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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...

Chloroplast Structure & Light Dependent Reactions (Photosystem 1 and 2 Cyclic Electron Flow)

By: HWC, Views: 6301

The leaf is the principle photosynthetic organ of the plant. This is a cross section of a leaf. The rectangular-shaped cells are part of the photosynthetic tissue called the palisade mesophyll. Each photosynthetic cell can contain several hundred organelles known as chloroplasts. The chlorop...

Neurotransmission at chemical synapses & Excitory and inhibitory potentials

By: HWC, Views: 6581

• A series of events occur at chemical synapses in order to communicate with the adjacent cell. • The action potential arrives at the presynaptic membrane. • The depolarization phase of the action potential opens voltage gated Ca+ channels. • increased inflow of Ca+' into the cyto...

Glycolysis Animation

By: HWC, Views: 597

In glycolysis, a six-carbon glucose molecule is split into two three-carbon pyruvate molecules. In this animation, each carbon molecule is represented by a red ball. The end products of glycolysis are two molecules of pyruvate. Glycolysis is the breakdown of glucose into two molecules of ...

Secondary Active Transport

By: HWC, Views: 7192

Energy stored (in a hydrogen or sodium concentration gradient) is used to drive other substances against their own concentration gradients Secondary active transport, is transport of molecules across the cell membrane utilizing energy in other forms than ATP. In many cells, antiporters mov...

What are Strong & Weak Acids and How they're different?

By: HWC, Views: 5499

Let's consider the changes that take place when hydrogen chloride, HCI, is added to water. You will need to recognize space-filling models of HCI molecules, hydronium ions (H30+), chloride ions (C11, and water molecules (H20). They are shown at the right. When HC1 molecules dissolve in water, ...

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

By: HWC, Views: 6771

• Most cells which have CD4 on their surface become Helper T cells (TN cells). • The CD4 1 cells only recognize a foreign antigen when it is presented with an antigen presenting immune cell (APC) that includes MHC-II protein. • The Helper T cell antigen receptor must match the presented...

Phases of mitosis

By: HWC, Views: 4645

Prophase is the first step in the mitotic process. During prophase, the chromosomes condense. The centrosomes begin to form a spindle and move into position on opposite sides of the cell. Sister chromatids are held together by a protein called cohesin at the centromere. Prometaphase is the sec...

Chemical Synapse Animation

By: HWC, Views: 4017

A neuromuscular junction is a chemical synapse between the axon endings of a motor neuron and a muscle cell. A narrow synaptic cleft separates the presynaptic cell (the motor neuron) from the postsynaptic cell (the muscle cell). The presynaptic cell contains vesicles filled with neurotransmitt...