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Second Messengers in the Inositol-lipid Signaling Pathway

By: HWC, Views: 7019

Extracellular signals produce specific responses in target cells through the action of intracellular second messengers. Here, we focus on three second messengers, IP3, DAG, and Ca2+, all involved in the inositol-lipid signaling pathway. A hormone-receptor signal on the cell surface leads to the a...

The Krebs Cycle Animation

By: HWC, Views: 1946

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 ...

Fertilization Animation

By: Administrator, Views: 429

At conception, the gender and other biologic traits of the new individual are determined. The zygote is genetically complete and immediately begins to divide, forming a solid mass of cells called a morula. When the developing embryo (stage of development between weeks 2 and 8) reaches the ute...

ribosome

By: HWC, Views: 7484

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...

Baroreceptor Reflex

By: HWC, Views: 7091

Baroreceptors located In the carotid sinus and the arch of the aorta respond to increases in blood pressure. Increased blood pressure stretches the carotid arteries and aorta causing the baroreceptors to increase their basal rate of action potential generation. Action potentials are conduct...

Sperm Formation Animation

By: Administrator, Views: 454

A man’s reproductive system is specifically designed to produce, store, and transport sperm. Unlike the female genitalia, the male reproductive organs are on both the interior and the exterior of the pelvic cavity. They include: the testes (testicles) the duct system: epididymis and vas def...

Central Nervous System Animation

By: Administrator, Views: 10862

Consists of the brain and spinal cord. CNS receives impulses from throughout the body processes the information responds with an appropriate action Brain and spinal cord can be divided into: gray matter (unsheathed cell bodies and true dendrites) white matter (myelinated nerve fibers) ...

Introduction to Genetics

By: Administrator, Views: 10666

Genetics is a branch of biology concerned with the study of genes, genetic variation, and heredity in organisms. Gregor Mendel, a scientist and Augustinian friar, discovered genetics in the late 19th-century. Mendel studied "trait inheritance", patterns in the way traits are handed down from p...

How does an animal choose what food to eat?

By: HWC, Views: 7204

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. ...