1.How many strands of mRNA are transcribed from the two "unzipped" strandsof DNA?
2.What are the three parts of an RNA nucleotide?
3.How does base pairing differ in RNA and DNA?
4.What is the function of mRNA?
5. What is a codon?
thank you. the reason i had put those questions is because im not good with a book i kinda need a verbal explination. But in the mean time i am reading my text book over and over and over but i just can't seem to find the answers.
Awe, this sucks, I hate when that happens. I am trying to find my book though. When do you need this homework by? Just before you go back to school, yes? I think I should be able to find it soon, so just keep checking back.
yes i do have to have it by the time i get back to school. and none of my friends don't want to help me and my mom or dad doesn't know much about it so thank you for trying. o and i have my notes its just b4 c-mas break came i had surgery so i didn't get the notes hat i need for my work so yea it kinda sux! so i'll keep checking back thank you again!
1. The number of strands of mRNA transcribed from the two "unzipped" strands of DNA is, in general, one. This process is called transcription. During transcription, only one of the two DNA strands, called the template strand, is used as a template to synthesize mRNA. The other DNA strand, known as the non-template strand or the coding strand, is not directly involved in mRNA synthesis.
To determine which DNA strand acts as the template, look for the presence of the promoter region at the beginning of a gene. The promoter region indicates which strand will be transcribed into mRNA. Once the template strand is identified, it serves as a template for the synthesis of a single mRNA molecule.
2. A nucleotide is the building block of RNA, and it consists of three parts:
- Phosphate group: This is a phosphate molecule attached to the 5' carbon of the sugar molecule. It provides the "backbone" structure of RNA.
- Sugar molecule: RNA uses ribose as its sugar molecule, which is different from the deoxyribose used in DNA.
- Nitrogenous base: RNA nucleotides can have four different nitrogenous bases: adenine (A), guanine (G), cytosine (C), and uracil (U). Unlike DNA, RNA does not have thymine (T); instead, it uses uracil.
These three components come together to form RNA nucleotides, which then combine to form RNA molecules.
3. Base pairing in RNA and DNA involves the pairing of nitrogenous bases. However, there is one key difference between the two:
- In DNA, adenine (A) pairs with thymine (T) through two hydrogen bonds, while cytosine (C) pairs with guanine (G) through three hydrogen bonds.
- In RNA, adenine (A) still pairs with uracil (U) but also through two hydrogen bonds. Cytosine (C) still pairs with guanine (G) through three hydrogen bonds.
So, the base pairing rules are the same for A-U and C-G, but the base thymine (T) is replaced by uracil (U) in RNA.
4. The function of mRNA (messenger RNA) is to carry the genetic information from DNA to the ribosomes in the cytoplasm. It serves as an intermediate molecule between DNA and protein synthesis. mRNA is synthesized during transcription and carries the genetic code in the form of codons, which are sequences of three nitrogenous bases. These codons are then translated into specific amino acids during protein synthesis.
In simpler terms, mRNA acts as a "messenger" molecule, carrying the instructions for building proteins from the DNA in the nucleus (where it is transcribed) to the ribosomes (protein synthesis factories) in the cytoplasm.
5. A codon is a sequence of three nitrogenous bases in mRNA that specifies a particular amino acid during protein synthesis. Each codon in mRNA is complementary to a specific anticodon in tRNA (transfer RNA), which brings the corresponding amino acid to the ribosome.
There are 64 possible codons (4 bases raised to the power of 3) but only 20 amino acids found in proteins. This is due to redundancy in the genetic code, where multiple codons can specify the same amino acid. Additionally, there are specific codons called start codons (e.g., AUG) that specify the initiation of protein synthesis, and stop codons (e.g., UAA, UAG, UGA) that signal the end of protein synthesis.