So... mRNA = planner "Architect" who makes the blueprint. tRNA = supplier "Home Depot" who gets the material and brings it to the job site. rRNA = builder "Carpenter" who assembles the material (proteins) brought in by tRNA and puts them together according to the instructions given by mRNA. I know that's overly-simplified, but is it pretty much on track Andrey?
The Thymine structure looks a little different in my textbook which shows that Thymine has two double O bonds instead of one double O bond and an NH2 group.
7.08 Is a mistake. My comment: In Eucariotic cells single gene is used to make many different proteins due to alternative splicing of introns, and procariotic gene usually code for single protein, cause procariotic genes mostly do not have introns.
The Thymine molecule have a carbonyl group between the nitrogen atoms. it is identical to the uracil, but in addition it has a methyl group left to the first carbonyl group.
well explained and in a very effective style of speaking. i look forward to watching more of your lectures to help myself better understand these processes. thank you.
I think you made a slight oversimplification when saying that RNA consists primarily in the linear form. For example, the yeast phenylanyl-tRNA molicule primarily exists in an L-shaped structure that is formed as a result of hydrogen-base pairing. This three dimensional structure of RNA is what gives it many of its unique properties
Can you be specific as to where I said that? Im pretty sure that by linear I meant single-stranded. The three-dimensional structure of RNA does in fact give it its unique properties (i.e. the structure of tRNA gives it the ability to act as a carrier of amino acids)
I just don't know how to appreciate your good work towards me, you are such an amazing tutor , you will live long to enjoy the goodness of the Lord in the land of the living,💖 once again, thank you so much.
Thank you so much! Your lectures are really helpful and easy to understand. Cleared up many important concepts for me, especially for biochemistry and biology.
I find all these lectures fascinating as I'm just starting out in this field. I have a three questions which I simply can't find answers to, but perhaps nobody knows yet!! If you're able to point me to a source I'd be very appreciative... 1) How do molecular machines know what to do? What signal / code / instruction / information do they receive, and from where? For example, there are many tRNA molecules carrying their amino acids in the cytoplasm - how do they know its their ‘turn’ to descend to the ribosome and release their amino acid on the correct codon? I could think of dozens more……! 2) Regarding the 23 pairs of chromosomes, how does the RNA polymerase know which gene to transcribe, and how is the tightly-knit DNA unwound from the chromosome? What coils it back again? 3) How does the barrel receiving the recently folded protein know what shape to fold it? If the cell is producing a protein, its because the body needs it. So, did the barrel receive this information? Does it recognise the protein and understand what it needs to become? Does it have a ‘memory bank’ of all the types of proteins the body produces? Thanks in advance....
Drumming Spain I think its much more productive to you if you discover these answers on your own. Its natural to have these questions at the beginning and you will appreciate it much more if you get to the answers yourself. However you should note that to really appreciate nature and its many micro-processes, you have to study it from all different sorts of angles (don't only focus on biology but also on physics, chemistry, biochemistry). To fully appreciate the answers to the questions you've listed above, you should probably have a strong foundation in biochemistry and physics.
1. Everything is signaled/coded/instructed originally from DNA. Trial and error similar to hydrogen bonding will take place with tRNAs that are trying to attach to the mRNA until there is a right fit. If the bonding isn't strong enough it will leave the ribosome either be broken down for parts or reused. There are only 21 different amino acids. This brings up the idea that our genetic code is redundant. That is, we have 64 different codons and only 21 amino acids. More than one codon can specify for an amino acid. 2. When mRNA leaves the nucleus, it first goes looking for a ribosome, special proteins built to accept the mRNA strand. When translating at least one kind of tRNA is present for each of the 20 amino acids used in protein synthesis.Topoisomerase deals with super helical DNA. Helicases are enzymes that use ATP-driven motor force to unwind double-stranded DNA or RNA. Recently, increasing evidence demonstrates that some helicases also possess rewinding activity-in other words, they can anneal two complementary single-stranded nucleic acids. Single stranded binding proteins prevent premature annealing, to protect the single-stranded DNA from being digested by nucleases, and to remove secondary structure from the DNA to allow other enzymes to function effectively upon it. 3.The amino-acid sequence of a protein determines its conformation. A protein molecule folds spontaneously during or after biosynthesis. While these macromolecules may be regarded as "folding themselves", the process also depends on the solvent (water or lipid bilayer), the concentration of salts, the pH, the temperature, the possible presence of cofactors and of molecular chaperones. Minimizing the number of hydrophobic side-chains exposed to water is an important driving force behind the folding process. Formation of intramolecular hydrogen bonds provides another important contribution to protein stability. The strength of hydrogen bonds depends on their environment, thus H-bonds enveloped in a hydrophobic core contribute more than H-bonds exposed to the aqueous environment to the stability of the native state. Also reference Anfinsen's dogma and Levinthal's paradox. Hope this could help! These answers are from several sources: www.hindawi.com/journals/jna/2012/140601/ education-portal.com/academy/lesson/trna-role-function-synthesis.html en.wikipedia.org/ education-portal.com/academy/lesson/the-role-of-ribosomes-and-peptide-bonds-in-genetic-translation.html
Yes, perhaps I should have cleared that up. The rRNA are assembled in the nucleolus and trimmed there as well. They then bind to their appropriate proteins (which come from the cytoplasm) to form the 40S and 60S subunits. However, the two subunits do not combine inside the nucleolus to form the ribosome. They are transported out of the nucleus at different times and then combine with their appropriate mRNA molecule in the cytoplasm. Sorry for the confusion! I put an annotation to clear that up.
Question: So the tRNA brings the raw material amino acids to the ribosome factory to make longer chain proteins. Who makes these "raw material" amino acids then?
If rRNA makes ribosomes utilizing proteins that mRNA created with the ribosomes, thjs sounds like a logical fallacy... Which came first? How do you create the ribosome with a protein that required a ribosome to be created?
according to my biology teacher, uracil requires less energy than thymine and because proteins are constantly being synthesized in large numbers, the body tries to save as much as energy as possible
