Week 4 Cellular Transport PDF

SHARING TIME! Inspired by Mission, Driven by Excellence  LEARNING OBJECTIVES By the end of the lesson, the learners should have: 1. Described the structural components of the cell membrane. 2. Related the structure and composition of the c...

SHARING TIME! Inspired by Mission, Driven by Excellence  LEARNING OBJECTIVES By the end of the lesson, the learners should have: 1. Described the structural components of the cell membrane. 2. Related the structure and composition of the cell membrane and its function. 3. Enumerated and describe transport mechanisms in cells. 4. Differentiated exocytosis and endocytosis Inspired by Mission, Driven by Excellence  CELLULAR TRANSPORT Inspired by Mission, Driven by Excellence TYPES OF CELLULAR TRANSPORT FACILITATED DIFFUSSION Inspired by Mission, Driven by Excellence  - The movement of substances across membranes without the use of energy. - Diffusion- the net movement of solute substances from an area of higher concentration to an area of lower concentration. For example: - If you spray air freshener in a certain part of your room, you will notice that the air freshener you just sprayed will slowly diffuse or spread to other parts of the room. This happens because the molecules of the air freshener DIFFUSION diffused from the higher concentration (the area where you sprayed) to areas of lower concentration in the room. Inspired by Mission, Driven by Excellence - The diffusion of water molecules across a selectively permeable membrane. - The process where solvent molecules such as water move from region of less concentrated solutions (hypotonic solution) to a region of more concentrated solution (hypertonic solution) through selectively permeable membrane. When these two regions have equal concentrations of solute )their solutions have a equal concentrations), the water molecules will stop moving. Inspired by Mission, Driven by Excellence  OSMOTIC SOLUTIONS Inspired by Mission, Driven by Excellence  OSMOTIC SOLUTIONS - Has a lower tendency to gain water from the another solution. * If a cell is placed in this type of solution, water will enter the cell, causing it to bulge or become turgid and could lead to cell rupture. Inspired by Mission, Driven by Excellence  OSMOTIC SOLUTIONS - Has a stronger tendency to cause water movement from another solution. * If a cell is placed in this type of solution, it will shrink because water of the cytoplasm will be drawn out. Inspired by Mission, Driven by Excellence  OSMOTIC SOLUTIONS - Two solutions that have equal amounts of water and solutes. * If a cell placed in this type of solution, it can maintain its equilibrium; therefore, there will be no change in the cell. Inspired by Mission, Driven by Excellence HYPOTONIC SOLUTION - The concentration is lower than inside the cell. - Harmful to a living cell. HYPERTONIC SOLUTION - The solute concentration is higher than that inside the cell, water leaves the cell, causing it to shrivel and die. ISOTONIC SOLUTION - Cells survive wherein the solute concentration is equal to that inside the cell. Inspired by Mission, Driven by Excellence HYPOTONIC SOLUTION - The inward movement of water builds up the turgor pressure of the cell, and the cell then become very firm. HYPERTONIC SOLUTION - The water moves out, causing the plasma membrane to pull away from the cell wall and the to wilt or plasmolyze (plasmolysis) ISOTONIC SOLUTION - There is no net gain of water, the plant cells lose their turgor pressure—the pressure exerted by the cell membrane against the cell wall due to water intake. Without this pressure, the cells become flaccid, and the plant may wilt because the cells are not firm enough to support the plant's structure. Inspired by Mission, Driven by Excellence  FACILITATED DIFFUSSION - Another form of passive transport. - It is the movement of solutes through protein channels down the concentration gradient without energy expenditure. - Water and certain hydrophilic (water loving) solutes cross the membrane. Inspired by Mission, Driven by Excellence  TWO TYPES OF FACILITATED DIFFUSSION CARRIER PROTEINS CHANNEL PROTEINS - Change in shape, which is triggered by the - Open and close as they respond to stimuli. binding and release of a substance it - Some channel proteins open and close transports. when specific substance, other than the substance to be transported binds to the channel. Inspired by Mission, Driven by Excellence Values Integration: Unity Inspired by Mission, Driven by Excellence - Uses energy in moving solutes across a membrane by moving up the concentration gradient. - Carrier protein A process requires the expenditure of energy through transport proteins. - The movement in active transport across membranes is unidirectional. Inspired by Mission, Driven by Excellence - Essential to the cell mainly for three seasons: 1. It enables the transport of nutrients to the cell even when the concentration on the inside is already higher. 