ribosomal RNA

[slinquii]

I have always had trouble understanding what rRNA is. I want to understand it once and for all as I study for the MCAT. I can't find a simple explanation of what it is...
Here is my understanding of it. Please offer some help? Thanks

DNA codes for RNA which makes protein.
rRNA does not code for protein.
DNA codes for rRNA which is just... part of a ribosome?
Why doesn't it move through the ribosome, creating protein like mRNA does?
Is it the way it folds on itself?
Is this all there is to it? I can't help but feel I'm missing something.
Ughh

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[jbuc1081]

Ribosomes have to be made of something, so they're made of 60% rRNA and 40% protein. The large and small ribosomal subunits help create the E,P, and A sites where mRNA is translated into polypeptides.

 

[TraumaBlonde]

I have always had trouble understanding what rRNA is. I want to understand it once and for all as I study for the MCAT. I can't find a simple explanation of what it is...
Here is my understanding of it. Please offer some help? Thanks

DNA codes for RNA which makes protein.
rRNA does not code for protein.
DNA codes for rRNA which is just... part of a ribosome?
Why doesn't it move through the ribosome, creating protein like mRNA does?
Is it the way it folds on itself?
Is this all there is to it? I can't help but feel I'm missing something.
Ughh

So what are you using to study that subject?
Do you know where you start getting confused?
I made myself study guides for each topic/concept/ objective when I was prepping for the MCAT stuff

If you'd like, I can send you the one I made about that stuff

 

[RH8448]

Start from bottom to top in this case. Watch the Khan Academy videos (I would start there). Understand it from the most elemental purpose of it, to the structure. Know it's location. It's size. What it is made of. It's a protein/RNA mass usually embedded in the ER. What happens if it's gone - things like that. It's important to know.

 

[slinquii]

I am using a cell biology book, as well as searching online and looking at youtube. I was just thinking about making some type of journal. I printed out the entire content summary from the AAMC website and am trying to check off each concept. I also have the comprehensive Princeton review book that comes with 4 practice tests... and Kaplan flash cards. I have pretty much just started my MCAT studing and I am overwhelmed at where to start and what approach to take. It doesn't help that I am super detail-oriented and will focus on the same thing for way too long.

I get confused when I wonder how mRNA and rRNA are different... if they are both single strands of ribonucleic acids... what makes them do different things? Is it the way that they fold on themselves three-dimensionally? What keeps mRNA from doing this?

Anything helps, I would appreciate the study guide you made

Thanks for the replies

 

[basophilic]

I am using a cell biology book, as well as searching online and looking at youtube. I was just thinking about making some type of journal. I printed out the entire content summary from the AAMC website and am trying to check off each concept. I also have the comprehensive Princeton review book that comes with 4 practice tests... and Kaplan flash cards. I have pretty much just started my MCAT studing and I am overwhelmed at where to start and what approach to take. It doesn't help that I am super detail-oriented and will focus on the same thing for way too long.

I get confused when I wonder how mRNA and rRNA are different... if they are both single strands of ribonucleic acids... what makes them do different things? Is it the way that they fold on themselves three-dimensionally? What keeps mRNA from doing this?

Anything helps, I would appreciate the study guide you made

Thanks for the replies

rRNA is made in nucleolus using RNA pol II. mRNA and tRNA are made in nucleus, but outside nucleolus. they do different things despite being made of same type of material probably because rRNA is processed in nucleolus while mRNA and tRNA are processed in nucleus, with different proteins facilitating each (proteins for rRNA synthesis/processing are localized within nucleolus and those for mRNA/tRNA are outside nucleolus). rRNA has a more structural purpose because of its 3D folding (facilitated by some double-stranded regions) while mRNA doesn't fold up on itself

 

[hopeful2019]

So what are you using to study that subject?
Do you know where you start getting confused?
I made myself study guides for each topic/concept/ objective when I was prepping for the MCAT stuff

If you'd like, I can send you the one I made about that stuff

Hey, I could not send you a PM. Can you please send me the study guide that you used to study for MCAT? I would really appreciate it, thanks!

