Search results for: 'HWC'

Watch Later 3:42

Photosynthesis and Van Helmont Experiment

By: HWC, Views: 6979

All energy on Earth comes from a star, the Sun. Light must travel 160 million kilometers to reach Earth where plants capture this light energy and convert it to chemical energy in the form of sugars. This biochemical process is called PHOTOSYNTHESIS. The summary equation for photosynthesis is ...

Watch Later 2:34

Electromagnetic Spectrum, Chlorophyll and Pigment & Light

By: HWC, Views: 7497

The sun gives off radiation that is called the electromagnetic spectrum. This is energy that travels as wavelengths and includes radio waves, X-rays and ultraviolet light. A portion of this radiation is known as visible light, and is the type of radiation that plants use to manufacture sugars. ...

Watch Later 4:06

Chloroplast Structure & Light Dependent Reactions (Photosystem 1 and 2 Cyclic Electron Flow)

By: HWC, Views: 7299

The leaf is the principle photosynthetic organ of the plant. This is a cross section of a leaf. The rectangular-shaped cells are part of the photosynthetic tissue called the palisade mesophyll. Each photosynthetic cell can contain several hundred organelles known as chloroplasts. The chlorop...

Watch Later 1:36

Calvin cycle (The light-independent reactions )

By: HWC, Views: 7479

The light-independent reactions of photosynthesis occur in the stroma of the chloroplast. Carbon dioxide enters the leaf through tiny pores or stomata and diffuses into the chloroplast. The first stage of the Calvin cycle is the attachment of a carbon dioxide molecule to a 5-carbon ribulose bi...

Watch Later 1:10

How does an animal choose what food to eat?

By: HWC, Views: 7182

One might assume that natural selection has influenced the foraging behaviors of animals, and that most animals forage efficiently, spending the least energy to gain the most nutrients. This is the underlying assumption of optimality modeling, a scientific approach to studying foraging behavior. ...

Watch Later 3:03

Semidiscontinuous DNA replication

By: HWC, Views: 7337

During DNA replication, one of the two DNA strands, the leading strand, is replicated continuously, or all at once, in the 5' to 3' direction. The other strand, called the lagging strand, is replicated discontinuously, or in pieces, in the 3' to 5' direction. This is necessary because DNA poly...

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How antibiotics works? 💊

By: HWC, Views: 7431

The Crisis in Antibiotic Resistance More than 70 years ago, Alexander Fleming discovered penicillin. A few decades later, when this antibiotic was used in World War II, Fleming's discovery had revolutionized medicine. No longer did people have to die from something as trivial as an infected cut.Y...

Watch Later 3:43

Chemical Equilibrium between N2O4 (colorless gas) and NO2 (brown gas)

By: HWC, Views: 6968

For a system at equilibrium: ◆ both forward and reverse reactions are occurring simultaneously ◆ rate of forward reaction must equal rate of reverse reaction OR Rate forward = Rate reverse ◆ concentrations of reactants and products remain constant with time the equilibrium positio...

Watch Later 0:37

Chemical Changes

By: HWC, Views: 7122

Observe the burning logs of wood. The logs burn to emit heat, light and carbon dioxide. What is left behind is ash. This residue is a new substance with a different molecular structure than the original wood. Similarly when baking the dough into bread, it becomes fluffy and light. There is a ch...

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