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Which solute is the least likely to cross a membrane by simple diffusion?
Large polar molecules and ions are the least likely to cross a membrane by simple diffusion due to their size and charge, which hinders their ability to pass through the hydrophobic lipid bilayer.
What would be least affected by defective receptor proteins on a cell membrane?
The transport of nutrients and waste across the cell membrane would be least affected by defective receptor proteins. This is because transport proteins, not receptor proteins, are primarily responsible for moving molecules across the cell membrane.
Which one of the following statements about phospholipids is least accurate?
Phospholipids are only found in the cell membrane.
What is the function of the vesicle?
Vesicles are mainly involved in the transportation of material in/out or within the cell. They are made of at least one layer of the phospholipid-bilayer; which is the major constituent of the cell membrane. The term used for the transportion of solid material into the cell is endocytosis; when this happens the vesicle carrying the material will join to the cell membrane and become part of it, releasing its contents into the cytoplasm. Also pinocytosis is a related term to endocytosis and refers to the intake of specifically aqueous material; Vesicles can also transport material within the cell. For example, vesicles transport proteins from the rough endoplasmic reticulum to the Golgi apparatus. Some veiscles serve as storage vessels as well.
Is diffusion of molecules across the cell membrane the most complex type of active?
Diffusion of molecules across the cell membrane is actually a passive process, not active. Active transport, which requires energy in the form of ATP, is a more complex process as it moves molecules against their concentration gradient.
Where are you least likely to find water in the plasma membrane?
You are least likely to find water in the hydrophobic interior of the lipid bilayer of the plasma membrane. Water tends to be excluded from this region due to the hydrophobic interactions between the lipid molecules.
What are the characteristics of the plasma membrane?
The membrane that surrounds the cytoplasm of a cell; it is also called the plasma membrane or, in a more general sense, a unit membrane. This is a very thin, semifluid, sheetlike structure made of four continuous monolayers of molecules. The plasma membrane and the membranes making up all the intracellular membranous organelles display a common molecular architectural pattern of organization, the unit membrane pattern, even though the particular molecular species making up the membranes differ considerably. All unit membranes consist of a bilayer of lipid molecules, the polar surfaces of which are directed outward and covered by at least one monolayer of nonlipid molecules on each side, most of which are protein, packed on the lipid bilayer surfaces and held there by various intermolecular forces. Some of these proteins, called intrinsic proteins, traverse the bilayer and are represented on both sides. The segments of the polypeptide chains of these transverse proteins within the core of the lipid bilayer may form channels that provide low-resistance pathways for ions and small molecules to get across the membrane in a controlled fashion. Sugar moieties are found in both the proteins and lipids of the outer half of the unit membrane, but not on the inside next to the cytoplasm. The molecular composition of each lipid monolayer making up the lipid bilayer is different. The unit membrane is thus chemically asymmetric.
What molecule could move through a phospholipid membrane with the least difficulty?
A small, non-polar molecule like oxygen or carbon dioxide would move through a phospholipid membrane with the least difficulty, as they can easily pass through the hydrophobic interior of the membrane without the need for a specific transport protein.
What are some components of the plasma membrane?
Plasma membranes are made up of phospholipids, these molecules are composed of fatty acid chains that are hydrophobic and phosphate group that are hydrophilic. Due to the properties of these subunits, phospholipids arrange themselves in a bilayer arrangement. The membrane also contains an abundance of proteins that may have various functions such as transport, identification and more.
What are properties of a cell membrane that allows particules to pass through it?
Note ... the property of a cell membrane is that no particles can pass through it. At least not unaided. Cells have (make) specific proteins that are embedded within the membrane to pass materials back and forth. Due to the construction of a cell membrane (fat on both sides of a monomolecular layer of water) only molecules that are soluble in both lipids and water can get through at all.
What make osmosis?
