from gene to protein guide answers key

from gene to protein guide answers key

LINK 1 ENTER SITE >>> Download PDF
LINK 2 ENTER SITE >>> Download PDF

File Name:from gene to protein guide answers key.pdf
Size: 4832 KB
Type: PDF, ePub, eBook

Category: Book
Uploaded: 16 May 2019, 15:25 PM
Rating: 4.6/5 from 710 votes.

Status: AVAILABLE

Last checked: 13 Minutes ago!

In order to read or download from gene to protein guide answers key ebook, you need to create a FREE account.

Download Now!

eBook includes PDF, ePub and Kindle version

✔ Register a free 1 month Trial Account.

✔ Download as many books as you like (Personal use)

✔ Cancel the membership at any time if not satisfied.

✔ Join Over 80000 Happy Readers

from gene to protein guide answers keyIt looks like your browser needs updating. For the best experience on Quizlet, please update your browser. Learn More. The process by which DNA directs the synthesis of proteins (or sometimes just RNA's). What situation did Archibald Garrod suggest caused inborn errors of metabolism.State the hypothesis formulated by George Beadle while styuding eye color mutations in drosophila: Each of the various mutations affecting eye color blocks pigment synthesis at a specific step, by preventing the production of the enzyme that catalyzes that step. What strategy did Beadle and Tatum adopt to test the hypothesis George Beadle made about eye color mutations in drosophila. They experimented on neuspora, which only need a minimal food supply. After mutating some of them with xrays, some couldn't survive on minimal since their enzymes couldn't synthesize needed molecules from that food. Complete growth medium allowed them to survive though. (Their natural food with lots added.) How did Beadle and Tatum figure out what mutant was defective in what area. If several identical mutants were put in different solutions, and one of these was Arginine and that was the only one that survived, the mutant must have been defective in making arginine since that's the one that survived. Cite two significant findings that resulted from the research of Beadle and Tatum 1. The function of a gene is to dictate the production of a specific enzyme 2. Not all proteins are enzymes What is the hypothesis of gene expression. Many eukaryotic genes can code for a set of related proteins though, called alternative splicing. And many genes code for RNAs that don't become proteins. What are three ways that RNA differs from DNA 1. It contains ribose instead of deoxyribose 2.it has uracil instead of thymine 3. it's usually one stranded instead of double stranded. What are the monomers of DNA, RNA or proteins.http://organicearthfiji.com/documents/file/canon-2500-manual.xml

Tags:
• chapter 17 from gene to protein reading guide answer key, from gene to protein guide answers key, from gene to protein guide answers key quizlet, from gene to protein guide answers key test, from gene to protein guide answers key quiz, from gene to protein guide answers key pdf.

