Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [ribosome]

Organelles responsible for protein synthesis in cells. They are distinguished into "free" and "membrane-bound" classes.

1
vote
1answer
53 views

Do ribosomes read mRNA?

So I understand that tRNA bonds to a codon (with an anticodon) in the translation process. I read in my biology textbook that the ribosomes "read" the mRNA strand. Why do the ribosomes need to read ...
0
votes
0answers
17 views

Are there E-sites on eukaryotic ribosomes?

One of my professors mentioned something about the e-site (the exit site for the t-RNA) on a eukaryotic ribosome. There was a student in the class who objected, saying that there is no e-site on ...
1
vote
1answer
39 views

When does protein folding begin?

I had always assumed that protein folding is an independent activity that occurs after translation is complete. However, recently, I learned that intermolecular forces begin shaping the peptide bonds ...
6
votes
2answers
316 views

Can ribosomes read ssDNA?

My question is whether translation can be done, either naturally or artificially, through a ribosome reading (single-stranded) DNA directly. If not, I would like to know what allows ssRNA to be ...
1
vote
0answers
28 views

Eukaryotic equivalent of bacterial tmRNA

According to this Wikipedia article, tmRNA is only found in bacteria, with its purpose being to “rescue stalled ribosomes”. This brings me to the question of is there a eukaryotic equivalent of this ...
2
votes
2answers
84 views

Ribosomes producing proteins, but need proteins to be produced?

So according to my textbook: RNA is used to create ribosomal RNA (known as rRNA) which is then combined with proteins to form the ribomsomes necessary for protein synthesis. I'm a bit confused ...
3
votes
0answers
48 views

How rapidly do human mitochondrial ribosomes turn over?

How rapidly do human mitochondrial ribosomes turn over? The inside of the mitochondrion is a highly oxidizing environment that can damage RNA and DNA. How long do mitochondrial ribosomes last before ...
1
vote
0answers
68 views

How a biologist attempts to explain the structure of the ribosomal proteins?

I have a Computer Science background and a minimal biology knowledge. This is the question I am asked to answer in one of the biology courses: What would be the structure of ribosomal proteins when ...
2
votes
1answer
473 views

Why is translation so much faster in prokaryotes than eukaryotes?

Prokaryotes perform transcription and translation much faster than eukaryotes. If memory serves, a single 70S prokaryotic ribosome can incorporate around 20 amino acids per second, whereas the 80S ...
3
votes
1answer
114 views

How is mRNA directed out of the nucleus to its ultimate cytoplasmic location?

In the process of translation, I learnt that following formation the mRNA must exit the nucleus through a nuclear pore and attach to a ribosome. My question is how does mRNA navigate itself out of ...
10
votes
3answers
16k views

Why do 60S & 40S ribosomal subunits make an 80S ribosome (not 100S)?

Why do 60S & 40S subunits make an 80S (not 100S) ribosome and, similarly, 50S & 30S make 70S? 60+40 is not equal to 80, nor is 50+30 equal to 70, so why are the subunits of the 80S and 70S ...
3
votes
0answers
135 views

Consensus sequence for selection of initiation codon in eukaryotes

In bacteria the AUG (or other) codon at which translation of mRNA is initiated is preceded at a precise distance by a sequence known as the Shine and Dalgarno sequence, to which the 30S subunit ...
4
votes
1answer
6k views

What is the Shine–Dalgarno sequence?

I am trying to understand the Shine–Dalgarno sequence. I currently know it is related to ribosomal binding sites, it is only found in prokaryote cells and it is in front of the initial codon. Also, ...
3
votes
1answer
401 views

Translation of Poly-U in the Nirenberg and Matthaei experiment

In the Nirenberg and Matthaei experiment the artificial mRNA, polyU, was translated into polyphenylalanine in a cell-free system, establishing that UUU was the codon for Phe. How did this work as the ...
1
vote
1answer
2k views

What causes the variable/conserved structure in the 16S rRNA gene?

See the image below for a visual representation of the 16S rRNA gene. It is composed of conserved and variable regions however I can't see to find a reasoning for why this is the case Thanks
0
votes
1answer
275 views

How the size of ribosomes are calculated?

When I was studying microbiology, something didn't make sense to me. We all know ribosomes have two subunits; the large subunit and the small subunit. Such as for eukaryotic cells, the large subunit ...
5
votes
1answer
2k views

Why do ribosomes associate with rough endoplasmic reticulum but not other membranes?

As far as I am aware, all eukaryotic membranes consist of a lipid bilayer. Smooth endoplasmic reticulum (ER) and rough ER are distinguished by the presence of ribosome on the rough ER surface, but are ...
-3
votes
2answers
1k views

How many proteins do all human ribosomes together produce per hour? [closed]

Very roughly how many proteins (chains) are synthesized in the human body per hour under normal conditions? (And how many ribosomes does the human body have?)
3
votes
2answers
981 views

Why does azithromycin not affect human mitochondria?

Drugs like tetracyclines, macrolides and aminoglycosides bind to prokaryotic ribosomes. It is interesting that our body too having mitochondria, which have prokaryotic ribosomes, there is little(?) ...
5
votes
1answer
2k views

Structure of mitochondrial ribosomes

Is the ribosome found in mitochondrion and choloroplast formed of 30S and 50S subunits as in prokaryotes. I couldn't find any information on internet concerning it. The general wikipedia page has no ...
4
votes
1answer
48 views

Identification of proteins in this animation of a ribosome translating mRNA

This gif is from this page After each aminoacyl-tRNA enters the ribosome, one blue thing comes and pushes the whole tRNAs whats that? I couldn't find it anywhere.(maybe some elongation factor?) Also ...
3
votes
2answers
355 views

What signals a ribosome to stop production when the cell is out of available amino acids?

