is prone to binding to oxygen under certain conditions, particularly if the weather is hot. This triggers an extremely inefficient process called photorespiration; the plant can still photosynthesize but only at a reduced rate of about 75%. In addition, the process produces waste, and costs more ATP. C4 and CAM Plants are specialists at avoiding photorespiration, and have a number of useful mechanisms and structures for doing it. Both specialized processes cost ATP, but they are still far more efficient than photorespiration.

C4 plants split the process of carbon fixation and the Calvin Cycle into two separate cells; palisade mesophyll and bundle sheath cells, respectively. This keeps RuBisCO from coming into contact with oxygen. C4 Plants also have Kranz anatomy, where the palisade mesophyll cells and bundle sheath cells are close together to facilitate this process.

CAM Plants collect CO2 at night when the air is cooler and having stomata open is less risky. They "fix" CO2 into malate or other organic acids, which are stored until the next day. The acids are then split into carbon dioxide, which feeds the Calvin Cycle, and pyruvate which is re-invested to keep the nighttime fixation process going. CAM Plants also store water when they have a chance, usually in structures called aquiferous parenchyma.

This information can be highly useful to anyone attempting to grow crops; matching the crop to the local environment is essential in order to maximize yield. If the plants are to be grown in a greenhouse, first priority is to ensure water and sunlight, second priority is to optimize the temperature to the plant type, and third priority is to consider supplements such as CO2 in order to boost the rate of photosynthesis and minimize photorespiration.

0:00-0:19 Introduction
0:19-1:07 Photosynthesis and Carbon Fixation Overview
1:07-2:22 C3 Photosynthesis & RuBisCO
2:22-4:00 What is Photorespiration?
4:00-5:00 Relationship between Photorespiration and Temperature
5:00-7:24 C4 Photosynthesis
7:24-8:37 CAM Photosynthesis
8:37-9:35 C3 C4 CAM Leaf Structure and Anatomy
9:35-10:35 Practical Application: Optimizing Setup
10:35-11:57 Limiting Factors to Photosynthesis
11:57-14:04 Cost-Benefit Analysis of Adding CO2

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[wyldevin]

Hey! My teacher included a link to this resource in our notes, and I've had to say this has been extremely helpful! Perfectly concise, great recordings, and all in an easy-to-digest format! Thank you so much for all of these resources! Please also let me know if there's anything else I can do to support this channel!

[juveriabanu]

this explanation pulled me out of a slump, i needed a quick understanding and this video explained it in ways, i would not have been able to understand ever.
thank you!

[aytaktamizkar]

Thank you so much for this nice productive video, and i'm grateful that it has persian subtitle too🙏🏻🙏🏻

[architanaik]

comparing them together makes understanding so much more better :)

[achyuthankarthikeyan]

Your channel is a treasure trove of great biology videos! I'd love to see one on plant anatomy (dicot and monocot root, dicot and monocot stem) from you. Either way, your content is first class and quite easily understandable, thank you!

[danial_amini]

thanks for the explanation! i never knew cactus and pineapple is a whole different class (cam plant), I also knew that c3 plants are the majority of the plants but didn't realize how vulnerable they are to climate change! great explanation, subscribed!

[petersiska]

I recommend to always explain abbreviations like PGL, PGAL etc

[najibanurisma]

Thank you so much for discussing this topic💕

[janehuang]

thank you so much such a clear explanation🤩

[鶴岡市リット]

In CAM plant, when O2 release into environment? If answer night, where is the O2 in the daytime?

[DrStrange-ctfd]

Probability and statistics of inheritance, are very needed

[arcaeae]

i dont know how i got here but here i am