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Homologous chromosomes during prophase I - Animation

By: HWC, Views: 5680

The chromosomes were duplicated during interphase and the sister chromatids are now in thin threadlike form. Each chromosome becomes zippered to its homologue, so that all four chromatids are closely aligned. The chromosomes are tightly aligned, but we will show them as separate so that y...

Neuron Structure Animation

By: Administrator, Views: 11137

There are several types of neurons, three of which are: Motor neurons, Sensory neurons, Interneurons. The nervous system is usually described as having two interconnected divisions: the central nervous system (CNS) and the peripheral nervous system (PNS). CNS: Includes the brain and spinal...

Spinal Cord Injury Animation

By: Administrator, Views: 11070

The most common cause of spinal cord injury is trauma. Spinal cord injury is most common in young, white men. Spinal cord injury can be either complete or incomplete. In complete injuries there is no function below the level of injury. In incomplete injuries there is some function remaining...

Male Reproductive System - Testosterone

By: HWC, Views: 8398

• Under the influence of FSH and testosterone, Sertoli cells produce androgen-binding protein (ABP) that binds to testosterone and maintains high levels of the hormone near spermatogenic cells. • Testosterone stimulates the final stages of spermatogenesis. • In addition, testosterone is...

DNA fingerprinting Animation

By: HWC, Views: 4747

DNA fingerprinting enables a scientist to compare the DNA from two biological samples, such as a blood stain and a suspect's blood. A restriction enzyme is added to the samples to be compared. The enzyme cuts the DNA into smaller fragments. The DNA fragments are placed on an electrophor...

ETC Protein Complexes & Chemiosmosis (Total ATP Production and ATP Synthase)

By: HWC, Views: 7479

You will notice that FADH2 donates two electrons further downstream than NADH. This results in only two protons being pumped across the inner membrane. The final electron acceptor for these transported electrons is oxygen. Oxygen receives these electrons, plus protons from the aqueous matrix. ...

Summary of female reproductive cycle days 1-28

By: HWC, Views: 8227

■ The first five days of the cycle include the menstrual phase. ■ Progesterone and estrogen levels are low. ■ Menses occurs. ■ GnRH pulses more frequently promoting FSH and LH levels to rise. ■ Primary follicles are stimulated to develop. ■ Days five through thirteen consist o...

Body plan of euglena Animation

By: HWC, Views: 2115

Euglenoids are single-celled organisms that live in lakes and ponds. A contractile vacuole pumps out the water that diffuses into the cell from its hypotonic surroundings. The body is covered by a translucent pellicle composed of flexible strips of a protein-rich material. Light passe...

Interpreting a cladogram Animation

By: HWC, Views: 1445

Using a cladogram to determine relative relatedness and whether the lungfish is more closely related to a human or to a trout. To determine the relative relatedness, we begin by tracing the branches from the human and the lungfish to the point where they meet. We'll call this node 1. Now...