Translates codons to amino acids at ribosomes where does translation occur in a eukaryotic cell the cytoplasm in eukaryotes, what is the pre-mRNA called.It's only called this in the nucleus, before modification. How many nucleotide bases are there. What is the coding strand called. Either strand can be a template for different genes at different times. What are codons? the mRNA base triplets Describe nirenberg's experiment in which he identified the first codon: he synthesized an artificial mRNA by linking identical RNA nucleotides containing uracil at their base: one codon in repetition: UUU. What was the first codon-amino acid pair to be identified. UAA, UAG, and UGA are stop signals what is the start codon.Which enzyme, DNA pol III or RNA pol doesn't need a primer to begin synthesis. RNA pol doesn't need a primer What is a transcription unit. In the wake of transcription, the DNA strands re-form a double helix. 3. Termination: Eventually, the RNA transcript is released, and the polymerase detaches from the DNA. What are the 3 stages of initiation? 1. The eukaryotic promoter includes a nucleotide sequence containing TATA about 25 nucleotides upstream from the start point. 2. one or a few transcription factors recognize the TATA box and bind to the DNA so that RNA pol II can do so. 3. Additional transcription factors bind to the DNA along with RNA pol II, forming the transcription initiation complex. The DNA double helix then unwinds, and RNA syn beings at the start point on the template strand. What is the TATA box.What comprises a transcription initiation complex.What happens at the 5' end of the primary transcript in RNA processing.What happens at the 3' end of the primary transcript in RNA processing. An enzyme adds 50-250 adenine nucleotides, forming a poly-A tail.What are UTR's? untranslated regions: parts of mRNA that won't be translated to protein but have functions like ribosome binding.http://247christianity.org/fckeditor/userfiles/file/canon270exiimanual1599071618.xmlDistinguish between introns and exons: Introns are noncoding segments of nucleic acid between coding regions. Exons are expressed regions that exit the nucleus. Eukaryotic Termination: RNA pol II transcribes the polyadenylation (PD) signal sequence, which codes for a PD signal in the pre-mRNA. Then 10-35 nucleotides downstream, associated proteins with the growing RNA cut it free from the pol. The pol continues transcribing though for 100s of nucleotides past termination. This extra RNA is then digested by an enzyme that moves along the pre-mRNA until it reaches the pol, then the pol falls off and transcription is terminated. What are snRNPs? what two types of molecules make up snurps.What type of RNA is in a snRNP.How do spliceosomes work.They catalyze this process, participate in spliceosome assembly, and splice site recognition. List the 3 steps of modifying a pre-mRNA: 1. snRNPs and other proteins together form a spliceosome on a pre-mRNA molecule containing introns and exons. 2. Within the spliceosome, snRNPs base pair with nucleotides at specific sites along the intron. 3. The spliceosome cuts out the intron and at the same time splices the exons together. The spliceosome then comes apart itself and releases the only-exon mRNA. Explain hwo splice sites are recognized: the RNA parts of snRNP base-pair to specific sites along an intron. What are ribozymes? RNA molecules that function as enzymes. In some organisms, RNA splicing can occur without any other proteins or RNAs: the intron acts as its own excisor. What commonly held idea was rendered obsolete by the discovery of ribozymes.What are the 3 properties of RNA that allow it to function as an enzyme? 1. Since RNA is single-stranded, a region of an RNA molecule may base-pair with a complementary region in the same molecule, giving it a 3D shape that's specific. What is the consequence of alternative splicing of identical mRNA transcripts.https://www.thebiketube.com/acros-43-vortec-repair-manual A single gene can encode more than one kind of polypeptide, depending on which segments are treated as exons during RNA processing. What is an anticodon.Functions to transfer amino acids from the cytoplasm to the mRNA, at the ribosome. Exon shuffling: introns increase the probability of beneficial cross-overs between the exons of alleles by not interrupting coding sequences. Either allelic or nonallelic shuffling can lead to new proteins with new functions. Where is tRNA made and where are the bonds it makes Hbonds between base pairs of itself (in the T), and Hbonds anticodon to codon. How many different aminoacyl-tRNA sythetases are there, and what are they? 20, one for each amino acid. They are a group of related enzymes that facilitate the correct matching up of tRNA and amino acids. What is wobble? Wobble explains why the synonymous codons for a given amino acid can differ in their third base, but usually not in their other bases Explain the process of a specific amino acid being joined to a tRNA. 1. Active site of aminoacyl-tRNA synthetase binds the amino acid and ATP. 2. ATP loses two P groups and joins amino acid to AMP. 3. Appropriate tRNA covalently bonds to an amino acid, displacing AMP. 4. The tRNA charged with amino acid is released by the enzyme. Describe the structure of a eukaryotic ribosome and how it's made: In the nucleus, rRNA genes on the chromosomal DNA are transcribed, and the RNA is processed and assembled with proteins from the cytoplasm. The resulting ribsomal subunits are then exported to cytoplasm. How does a prokaryotic ribosome differ from a eukaryotic ribosome. What is the medical significance of this difference. Pro: smaller, 3 rRNA mc's. Euk: larger, 4 rRNA mc's. Certain antibiotic drugs can inactivate bacterial ribosomes without inhibiting the ability of euk ribo's to make proteins.Explain the functions of the APE sites. A site holds the tRNA carrying the next amino acid to be added to the chain.https://gabrieliassociati.com/images/bsa-bantam-d1-workshop-manual.pdf P site (start site) holds the tRNA carrying the growing polypeptide chain. E site is where discharged tRNAs exit the ribosome. 