Related Concept Videos
01:46The Calvin Benson Cycle
Ribulose 1,5- bisphosphate carboxylase/oxygenase (RuBisCo) is a critical enzyme that catalyzes carbon dioxide assimilation during photosynthesis. However, it is an inefficient enzyme, having an extremely slow catalytic rate. A typical enzyme can process about a thousand molecules per second; however, RuBisCo fixes only around three-carbon dioxides per second. Photosynthetic cells compensate for this slow rate by synthesizing very high amounts of RuBisCo, making it the most abundant single...
02:04Regulation of Transpiration by Stomata
During photosynthesis, plants acquire the necessary carbon dioxide and release the produced oxygen back into the atmosphere. Openings in the epidermis of plant leaves is the site of this exchange of gasses. A single opening is called a stoma—derived from the Greek word for “mouth.” Stomata open and close in response to a variety of environmental cues.
01:27C4 Pathway and CAM
Most plants use the C3 pathway for carbon fixation. However, some plants, such as sugar cane, corn, and cacti that grow in hot conditions, use alternative pathways to fix carbon and conserve energy loss due to photorespiration. Photorespiration is the process that occurs when the oxygen concentration is high. Under such conditions, the rubisco enzyme in the Calvin cycle binds O2 instead of CO2, which halts photosynthesis and consumes energy.
C4 Pathway
The C4 pathway is used by plants such as...
C4 Pathway
The C4 pathway is used by plants such as...
01:20Gas Exchange and Transport
Gas exchange, the intake of molecular oxygen (O2) from the environment and the outflow of carbon dioxide (CO2) into the environment, is necessary for cellular function. Gas exchange during respiration occurs largely via the movement of gas molecules along pressure gradients. Gas travels from areas of higher partial pressure to areas of lower partial pressure. In mammals, gas exchange occurs in the alveoli of the lungs, which are adjacent to capillaries and share a membrane with them.
01:19Carbon Dioxide Transport in the Blood
Carbon dioxide (CO2) transport in the blood is critical to human physiology. On average, our body cells produce around 200 mL of CO2 per minute, precisely the quantity expelled by the lungs. This process involves the transportation of CO2 from the tissue cells to the lungs in three primary forms.
Forms of CO2 Transport
1. Dissolved in plasma: A small percentage (7-10%) of CO2 is transported and dissolved directly in the plasma.
2. Carbaminohemoglobin: Just over 20% of CO2 is chemically bound to...
Forms of CO2 Transport
1. Dissolved in plasma: A small percentage (7-10%) of CO2 is transported and dissolved directly in the plasma.
2. Carbaminohemoglobin: Just over 20% of CO2 is chemically bound to...
02:12Short-distance Transport of Resources
Short-distance transport refers to transport that occurs over a distance of just 2-3 cells, crossing the plasma membrane in the process. Small uncharged molecules, such as oxygen, carbon dioxide, and water, can diffuse across the plasma membrane on their own. In contrast, ions and larger molecules require the assistance of transport proteins due to their charge or size. Transport across membranes also occurs within individual cells, playing a variety of essential roles for the plant as a whole.
You might also read
Related Articles
Articles linked to this work by shared authors, journal, and citation graph.
Sort by
Same author
Photosynthesis in transition: the importance of wavelengths in the green gap for <i>Ocimum basilicum</i> L.
Frontiers in plant science·2026
Same author
Effect of Light Intensity and Light Spectrum of LED Light Sources on Photosynthesis and Secondary Metabolite Synthesis in <i>Ocimum basilicum</i>.
Plants (Basel, Switzerland)·2025
Same author
Effects of high light intensity and spectral variability on maize photosynthesis and growth.
Frontiers in plant science·2025
Related Experiment Video
Updated: May 25, 2026
06:04
Assessing Structural Traits in Triticum aestivum and Zea mays for C3 and C4 Photosynthetic Differentiation Using Free-hand and Semi-thin Sections
Published on: July 12, 2024
Mechanisms underlying CO2 diffusion in leaves.
1Applied Plant Science, Technische Universität Darmstadt, Schnittspahnstrasse 10, Darmstadt, Germany. (kaldenhoff@bio.tu-darmstadt.de)
Current Opinion in Plant Biology
|February 4, 2012
Summary
Plant CO2 diffusion is crucial for photosynthesis, with leaf conductance varying rapidly. Membranes and aquaporins may regulate this CO2 transport, a topic of ongoing scientific debate.
Area of Science:
- Plant physiology
- Biophysics
- Photosynthesis research
Background:
- Carbon dioxide (CO2) availability limits photosynthesis in plants under light saturation.
- Recent research highlights rapid fluctuations in leaf CO2 diffusion.
- Membranes and aquaporins are implicated as key regulators of mesophyll CO2 conductance.
Purpose of the Study:
- To investigate the role of membranes and aquaporins in regulating CO2 diffusion within plant leaves.
- To address the controversy surrounding the mechanisms of CO2 diffusion across biological membranes.
Main Methods:
- Analysis of biophysical data on CO2 diffusion independent of membrane structure.
- Physiological studies examining the impact of membrane composition changes on CO2 diffusion.
Main Results:
- Conflicting data exists regarding CO2 diffusion mechanisms in plants and animals.
- Biophysical evidence suggests CO2 diffusion is independent of membrane components.
- Physiological evidence increasingly supports a role for membrane composition in CO2 diffusion.
Conclusions:
- The precise mechanism of CO2 diffusion across membranes remains a subject of debate.
- Further research is needed to reconcile biophysical and physiological findings.
- Understanding membrane-mediated CO2 transport is critical for plant CO2 assimilation.