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Protein Secondary and Tertiary Structures - Animation

By: HWC, Views: 3918

Amino acid sequence dictates a protein's final shape. The presence of certain amino acids favors a pattern of hydrogen bonding that causes part of the polypeptide chain to coil and twist into an alpha helix. The presence of other amino acids enables hydrogen bonding between strand like r...

Energy inputs and release in glycolysis Animation

By: HWC, Views: 1675

Glycolysis breaks the six-carbon sugar glucose into two three-carbon molecules of pyruvate. The first steps of glycolysis require an energy input in the form of two phosphate-group transfers from ATP. These phosphorylations raise the energy level of glucose enough to allow the energy-releas...

The Nerve Impulse

By: Administrator, Views: 12733

The action potential explained.

Anatomy and Chemical Makeup of a Single Hair (Animation)

By: HWC, Views: 5936

The hair's outer cuticle surrounds hair cells filled with tough keratin macrofibrils. Each macrofibril consists of smaller microfibrils. A microfibril is made up of three keratin polypeptide chains. The chains are linked together by disulfide bonds. A hair consists of keratin chains held...

Chemical Synapse Animation

By: HWC, Views: 5111

A neuromuscular junction is a chemical synapse between the axon endings of a motor neuron and a muscle cell. A narrow synaptic cleft separates the presynaptic cell (the motor neuron) from the postsynaptic cell (the muscle cell). The presynaptic cell contains vesicles filled with neurotransmitt...

Digestion Animation

By: Administrator, Views: 11362

The mouth or oral cavity is formed by: - The hard and soft palates at the top or roof - the cheeks - the tongue - the lips Contains the teeth and salivary glands. The gingivae (gums) surround the necks of the teeth. The lingual frenulum is a thin fold of mucous membrane that connects...

Chemical Messengers Animation

By: Administrator, Views: 11311

Three types of chemical messengers.

Green alga life cycle Animation

By: HWC, Views: 2362

Chlamydomonas zoospores are haploid flagellated cells. As long as conditions are favorable, these cells reproduce asexually. As many as sixteen cells may form by mitosis within a parent cell. Daughter cells escape when the cell wall ruptures. When conditions become less favorable, the...

DNA close up Animation

By: HWC, Views: 1666

A section from a DNA double helix The backbone of each DNA strand consists of alternating deoxyribose sugars and phosphate groups. The two strands run in opposite directions. One runs from the 5' to 3' direction, the other in the 3' to 5' direction. Think of the deoxyribose units o...