3 stages of translation: 1. Initiation: Initiation factors bring together mRNA and tRNA carrying 1st amino acid met. 2. Elongation: Amino acids are added one by one to the preceding amino acid. Stimulated by elongation factors. 3. Termination: UAG, UAA, or UGA codes for a stop signal and release factor binds. Summary of initiation: 1. Small ribosomal subunit binds to mRNA, and initiator tRNA with the anticodon UAC base pairs with the start codon AUG, carrying the amino acid met. 2. Large RS binds to complete the complex, using GTP. Initiation factor proteins bring all the components together. Is a ribosome an enzyme. Yes, it's a big ribozyme since it's the catalyst of peptide bond formation. Summary of Elongation: 1. Codon Recognition: The tRNA anticodon base-pairs with the mRNA codon in the A site. Hydrolysis of GTP here increases the efficiency and accuracy of this step. 2. Peptide bond formation: the large ribosomal subunit catalyzes the formation of a peptide bond between the new amino acid in the A site the growing polypeptide in the P site. This removes the polypeptide from the tRNA in the P site and attaches it to the amino acid on the tRNA in the A site. 3. Translocation: The ribosome moves the tRNA in the A site to the P site. At the same time, the empty tRNA in the P site is moved to the E site, where it is released to go find another amino acid. The mRNA moves along with its bound tRNAs, bringing the next codon to be translated into the A site. What is a release factor. By what mechanism is termination accomplished. A protein that binds directly to the stop codon in the A site. Causes the addition of an H20 mc instead of an amino acid. This hydrolyzes the bond between the completed polypeptide and the tRNA on the P site, releasing the polypeptide through the E site of the ribosome.https://www.justgiveahand.org/wp-content/plugins/formcraft/file-upload/server/content/files/1629143f5edfad---752a-manual.pdf Requires the hydrolysis of two more GTP molecules. What is a polyribosome.What are some of the things that will result in a final-form functional protein. Post-translational modifications: attachments (sugars, phosphates) or removal (of 1 or more amino acids) have to occur sometimes for the protein to function in the cell. Define a mutation in terms of molecular genetics: changes to the genetic information of a cell or virus. Responsible for the huge diversity of genes among organisms. Define point mutations: chemical changes in a single base pair of a gene. What are frameshift mutations: insertions or deletions of base pairs that cause the whole later sequence to be off, shifted by one or more. Easier to catch than substitutions. Explain how proteins are targeted for the ER (6 steps) 1. polypeptide synthesis begins on a free ribosome in the cytosol. 2. Signal recognition particle (SRP) binds to signal peptide (end of polypeptide) momentarily halting synthesis. 3. SRP binds to a receptor protein in the ER membrane. This is part of the T complex that has a membrane pore and a signal-cleaving enzyme. 4. The SRP leaves and polypeptide synthesis resumes, with simulaneous translocation across the ER membrane. 5. signal cleaving enzyme cuts off the signal peptide 6. The rest of the completed polypeptide leaves the ribosome and is processed in the ER.What is the difference between a nonsense and missence mutation. Nonsense causes translation to be terminated too early, so the protein is cut short. Nearly all of these lead to non-functional proteins. Missense Identify two mechanisms by which frameshifts may occur. Insertion and deletion. Occurs whenever the nucleotides deleted or inserted aren't in multiples of 3. All downstream will be incorrectly grouped into the wrong codons. How can a base pair substitution result in a silent mutation. I'm just kind of drawing it as a random long strand of. DNA all wound up in itself.gakhongloithoat.com/upload/files/conair-blender-manual.pdf And on that strand, you have sequences which we call genes, so that might be oneAnd each of those genes canAnd the key question is,How do you go from the gene, which is encoded in DNA, how do you go from that to protein. Which is made up of polypeptides, which are made up of amino acids. And this is often called theAnd then the next stepAnd you can see a littleBut you start with the DNA, you have your RNAIt can travel to a ribosome, which is where it will be translated into a polypeptide sequence. And you see the analogousSo the questions are wellAnd what even is a ribosome. So let's zoom in a little bitOne, as you can imagine,So in the video on transcription, we're already familiar with messenger RNA and we often view RNA like DNA as primarily encoding information, it's acting as a transcript for a gene, but it doesn't have toIt can also, so it's proteins plus, it's not a 'T' there, this is a plus. It can also provide aAnd this big, you know, this looks like a an oversized hamburger bunSo this is the site, and you can broadly think of the ribosome as having