 

[Altius Premier Tutor]

I have always had trouble understanding what rRNA is. I want to understand it once and for all as I study for the MCAT. I can't find a simple explanation of what it is...
Here is my understanding of it. Please offer some help? Thanks

DNA codes for RNA which makes protein.
rRNA does not code for protein.
DNA codes for rRNA which is just... part of a ribosome?
Why doesn't it move through the ribosome, creating protein like mRNA does?
Is it the way it folds on itself?
Is this all there is to it? I can't help but feel I'm missing something.
Ughh

I suggest you think of rRNA as almost a unique kind of biomolecule, different from mRNA. rRNA is specifically coded for by its own specialized regions of the DNA. Think of the "regular" mRNAs for all of the other proteins (structural, protein factors, enzymes, etc.) as being coded for in the "generic" coding regions found throughout euchromatin. By contrast, rRNA coding regions are not found here, their codes are found in separate locations (within the nucleolus), and on only 5 specific chromosomes. These DNA sequences that are especially for rRNA even have their own name "Ribosomal DNA." rRNAs have their own factors and chaperones that target and guide their unique functions, which explains why they don't behave like mRNA, why they do fold-up much like a protein, etc. Above all, they are themselves RIBOZYMES...that's odd. No mRNA acts like an enzyme. They also do really cool, unique stuff. For example, in long-term-potentiation (memory creation) in CNS neurons recent research suggests part of "teaching" the neuron the memory involves specific regulation of rRNA so that there will be more ribosomes around to quickly translate the proteins needed for later recall.

Summary: I think it is helpful to think of mRNA as one thing, and as rRNA as a quite unique biomolecule coded for differently and from a different place. (on the subject, remember that tRNAs come directly from a code on the DNA too; seen a few students get perplexed on where tRNA would come from).

On the central dogma topic, my students have found it helpful to emphasize in their minds that DNA directs EVERYTHING. We often think of DNA in terms of the central dogma only. True that all proteins are CODED for by DNA, but we've got DNA making functional rRNAs, microRNAs, and other stuff as well. Then, you've got things like fats and carbohydrates. They are NOT coded for by DNA, but they are still controlled by it. If there is a carbohydrate on the surface of a cell, for example, it got there because of DNA--most likely because DNA coded for an mRNA which coded for a protein and that protein was an enzyme that catalyzed the addition of the carbohydrate to its attachment point.

 

[kingtal0n]

To see RNA I first must consider what a nucleotide is and how the atom's electronic fields are used to chain certain atoms together and then hold shapes whose exact shapes are predicted within an interval of confidence at specific environmental conditions solely due to the location of electrons in orbits, as can be said for all biochemical reactions and relationships, it is ultimately the electron's "fault". I find it in water, the length and mass of each hydrogen and oxygen and their bonds, as electronic fields interact with my nucleotide in various places, and the polarities and directions each as these molecules would seek a comfortable position in my tranquil, 7.4 PH, cup of water.

One I have established what a single nucleotide is, its length and mass, sitting in water by itself, (details about the entity as a real thing floating around), I can imagine what a length of this repeating unit might look like, and discuss its possible shapes, again taking into account that it is the electrons in their orbits with shapes predicted over time within an interval of confidence that give the many possibilities of structure arrangements. At this point we should begin to load the 3d structures of these ribosomes and RNA molecules (it is freely available to download and view the 3-dimensional shapes of many cellular structures such as membrane pores and enzymes now) and examine them, and how they move, to begin to assess the nature of RNA (and protein while you are in there!).

From there you may attain practical biotechnology experience using RNA assays and fun actually used experimental equipment such as real-time pcr (playing with DNA is kind of like playing with RNA) to further gain insight on how easily RNA is ruined, how to find it in a tube, how the sequences can fold to make shapes with activity, how to establish what RNA is being transcribed in a running cell at what intervals, building models of active transcription to predict cellular products from RNA concentrations, a gold mine of opportunity awaits those who unlock the practical applications of RNA.