An explanation of the Calvin cycle, including why it needs to run six times to create glucose

The three categories of photosynthesis, which each help plants survive in different environments

In the vast majority of plants, C3 photosynthesis produces three-carbon intermediate molecules in the Calvin cycle within the cells of leaves. Plants in hot, dry climates use C4 photosynthesis across two types of cells to produce four-carbon molecules before the Calvin cycle. Plants in drought conditions use CAM to store carbon dioxide as an acid at night, minimizing water loss.

Rubisco, the crucial enzyme powering photosynthesis

Photosynthesis is the crucial process by which plants absorb sunlight, take up water, and breathe in carbon dioxide, prompting chemical reactions that result in the byproducts sugar and oxygen. A key enzyme, rubisco, is responsible for it all, but it is inefficient. This video explores the key protein and reveals fascinating facts about oxygen and photosynthesis.

The research pipelines being explored by the RIPE Project to improve photosynthesis

These include engineering plants with faster stomata, which would allow photosynthesis to resume more quickly amid fluctuations in available light due to clouds or shading from other plants, and resolving bottlenecks in the regeneration of RuBP, the molecule to which carbon dioxide is fixed during photosynthesis to initiate the Calvin cycle. (Some readers may experience a paywall.)

Why the abundance of RuBisCO in photosynthetic cells may come from its inefficiency

Despite pulling about 115 billion tons of carbon dioxide from the atmosphere to build organic molecules each year, the enzyme instead binds oxygen at least one in five times, needlessly costing cells energy. To compensate for this and its processing of no more than 10 molecules per second—versus thousands processed by a typical enzyme—it's become the most abundant enzyme on Earth.

An overview of oxygenic photosynthesis, which releases oxygen from breaking down water

Within the membranes of chloroplasts, electrons in pigments are energized by light and transferred across a series of molecules until they create the energetic NADPH molecule. This transfer also powers a hydrogen pump, which creates an ion imbalance that, when relieved, produces energetic ATP molecules. Outside the membranes, both NADPH and ATP are used to synthesize G3Ps, which are funneled into other metabolic pathways to produce sugars.

How does your body turn food into energy?

Cells get energy via a process known as cellular respiration, which involves turning glucose into ATP or adenosine triphosphate. Breaking the phosphate bonds of ATP results in usable energy being released into cells, which can then use that energy to power biological processes. This 10-minute video explains how glucose turns into ATP, giving the body the energy it needs to survive.

Understanding the role of photosynthesis as a sink within the carbon cycle

Photosynthetic organisms are net carbon absorbers, pulling carbon dioxide from the atmosphere and storing it in organic compounds and within soil. Approximately one-third of humanity's carbon emissions are stored by these organisms.

Artificial photosynthesis turns CO₂ into sustainable fuel

Carbon conversion focuses on a central perplexing question: if carbon dioxide is a leading driver of climate change, and fossil fuels are made of carbon-based molecules, can we devise a way to convert CO₂ into useful alternatives efficiently? This video breaks down a potential pathway using artificial photosynthesis, which uses sunlight to convert CO₂ into fuel.

Explore the efficiency of photosynthesis under various conditions

In this simulation, users can track how the cellular concentrations of ATP, NADPH, glucose, and oxygen vary over time in response to changes in temperature, acidity, carbon dioxide concentration, and the properties of incoming light. Through multiple trials, users can identify the optimal conditions for photosynthetic reactions.

Single-cell organisms have circadian clocks that direct daily biochemical routines

Cyanobacteria, a type of light-sensitive bacteria, use this clock to signal when to alternate between making organic compounds through photosynthesis and when to convert atmospheric nitrogen into usable ammonia. Upregulating photosynthetic machinery before dawn helps ensure efficient photosynthesis.

From evaporation to precipitation: An overview of the water cycle

The water cycle is a natural process that continuously circulates water throughout Earth's systems. View this diagram from NASA to understand how the water cycle incorporates evaporation, condensation, precipitation, and more. First, the sun's heat...

Cells create more organelles and duplicate their genetic material before dividing

As part of the cell cycle, this ensures that after mitosis—the process of cell division—the two resulting daughter cells possess the tools necessary to complete the functions of their parent cell, including accumulating energy and making proteins. During meiosis, four egg or sperm cells are created, each with half the parent cell's DNA.

During the fall, chlorophyll breakdown in leaves produces color changes

With shorter days and less sunlight, the concentration of the green pigment diminishes, revealing yellow and orange pigments. Red leaves result from trapped sugars, producing new pigments called anthocyanins, which weren't present in leaves during the growing season.

Stacking nucleotide molecules like toy blocks helps build DNA's structure

Each nucleotide is made up of a sugar—deoxyribose—a phosphate group, and one of four bases that contain nitrogen. Like building a two-tone, spiral staircase from the ground up, nucleotides are linked one on top of another so that sugars and phosphates alternate. The twisted strands are held together by hydrogen bonds between base pairs.

There are 6 essential steps in cheesemaking

The six basic steps that are required to turn milk into cheese start with acidification and end with ripening (aka aging). This guide explains what happens at each step and how it contributes to the finished product.

The REM cycle happens around four to six times per night

Sleep is a natural process that is critical to maintaining life—a process conserved throughout evolution across just about any animal with a brain. Generally speaking, the first three stages involve increasingly deep phases of non-REM sleep, followed by a roughly 90-minute period of REM sleep that repeats throughout the night.

