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Natural Selection, Species Isolation and Real World Example

By: HWC, Views: 6096

`Natural selection' is the process in which organisms with adaptive traits survive and breed in greater number than organisms without such traits. Eventually, almost all of the individuals in the population will have the same adaptive trait. This was the concept presented by Charles Darwin in ...

Alzheimer's Disease

By: Administrator, Views: 9858

Alzheimer's disease (AD), also referred to simply as Alzheimer's, is a chronic neurodegenerative disease that usually starts slowly and gradually worsens over time. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As the d...

Types of antimicrobial substances (interferons & complement protein)

By: HWC, Views: 6740

• Found in blood and interstitial fluids. • Discourage microbial growth. • Include interferon and complement proteins. • Produced and released by virus-infected lymphocytes. • Enter new cells and inhibit viral replication. • Act against a large variety of viruses (non-speci...

Proteins

By: HWC, Views: 5689

Living things must accomplish a great number of tasks just to get through a day, and these tasks are accomplished by a diverse range of biological molecules. In the range of tasks that molecules accomplish, however, proteins reign supreme. Almost every chemical reaction that takes place in living...

Cytotoxic T cell receptors, activation, proliferation, differentiation & action

By: HWC, Views: 7009

• Most cells which have CD8 on their surface become cytotoxic T cells (Tc cells). • CD8 T cells recognize a foreign antigen when it is presented in conjunction with the protein, MHC-I. • Nearly all nucleated cells in the body express MHC-I molecules. • T cells that recognize self-pe...

Structures that affect circulation - arterioles and vasomotor responses and venous return

By: HWC, Views: 6749

■ Small arteries and arterioles determine SVR. • Blood pressure drops significantly as blood passes through arterioles. • Decreasing arteriole radius and decreased wall elasticity are the main reasons for increased SVR. ■ Small changes in arteriole radius can cause large changes in ...

Mechanisms for chromosome movement Animation

By: HWC, Views: 3659

At mitotic metaphase, the fully-formed spindle is composed of many microtubules that extend from the poles. Some of these, the kinetochore microtubules, are attached to the kinetochores of each chromosome. Kinetochores are located at the centromeres. At anaphase, sister chromatids separate and...

Wound Cultures

By: Administrator, Views: 9658

Wound Culture is performed on wound exudate to determine the presence of microorganisms and to identify the specific type.

Dietary Cholesterol & LDL

By: HWC, Views: 6060

LDL comprises 60–70% of total blood lipoproteins and is responsible for carrying cholesterol particles throughout your body. Having a lot of cholesterol carried by LDL lipoproteins is associated with an increased risk of heart disease. In fact, the higher the level, the greater the risk. ...