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Red alga life cycle Animation

By: HWC, Views: 3530

Life cycle of Porphyra. The most conspicuous part of this algal life cycle is the haploid gametophyte. This sheetlike form is collected and dried for use as nori, the wrapping for sushi. Gametes form in packets interspersed between vegetative cells near the sheet margins. The gamet...

Protein Secondary and Tertiary Structures - Animation

By: HWC, Views: 5490

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: 3220

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...

Random alignment at Metaphase I Animation

By: HWC, Views: 3764

Possible outcomes of random alignment at metaphase I. In this example, three types of chromosomes are labeled 1, 2, and 3. Maternal chromosomes are dark blue; paternal ones are light blue. Suppose that at metaphase I all the maternal chromosomes became attached to one spindle pole and all the ...

The Nerve Impulse

By: Administrator, Views: 14899

The action potential explained.

B cells and antibodies

By: HWC, Views: 10137

What Are Antibodies? Antibodies, also known as immunoglobulins, are Y-shaped proteins that are produced by the immune system to help stop intruders from harming the body. When an intruder enters the body, the immune system springs into action. These invaders, which are called antigens, can be vi...

Anatomy and Chemical Makeup of a Single Hair (Animation)

By: HWC, Views: 7606

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...

Labor and Delivery - Placenta Cord

By: Administrator, Views: 380

Soon after a baby is conceived, a support system, comprised of the placenta and umbilical cord, begins to develop. These two structures are essential for sustaining a healthy pregnancy, explains Donald Davis, an obstetrician in Medicine Hat, Alta., and past president of the Society of Obstetricia...

Chemical Synapse Animation

By: HWC, Views: 6745

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...