An overview of crude oil, including its constituent hydrocarbons and refinement outputs

The mixture is primarily composed of molecules of carbon and hydrogen atoms bonded into a variety of shapes and lengths, giving each different chemical properties, such as boiling points. Refining can remove elemental impurities—such as sulfur—after hydrocarbons are separated, ensuring the resulting products can be used effectively in other machines, such as car engines.

Watch Ray Dalio explain how the economy works

Dalio describes the economy as a machine that runs on three main cycles: productivity growth, the short-term debt cycle, and the long-term debt cycle. Dalio says layering these three cycles on top of each other essentially creates a template for understanding changes in the economy.

Watch a pinecone become a pine tree

Sometimes a closer look at an ordinary process can uncover its glory This timelapse video presents the wondrous natural process of a withering pinecone turning into a full sprouted tree. A nearly two year growth, watch the seed turn to seedling and rise over time.

Wine explained

Wine is the sublime product of fermentation, the process of breaking down fruit—typically grapes. As the grapes ferment, yeast consumes the natural sugars and converts them to alcohol. With the process first developed and refined thousands of years ago, wine has been a central feature of celebrations throughout modern history. Want to learn more about its origins? Check out 1440's explainer on wine.

Fusion reactions and radioactive decay produce elements inside stars

Hydrogen, present since the early universe, serves as fuel for the proton-proton chain, producing helium, which is then incorporated into the CNO cycle to produce carbon, nitrogen, and oxygen. Additional fusions of helium with these elements and subsequent decays via the alpha ladder produce elements up to iron and bismuth.

Jupiter’s size forced the creation of modified planetary formation models

Since solar winds remove gases from protoplanetary disks within millions of years of a star’s birth, models needed to provide a mechanism to jump-start Jupiter’s formation and growth. The solution involved incorporating pebbles of matter into the disk.

How the brain processes a calendar year

When most of us picture a calendar year, we have a foggy image in our minds of the months, in rough, calendar-like grids. But for some folks, that picture is a whole lot more clear. Around 1 percent of the population has a strange ability known as "calendar synaesthesia," which means they're able to visualize in crisp detail an elaborate calendar of the months of the year. Learn how it works here.

Barbecue relies on a unique scientific equation

Barbecue's distinct flavor starts with an interaction between the heat source and food, which creates a Maillard Reaction—better known to diners as those crunchy, caramelized bits on the outside.

A fascinating look at why cucumber tendrils coil in opposite directions

The tendrils of cucumber plants coil when they hit a surface, creating a distinct telephone-cord look. Charles Darwin wrote about the mystery in the 1850s, though it wasn't until the 21st century that scientists figured out just how mysterious the coil is: its tendrils coil in opposite directions.

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

Scientists testing how climate change affects plants found, in a years-long simulation study, that poison ivy grew 70% faster with the resulting extra carbon dioxide.

Coral reefs get their colors from zooxanthellae—microorganisms that line corals' digestive tracts and provide them with sugars in exchange for a home within this protective tissue.

All rainbows are 'raincircles' caused by water droplets separating white sunlight into a spectrum of colors, but Earth's surface blocks the bottom half of the circle from our line of sight.

While the sun's gravity keeps the planets in orbit, their gravity also pulls on the sun, causing it and everything else in the solar system to orbit around a mutual balance point called the barycenter—the true center of the solar system.

The syncytiotrophoblast is the outer layer of the placenta and the largest human cell, spanning an area about twice that of a king-sized bedsheet.

How Amazon operates a 'flywheel' business model, a self-reinforcing cycle that drives continuous growth

See how each of the more than two million known species relates to each other—and to common ancestors—in this zoomable tree of life.

Learn how your body is, scientifically, like a firework with its own slow, controlled burn.

When you complete a CAPTCHA on a website to prove you are human, you may be unknowingly training algorithms for self-driving cars, whose systems require training data to help identify crosswalks, bicycles, and other outdoor objects.

Some renewable energy sources may weaken the resiliency of electric grids by removing outage buffers provided by coal- and natural gas-fired plants, which provide the system with more time to find a new power source if a plant goes down.

Researchers believe the brain consolidates memories, processes emotions, and plans for the future during dream states

The price of gas is a composite made up of several different factors, with the federal gas tax making up less than 20% of what drivers pay at the pump.

See how Budweiser's famous Clydesdales spend their days at Warm Springs Ranch, where roughly 70 to 80 of the beer brand's giant horses can be found at any given time.

The term 'algorithm' originated from the Latinized name of al-Khwārizmī, a 9th-century mathematician whose works introduced Arabic numerals and the decimal-based numeral system to Europe and whose treatise 'Al-Jabr' gave algebra its name.

Stanford built a Google Maps for the Roman Empire, revealing how much it cost to travel in the ancient world

Some coin denominations have ridges etched on their sides, partly to prevent counterfeiting, in a practice called 'reeding.'

An initial public offering or 'IPO' is the process of a private company becoming public by putting shares of the company on the stock market for purchase.

Sunflowers have long been a symbol of nuclear disarmament because they can extract large amounts of radioactive cesium from soil.

Use this tool to calculate the dollar value of your parental mental load, from meal planning to coordinating after-school care, then see resources that help generate solutions.

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by over 1.5 million Muslims.

Hear 50 years of iconic hip-hop samples, the genre's foundational looped tracks

To reduce wrinkles in clothing, research recommends gentle wash cycles with more water and tumble drying with smaller loads and longer times.

Trace how the Bill of Rights, inspired by centuries of political theory, took shape between 1774 and 1789.

The first steps to rebuilding your credit score include getting to know exactly what's on your credit report and figuring out how far you are from the '700 club,' or 'good score' range.