The membrane has to be semi-permeable in order for anything to have the ability to pass through it. Usually, something such as water will travel through the membrane from a higher to a lower concentration gradient. This causes the two sides to reach equilibrium. Osmosis can only occur when both sides do not have the same concentration and the membrane has to be at least semi-permeable for fluids to pass through.
How does the structure erythrocytes relate to their function?
The red cell membrane contains approximately equal amounts of lipids and proteins. Membrane lipids are either phospholipids or neutral lipids, mostly unesterified cholesterol. Membrane phospholipids are asymmetrically arranged into a lipid bilayer two molecules thick. Choline phospholipids are more abundant in the extracellular surface whereas amino phospholipids are more concentrated on the inner leaflet of the bilayer. Cholesterol is intercalated between the phospholipid molecules. The relative amounts of cholesterol and phospholipids are responsible for the fluid properties of the erythrocyte membrane. Alterations in the membrane cholesterol-phospholipid ratio result in morphologically abnormal erythrocytes with decreased life span. Membrane proteins are also asymmetrically oriented within the lipid bilayer and can be divided into three functional sets: structural, catalytic and receptor proteins. Sprectrin and actin are the two main structural proteins that together form a submembranous cytoskeletal meshwork that is responsible for the viscoelastic properties of the erythrocyte membrane. Band 3, or the anion channel, is a major transmembranous protein involved in the transport of water and anions and is a carrier of the blood-group-I antigen. Glycophorin A, a sialic-acid-rich glycoprotein, is the major contact or receptor membrane polypeptide that also spans the lipid bilayer. The MN blood group determinants and possibly other biologic receptor sites have been localized on the extracellular portion of glycophorin A. At least 35 to 40 enzymes are confined to the membrane and, undoubtedly, play a vital role in the maintenance of normal structure and function of the erythrocyte.
What makes osmosis possible?
The membrane has to be semi-permeable in order for anything to have the ability to pass through it. Usually, something such as water will travel through the membrane from a higher to a lower concentration gradient. This causes the two sides to reach equilibrium. Osmosis can only occur when both sides do not have the same concentration and the membrane has to be at least semi-permeable for fluids to pass through.
What is the basic structure of the cell membranes?
i got this paragraph from the library on this site: The membrane that surrounds the http://www.answers.com/topic/cytoplasm of a cell; it is also called the plasma membrane or, in a more general sense, a unit membrane. This is a very thin, semifluid, sheetlike structure made of four continuous monolayers of molecules. The plasma membrane and the membranes making up all the http://www.answers.com/topic/intracellular membranous http://www.answers.com/topic/organelle display a common molecular architectural pattern of organization, the unit membrane pattern, even though the particular molecular species making up the membranes differ considerably. All unit membranes consist of a http://www.answers.com/topic/bilayer of lipid molecules, the polar surfaces of which are directed outward and covered by at least one monolayer of nonlipid molecules on each side, most of which are protein, packed on the http://www.answers.com/topic/lipid-bilayer surfaces and held there by various http://www.answers.com/topic/intermolecular-force. Some of these proteins, called http://www.answers.com/topic/intrinsic proteins, traverse the bilayer and are represented on both sides. The segments of the http://www.answers.com/topic/polypeptide chains of these http://www.answers.com/topic/myelitis-1 proteins within the core of the lipid bilayer may form channels that provide low-resistance pathways for ions and small molecules to get across the membrane in a controlled fashion. Sugar moieties are found in both the proteins and http://www.answers.com/topic/lipid of the outer half of the unit membrane, but not on the inside next to the cytoplasm. The molecular composition of each lipid monolayer making up the lipid bilayer is different. The unit membrane is thus chemically http://www.answers.com/topic/asymmetric. See alsohttp://www.answers.com/topic/cell-organization. hope it helps
Which solute is the least likely to cross a membrane by simple diffusion?
Large polar molecules and ions are the least likely to cross a membrane by simple diffusion due to their size and charge, which hinders their ability to pass through the hydrophobic lipid bilayer.
What conclusion would you get from least permeable rock and most permeable rock?
rock type
What is Least permeable type of soil?
clay
