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RNA (ribonucleic acid)
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∙ 11y ago
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Why does uracil replace thymine in RNA?
Funnily enough, it is probably the other way round! Scientists believe, for various reasons, that RNA came first, and that there was an "RNA world" before DNA evolved. If this idea is correct, uracil was a component of nucleic acids before thymine. When DNA evolved, thymine may have proved a preferable material for storing genetic information because of its much greater stability; RNA breaks down relatively quickly, but DNA is stabilized by its double-stranded form. RNA is easily hydrolised than DNA. It is interesting to note that in our own bodies we can synthesize RNA from simpler compounds, but to make DNA we first build RNA nucleotides, then convert them. We remove one oxygen atom from the ribose component of the nucleotide, to form deoxyribose. Then, if the base is uracil, we add a methyl group to it to form thymine. But this leaves the question: what advantage does thymine have over uracil in DNA? One suggestion is this: cytosine (C) occasionally converts into uracil (U) by deamination. If this U is not removed, at the next replication it will act as a template for an adenine (A) on the new strand, and there will have been a mutation from G to A. Having thymine (T) as the regular base in DNA makes it easy for a cell to spot a deamination, because U should not be there at all. The cell then removes the U with a DNA repair enzyme (e.g. uracil glycosylase).
What may contain DNA or RNA but not both?
a virus.
A nucleotide may contain?
thymine and deoxyribose
What is the part of the nucleotide that differs among the other different nucleotides?
All nucleotides are similar except for the nitrogen bases, which may either be adenine, cytosine, guanine, thymine, or uracil..
How many different DNA nucleotides are there?
There are five types of nucleotides found in nucleic acids. In DNA there are four types of nucleotides, each containing one of four bases adenine (A), thymine (T), guanine (G) and cytosine (C). In RNA there are also four types of nucleotides but the base thymine is replaced by uracil (U). So in total there are five types of nucleotides, but any DNA or RNA molecule will only contain four of them.
What base is missing on RNA and what other base replaces it?
No nitrogen base is missing. You may be referring to the fact that DNA contains the nitrogen base thymine, while RNA contains the nitrogen base uracil. They both contain adenine, cytosine, and guanine.
The components of a nucleoside are?
The components of a nucleoside are: A pentose sugar(generally ribose or deoxyribose), and a nitrogenous base which may be Adenine/Guanine/Thymine/Cytosine/Uracil. It becomes a nucleotide on addition of a phosphate group.
What is the one part of nucleotide that differs among the other different nucleotide?
All nucleotides are similar except for the nitrogen bases, which may either be adenine, cytosine, guanine, thymine, or uracil..
A virus may contain ethier DNA or RNA To identify which nucleic acicd is present a biochemist could chemically analyze the virus for the presence of which nitrogen base?
The "NA" in DNA and RNA stands for nucleic acid, so in this question, you are trying to find which nitrogen base ethier only DNA or only RNA has. DNA has thymine, but RNA has uracil. Therefore, the biochemist could chemically analyze the virus for the presence of uracil.
Why does DNA have thymine when RNA has uracil?
Cytosine bases may spontaneously change into uracil bases. DNA has an enzyme asssociated with it that corrects this fault. If DNA contained uracil as a base, the repair enzyme would have no way of distinguishing between uracils normally present in the DNA code and uracils that had formed from cytosine. Therefore thymine is present instead of uracil.
What elements form a nitrogen base?
A nitrogen base is an y organic chemical which contains nitrogen and has the properties of a base. It will contain carbon, hydrogen and oxygen but may contain other elements.
Where do plants get free nucleotides?
The first step of nucleotide synthesis is the formation of a nucleoside (the nitrogenous base joined to a sugar). The sugar involved in the synthesis and structure of a nucleotide may be either ribose or deoxyribose; in the latter case, the prefix 'deoxy' may be added before the name of the nucleoside in all cases except Uracil. A functional group of phosphate is then esterified to the sugar, creating a nucleotide. The phosphate group may consist of one, two, or three phosphates, forming monophosphates, diphosphates, or triphosphates, respectively.
A solution which turns red litmus paper blue may contain?
the solution is a base
Nitrogenous compounds may be used by plants in the synthesis of?
protiens
What kind of molecules are the nucleotides?
All nucleotides have: 1) a phosphate group (same for all nucleotides) 2) a 5-carbon sugar (same for a particular type of nucleic acid - deoxyribose for DNA, ribose for RNA) 3) nucleoside (purine or pyrimidine base - varies for each nucleotide - there are 5 total - 4 for DNA (adenine, cytosine, guanine, thymine) - 4 for RNA (adenine, cytosine, guanine, uracil)
Nitrogenous wastes is it creatinine or fatty acid or lipid or carbon dioxide or sugar?
Nitrogenous wastes are waste substances which contain nitrogen. Generally these are produced in the liver by the breakdown of unwanted amino acids. Most of the waste (in mammals) is in the form of urea, but smaller amounts of other substances, such as creatinine, are also produced. Carbon dioxide only contains carbon and oxygen. Sugar and fatty acids only contain carbon, hydrogen and oxygen. Some lipids (phospholipids) may contain small amounts of nitrogen.
What are the subunits of DNA?
DNA and RNA are polymers. Collectively, DNA and RNA are called nucleic acids. The subunits of nucleic acids are called nucleotides. Nucleotide monomers form nucleic acid polymers. A nucleotide has 3 parts to it: a phosphate group, a sugar (ribose in RNA and deoxyribose in DNA), and a base (Adenine, Guanine, Cytosine, Thymine or Uracil - Thymine is found only in DNA and Uracil is found only in RNA, but the other 3 bases may be found in either.) Another name for it would be nitrogenous base.