this, you know,And it's going to travel along the mRNA from the five prime end, to the three prime end, reading it, and taking that information, and turning it into aSo how does that actually happen. Well, each, each of these three, every three nucleotides, every three nucleotides there, we call that a codon, so that's a codon, this is, let me do this in a color that is visible on both white and black. So these next threeSo this first codon right over here, we see it's AUG, so theAnd this has, this codon,AUG is know as the start codon. Start codon. This is where the ribosomeSo how does that actually happen. How do we get from theseWell let's think about it, how many, how many possible threeWell, there are, there are four possibleThere's four possible things that could be in the second place, and there's four possibleSo there are 64 possible permutations. 4 times 4 times 4.https://totalyoumovement.com/wp-content/plugins/formcraft/file-upload/server/content/files/162914402d6b24---753-service-manual.pdf Permutations, so you canSo we have more than enough,And it's not hard to find tablesSo you can see here, youAUG, adenine, uracil, guanine. That codes for methanine. Right over here. You could do that with any of them, you could say cytosine, uracil, uracil, that codes for leucine. And you can see that it'sAnd so it turns out that 61 of the codons, let me write this down. So 61 of the codons, of the possible 64, code for amino acids, amino acids, and three play a roleUAA, UAG, UGA, that'sSo AUG, that's a start codon, and it codes for methionine. So that lets you know thatBut how do, how does the amino acid actually get, how do theyAnd how do they get matched up, how do they actually get matched up with the appropriate codon. And that's where we haveSo tRNA, the t stands for transfer, transfer RNA. There's a bunch of different tRNAs that each combined toThat pair with the appropriate codon. So this tRNA, and that'sAnd then at the other end of the molecule, though that's in the middleAnd your anticodon matchesAnd so this is how they bumpAnd if we look at whatSo this is a strand of tRNA, you get a sense of, okay,But then it wraps around itself to form this fairly complex molecule. And the anticodon, which is right here, it's kind of in theSo I know what you're thinking, alright, I see that the ribosome,I see how the appropriate tRNA can bring the appropriate amino acid, but how does the chain actually form. And you can view this in three steps, and associated with thoseAnd the three sites, weA, or yellow, alright, let me write it in blue. So that is the A-site. This is the P-site, and this is the E-site. And I'll talk in a secondAnd so you can see, we'reSo why is that called the A-site. Well A stands for aminoacyl. An easy way to remember it it's the tRNA, it's theAnd so once that happens, once this character comes here, let me draw that. Once this character comes right over here, it's gonna be AUA, and it's bound to the tyrosine.http://www.unidacardoso.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/162914404e48d9---7535-g2-service-manual.pdf Well then you couldSo this, this tRNA will then be in the E-site. This tRNA will then be in the P-site, and then the A-site will beSo what this, what do the. P and E sites stand for. Well you can see a little bitSo the P-site is where youAnd then the ribosome is going to shift, once this is bound, the ribosome, the peptide bond forms,It is now ready to exit, and that's why it's called the E-site. Because that's the siteAnd when you get toThis is, and in fact ifAnd so if you have bacteriaOur mission is to provide a free, world-class education to anyone, anywhere. Khan Academy is a 501(c)(3) nonprofit organization. Donate or volunteer today. The process of translation can be seen as the decoding of instructions for making proteins, involving mRNA in transcription as well as tRNA. In the simplest sense, expressing a gene means manufacturing its corresponding protein, and this multilayered process has two major steps. In the first step, the information in DNA is transferred to a messenger RNA ( mRNA ) molecule by way of a process called transcription. During transcription, the DNA of a gene serves as a template for complementary base-pairing, and an enzyme called RNA polymerase II catalyzes the formation of a pre-mRNA molecule, which is then processed to form mature mRNA (Figure 1). The resulting mRNA is a single-stranded copy of the gene, which next must be translated into a protein molecule. Figure 1: A gene is expressed through the processes of transcription and translation. During transcription, the enzyme RNA polymerase (green) uses DNA as a template to produce a pre-mRNA transcript (pink). Each group of three bases in mRNA constitutes a codon, and each codon specifies a particular amino acid (hence, it is a triplet code ). The mRNA sequence is thus used as a template to assemble—in order—the chain of amino acids that form a protein. Figure 2: The amino acids specified by each mRNA codon. Multiple codons can code for the same amino acid.www.futong365.com/d/files/conair-beard-trimmer-manual.pdf The codons are written 5' to 3', as they appear in the mRNA. Figure Detail But where does translation take place within a cell. What individual substeps are a part of this process. And does translation differ between prokaryotes and eukaryotes. The answers to questions such as these reveal a great deal about the essential similarities between all species. Where Translation Occurs Within all cells, the translation machinery resides within a specialized organelle called