Quiz Protein Synthesis
Test your knowledge on nucleic acids! Which of the following statements is true regarding DNA structure? Choose 1 DNA is composed of amino acids. Stuck. In a DNA molecule, none of the following base-pairs are possible, EXCEPT: A. Cytosine - Adenine. B. Guanine - Cytosine. C. Thymine - Uracil. Quiz Protein Synthesis! Home · Study Guides · Biology · Quiz Protein Synthesis. All Subjects. Biology Test Prep. Biology Test Prep Review. The Science of.
The Nucleic Acids
Don't worry too much about this now, we'll go into some depth in this in future videos when we talk about DNA and how information is stored in it. But for the sake of this video, just appreciate that the monomer for a nucleic acid like DNA is a nucleotide. So monomer, and to be very clear, this would not be the only monomer, the analogous nucleotide in RNA, which stands for ribonucleic acid would be adenosine monophosphate right over here.Molecular Basis of inheritance - Nucleic Acid & Nucleotide
You can see the difference between the two that we have an oxygen right over here, and we don't have an oxygen right over here. That's why this is called deoxy, and that's why it's deoxyribonucleic acid.
az-links.info: Biochemistry: Nucleic Acids
You're missing one of those oxygens on your five carbon sugar. But adenine as I mentioned is not the only nitrogenous base. You could have a nucleotide where the nitrogenous base is thiamine, and so once again, this looks very similar but notice what is going on over here. You could have a nucleotide that looks like this. Once again, you have your five carbon sugar here, you have your phosphate group, but the nitrogenous base here keeps on changing.
And it's the order of these different nucleotides that actually encodes the information in DNA.
Nucleic Acids And Protein Synthesis - ProProfs Quiz
Now one question you might say is, well look, if I have this part of the molecule that has basic characteristics, why is it considered an acid? Well look at how this molecule is structured. The basic parts form the rungs of this ladder. So they're not going to be as reactive because they're really tied, they're closer to the inside of the molecule while the acidic parts, the phosphate groups are on the outside.
So they're going to be more reactive. The nucleosides inosine, xanthosine and guanosine are degraded respectively to hypoxanthine, xanthine and guanine and, in the process, the ribose sugar, which was attached by its C1 to the base is phosphorylated: What's really interesting here is that the ribose sugar is recycled in the form of ribosephosphate, which can be incorporated into PRPP which, as we now know, is integral to the biosynthesis of purines, pyrimidines, histidine and tryptophan.
That's a really efficient way to run a cell!
Hypoxanthine and guanine are each converted to xanthine by the actions of xanthine oxidase and guanine deaminase respectively. The xanthine is converted to uric acid in a reaction again catalyzed by xanthine oxidase. Xanthine oxidase contains a number of agents involved in the transport of electrons ultimately to dioxygen. Look at these reactions separately: This cycle of reactions is know as the "purine nucleotide cycle" and it is of physiologic importance in muscle metabolism.
Muscle tissue replenishes its citric acid cycle intermediates via the purine nucleotide cycle rather than through the usual "replenishing reactions", the most important of which is the generation of oxaloacetate from pyruvate catalyzed by pyruvate carboxylase. The purines are adenine and guanine. Purines consist of a double ring structure, a six membered and a five membered ring containing nitrogen.
The pyrimidines are cytosine and thymine. It has a single ringed structure, a six membered ring containing nitrogen.
Quiz Protein Synthesis
A purine base always pairs with a pyrimidine base guanine G pairs with cytosine C and adenine A pairs with thymine T or uracil U. DNA's secondary structure is predominantly determined by base-pairing of the two polynucleotide strands wrapped around each other to form a double helix. Although the two strands are aligned by hydrogen bonds in base pairs, the stronger forces holding the two strands together are stacking interactions between the bases.
These stacking interactions are stabilized by Van der Waals forces and hydrophobic interactions, and show a large amount of local structural variability. The secondary structure of RNA consists of a single polynucleotide. Both single- and double-stranded regions are often found in RNA molecules. The antiparallel strands form a helical shape.
Stem-loop or hairpin loop is the most common element of RNA secondary structure.