Now, when it comes to membrane transport, we're going to say that to perform its functions, a cell continuously needs to exchange substances with the extracellular fluid, so basically outside of itself. We're going to say, membrane transport allows cells to take in essential substances and expel waste products. Now here when it comes to membrane transport mechanisms, they can be broadly categorized into 2 types. We have our passive transport and we have our active transport. We're going to say here with passive transport, this does not require energy and substances move down the concentration gradient. But with active transport, we're going to say it requires energy and substances move against the concentration gradient. So here we have our membrane transport which is broken down into passive transport and active transport. Active requires energy. And with passive transport, it can be further broken down into simple diffusion and facilitated diffusion where we need some assistance for it to occur. Now, here remember a concentration gradient, this is the difference in concentration of a substance over a distance. And we'll see how to distinguish between active and passive transport.
- 1. Matter and Measurements4h 31m
- What is Chemistry?5m
- The Scientific Method10m
- Classification of Matter16m
- States of Matter8m
- Physical & Chemical Changes19m
- Chemical Properties8m
- Physical Properties5m
- Intensive vs. Extensive Properties13m
- Temperature (Simplified)9m
- Scientific Notation13m
- SI Units (Simplified)5m
- Metric Prefixes24m
- Significant Figures (Simplified)11m
- Significant Figures: Precision in Measurements7m
- Significant Figures: In Calculations19m
- Conversion Factors (Simplified)15m
- Dimensional Analysis24m
- Density12m
- Specific Gravity9m
- Density of Geometric Objects19m
- Density of Non-Geometric Objects9m
- 2. Atoms and the Periodic Table5h 23m
- The Atom (Simplified)9m
- Subatomic Particles (Simplified)12m
- Isotopes17m
- Ions (Simplified)22m
- Atomic Mass (Simplified)17m
- Atomic Mass (Conceptual)12m
- Periodic Table: Element Symbols6m
- Periodic Table: Classifications11m
- Periodic Table: Group Names8m
- Periodic Table: Representative Elements & Transition Metals7m
- Periodic Table: Elemental Forms (Simplified)6m
- Periodic Table: Phases (Simplified)8m
- Law of Definite Proportions9m
- Atomic Theory9m
- Rutherford Gold Foil Experiment9m
- Wavelength and Frequency (Simplified)5m
- Electromagnetic Spectrum (Simplified)11m
- Bohr Model (Simplified)9m
- Emission Spectrum (Simplified)3m
- Electronic Structure4m
- Electronic Structure: Shells5m
- Electronic Structure: Subshells4m
- Electronic Structure: Orbitals11m
- Electronic Structure: Electron Spin3m
- Electronic Structure: Number of Electrons4m
- The Electron Configuration (Simplified)22m
- Electron Arrangements5m
- The Electron Configuration: Condensed4m
- The Electron Configuration: Exceptions (Simplified)12m
- Ions and the Octet Rule9m
- Ions and the Octet Rule (Simplified)8m
- Valence Electrons of Elements (Simplified)5m
- Lewis Dot Symbols (Simplified)7m
- Periodic Trend: Metallic Character4m
- Periodic Trend: Atomic Radius (Simplified)7m
- 3. Ionic Compounds2h 18m
- Periodic Table: Main Group Element Charges12m
- Periodic Table: Transition Metal Charges6m
- Periodic Trend: Ionic Radius (Simplified)5m
- Periodic Trend: Ranking Ionic Radii8m
- Periodic Trend: Ionization Energy (Simplified)9m
- Periodic Trend: Electron Affinity (Simplified)8m
- Ionic Bonding6m
- Naming Monoatomic Cations6m
- Naming Monoatomic Anions5m
- Polyatomic Ions25m
- Naming Ionic Compounds11m
- Writing Formula Units of Ionic Compounds7m
- Naming Ionic Hydrates6m
- Naming Acids18m
- 4. Molecular Compounds2h 18m
- Covalent Bonds6m
- Naming Binary Molecular Compounds6m
- Molecular Models4m
- Bonding Preferences6m
- Lewis Dot Structures: Neutral Compounds (Simplified)8m
- Multiple Bonds4m
- Multiple Bonds (Simplified)6m
- Lewis Dot Structures: Multiple Bonds10m
- Lewis Dot Structures: Ions (Simplified)8m
- Lewis Dot Structures: Exceptions (Simplified)12m
- Resonance Structures (Simplified)5m
- Valence Shell Electron Pair Repulsion Theory (Simplified)4m
- Electron Geometry (Simplified)8m
- Molecular Geometry (Simplified)11m
- Bond Angles (Simplified)11m
- Dipole Moment (Simplified)15m
- Molecular Polarity (Simplified)7m
- 5. Classification & Balancing of Chemical Reactions3h 17m
- Chemical Reaction: Chemical Change5m
- Law of Conservation of Mass5m
- Balancing Chemical Equations (Simplified)13m
- Solubility Rules16m
- Molecular Equations18m
- Types of Chemical Reactions12m
- Complete Ionic Equations18m
- Calculate Oxidation Numbers15m
- Redox Reactions17m
- Spontaneous Redox Reactions8m
- Balancing Redox Reactions: Acidic Solutions17m
