Movement of Substances across a Plasma Membrane

What is Active Transport?Active transport is the movement of substances across the plasma membrane of cells against the concentration gradient (From lower concentration to higher concentration).Since it is against the concentration gradient, energy is needed in the process.Video below shows how particles are transported through the carrier protein in active transport. Take notes that the … Read more

What is Facilitated Diffusion?Facilitated diffusion is the passive transport of substances across the plasma membrane with the help of transport proteins such as the channel protein and the carrier protein.Substances Pass through the Plasma Membrane through Facilitated DiffusionParticles undergo facilitated diffusion are the particles that cannot diffuse through the phospholipid bilayer such asLarge particles such … Read more

What is Osmosis?Osmosis is the diffusion of a water through a semi-permeable membrane, from a solution of low solute concentration to a solution with high solute concentration.It is a physical process in which a solvent moves, without input of energy, across a semi-permeable membrane separating two solutions of different concentrations.Important Points:It is the diffusion of … Read more

What is passive transport?Passive transport is the movement of substances across the cell membrane without the use of energy by the cell.During passive transport, substances move down their concentration gradient, hence no energy is required.Passive transports can happen through three different channels, namelylipid bilayerpore proteincarrier proteinWhat is diffusion?Diffusion is the movement of particles from a … Read more

The Plasma MembraneThe plasma membrane is a semi-permeable lipid bilayer found in all cells that controls water and certain substances in and out of the cell.Function of the Plasma MembraneProtects the cell.Separates the intracellular components from the extracellular environment.Controls what enters and exits the cellNecessities for the Movement of Substances across the Plasma MembraneTo transport … Read more

Question 1:Explain what will happen to the following cells when they are soaked in a solution with a higher concentration of solutes compared to the intracellular fluid:(a) red blood cells(b) plant cells Answer:(a) Red blood cells undergo crenation.(b) Plant cells undergo plasmolysis. Question 2:Explain the effect of the hypotonic solution on red blood cells. Answer:When … Read more

Question 1:Give some examples of substances that are able to pass through the phospholipid bilayer. Answer:Oxygen, carbon dioxide, water. Question 2:Describe how sodium ions are transported out of the cell. Answer:Three sodium ions bind to the carrier protein. The ATP molecule is broken down to ADP and P. The phosphate group binds to the carrier … Read more

Question 1:What are the two main components of the plasma membrane? Answer:Proteins and phospholipids Question 2:Explain the meaning of fluid mosaic model. Answer:The fluid mosaic model refers to protein molecules that are suspended in the phospholipid bilayer forming an ever-changing mosaic pattern. The phospholipid bilayer, proteins and cholesterols are not static but form a dynamic … Read more

Question 1:Explain why green chillies are preserved using vinegar and sugar. Answer:The concentrated sugar solution is hypertonic to the cell sap of chili. Water diffuses out of the chili via osmosis. The chilli undergoes dehydration. Bacteria is unable to survive without water. Thus, pickled green chili can be kept for a long time.Vinegar reduces pH. … Read more