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Type of Cell Junctions - Desmosome, Hemidesmosomes and Gap Junctions

By: HWC, Views: 7017

Cell Junctions: Cell junctions are found in some multi-cellular organisms. They exist of complexes and are found between cells and between cells and other structures. The junctions provide a way for cells to connect and exchange signals. What are tight junctions, desmosomes, and gap junctions...

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

By: HWC, Views: 7008

• 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...

Replication of DNA and Chromosomes/ How do cells replicate their DNA? (Animation) no Audio

By: HWC, Views: 6402

DNA replication in E. coil begins at a site called oriC where a replication bubble forms. At either end of this bubble is a replication fork. Since DNA polymerase Ill can read its DNA template strand only in the 3' to 5' direction this means that one strand (leading) can be read continuously b...

What Are Carbohydrates? Importance of Carbs & High Carb Food

By: HWC, Views: 6724

We hear a lot about carbohydrates in the news. Everybody seems to be on a low-carb diet. The news media often has stories on this diet fad, and companies are busy producing products with reduced carbohydrates. What's this fascination with carbohydrates? In a word: "Diet." The fact is that carb...

Bond in biological molecules (Ionic, Covalent and Hydrogen bonds)/ How atoms bond?

By: HWC, Views: 3995

Sodium atoms and chloride atoms have unfilled orbitals in their outer shells. The lone electron in the outermost shell of a sodium atom can be pulled or knocked out. This ionizes the atom. It is now a positively charged sodium ion. A chlorine atom has an electron vacancy in its outer shell and...

Brain Anatomy Animation (Part 2 of 2)

By: Administrator, Views: 10912

Its nervous tissue consists of millions of nerve cells and fibers. It is the largest mass of nervous tissue in the body. The brain is enclosed by three membranes known collectively as the meninges: dura mater arachnoid pia mater The major structures are the: cerebrum cerebellum dienc...

Rods and Cones Animation

By: Administrator, Views: 10090

A photoreceptor cell is a specialized type of neuroepithelial cell found in the retina that is capable of visual phototransduction. The great biological importance of photoreceptors is that they convert light (visible electromagnetic radiation) into signals that can stimulate biological processes...

What are the Parts of a Plant Cell?

By: HWC, Views: 5704

Every chloroplast in a plant cell is packed with stacks of flattened sacs called thylakoids. The thylakoid membranes contain chlorophyll, as well as most of the other components required for the light reactions of photosynthesis. The chlorophyll-containing structures within the membranes are c...

Krebs cycle : Formation of acetyl coenzyme A and Electron transport chain

By: HWC, Views: 6789

The oxidation of glucose to produce ATP is cellular respiration. Four sets of reactions are involved: Glycolysis Formation of acetyl coenzyme A Krebs cycle reactions Electron transport chain reactions • The second pathway of glucose catabolism, formation of acetyl coenzyme A, is a transi...