the ribosome. In eukaryotes, mature mRNA molecules must leave the nucleus and travel to the cytoplasm, where the ribosomes are located. On the other hand, in prokaryotic organisms, ribosomes can attach to mRNA while it is still being transcribed. In this situation, translation begins at the 5' end of the mRNA while the 3' end is still attached to DNA. In all types of cells, the ribosome is composed of two subunits: the large (50S) subunit and the small (30S) subunit (S, for svedberg unit, is a measure of sedimentation velocity and, therefore, mass). Each subunit exists separately in the cytoplasm, but the two join together on the mRNA molecule. The ribosomal subunits contain proteins and specialized RNA molecules—specifically, ribosomal RNA ( rRNA ) and transfer RNA ( tRNA ). The tRNA molecules are adaptor molecules—they have one end that can read the triplet code in the mRNA through complementary base-pairing, and another end that attaches to a specific amino acid (Chapeville et al., 1962; Grunberger et al., 1969). The idea that tRNA was an adaptor molecule was first proposed by Francis Crick, co-discoverer of DNA structure, who did much of the key work in deciphering the genetic code (Crick, 1958). Within the ribosome, the mRNA and aminoacyl-tRNA complexes are held together closely, which facilitates base-pairing. The rRNA catalyzes the attachment of each new amino acid to the growing chain. The Beginning of mRNA Is Not Translated Interestingly, not all regions of an mRNA molecule correspond to particular amino acids. In particular, there is an area near the 5' end of the molecule that is known as the untranslated region (UTR) or leader sequence. This portion of mRNA is located between the first nucleotide that is transcribed and the start codon (AUG) of the coding region, and it does not affect the sequence of amino acids in a protein (Figure 3). So, what is the purpose of the UTR. It turns out that the leader sequence is important because it contains a ribosome-binding site. In bacteria, this site is known as the Shine-Dalgarno box (AGGAGG), after scientists John Shine and Lynn Dalgarno, who first characterized it. A similar site in vertebrates was characterized by Marilyn Kozak and is thus known as the Kozak box. In bacterial mRNA, the 5' UTR is normally short; in human mRNA, the median length of the 5' UTR is about 170 nucleotides. If the leader is long, it may contain regulatory sequences, including binding sites for proteins, that can affect the stability of the mRNA or the efficiency of its translation. Figure 3: A DNA transcription unit. A DNA transcription unit is composed, from its 3' to 5' end, of an RNA-coding region (pink rectangle) flanked by a promoter region (green rectangle) and a terminator region (black rectangle). Genetics: A Conceptual Approach, 2nd ed. All rights reserved. Translation Begins After the Assembly of a Complex Structure The translation of mRNA begins with the formation of a complex on the mRNA (Figure 4). First, three initiation factor proteins (known as IF1, IF2, and IF3) bind to the small subunit of the ribosome. This preinitiation complex and a methionine-carrying tRNA then bind to the mRNA, near the AUG start codon, forming the initiation complex. Figure 4: The translation initiation complex. When translation begins, the small subunit of the ribosome and an initiator tRNA molecule assemble on the mRNA transcript. The small subunit of the ribosome has three binding sites: an amino acid site (A), a polypeptide site (P), and an exit site (E). The initiator tRNA molecule carrying the amino acid methionine binds to the AUG start codon of the mRNA transcript at the ribosome’s P site where it will become the first amino acid incorporated into the growing polypeptide chain. Here, the initiator tRNA molecule is shown binding after the small ribosomal subunit has assembled on the mRNA; the order in which this occurs is unique to prokaryotic cells. In eukaryotes, the free initiator tRNA first binds the small ribosomal subunit to form a complex. Figure Detail Although methionine (Met) is the first amino acid incorporated into any new protein, it is not always the first amino acid in mature proteins—in many proteins, methionine is removed after translation. In fact, if a large number of proteins are sequenced and compared with their known gene sequences, methionine (or formylmethionine) occurs at the N-terminus of all of them. However, not all amino acids are equally likely to occur second in the chain, and the second amino acid influences whether the initial methionine is enzymatically removed. For example, many proteins begin with methionine followed by alanine. In both prokaryotes and eukaryotes, these proteins have the methionine removed, so that alanine becomes the N-terminal amino acid (Table 1). However, if the second amino acid is lysine, which is also frequently the case, methionine is not removed (at least in the sample proteins that have been studied thus far). These proteins therefore begin with methionine followed by lysine (Flinta et al., 1986). Table 1 shows the N-terminal sequences of proteins in prokaryotes and eukaryotes, based on a sample of 170 prokaryotic and 120 eukaryotic proteins (Flinta et al., 1986). In the table, M represents methionine, A represents alanine, K represents lysine, S represents serine, and T represents threonine. The large subunit of the ribosome has three sites at which tRNA molecules can bind. The A (amino acid) site is the location at which the aminoacyl-tRNA anticodon base pairs up with the mRNA codon, ensuring that