- Balancing Redox Reactions: Basic Solutions17m
- Balancing Redox Reactions (Simplified)13m
- Galvanic Cell (Simplified)16m
- 6. Chemical Reactions & Quantities2h 37m
- 7. Energy, Rate and Equilibrium3h 45m
- Nature of Energy5m
- First Law of Thermodynamics7m
- Endothermic & Exothermic Reactions7m
- Bond Energy14m
- Thermochemical Equations12m
- Heat Capacity19m
- Thermal Equilibrium (Simplified)8m
- Hess's Law23m
- Rate of Reaction11m
- Energy Diagrams12m
- Chemical Equilibrium7m
- The Equilibrium Constant14m
- Le Chatelier's Principle23m
- Solubility Product Constant (Ksp)17m
- Spontaneous Reaction10m
- Entropy (Simplified)9m
- Gibbs Free Energy (Simplified)18m
- 8. Gases, Liquids and Solids3h 25m
- Pressure Units6m
- Kinetic Molecular Theory14m
- The Ideal Gas Law18m
- The Ideal Gas Law Derivations13m
- The Ideal Gas Law Applications6m
- Chemistry Gas Laws16m
- Chemistry Gas Laws: Combined Gas Law12m
- Standard Temperature and Pressure14m
- Dalton's Law: Partial Pressure (Simplified)13m
- Gas Stoichiometry18m
- Intermolecular Forces (Simplified)19m
- Intermolecular Forces and Physical Properties11m
- Atomic, Ionic and Molecular Solids10m
- Heating and Cooling Curves30m
- 9. Solutions4h 10m
- Solutions6m
- Solubility and Intermolecular Forces18m
- Solutions: Mass Percent6m
- Percent Concentrations10m
- Molarity18m
- Osmolarity15m
- Parts per Million (ppm)13m
- Solubility: Temperature Effect8m
- Intro to Henry's Law4m
- Henry's Law Calculations12m
- Dilutions12m
- Solution Stoichiometry14m
- Electrolytes (Simplified)13m
- Equivalents11m
- Molality15m
- The Colligative Properties15m
- Boiling Point Elevation16m
- Freezing Point Depression9m
- Osmosis16m
- Osmotic Pressure9m
- 10. Acids and Bases3h 29m
- Acid-Base Introduction11m
- Arrhenius Acid and Base6m
- Bronsted Lowry Acid and Base18m
- Acid and Base Strength17m
- Ka and Kb12m
- The pH Scale19m
- Auto-Ionization9m
- pH of Strong Acids and Bases9m
- Acid-Base Equivalents14m
- Acid-Base Reactions7m
- Gas Evolution Equations (Simplified)6m
- Ionic Salts (Simplified)23m
- Buffers25m
- Henderson-Hasselbalch Equation16m
- Strong Acid Strong Base Titrations (Simplified)10m
- 11. Nuclear Chemistry56m
- BONUS: Lab Techniques and Procedures1h 38m
- BONUS: Mathematical Operations and Functions47m
- 12. Introduction to Organic Chemistry1h 34m
- 13. Alkenes, Alkynes, and Aromatic Compounds2h 12m
- 14. Compounds with Oxygen or Sulfur1h 6m
- 15. Aldehydes and Ketones1h 1m
- 16. Carboxylic Acids and Their Derivatives1h 11m
- 17. Amines38m
- 18. Amino Acids and Proteins1h 51m
- 19. Enzymes1h 37m
- 20. Carbohydrates1h 46m
- Intro to Carbohydrates4m
- Classification of Carbohydrates4m
- Fischer Projections4m
- Enantiomers vs Diastereomers8m
- D vs L Enantiomers8m
- Cyclic Hemiacetals8m
- Intro to Haworth Projections4m
- Cyclic Structures of Monosaccharides11m
- Mutarotation4m
- Reduction of Monosaccharides10m
- Oxidation of Monosaccharides7m
- Glycosidic Linkage14m
- Disaccharides7m
- Polysaccharides7m
- 21. The Generation of Biochemical Energy2h 8m
- 22. Carbohydrate Metabolism2h 22m
- 23. Lipids2h 26m
- Intro to Lipids6m
- Fatty Acids25m
- Physical Properties of Fatty Acids6m
- Waxes4m
- Triacylglycerols12m
- Triacylglycerol Reactions: Hydrogenation8m
- Triacylglycerol Reactions: Hydrolysis13m
- Triacylglycerol Reactions: Oxidation7m
- Glycerophospholipids15m
- Sphingomyelins13m
- Steroids15m
- Cell Membranes7m
- Membrane Transport10m
- 24. Lipid Metabolism1h 45m
- 25. Protein and Amino Acid Metabolism1h 37m
- 26. Nucleic Acids and Protein Synthesis2h 55m
- Intro to Nucleic Acids4m
- Nitrogenous Bases16m
- Nucleoside and Nucleotide Formation9m
- Naming Nucleosides and Nucleotides13m
- Phosphodiester Bond Formation7m
- Primary Structure of Nucleic Acids11m
- Base Pairing10m
- DNA Double Helix6m
- Intro to DNA Replication20m
- Steps of DNA Replication11m
- Types of RNA10m
- Overview of Protein Synthesis4m
- Transcription: mRNA Synthesis9m
- Processing of pre-mRNA5m
- The Genetic Code7m
- Introduction to Translation7m
- Translation: Protein Synthesis18m
Membrane Transport - Online Tutor, Practice Problems & Exam Prep
Membrane transport is essential for cells to exchange substances with extracellular fluid, allowing the intake of nutrients and expulsion of waste. It is categorized into passive transport, which requires no energy and includes simple diffusion and facilitated diffusion, and active transport, which requires energy to move substances against their concentration gradient. Simple diffusion involves nonpolar molecules like oxygen, while facilitated diffusion uses protein channels for polar molecules and ions, such as glucose. Active transport, exemplified by sodium-potassium pumps, is highly selective and energy-dependent.
