The first step in making a protein is transcription of a gene. This occurs in the 1._______of a eukaryotic cell. An enzyme called 2.______ carrres out the process of transcribing RNA from the DNA. It starts at a specific nucleotide sequence called a 3.______ next to the gene. RNA polymerase attaches, and the two DNA strands separate. RNA polymerase moves along one strand, and as it does, RNA 4._____________ take their places one at a time along the DNA template. They hydrogenbond with complementary bases, following the same pairing rules as in DNA--{ with G, and U (replacing T in RNA) with A. As the RNA molecule elongates, it peels away from the DNA. Finally, the enzyme reaches the 5._______. a base sequence that signals the end of the gene, and the polymerase molecule lets go of the gene and the RNA molecule. In a prokaryote, the RNA transcribed from a gene, called 6.________ (mRNA), can be used immediately in polypeptide synthesis. In a eukaryotic cell, the RNA is further modified, or 7.________ before leaving the nucleus as mRNA. Extra nucleotides are added to the ends of the transcript, and noncoding regions called 8.________ are removed. The remaining 9._________ are spliced together to from a continuous coding sequence. The finished mRNA leaves the nucleus and enters the 10.________ where translation takes place.
Translation of the "words" of the mRNA message into the 11._______ quence of a protein requires an interpreter-l2.______ (tRNA)-which links the appropriate 13._______ with each 14.______ in the mRNA message. A IRNA molecule is a folded strand of RNA. At one end, a special 15._____ attaches a specific amino acid. The other end of the IRNA molecule bears three bases called the 16.________ which is complementary to a particular mRNA codon. During the translation process, the IRNA matches its amino acid with an mRNA codon.
17._______are the "factories" where the information in mRNA is translated and polypeptide chains are constructed. A ribosome consists of protein and 18.______ (rRNA). Each ribosome has a groove that serves as a binding site for nRNA. There are two binding sites for IRNA: The P site holds the IRNA carrying the growing 19._____, while the A site holds a tRNA bearing the next amino acid.
Translation begins with initiation. An mRNA and a special 20._______ tRNA bind to the ribosome and a specific mRNA codon, the 21.________ where translation begins. The initiator IRNA generally carries the amino acid methionine (Met). Its anticodon UAC binds to the start codon. AUG. The initiator IRNA fits into the P site on the ribosome.
The next step in 22._____ synthesis is elongation-adding amino acids to the growing chain. The anticodon of an incoming IRNA, carrying its amino acid, pairs with the mRNA codon at the open A site. With help from the ribosome, the polypeptide separates from its IRNA and forms a peptide bond with the 23.______ attached to the IRNA in the A site. Then the "empty" tRNA in the P site leaves the ribosome, and the IRNA in the A site, with the polypeptide chain, is shifted to the P site. The mRNA and IRNA move as a unit, allowing the next codon to enter the A site. Another IRNA, with a complementary anticodon, brings its amino acid to the A site. Its amino acid is added to the chain, the IRNA leaves, and the complex shifts again. In this way,24._______ added to the chain, one at a time.
Finally, a 25.______ reaches the A site of the 26.________ terminating the polypeptide. A stop codon causes the polypeptide to separate from the last tRNA and the 27._______ . The polypeptide folds up, and it may join with other polypeptides to form a Iarger 28.______ molecule.
nucleus
1. The first step in making a protein occurs in the "kitchen" of a eukaryotic cell.
2. An enzyme called "Gene Genie" carries out the process of transcribing RNA from the DNA.
3. It starts at a specific nucleotide sequence called a "secret handshake" next to the gene.
4. RNA "party crashers" take their places one at a time along the DNA template.
5. Finally, the enzyme reaches the "exit sign," a base sequence that signals the end of the gene.
6. In a prokaryote, the RNA transcribed from a gene, called "mRNA Express," can be used immediately in polypeptide synthesis.
7. In a eukaryotic cell, the RNA is further modified, or "glamorized," before leaving the nucleus as mRNA.
8. Extra nucleotides are added to the ends of the transcript, and noncoding regions called "Gibberish Junctions" are removed.
9. The remaining "coding party animals" are spliced together to form a continuous coding sequence.
10. The finished mRNA leaves the nucleus and enters the "protein dance club" where translation takes place.
11. Translation of the "words" of the mRNA message into the "secret recipe" of a protein requires an interpreter called "tRNA Master" which links the appropriate "ingredients" with each "step" in the mRNA message.
12. A tRNA molecule is a folded strand of RNA. At one end, a special "chef's hat" attaches a specific amino acid.
13. The other end of the tRNA molecule bears three bases called the "menu," which is complementary to a particular mRNA codon.
14. During the translation process, the tRNA matches its amino acid with an mRNA codon.
17. Ribosomes are the "factories" where the information in mRNA is translated and polypeptide chains are constructed. A ribosome consists of protein and "ribosome rats" (rRNA).
18. Each ribosome has a groove that serves as a binding site for mRNA.
19. There are two binding sites for tRNA: The P site holds the tRNA carrying the growing "protein building block," while the A site holds a tRNA bearing the next amino acid.
