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Course: NOVA Labs > Unit 1
Lesson 3: RNA: the wonder molecule- The RNA enigma
- The RNA engima quiz
- RNA: The basics
- Protein synthesis in the cellular factory
- Protein synthesis in the cellular factory quiz
- Protein synthesis
- The RNA origin of life
- The RNA origin of life quiz
- RNA world
- Virus wars
- Virus wars quiz
- Viruses
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RNA: The basics
RNA Building Blocks
Every strand of RNA is a sequence of four building blocks called nucleotides. Each RNA nucleotide consists of three parts: a sugar, a phosphate group, and a nitrogen-containing base.
The four RNA bases are adenine, uracil, guanine, and cytosine—often referred to as A, U, G, and C. RNA shares three bases in common with DNA: adenine, guanine, and cytosine. Instead of uracil, DNA contains thymine.
The sugar and phosphate groups form the backbone of a strand of RNA, and the bases bond to each other. RNA nucleotides contain a sugar called ribose, whereas DNA nucleotides contain a sugar called deoxyribose. This is spelled out in the full names of RNA and DNA: ribonucleic acid and deoxyribonucleic acid.
The four RNA bases bond together in complementary pairs. Different bases form bonds of different strengths. Guanine-Cytosine form the strongest bond, Adenine-Uracil form the next strongest bond, and Uracil-Guanine form the weakest bond.
Comparing RNA and DNA
DNA and RNA are both strings of chemical building blocks called nucleotides. And these nucleotides spell out a genetic code. That’s about where the similarities end though; these two molecules carry out very different functions in living things.
Structural differences
DNA is double stranded, forms a double helix (the two strands spiral around each other) is stable and stays in the nucleus. RNA is single stranded (except in rare cases), can fold into complex 3D shapes, is relatively unstable and can leave the nucleus.
Functional differences
DNA stores information as genes. Genes contain the blueprints for RNAs and proteins. Many "non-coding" RNAs act as molecular machines. They carry out various functions that keep us alive. Some of their functions include facilitating cellular processes, protecting the cell from invading viruses, and altering other biomolecules.
Messenger RNA (mRNA)
Messenger RNAs (mRNAs) are messengers between DNA and a cell’s protein-assembly machines (ribosomes). They carry coded instructions for building proteins.
Simple structure
Unlike most of the VirtuaLab RNAs, mRNAs do not usually fold into 3D shapes (and when they do, they have to be unfolded in order to be read by a ribosome). Instead, they resemble long twisted strings.
mRNAs form from a DNA template in a process called transcription. When an mRNA is made, it often needs to be edited before it can be translated into a protein. This is carried out by a spliceosome, a molecular machine made of RNAs and proteins, which splices out unwanted RNA from newly made mRNA.
Translating the mRNA code
The four nucleotides, A, U, C, and G, are the basis of the code in mRNA. Every set of three nucleotides corresponds to a specific amino acid (amino acids are the building blocks of proteins). For example, the code UAC, CGA, GGA on mRNA means “tyrosine, arginine, glycine.” Every three nucleotides of mRNA are recognized by a particular transfer RNA (tRNA) that carries a particular amino acid. Amino acids from tRNAs are linked together to make a protein in a cell’s protein-assembly machine (ribosome) in the order specified in an mRNA.
Want to join the conversation?
- Does RNA mainly fight off virus and stuff? Because I found out that its possible for RNA to cut-off cancer genes.(3 votes)
- White blood cells are the bodies' defense against viruses, bacteria, and other foreign harmful bodies. If RNA does play a part in fighting cancer, it would be to help it divide itself properly again or something within the coding of the cell, not by fighting the cell itself.(8 votes)
- How do the molecules know how to interact with other molecules and how do they find them? Is there a chemical sensor or something?(3 votes)
- Molecules interact by electric interaction,
Atoms with a positive charge will be attracted to negatively charged atoms to form a molecule. This bonding between atoms is how the molecules interact.
Please correct me if I am wrong, I am not an expert, just a learner.(4 votes)
- if RNA is not the same as DNA then what about WBC, CO2, RBC, Nutro transmitter and etc? are those the same things?(3 votes)
- just wow how can that stuff stop cancer? how can a game stop cancer? i call life hacks -.- its amazing(1 vote)
- The game is to find folds for the RNA to chemically destroy a cancer causing gene(2 votes)
- What does unstable and stable mean in Structural Differences?(1 vote)
- stable Structured thing is like DNA, it doesn't and it doesn't leave the nucleus. Unstable Structured things are like RNA, it can fold and can leave the nucleus whenever it needs to/can(1 vote)
- Is it possible that cancer is caused when the RNA is not in the correct shape to fight off the certain cells that are causing cancer and cancer-related diseases?(1 vote)
- In the fourth paragraph, it notes "Guanine-Cytosine form the strongest bond, Adenine-Uracil form the next strongest bond, and Uracil-Guanine form the weakest bond."
Why is U-G mentioned? Is this in the event of a mispairing? If so, what is the relative strength with A-C and G-C?
And to take it one step further, is it true that any mispairing results in a weaker bond?(1 vote) - What can RNA do?(1 vote)
- Things that DNA and proteins can do--and more.(0 votes)
- so is it the mRNA that gives each person a distinctive cellular structure(0 votes)
- mRNA tells Ribosomes what to do. The cellular structure depends on hormones and genes. tRNA gets the special acids and mixes gives them to the Ribosomes to translate what mRNA tells and makes a protein(1 vote)