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

By: HWC, Views: 7005

• 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...

Primary Active Transport - electrochemical gradient and ion transport / water movement

By: HWC, Views: 6774

Energy derived from ATP changes the shape of a transporter protein which pumps a substance across a plasma membrane against its concentration gradient An electrochemical gradient is a gradient of electrochemical potential, usually for an ion that can move across a membrane. The gradient consis...

Mechanisms of capillary exchange

By: HWC, Views: 6775

■ The primary role of capillaries is to permit the exchange of nutrients and wastes between the blood and tissue cells (via interstitial fluid). ■ Oxygen and nutrients move from the blood to the cells. ■ Carbon dioxide and other wastes move from the cells to the blood. The three ba...

What are the Parts of a Plant Cell?

By: HWC, Views: 5702

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...

Junction Types - Tight and Adherens Junctions

By: HWC, Views: 6998

Many tissues contain in tercellular junctions between cells. 1. Tight junction 2. Adherens junction 3. Desmosome 4. Hemidesrnosome 5. Gap junction 1. Tight junction • Web-like strips of proteins fuse together adjacent plasma membranes. • Tight junctions prevent the transport...

Requirements for nervous signals

By: HWC, Views: 6637

• The function of neurons is to allow communication between cells, thereby maintaining homeostasis. • Electrical signals, called membrane potentials, travel along the membranes of the neurons. • Voltage variability and distance traveled determine the type of nervous signal. 1. Graded...

Non-polar compounds - insolubility

By: HWC, Views: 6699

• A non-polar molecule has uniform distribution of electrons. • Non-polar compounds like fatty acids in lipids have a high proportion of carbon and hydrogen. • Lipids possess no charge or partial charge. • Lipids are not attracted to water molecules. • Lipids are not soluble in...

Import of Dietary Glucose from Intestines to Bloodstream

By: HWC, Views: 6117

• Membranes have hydrophobic interiors. which resist the passage of hydrophilic compounds and ions. • However. transporter membrane proteins facilitate the passage of these molecules. • Passive transporters accelerate diffusion of molecules towards equilibrium (decrease a concentrat...

How proteins function? How do proteins work?

By: HWC, Views: 6283

How proteins function is really about how proteins "do work" in cells. How do proteins work? Let's start thinking about protein function by looking at something important to you: your hair. Keratin is a structural protein that is composed of 2 intertwined or helical strands. Keratin is also f...