20. Translation begins with initiation. An mRNA and a special "VIP" tRNA bind to the ribosome at a specific mRNA codon, the "red carpet" where translation begins.
21. The initiator tRNA generally carries the amino acid methionine (Met). Its anticodon UAC binds to the start codon AUG. The initiator tRNA fits into the P site on the ribosome.
22. The next step in protein synthesis is elongation-adding amino acids to the growing chain. The anticodon of an incoming tRNA, carrying its amino acid, pairs with the mRNA codon at the open A site.
23. With help from the ribosome, the polypeptide separates from its tRNA and forms a peptide bond with the "waiter" attached to the tRNA in the A site.
24. Then the "empty" tRNA in the P site leaves the ribosome, and the tRNA in the A site, with the polypeptide chain, is shifted to the P site. The mRNA and tRNA move as a unit, allowing the next codon to enter the A site. Another tRNA, with a complementary anticodon, brings its amino acid to the A site. Its amino acid is added to the chain, the tRNA leaves, and the complex shifts again. In this way, "protein party animals" are added to the chain, one at a time.
25. Finally, a "party pooper" reaches the A site of the "dance floor," terminating the polypeptide. A stop codon causes the polypeptide to separate from the last tRNA and the ribosome.
26. The polypeptide folds up, and it may join with other polypeptides to form a larger "protein masterpiece" molecule.
1. The first step in making a protein is transcription of a gene. The transcription process occurs in the nucleus of a eukaryotic cell.
2. An enzyme called RNA polymerase carries out the process of transcribing RNA from the DNA.
3. Transcription starts at a specific nucleotide sequence called a Promoter next to the gene.
4. RNA nucleotides (A, U, G, C) take their places one at a time along the DNA template, and they hydrogen bond with complementary bases following the same pairing rules as in DNA.
5. Finally, the enzyme reaches the Terminator, which is a base sequence that signals the end of the gene, and the RNA polymerase molecule lets go of the gene and the RNA molecule.
6. In a prokaryote, the RNA transcribed from a gene, called messenger RNA (mRNA), can be used immediately in polypeptide synthesis.
7. In a eukaryotic cell, the RNA is further modified, or processed, before leaving the nucleus as mRNA. Extra nucleotides are added to the ends of the transcript, and noncoding regions called introns are removed.
8. The remaining exons are spliced together to form a continuous coding sequence.
9. The finished mRNA leaves the nucleus and enters the cytoplasm where translation takes place.
10. Translation of the "words" of the mRNA message into the amino acid sequence of a protein occurs in the ribosomes.
11. A genetic code is the sequence of nucleotides in mRNA that determines the sequence of amino acids in a protein.
12. Transfer RNA (tRNA) acts as an interpreter during translation. It links the appropriate amino acids with each codon in the mRNA message.
13. Each tRNA molecule is a folded strand of RNA that has a specific anticodon, which is complementary to a particular mRNA codon.
14. During the translation process, the tRNA matches its anticodon with an mRNA codon, bringing the corresponding amino acid.
15. At one end of the tRNA molecule, a special amino acid attachment site attaches a specific amino acid.
16. The other end of the tRNA molecule bears three bases called the anticodon, which is complementary to a particular mRNA codon.
17. Ribosomes are the "factories" where the information in mRNA is translated, and polypeptide chains are constructed. Ribosomes consist of protein and ribosomal RNA (rRNA).
18. Each ribosome has a groove that serves as a binding site for mRNA.
19. There are two binding sites for tRNA in a ribosome: the P site holds the tRNA carrying the growing polypeptide chain, while the A site holds a tRNA bearing the next amino acid.
20. Translation begins with initiation, where an mRNA and a special initiator tRNA bind to the ribosome at a specific mRNA codon, called the start codon.
21. The initiator tRNA generally carries the amino acid methionine (Met), and its anticodon UAC binds to the start codon AUG. The initiator tRNA fits into the P site on the ribosome.
22. The next step in protein synthesis is elongation, where amino acids are added to the growing polypeptide chain.
23. The anticodon of an incoming tRNA, carrying its amino acid, pairs with the mRNA codon at the open A site. The polypeptide separates from its tRNA and forms a peptide bond with the amino acid attached to the tRNA in the A site.
24. The "empty" tRNA in the P site leaves the ribosome, and the tRNA in the A site, with the polypeptide chain, is shifted to the P site. The mRNA and tRNA move as a unit, allowing the next codon to enter the A site. Another tRNA, with a complementary anticodon, brings its amino acid to the A site, which gets added to the growing chain.
25. Finally, a stop codon reaches the A site of the ribosome, terminating the polypeptide. The stop codon causes the polypeptide to separate from the last tRNA and the ribosome.
26. The polypeptide folds up, and it may join with other polypeptides to form a larger protein molecule.
The first step in making a protein is transcription of a gene. This occurs in the 1._______of a eukaryotic cell. An enzyme called 2.____
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