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Secondary Active Transport

By: HWC, Views: 8261

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...

Simple Diffusion - Ion transport

By: HWC, Views: 7744

In the process of diffusion, a substance tends to move from an area of high concentration to an area of low concentration until its concentration becomes equal throughout a space. Ions must diffuse through membrane pores or gated channels. Pores are always open. More pores allow more ions...

HIV replication/ Replication cycle of HIV

By: HWC, Views: 4906

Replication cycle of HIV, one of the retroviruses. The HIV virus is surrounded by a lipid envelope with embedded proteins. A coat of viral proteins surrounds two strands of RNA and the enzymes used during replication. The virus attaches to and enters the host cell. Viral reverse trans...

Facilitated Diffusion - Glucose transport

By: HWC, Views: 8006

Transmembrane proteins help solutes that are too polar or too highly charged move through the lipid bilayer The processes involved are: Channel mediated facilitated diffusion Carrier mediated facilitated diffusion In facilitated diffusion, molecules only move with the aid of a protein i...

Non-polar compounds - insolubility

By: HWC, Views: 7843

• 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...

Olfaction. or the sense of smell

By: HWC, Views: 5144

Do you ever wonder how you can distinguish thousands of different odors? Olfaction. or the sense of smell, is used by all mammals to navigate, find food, and even find mates. We have millions of olfactory receptors for smelling in our nose. These receptor neurons bind water-soluble or volatil...

Type of Transport - Active and Passive Processes

By: HWC, Views: 7951

Active transport moves materials from lower to a higher concentration, while passive transport moves materials from higher to lower concentration. Active transport requires energy to proceed, while passive transport does not require the input of extra energy to occur. Transport processes that ...

Plant Defense Mechanisms from Pathogens

By: HWC, Views: 7182

Plants and pathogens have coevolved such that pathogens can recognize plants by the sugars, or other molecules, they produce. Plants, in turn, can recognize pathogens by the molecules they produce. The ability to recognize pathogens allows plants to activate defense systems that can prevent wides...

Import of Dietary Glucose from Intestines to Bloodstream

By: HWC, Views: 7148

• 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...