What material "reads" the genetic information carried by DNA and guides the protein-making process?

Question

I can't seem to find the answer :/
I've looked in my Genetics and Biology book.
Help??? (:

Answer 1

mRNA takes the information from the DNA and connects with a ribosome. The ribosome then takes the sequence from mRNA and makes the protein associated with the mRNA strand

Answer 2

RNA polymerase II reads the DNA to create mrna which then goes from the nucleus to the cytoplasm to be read in order to make proteins. trna reads the Mrna and connects the right amino acids with the code on the mrna. The translation of Mrna to a protein is done at a ribosomes.

Answer 3

I'd say it's mRNA because:
-- mRNA is made by matching up the DNA sequence in the gene during transcription
-- mRNA travels to the ribosome to carry the sequence of instructions for the protein to be built.

Answer 4

DNA in no way, ever makes proteins. that's RNA, which comes from DNA - so this is virtually a trick question. DNA is in no way in contact in protein synthesis (mRNA is). in reality, in case you declare that DNA is the genetic fabric that makes proteins, what approximately retroviruses? they simply carry RNA - yet are able to surviving completely fantastic - and humorous sufficient, all they could do is inject their RNA into human cells and the human cells make the viral proteins for them. No DNA in contact. (to 3 volume RNA is preserved by way of substrates related to DNA yet that may no longer for protein synthesis). i does no longer additionally be stunned in case your instructor believes DNA makes protein as that's for sure no longer in contact in honestly protein synthesis! -Kevin

Answer 5

try this link:
http://en.wikipedia.org/wiki/RNA_transcription

Answer 6

Transcription & Translation
RNA types

1. Ribosomal RNA (rRNA): make up ribosomes
2. Transfer RNA (tRNA): transport amino acids to ribosomes
3. Messenger RNA (mRNA): copied from DNA, conveys information from chromosomes to ribosomes

Transcription: production of mRNA copy of the DNA gene.
Gene: Section of DNA within a chromosome that codes for the synthesis of one protein. There are roughly 20-30,000 genes on the 23 pairs of human chromosomes.
Only 1 side of DNA in a gene gets transcribed:

A. Sense Strand: Strand of DNA in a gene which has the same nucleotide sequence as the m-RNA (except with T instead of U).
B. Antisense Strand: Name of strand of DNA that is transcribed to create m-RNA. It is the template used for making m-RNA.

RNA polymerase: enzyme that initiates transcription by binding to promoter (TAC code on DNA) at the 3' end of DNA

Promoter site: sequences in the DNA strand which accept RNA polymerase and initiate transcription
Elongation: mRNA bonds with DNA in small units, transcription bubble, adding bases Adenine to uracil & Guanine to cytosine, etc.. in the 5' to 3' direction (on the new m-RNA).
Termination: stop signal disengages RNA polymerase

Codon: sequence of 3 nucleotides on m-RNA that codes for one amino acid. Each amino acid has one to several different codons.


Much of DNA is non-coding base sequences, not genes
Intron: part of gene (DNA or mRNA) that does not code for polypeptide. It must be removed before translation.
Exon: coding part of DNA (or mRNA). The exon is translated during protein synthesis.


Translation: synthesis of protein by ribosomes

Anticodon: the 3 nucleotide sequence on t-RNA which the ribosome must fit against m-RNA to ensure that the correct amino acid is placed in the growing protein during translation.
Initiation: Initiates translation. rRNA polymerase of ribosome binds to mRNA strand. 1st tRNA is bonded to mRNA.
Elongation: Ribosome reads mRNA chain in three nucleotide groups (codon) & inserts 2nd tRNA.

tRNA anti-codon (with amino acid) binds to mRNA codon
Translocation: 5' to 3' sequence continues building amino acid polymers (protein), one codon at a time.

Termination: tRNA recognizes release factors of nonsense codon. Newly completed polypeptide is released from ribosome

General information:

1. Universality of Nucleic Acids: All organisms contain nucleic acids. It is a common thread of all life! It's possible to transplant nucleic acids from one species to another as a result!
1. Degeneracy of genetic code: 64 codons possible for 20 amino acids (Ensures several possible codon combinations for each amino acid which helps prevent mutations.)
2. Anticodon & codon both three nucleotides long
3. 45 types of tRNA
4. Much of DNA is base sequences, not genes
5. Intron: part of gene (DNA or mRNA) that doesn't code for polypeptide
6. Exon: coding part of DNA (or mRNA)
7. Splicing: as mRNA matures, non-coding (introns) parts are removed
8. nonsense (stop) codons are UAA, UAG, UGA
9. Start (promotor codon) signal is AUG
10. A gene is a DNA base sequence, a polypeptide is the protein coded by the gene.


I. How in the information in DNA turned into Protein? The Central Dogma.

DNA is a huge information database that carries the complete set of instructions for making all the proteins a cell will ever need! Although there are only four different bases in DNA (A, C, G and T), the order in which the bases occur determines the information to make a protein, just like the 26 letters of the alphabet combine to form words and sentences:

Compare: RAT - TAR - ART - same 3 letters; completely different meanings.
And with DNA: GAC - AGC - CGA - same 3 'letters'; completely different meanings to the cell (specifies the amino acids Aspartic Acid, Serine, and Arginine)

Q: Review: What are genes?
A: We know from the results of the Human Genome project, that most of the cell's DNA (~97%) does NOT code for proteins, but has structural or regulatory functions. The DNA in each chromosome that DOES provide the instructions for a protein is called a gene.

