Transcription and Translation PDF

# Transcription and Translation ## Part 1: Transcription and Translation ### 1. Processes in Eukaryotic Cells - **Replication** takes place in the nucleus. - **Transcription** takes place in the nucleus. - **Translation** takes place in the cytoplasm. ### 2. DNA vs. RNA | Feature | DNA | RNA |...

# Transcription and Translation ## Part 1: Transcription and Translation ### 1. Processes in Eukaryotic Cells - **Replication** takes place in the nucleus. - **Transcription** takes place in the nucleus. - **Translation** takes place in the cytoplasm. ### 2. DNA vs. RNA | Feature | DNA | RNA | |---|---|---| | Sugar | Deoxyribose | Ribose | | Bases | A, C, G, T | A, C, G, U | | Strands | Double | Single | ### 3. Enzyme for RNA Synthesis The enzyme that helps to make a strand of RNA is called **RNA polymerase**. ### 4. Transcription Complex A large transcription complex, including RNA polymerase and other proteins, assembles at the start of a gene and begins to unwind the **DNA**. ### 5. Complementary Strand of RNA Using one strand of the DNA as a template, **RNA polymerase** strings together a complementary strand of RNA. ### 6. DNA and RNA Separation The RNA strand **detaches** from the DNA as it is transcribed, and the DNA zips back together. ## Part 2: Mutations ### 7. Types of RNA * **tRNA**: brings amino acids from the cytoplasm to a ribosome to help make the growing protein. * **rRNA**: forms part of ribosomes. * **mRNA**: is an intermediate message that is translated to form a protein. ### 8. Ribosome Subunits The **large** subunit of a ribosome holds onto the mRNA strand. The **large** subunit of a ribosome has binding sites for tRNA. ### 9. tRNA Structure A tRNA molecule is attached to an **amino acid** at one end and has an **anticodon** at the other end. ### 10. Steps of Translation **A.** The ribosome pulls the mRNA strand the length of one codon, the first tRNA exits the ribosome, and another codon is exposed. **B.** The ribosome forms a peptide bond between the amino acids. It breaks the bond between the first amino acid and tRNA. **C.** An exposed codon attracts a complementary tRNA bearing an amino acid. ## Part 3: Fill in the Blank 1. Translation is the process that converts an mRNA message into a **polypeptide**. 2. A codon is a sequence of **three** nucleotides that code for an amino acid. 3. A reading frame is the order in which **nucleotides** are read. 4. AGG, GCA, and GUU are examples of **codons**. 5. A(n) **anticodon** is a set of three nucleotides on a tRNA molecule that is complementary to an mRNA codon. 6. A **stop codon** indicates where translation is to stop. ## Part 4: Mutations **A.** ATGCGTCCATGA **B.** ATGCGTCCATGA **C.** [ATG] C[GT] C[CAT] GA ### 17. Definition of Mutation A mutation is a change in an organism's **DNA**. ### 18. DNA Polymerase and Errors Can DNA polymerase catch and correct every replication error? **No**. ### 19. Mutagen An agent in the environment that can change DNA is called a **mutagen**. ### 20. UV Light Damage UV light damages a DNA strand by causing neighboring **thymine** nucleotides to break their hydrogen bonds to adenine and bond with each other instead. ### 21. Frameshift Mutation If a nucleotide is deleted from DNA, what type of mutation has occurred? **Frameshift mutation**. ## Part 5: Short Answer ### 22. Amino Acid Sequence Given the following DNA sequence, write the amino acid sequence that would result. DNA Sequence: TAC TAT ACC GGT ACT AUG AUA UGG CCA UGA **Methionine-Isoleucine-Tryptophan-Proline-STOP** ### 23. Reasons Why Point Mutations May Not Result in Problems Point mutations do not always result in problems for the organism. Here are three reasons why: 1. **Excess in the genetic code:** Some amino acids are coded by more than one codon, so a substitution may still result in the same amino acid. 2. **Silent mutations:** A mutation might change a codon to another codon that codes for the same amino acid. 3. **Location of mutation:** If the mutation occurs in a non-coding region or does not affect a crucial part of the protein, the function may not be impacted.