Semipermeable membrane

Receptors are protein molecules that receive chemical signals in the form of ligands and induce responses at cellular level. They are localized at the cell surface, cytoplasm or the nucleus, depending on their amino acid sequences. In addition to using these three different localizations to categorize receptors, the types of action of receptors are also used as a mean of classification. The four main classifications of receptors are: 1. Ionotropic (or ligand-gated ion channel) receptors, 2.…

cytoplasm by the outer and inner mitochondrial membrane.The outer membrane is porous and freely traversed by ions and small, uncharged molecules through pore-forming membrane proteins (porins), such as the voltage-dependent anion channel VDAC [19]. Any larger molecules, especially proteins, have to be imported by special translocases. Because of its porosity, there is no membrane potential across the outer membrane. By contrast, the inner membrane is a tight diffusion barrier to all ions and…

cell is, the more difficult it is to transport nutrients and oxygen from outside of the cell into the inside of the cell. Consequently, the large cell would have more trouble transporting water, nutrients, and oxygen across the cell membrane and through the plasma membrane. In reality, the Blob would have problems maintaining sufficient transport and would suffer from malnutrition. The size of a cell determines the amount of nutrients, water, and oxygen needed, therefore, the volume of a cell…

length played a role in the amount of force a muscle produces. In order to fully understand how a muscle contracts, it is necessary to first understand the structure of muscle cells. Muscles cells are large cells that are surrounded by a special membrane called the sarcolemma and are filled with fluid called sarcoplasm. The sarcoplasm abounds with mitochondria for energy production and ribosomes for protein manufacturing. Muscle cells are also packed with many…

Neurons are one of the most important cells in living animals. There are billions of neurons throughout our bodies, especially the brain which is the control house of the body. Neurons are what help us see, hear, taste, and feel sensation. This is all do to a critical phenomenon known as action potential. Action potential is caused by a change in various ions, specifically sodium and potassium. When the neuron is in a resting state with -70mV, there is a great amount of potassium ions inside the…

blood, the student noticed that the cells appeared to become smaller.” Now the question stands, why did the red blood cells appear smaller? There were three possible explanations proposed. Explanation one reads, “Sugar molecules push on the cell membranes and make the cells appear smaller.” Explanation two states,”Water molecules move out of the cell because the concentration of water is greater inside the cell than it is outside the cell.” Finally, explanation three reads, “Sugar molecules…

laboratory developed the SNARE hypothesis describing a model of SNAREs involvement in vesicle targeting and fusion. Their model explains that a transport vesicle (v-SNARE) and a target membrane (t-SNARE) with the aid of NSF, SNAPs and other yet unknown proteins bring the v-SNARE in close proximity to the t-SNARE facilitating membrane fusion (Sollner et al., 1993). It is now widely accepted that SNAREs serve as the core machineries necessary for vesicle targeting and fusion but are regulated by…

Ion channels are membrane proteins that selectively allow the permeation of ions into and out of cells (Fig.1a ###image messes with formatting). Some channels have evolved to also sense changes in the electrical potential across a membrane. A potential above a certain voltage will trigger the opening of these ion-conducting pores, releasing large stores of ions across the membrane. These voltage-gated ion channels allow for the generation of electrical stimuli (the firing of neurons via the…

Beetroot tissues will be the model investigated in this lab. Specifically the effects of temperature stress on the beetroots cellular membrane. Beetroot is known as Beta Vulgaris, it is one of the healthiest vegetables one can eat with plenty of minerals and vitamins. One of the main vitamins in beetroot is betaine which serve as organic osmolytes that are synthesized or taken from the surroundings by the cells to protect against osmotic stress, high temperature or, drought. Roots of beet also…

All things alive are made of cells. We humans have way too many to count. All the cells cluster and act together in the way so that we can function normally. Thanks to Agre and MacKinnon we now have more knowledge over molecular machines such ass channels, gates, and valves. The fact that water could go through the cell wall has always been a known thing, however, how the pores looked under function had been unknown. That is, until 1990 when Agre became the first to discover one. Chemical…