correct amino acid is added to the growing polypeptide chain. The P (polypeptide) site is the location at which the amino acid is transferred from its tRNA to the growing polypeptide chain. The initiator methionine tRNA is the only aminoacyl-tRNA that can bind in the P site of the ribosome, and the A site is aligned with the second mRNA codon. The ribosome is thus ready to bind the second aminoacyl-tRNA at the A site, which will be joined to the initiator methionine by the first peptide bond (Figure 5). Figure 5: The large ribosomal subunit binds to the small ribosomal subunit to complete the initiation complex. The initiator tRNA molecule, carrying the methionine amino acid that will serve as the first amino acid of the polypeptide chain, is bound to the P site on the ribosome. The Elongation Phase Figure 6 Figure Detail The next phase in translation is known as the elongation phase (Figure 6). First, the ribosome moves along the mRNA in the 5'-to-3'direction, which requires the elongation factor G, in a process called translocation. The tRNA that corresponds to the second codon can then bind to the A site, a step that requires elongation factors (in E. coli, these are called EF-Tu and EF-Ts), as well as guanosine triphosphate (GTP) as an energy source for the process. Upon binding of the tRNA-amino acid complex in the A site, GTP is cleaved to form guanosine diphosphate (GDP), then released along with EF-Tu to be recycled by EF-Ts for the next round. Next, peptide bonds between the now-adjacent first and second amino acids are formed through a peptidyl transferase activity. For many years, it was thought that an enzyme catalyzed this step, but recent evidence indicates that the transferase activity is a catalytic function of rRNA (Pierce, 2000). After the peptide bond is formed, the ribosome shifts, or translocates, again, thus causing the tRNA to occupy the E site. The tRNA is then released to the cytoplasm to pick up another amino acid. In addition, the A site is now empty and ready to receive the tRNA for the next codon. This process is repeated until all the codons in the mRNA have been read by tRNA molecules, and the amino acids attached to the tRNAs have been linked together in the growing polypeptide chain in the appropriate order. At this point, translation must be terminated, and the nascent protein must be released from the mRNA and ribosome. Termination of Translation There are three termination codons that are employed at the end of a protein-coding sequence in mRNA: UAA, UAG, and UGA. No tRNAs recognize these codons. Thus, in the place of these tRNAs, one of several proteins, called release factors, binds and facilitates release of the mRNA from the ribosome and subsequent dissociation of the ribosome. Comparing Eukaryotic and Prokaryotic Translation The translation process is very similar in prokaryotes and eukaryotes. Although different elongation, initiation, and termination factors are used, the genetic code is generally identical. As previously noted, in bacteria, transcription and translation take place simultaneously, and mRNAs are relatively short-lived. In eukaryotes, however, mRNAs have highly variable half-lives, are subject to modifications, and must exit the nucleus to be translated; these multiple steps offer additional opportunities to regulate levels of protein production, and thereby fine-tune gene expression. References and Recommended Reading Chapeville, F., et al. On the role of soluble ribonucleic acid in coding for amino acids. Point mutations define a sequence flanking the AUG initiator codon that modulates translation by eukaryotic ribosomes. An analysis of 5'-noncoding sequences from 699 vertebrate messenger RNAs.Do you want to LearnCast this session. Learn more It consists of two major steps: transcription and translation. Together, transcription and translation are known as gene expression. Both RNA and DNA are made up of a chain of nucleotide bases, but they have slightly different chemical properties. The type of RNA that contains the information for making a protein is called messenger RNA (mRNA) because it carries the information, or message, from the DNA out of the nucleus into the cytoplasm. Each sequence of three bases, called a codon, usually codes for one particular amino acid. (Amino acids are the building blocks of proteins.) A type of RNA called transfer RNA (tRNA) assembles the protein, one amino acid at a time. Protein assembly continues until the ribosome encounters a “stop” codon (a sequence of three bases that does not code for an amino acid). It is so important that it is sometimes called the “central dogma.” This tool also gives examples of how modern technologies that target the different stages are used to treat genetic diseases. How do genes direct the production of proteins. Can genes be turned on and off in cells. What is epigenetics. How do cells divide. How do genes control the growth and division of cells. How do geneticists indicate the location of a gene. Other chapters in Help Me Understand Genetics Learn more Users with questions about a personal health condition should consult with a qualified healthcare professional. Google Classroom Facebook Twitter Email Translation Translation (mRNA to protein) Overview of translation Retroviruses Differences in translation between prokaryotes and eukaryotes DNA replication and RNA transcription and translation Intro to gene expression (central dogma) The genetic code This is the currently selected item. Our mission is to provide a free, world-class education to anyone, anywhere.