Tous les mammifères, et donc tous les humains, ont besoin d’oxygène pour vivre. Ce gaz représente environ 20 % de l’air qui nous entoure. Mais d’où vient-il ? Il est le résultat de la photosynthèse, une réaction physico-chimique complexe qui se déroule dans les feuilles des végétaux.

Got oxygen? Got food? Well, then you've got to have photosynthesis! This video will break down photosynthesis into the "photo" part (capturing light energy and storing it) and the "synthesis" part (fixing carbon into carbohydrates). It's all a bit complicated, but take a deep breath and let's find out where that oxygen comes from.

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"Just as it does for humans, morning signals the time to wake up for plants. Sunlight triggers stomata, which are tiny pores on plant leaves, to open. This boosts photosynthesis by letting CO₂ in and O₂ out. Cells known as guard cells are the gatekeepers of this process, and opening the stomata requires a lot of energy. But scientists have long wondered where this energy comes from. Because while guard cells serve a key photosynthetic function, they appear less equipped than surrounding cells to perform photosynthesis. Now, researchers from HKU and ETH have discovered guard cells’ secret source of fuel. Experiments on Arabidopsis plants showed that guard cells import most of their energy in the form of sugar from surrounding mesophyll cells. Mesophyll cells contain many more chloroplasts than guard cells, helping them produce large amounts of sugar through photosynthesis..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"Chloroplast protein of 12 kDa (CP12) participates in the Calvin Benson Bassham (CBB) cycle and many other processes in higher plants, microalgae, and cyanobacteria. The CP12-encoding gene is conserved in many diatoms, but CBB cycle regulation differs between diatoms and other photosynthetic organisms, and CP12 has not been characterized in these ecologically important and evolutionarily complex microalgae. A recent study addressed this knowledge gap by characterizing CP12 in the marine diatom Thalassiosira pseudonana. Using a variety of techniques, researchers found that this CP12 is expressed under both light and dark conditions and throughout growth and that it exhibits some features of intrinsically disordered proteins, like CP12 proteins in other organisms. The protein is an elongated cylinder with kinks and numerous unstable dynamic α-helices. In addition, it exists as a dimer, in contrast to previously characterized monomeric CP12s..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.