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Origin of organelles Animation

By: HWC, Views: 1358

Possible origins of the nucleus and other organelles. Some prokaryotic cells have infoldings of their plasma membrane. These infoldings may have served as channels from the cytoplasm to the cell surface. These membranous folds may have evolved into the endoplasmic reticulum and the nuclear e...

How to make cDNA Animation

By: HWC, Views: 2276

This animation shows how an mRNA transcript can be used to make a cDNA strand.

Photosynthesis and Van Helmont Experiment

By: HWC, Views: 6978

All energy on Earth comes from a star, the Sun. Light must travel 160 million kilometers to reach Earth where plants capture this light energy and convert it to chemical energy in the form of sugars. This biochemical process is called PHOTOSYNTHESIS. The summary equation for photosynthesis is ...

The Lac Operon in E. Coli

By: Administrator, Views: 11787

The lac operon (lactose operon) is an operon required for the transport and metabolism of lactose in Escherichia coli and many other enteric bacteria. Although glucose is the preferred carbon source for most bacteria, the lac operon allows for the effective digestion of lactose when glucose is no...

Erythropoietin (EPO)

By: HWC, Views: 7218

■ Secreted by kidney cells when blood oxygen is low. ■ Targets cells in red bone marrow that will become red blood cells. ■ Promotes increased numbers of mature red blood cells. ■ More mature red blood cells carry more oxygen so blood oxygen level is restored to normal.

T cell receptors

By: HWC, Views: 7400

• T cells are responsible for cell-mediated immunity. • Each T cell contains a unique form of T cell receptor (TCR) on its membrane. • These T cell receptors are produced through a process of genetic recombination which is able to produce millions of different variations. • Each T ce...

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

By: HWC, Views: 8030

• 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...

Cardiac conductile cells

By: HWC, Views: 7969

• In order for the heart to function properly, all of its cells must contract in a specific sequence. This sequence is determined by a pathway known as the conduction system. • Cardiac muscle cells have two attributes that enable the conduction system to work: • Connective. Action pot...

Griffith's experiments

By: HWC, Views: 4860

In the late 1920s, Fred Griffith was attempting to develop a vaccine against a bacterium that causes pneumonia. To find out why two strains of the bacteria differed in their deadliness, he injected mice with four different mixtures. Mice injected with R cells remained healthy. When Griffith ex...