Membrane Transport Concept 1
Video transcript
Membrane Transport Example 1
Video transcript
Here it says, in the electron transport chain or ETC, complexes 1, 3 and 4 pump H+ ions from the mitochondrial matrix which has a low hydrogen ion concentration to the intermembrane space where we have a high H+ ion concentration. What type of membrane transport is this? Alright. So, what's happening here? Well, we're taking H+ from an area where the concentration of H+ is low, and we're pumping it to where it is high. This is the opposite of what we should expect because typically, we would have the movement of ions from an area of high concentration to an area of low concentration. This is what passive transport would be. Here we're doing the exact opposite. We're taking where H+ ions are low and pumping them somewhere where it's already high. There's gonna be a resistance there, which means we're gonna have to supply energy in order to do this. Because of that, this represents active transport. We're working against the concentration gradient. Again, normally we want to go from high concentration to low concentration, but here the opposite is occurring, which means energy will be needed. So again, option A, active transport, would be the best answer.
During respiration, oxygen gas diffuses into cells spontaneously. Which type of transport is this?
Active transport
Passive transport
Both
None of the above
Membrane Transport Concept 2
Video transcript
In this video, we'll take a look at different types of membrane transport mechanisms. Now, here we're going to discuss how non-polar molecules, polar molecules, and ions move across the cell membranes differently. Because of this, we'll need different types of mechanisms.
The first one is simple diffusion. Here, this is the movement driven by concentration gradients. We're going to say that small, non-polar molecules and water are involved. Examples would be oxygen, CO2, or steroids. If we take a look here, we're going to say this is the outside of the cell and this is the inside of the cell, we can see that these particles are just kind of going through the lipid bilayer, going from the outside, through the bilayer, and winding up on the inside of the cell. This represents simple diffusion.
Next, we have facilitated diffusion. This is gradient-driven and it's through a protein channel. Now, here we're going to discuss dealing with polar molecules and ions. Examples would be glucose, water, chloride ions, and bicarbonate. If we take a look here, we have our integral protein, which, remember, goes through the entire thickness of our lipid bilayer. We're going to say that these particles are going through the protein channel, which goes on both sides of the lipid bilayer. So they go through here, which is on the outside, and exit out here onto the inside. This would be facilitated diffusion, where we are using the protein channel to help move the particles from the outside to the inside of the cell.
Then finally, we have active transport. In this, we're going to say protein channels or pumps use energy to move substances against a concentration gradient. We're going to say this is highly selective and regulated, with different pumps for different substances. Some examples are our Sodium Potassium Pumps, which move sodium out and then potassium inside the cell. So, if we take a look here, energy is involved, and that's what makes this active transport. It's not just simply having an integral protein; we also have the inclusion of energy in order for our particles to go in and out of the cell.
Alright. Just remember, we have different types of membrane transport mechanisms, and they deal with the transporting of materials inside and out of the cell. This involves non-polar molecules, polar molecules, ions, and when it comes to active transport, the inclusion of energy.
Membrane Transport Example 2
Video transcript
This example question asks, "How would a molecule of stearic acid cross the cell membrane?" Remember, stearic acid represents a saturated fatty acid. It has the shorthand notation of 18:0, meaning it has 18 carbons and 0 pi bonds. Due to this large number of carbons, it is considered a nonpolar molecule. Remember, fatty acids tend to be nonpolar overall because of their long hydrocarbon tail. Since it is a nonpolar molecule, it is most likely going to cross the cell membrane by simple diffusion. Remember, simple diffusion is the transport mechanism of choice when it comes to small nonpolar molecules, as well as water. Therefore, the answer here would be option a.
How would you expect an H+ ion to move out of the cell if [H+] inside the cell is lower than extracellular fluid?
Simple diffusion
Facilitated diffusion
Active transport
None of these
In oxidative phosphorylation, H+ ions from the intermembrane space of mitochondria to the mitochondrial matrix, which type of membrane transport is this?
Simple diffusion
Facilitated diffusion
Active transport
None of these