* In the 1940s, scientists proposed, fairly correctly, that each gene "codes for" (contains the instructions for) one protein. This is referred to as the "one-gene, one-protein" hypothesis.
* As we have learned more about the human genome in the last 10 years or so, however, we are now finding that more often than not, one gene will code for perhaps two or more related proteins.
* This was a Big Surprise of the Human Genome Project in 2001 - scientists realized that we had only about 30,000 genes, coding for 100,000 different proteins - rather than the 100,000 genes that had been estimated for the human genome
* The basic hypothesis is still the same, but we know a lot more details now!

Q: If DNA is in the nucleus and proteins are synthesized in the cytoplasm, on ribosomes and in the rER, how to they "get together"?
A: The answer: use a "messenger" to carry the instructions from DNA out into the cytoplasm. A nucleic acid very similar to DNA, called mRNA or messenger RNA, is a copy of a gene, and serves this function the "bridge" between DNA and protein:
The Central Dogma:

DNA encodes the information to make RNA.........and RNA molecules function together to make protein
I. What is RNA and how is it different from DNA?

Two big differences between DNA and RNA:

* 1. The sugar in DNA is deoxyribose; in RNA it is ribose
* 2. The nitrogenous base uracil (U) is used in RNA in place of T (they are very similar bases; in RNA U= A just like T = A.)
IlI. Transcription = Re-writing DNA into RNA
DNA is "transcribed" or re-written into RNA in a very complicated process called transcrption. (Think of a transcriptionist that takes spoken words from one source, like a court judge, and makes a copy of those words on paper. If that helps...).

Simply stated, during transcription, one gene (DNA) is 're-written' into an RNA in the nucleus:

* A team of enzymes and proteins binds to the promoter, or starting region, of a gene.
* These enzymes and proteins unzip the DNA double helix just at the region of the gene.
* The enzyme RNA polymerase uses one of the DNA strands to make an RNA copy of that one gene.
* This copy, which contains the instructions to make 1 protein, is called an mRNA or messenger RNA.
* After the mRNA is made, it is trimmed down to a final size, and shipped out of the nucleus!
* When the mRNA gets into the cytoplasm, it is made into protein.

IV. What's the connection between mRNA and protein?

The order of the bases in the DNA specifies the order of bases in the mRNA, and

The order of bases in the mRNA specifies the order of amino acids in a protein.

The genetic code is a triplet code (handout)

1. Nucleotides on mRNA are read "three at a time" by the ribosome.

* Every three nucleotides in an mRNA (a 'codon') specifies the addition of one amino acid in a protein.
* For example, a 600 nucleotide mRNA will code for a 200 amino acid protein.

2. The amino acids corresponding to all 64 codons have been determined - this was all worked out in the 1960s by Marshall Nirenberg, Robert Holley, and Hargobind Khorana (Nobel Prize!)

* All proteins start with the initiation codon AUG (Met)
* All proteins end with stop codons -either UAA, UGA, or UAG
* Some codons that differ in the third nucleotide can still code for the same amino acid - this is called "wobble".
All living organisms and viruses use this triplet genetic code - its that "biological unity" idea again!!!
V. Translation = De-coding RNA into protein

During translation, the mRNA transported to the cytoplasm is "de-coded" or "translated" to produce the correct order of amino acids in a protein.. Translation requires numerous enzymes. To know the full story, we need to look at two other RNA "Key Players" - rRNA and tRNA

rRNA = ribosomal RNA; these RNA molecules associate with other proteins to form the ribosomes. Each ribosome can accept two tRNAs at a time (carrying amino acids) and one mRNA.

tRNA = transfer RNA; small RNA molecules that carry a specific amino acid at one end and an anticodon region that recognizes and binds mRNA at the other end. The tRNA that binds to that mRNA codon determines what amino acid is added to a protein chain.

The Three RNAs (mRNA, tRNA, and rRNA) all work together to turn the information in DNA into a beautiful, 3-dimestional protein!!!
The steps of translation:

1. Initiation: mRNA enters the cytoplasm and becomes associated with ribosomes (rRNA + proteins).

tRNAs, each carrying a specific amino acid, pair up with the mRNA codons inside the ribosomes. Base pairing (A-U, G-C) between mRNA codons and tRNA anticodons determines the order of amino acids in a protein.

2. Elongation: addition of amino acids one-by-one:
As the ribosome moves along the mRNA, the tRNA transfers its amino acid to the growing protein chain, producing the protein - codon by codon!

3. Termination: when the ribosomes hits a stop codon - UAA, UGA, or UAG - the ribosome falls apart!

The same mRNA may be used hundreds of times during translation by many ribosomes before it is degraded (broken down) by the cell.



How does translation relate to YOUR life? (Why do you need to know this, anyway?)
All the proteins that make up YOU, your cells, your body, the foods you eat, all the living cells in the world, etc - are made this way! Every time your body needs more of a protein -

* muscle protein,
* hair protein,
* enzymes,
* hormones,
* hemoglobin molecules,

a gene carrying the information for that protein is transcribed into mRNA, and the mRNA is made into protein!
Better living through transcription and translation.