2. It makes the removal of waste materials from the cell possible despite the higher concentration outside the cell. 3. It enables the cell to maintain the concentration of essential ions such as K+, Na+,Ca2+, and H+. Inspired by Mission, Driven by Excellence  Sodium-Potassium Pump - Molecules move against the concentration gradient. It involves the use of energy through ATP hydrolysis wherein ATP is hydrolyzed to ADP. - The enzyme Na+/K+- ATPase involved. - This is necessary to maintain - This unbalanced charge transfer is necessary in the greater amounts of Na+ ions performance of action potential, particularly in nerve outside the cell membrane and cells. The whole process helps maintain the greater amounts of K+ ions inside concentration of essential ions in the cell. the cell. Inspired by Mission, Driven by Excellence  Sodium-Potassium Pump Sodium (Na+): The pump kicks out sodium ions from inside the cell to the outside. This is important because too much sodium inside the cell can make it swell and not work properly. Potassium (K+): At the same time, the pump brings in potassium ions from the outside to the inside of the cell. Energy: The pump uses energy (from a molecule called Potassium helps the cell perform its ATP) to do this job. It works against the natural flow of functions, like sending signals in nerves these ions, which is why energy is needed. and muscles. So, the Sodium-Potassium Pump keeps the right balance of sodium and potassium inside and outside of the cell, making sure the cell stays healthy and functions correctly. Inspired by Mission, Driven by Excellence - Water and small solutes enter and leave the cell through passive and active diffusion. However, large molecules, such as polysaccharides cross membranes in bulk through the processes of exocytosis and endocytosis. Inspired by Mission, Driven by Excellence TYPES OF BULK TRANSPORT Inspired by Mission, Driven by Excellence - Process of removing materials from the cell through the vesicles that fuse with the plasma membrane, thus, subsequently releasing their contents outside the cell. - Common when a cell has to secrete substances for export. - An example is the secretion of digestive enzymes from the epithelial cells of digestive organs to the food passing through the digestive system. Inspired by Mission, Driven by Excellence - The reverse process of exocytosis wherein cells engulf materials. - A substance outside the cell is captured when the plasma membrane merges with that substance and engulfs it. - The engulfed substance then enters the cytoplasm while it is enclosed in a vesicle. - Happens either phagocytosis or pinocytosis. Inspired by Mission, Driven by Excellence DOODLE ME Inspired by Mission, Driven by Excellence Inspired by Mission, Driven by Excellence - “cellular eating” - The most common form of endocytosis. - Occurs when dissolved material enters the cell. - The plasma membrane wraps around the solid material and engulf - This describes how single-celled protists (e.g., Amoeba)capture food. - “Another example is how white blood cells engulf bacteria. Inspired by Mission, Driven by Excellence  - “cellular drinking” - Occurs when dissolved substances enter the cell. - Like phagocytosis, the plasma membrane wraps around the material and forms a vesicle that contains the engulfed material. - “For example, the human egg cell’s uptake of nutrients from its surroundings. Vesicle Inspired by Mission, Driven by Excellence LAB TIME! Inspired by Mission, Driven by Excellence QUIZ TIME! Inspired by Mission, Driven by Excellence THE IMPORTANT THINGS For example: The five important ideas I’ve learned today are ________________, ______________, ______________, _______________, but the most important thing I learned is ______________. Inspired by Mission, Driven by Excellence