Hey everyone. So, in this video, we're going to take a look at the processing of pre-mRNA. Now, with Eukaryotic species, mainly animals and plants, we're going to say DNA contains segments called Exons and Introns. Exons are the portions that code for proteins, while Introns are the portions that do not. Now, with transcription, we're going to say it copies both exons and introns to pre-mRNA, also called hnRNA. You might hear these two terms being used interchangeably. They're the same thing. Now, here, we have a process called processing where spliceosomes are going to process our pre-mRNA to produce mature mRNA for protein synthesis. Now, it cuts the introns out, and it's going to splice the exons together. Our memory tool here is that exons are expressed. If we take a look here at this image, we have our gene, our informational strand. It has exons and introns involved. Through transcription, we still have our exons and introns involved because we're just copying it. This is what we call our pre-mRNA or our hnRNA. Now, this starts to undergo processing. And through processing with our spliceosome, we're cutting the connections between our exons and our introns. And we're going to remove the introns, keeping the exons around. We're going to splice them together. Now we have only exons remaining at the end, and this represents our mature mRNA. Now, recall that when we talk about mRNA, it's going to then move out of the nucleus to the Ribosomes in the Cytoplasm for Protein Synthesis. So, just remember, we're copying a segment of our DNA to make this initial pre-mRNA. It still needs to be processed where we get rid of the introns so that the exons can be expressed later on. This is important so that we are left with what's necessary for proper protein synthesis.
- 1. Matter and Measurements4h 29m
- What is Chemistry?5m
- The Scientific Method9m
- 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 Analysis22m
- 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 35m
- 7. Energy, Rate and Equilibrium3h 46m
- Nature of Energy6m
- 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 54m
- 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 Code6m
- Introduction to Translation7m
- Translation: Protein Synthesis18m
Processing of pre-mRNA - Online Tutor, Practice Problems & Exam Prep
In eukaryotic cells, DNA contains exons, which code for proteins, and introns, which do not. During transcription, both are copied into pre-mRNA (hnRNA). The processing phase involves spliceosomes that remove introns and splice exons together, resulting in mature mRNA. This mature mRNA exits the nucleus to the ribosomes for protein synthesis. Understanding this process is crucial for grasping how genetic information is expressed and utilized in cellular functions.
Processing of Pre-mRNA Concept 1
Video transcript
Processing of Pre-mRNA Example 1
Video transcript
Here it says, which of the following statements is incorrect about hRNA, hnRNA processing? Remember, hnRNA is the same thing as pre mRNA. It's the non processed version of mature mRNA. Now, here, hnRNA is processed inside the nucleus in structures called spliceosomes. That's true. Introns that do not code for proteins are removed from hnRNA during processing. That is also true. Spliceosomes join the exons together after introns are removed. Yes, that's correct. Remember, the memory tool: exons are expressed. They're left behind and then spliced together so that they eventually leave the nucleus to go towards the ribosomes, which are in the cytosol for protein synthesis. hnRNA is processed to reduce its size so that it can fit inside ribosomes. Nor did we talk about having to cut out the introns because of spatial issues. It's not about size involved. We're just getting rid of the portions that do not code for proteins. Remember, the whole point of making mRNA is that we can eventually make the necessary proteins from it. So we just gotta get rid of the portions that don't help us code for protein. So here, the answer here would be option d.
The underlined sections of the pre-mRNA below are introns. Write the sequence for mature mRNA.
5’ GCC CGA UUU AUC AGG GAC CCA 3’
5’ GCC UUU AUC AGG 3’
5’ GCC UUU GAC CCA 3’
5’ GCC CGA AUC AGG 3’
5’ GCC CGA UUU CCA 3’
Do you want more practice?
Here’s what students ask on this topic:
What is the role of spliceosomes in the processing of pre-mRNA?
Spliceosomes are essential molecular complexes in the processing of pre-mRNA. They are responsible for removing introns, which are non-coding regions, from the pre-mRNA. The spliceosome cuts the connections between exons and introns, excising the introns and splicing the exons together. This process results in the formation of mature mRNA, which contains only the coding sequences necessary for protein synthesis. The mature mRNA then exits the nucleus and travels to the ribosomes in the cytoplasm, where it directs the synthesis of proteins. Understanding the role of spliceosomes is crucial for grasping how genetic information is accurately expressed in eukaryotic cells.
What are exons and introns in the context of pre-mRNA processing?
Exons and introns are segments of DNA that are transcribed into pre-mRNA. Exons are the coding regions that contain the information necessary to produce proteins. In contrast, introns are non-coding regions that do not contribute to protein synthesis. During the processing of pre-mRNA, spliceosomes remove the introns and splice the exons together to form mature mRNA. This mature mRNA, which consists only of exons, is then used in the cytoplasm for protein synthesis. The distinction between exons and introns is fundamental to understanding how genetic information is edited and utilized in eukaryotic cells.
How does pre-mRNA differ from mature mRNA?
Pre-mRNA, also known as hnRNA, is the initial transcript that is produced during transcription. It contains both exons (coding regions) and introns (non-coding regions). In contrast, mature mRNA is the result of the processing of pre-mRNA, where introns are removed, and exons are spliced together by spliceosomes. Mature mRNA contains only the coding sequences necessary for protein synthesis. This mature mRNA exits the nucleus and travels to the ribosomes in the cytoplasm, where it directs the synthesis of proteins. The key difference lies in the presence of introns in pre-mRNA and their absence in mature mRNA.
Why is the removal of introns important in mRNA processing?
The removal of introns is crucial in mRNA processing because introns are non-coding regions that do not contribute to protein synthesis. If introns were not removed, the resulting mRNA would contain sequences that could disrupt the translation process, leading to the production of non-functional or harmful proteins. By removing introns and splicing exons together, the cell ensures that the mature mRNA contains only the necessary coding sequences for accurate protein synthesis. This precise editing process is essential for the proper expression and function of genetic information in eukaryotic cells.
What happens to mature mRNA after it is processed?
After mature mRNA is processed, it exits the nucleus and travels to the ribosomes in the cytoplasm. Ribosomes are the cellular machinery responsible for translating the mRNA sequence into a specific protein. The mature mRNA serves as a template, guiding the ribosomes in assembling amino acids in the correct order to form a functional protein. This process, known as translation, is the final step in the expression of genetic information, allowing the cell to produce the proteins necessary for its various functions and activities.