In the production of a protein molecule, there have to be a ready supply of free-floating amino acids. When a given codon for adjoining, say, serine comes up, how are the serine molecules found out of ...
2
votes
1answer
492 views

Why does the inhibition of translation initiation cause the accumulation of 80S ribosomal monosomes?

As I have read in (1), inhibition of translation initiation will increase the number of 80S ribosomes while decreasing the fraction of polysomes due to the polysome-runoff. The net effect is to ...
1
vote
0answers
57 views

Are upstream activating factor (UAF) and upstream binding factor (UBF) the same thing?

During ribosome pre-40S and pre-60S synthesis, many sources state the importance of UAF or UBF in initiation complex of ribosome DNA transcription. None of the sources I've seen mentions the other ...
0
votes
2answers
46 views

Ribosomal DNA references sequences

I'm having a bit of trouble with searching for this piece of information. I'm doing a study related to phylogenetic susceptibility of hosts to pathogens (based on a recent Nature publication), ...
3
votes
0answers
61 views

Is there a cellular mechanism that detects Ribosomal damage?

What kinds of options, if any, do cells (Eukary and Prokary) have for detecting, and repairing damage in Ribosomes (of all types)? I am curious as to what happens when a cell sustains damage of some ...
2
votes
2answers
147 views

How does a cell create/gain its initial ribosomes for protein synthesis?

I did some quick google searches for how a cellular organism generates or acquires its first ribosomes, but I found nothing. For instance, do the organisms initiating replication form extra Ribosomes ...
4
votes
1answer
260 views

Ribosomal RNA amount in a Drosophila cell

I am isolation RNA from Drosophila larvae brain with TRIzol method. What percentage of extracted RNA will be ribosomal RNA? I am only interested in mRNA, so I am trying to figure out whether I need to ...
2
votes
2answers
190 views

Termination of translation

What dissociates first - the last tRNA, mRNA and release factors or the subunits of ribosomes? I tried searching this from Lehninger but couldn't get a clean answer.
7
votes
2answers
3k views

What exactly happens if during translation, an amino acid is not present?

Lets say that the cell wants to make a particular protein. Transcription of the appropriate gene is done and the mRNA is made. mRNA attaches to the ribosome and the translation is initiated in a "...
2
votes
1answer
1k views

How are the correct tRNAs transported to the ribosome?

I have been trying to understand how the tRNA transporting the correct amino acid required by the ribosome reaches the ribosome. The only way I can imagine this happening is that all types of tRNA+...
2
votes
1answer
238 views

How does GTP help in the step of codon recognition?

The anticodon of an incoming tRNA base pairs with the complementary mRNA codon in the A site.Hydrolysis of GTP increases the efficiency and accuracy of this step. How does GTP do so ?
5
votes
1answer
155 views

What is the advantage of the way eukaryotes initiate translation?

The eukaryote and prokaryote mechanism for translation is slightly different. Is there any advantage of the eukaryote translation mechanism ? Edit : I specifically want to know why eukaryotic ...
8
votes
1answer
795 views

How was the first ribosome theorized to have been made?

Seeing as ribosomes are what help perform the act of translation itself, and the blueprints for they themselves are in nucleotide sequences, how was the first ribosome theorized to have been made? ...
15
votes
1answer
739 views

Can DNA act as a translation substrate?

I get conflicting answers. One would think if it was true, it would be rather seminal and widely known. There are papers from Khorana[1], Holland[2], and Bretscher[3] (late 60s) that suggest that it ...
7
votes
2answers
112 views

Sequence of ribosomal RNA

Is it possible to sequence rRNA directly, that is, using the ribosome rather than the DNA from the nucleus? For example, this paper, Complete nucleotide sequence of a 16s rRNA gene from E. coli, ...
5
votes
1answer
144 views

Is it possible to sequence only the 16S rRNA component? If so, how?

There have recently been several papers on using 16S rRNA as a way of identifying species (here, and here). I'm wondering if it's possible to sequence either just that subunit of the ribosome or just ...
7
votes
4answers
14k views

RNA or ribosome, which one moves during translation?

During translation ribosomes decode the genetic information present in the mRNA and protein synthesis takes place. During this process which of those two does move, the ribosome or the mRNA?
5
votes
1answer
206 views

What is the distance between the 3' 18s rRNA (the Kozak consensus sequence) and the A-site of eukaryotic ribosomes during protein translation?

Reposted from Quora The Kozak sequence is shown to be important in translation initiation, and the A-site is the anti-codon recognition site. If the distance is not known, how could I find out what ...
6
votes
1answer
591 views

How do ribosomes contribute to their own synthesis?

In other words, what products synthesized by ribosomes are actual parts of ribosomes (if any)? How are they involved in their own synthesis otherwise? What is the cycle/chain of products starting ...
25
votes
1answer
7k views

What is the criticality of the ribosome binding site relative to the start codon in prokaryotic translation?

In prokaryotic translation, how critical for efficient translation is the location of the ribosome binding site, relative to the start codon? Ideally, it is supposed to be -7b away from the start. ...