Why do lipid soluble molecules diffuse more rapidly?
Why do lipid soluble molecules diffuse more rapidly?
Solubility: As discussed earlier, nonpolar or lipid-soluble materials pass through plasma membranes more easily than polar materials, allowing a faster rate of diffusion. Surface area and thickness of the plasma membrane: Increased surface area increases the rate of diffusion, whereas a thicker membrane reduces it.
How are most poisons transported through the body?
Ingestion. Ingestion is the most common route of exposure to toxic chemicals. Most chemicals diffuse across the cell membrane in the nonionized form, so that the degree to which the chemical is ionized is important in determining whether a chemical is absorbed (see above Transport of chemicals through a cell membrane).
What substances can pass through diffusion?
Water, carbon dioxide, and oxygen are among the few simple molecules that can cross the cell membrane by diffusion (or a type of diffusion known as osmosis ). Diffusion is one principle method of movement of substances within cells, as well as the method for essential small molecules to cross the cell membrane.
How do toxins attach to the cell membrane?
Intracellularly active toxins bind to specific cell surface receptors and then are embedded in endocytic vesicles generated by invagination of the cell membrane. Endocytic vesicle types and intracellular trafficking vary according to toxins and corresponding cell surface receptors.
What would move through the lipid bilayer most rapidly?
In general, the smaller the molecule and the more soluble it is in oil (the more hydrophobic, or nonpolar, it is), the more rapidly it will diffuse across a lipid bilayer. Small nonpolar molecules, such as O2 and CO2, readily dissolve in lipid bilayers and therefore diffuse rapidly across them.
What is the difference between a channel protein and a carrier protein?
Unlike channel proteins which only transport substances through membranes passively, carrier proteins can transport ions and molecules either passively through facilitated diffusion, or via secondary active transport. These carrier proteins have receptors that bind to a specific molecule (substrate) needing transport.
What are the three methods that poison easily enters the body?
There are four major routes by which a chemical may enter the body: Inhalation (breathing) Skin (or eye) contact. Swallowing (ingestion or eating)
Which of the following is a way in which diffusion through channels and facilitated diffusion are similar?
In facilitated diffusion, substances move into or out of cells down their concentration gradient through protein channels in the cell membrane. Simple diffusion and facilitated diffusion are similar in that both involve movement down the concentration gradient.
Does facilitated diffusion use energy?
Facilitated diffusion takes place due to a difference in concentration on both sides of the membrane, in the direction of the lowest concentration, and does not require energy.
What forms of evidence can toxins take?
Blood, Urine, Liver – Blood is often the specimen of choice for detecting, quantifying and interpreting drugs and other toxicant concentrations.
What are the chemical agents that can cause damage to the cell membrane?
Chemical disinfection and antiseptic agents:
- Agents which damage cell membrane. a) Antimicrobial detergents: (denature proteins, disrupt cell membrane permeability)
- Agents which denature proteins and nucleic acids. a) Acids: most commonly used are organic acids such as:
- Antibiotics and chemotherapeutic agents.
Why are fat soluble toxins more difficult to remove?
But fat-soluble toxins are more difficult for the body to remove. They tend to be the heavy metals, pesticides, preservatives, pollutants, plastics, and other environmental chemicals we encounter in our daily lives, and they must be converted to water-soluble toxins before the body has the ability to eliminate them.
How is the diffusion rate of a toxic substance determined?
–The rate of diffusion is primarily based on the differences in the concentration of the substance across the cell membrane, the surface area and thickness of the cell membrane. –Lipid solubility is also an important factor in determining the diffusion rate of a toxic substance since 75% of the cell membrane is composed of lipids.
When is facilitated diffusion and active transport important?
–Facilitated diffusion (transport) and active transport are important when: •moving molecules across the cell membrane against a concentration gradient; •the size of the toxic molecule is too large to diffuse through the pores of the cell membrane; and •there is low lipid solubility and the substance has an electrical charge associated with it.
Why do organic substances diffuse across the cell membrane?
»Organic substances such as nitrous oxide, ethylene, and divinyl ether diffuse across the cell membrane of the alveoli easily because they do not have an electrical charge and are lipid-soluble. Mechanisms of Absorption (3) •Carrier-mediated transport –Facilitated diffusion (transport) and active transport are important when:
But fat-soluble toxins are more difficult for the body to remove. They tend to be the heavy metals, pesticides, preservatives, pollutants, plastics, and other environmental chemicals we encounter in our daily lives, and they must be converted to water-soluble toxins before the body has the ability to eliminate them.
–The rate of diffusion is primarily based on the differences in the concentration of the substance across the cell membrane, the surface area and thickness of the cell membrane. –Lipid solubility is also an important factor in determining the diffusion rate of a toxic substance since 75% of the cell membrane is composed of lipids.
Where does the absorption of toxic substances take place?
Distribution of Toxic Substances (1) •Absorption into and out of the bloodstream occurs in only one part of the circulatory system: the capillaries. •Anatomy of the circulatory system Distribution of Toxic Substances (2) •Anatomy of the heart