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Male Reproductive System - Testosterone

By: HWC, Views: 7258

• 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...

Energy inputs and release in glycolysis Animation

By: HWC, Views: 611

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: 705

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 ...

Introduction to Eating Disorders

By: Administrator, Views: 9551

An eating disorder is a mental disorder defined by abnormal eating habits that negatively affect a person's physical or mental health. They include binge eating disorder where people eat a large amount in a short period of time, anorexia nervosa where people eat very little and thus have a low bo...

Blood Flow through the Human Heart

By: HWC, Views: 6437

The heart is the pump of the human circulatory system. The left side of the heart has two connected chambers, the left atrium and the left ventricle. The right side of the heart also has two connected chambers, the right atrium and the right ventricle. These two sides, or pumps, of the heart are ...

The Krebs Cycle Animation

By: HWC, Views: 891

The second-stage reactions of aerobic respiration. The second-stage reactions occur in a mitochondrion's inner compartment. In the first preparatory reaction, a carbon atom is stripped from pyruvate and released as carbon dioxide. The remaining carbons combine with coenzyme A and give ...

Activation Energy - Valence Electrons

By: HWC, Views: 6120

■ Shared electrons in the outermost orbital form bonds. These electrons are called valence electrons. ■ Valence electrons are disrupted and can be rearranged into a new bond. ■ The energy necessary to start a reaction and break bonds is called the activation energy. ■ Reactants have...

Embryonic development - week 1 and 2

By: HWC, Views: 6695

The first through eighth weeks after fertilization are called the embryonic. Week 1 • Within a day, the zygote begins mitotic cell division (cleavage) forming blastomeres. By the 4th day, the blastomeres have formed a solid ball called a morula. • The morula enters uterine cavity ar...

ribosome

By: HWC, Views: 6336

The trp operon in E. coli contains five structural genes corresponding to enzymes that convert chorismate into tryptophan. The trpE gene contains a 5' untranslated region that plays an important role in the regulatory mechanism called attenuation. The 5' UTR contains four regions. Region 1 en...