Gene Expression REVIEW Packet

Transcription

1 Name Pd. # Gene Expression REVIEW Packet 1. Fill-in-the-blank General Summary Transcription & the Big picture Like, ribonucleic acid (RNA) is a acid a molecule made of nucleotides linked together. RNA differs from in three ways. First, RNA consists of a strand of nucleotides instead of the two strands found in. Second, RNA nucleotides contain the five-carbon sugar rather than the sugar deoxyribose found in nucleotides. And third, RNA has a nitrogen base called (abbreviated as U) instead of the base (T) found in. No thymine (T) bases are found in RNA. Like thymine, uracil is complementary to whenever RNA base-pairs with another nucleic acid. 2. Defining and comparing Replication and Transcription a-define the following processes: -Replication -Transcription b-comparing the two processes. Think about this, and try to give 2 items for each box: How are these two processes SIMILAR How are these two processes DIFFERENT? 3. RNA vs Decide if each statement describes only, RNA only, both, or neither. Then check the appropriate column or columns (or neither!) a b c d e f g h i j k made of nucleotides single strand of nucleotides double helix contains amino acids contains uracil contains thymine contains adenine contains sugar contains deoxyribose contains ribose contains phosphate RNA l m n o p q r s t is a nucleic acid contains a base that pairs with adenine used as a template for making nucleic acid used in transcription used in replication used in translation does not leave the nucleus leaves the nucleus has more than one form RNA 1

2 4. Location, location, location Where within the cell does each of the following occur? a-replication? b-transcription? c-translation? 5. Transcription Practice Transcribe mrna from the following segments: a-ctccgat b-taacgtagttc c-attgctagt 6. Transcription Labeling #1 In transcription, RNA polymerase splits the two halves of a strand of. RNA then uses one half as a template to make a copy of the other half. RNA contains the nucleotide uracil instead of the nucleotide thymine. Label the and RNA. Then, label the missing nucleotides marked on the diagram. #6 7. Transcription Labeling #2 Label the following items: -RNA polymerase - coding strand - non-coding strand -mrna #7 8. RNA Labeling a-label these 3 types of RNA molecules b-circle the molecule in charge of bringing amino acids to the ribosome. c-put an X on the molecule that represents a temporary copy of. 9. Big Picture review a-groups of nitrogen bases are translated into amino acids. These trios bases are called, and they are located on RNA molecules. Amino acids are the building blocks of. 2

3 Translation 10. Translation Labeling #1 Review: During translation, transfer RNA(tRNA) anticodons match to messenger RNA(mRNA) codons. Each trna molecule can carry one particular amino acid. The amino acids are joined to form a polypeptide (protein). The Diagram: Below is a strand of mrna that needs to be translated into protein, and the 4 trna s that will match up with it. a-below the four trna anticodons, write the numbers 1-4 to show the order in which they would appear to match the codons in the mrna strand. b-below the mrna, identify which amino acid would be brought to make the protein. (Be Careful! Before you do this, make sure to read the TITLE of the table in the notes.) a-order of trna s b-amino acids: 11. Translation Labeling #2 First, locate these 2 items and label them: A-mRNA segment leaving the nucleus B-mRNA segment at the ribosome Then label the following items: C-tRNA D-ribosome E-a codon F-an anticodon G-use the table to identify the three specific amino acids on the 3 trna s) H-nucleus 12. Bio-Math Challenge: Alien codons a-with codons being 3 bases long, there are different combinations. Since there are only amino acids, there is quite enough for each amino acid to have its own word to stand for it. b-if you discovered a planet whose residents had 2-base codons, what is the maximum number of amino acids they could use? (Forget about stop codons for now.) c-let s say these aliens had only 2-base codons, but they also had a 5 th base (let s call it Biligine). THEN how many amino acids could they accommodate? (Forget about stop codons again.) 3

4 13. Translation practice a-identify the process responsible by writing its name in column B. b-complete column C by writing the mrna nitrogen bases that would match up with the bases in column A. Because you re making RNA, you should use the letters A, U, C & G. c-identify the process responsible by writing its name in column D. d-complete column E by writing the correct bases for the trna anticodon that bonds to each codon from column C. e-complete column F by writing the name of the correct amino acid that is coded by each base sequence. Use the table in your notes to translate the mrna (not trna!!) base sequences to amino acids for column F. A B C D E F (base sequence) Name of the process of converting from mrna mrna codon Name of the process of converting from mrna protein trna anticodon Amino acid AAT UUA GGG ATA AAA 14. Big Picture Labeling 1 Label this diagram using the word bank: Word Bank Nucleus Cytoplasm mrna leaving through Nuclear Pore unzipping mrna (label 2x) Transcription Growing Protein trna individual Amino Acids Ribosome 4

5 15. Decoding Complete the table below showing sequences of, mrna codons, anticodons, and corresponding amino acids. Use the list of mrna codons in the table in your notes to help you complete this exercise. Remember that the genetic code is based on mrna codons. Some have been done for you. mrna codon Anticodon Amino Acid Tryptophan (trp) UUC GAT UAU 16. Explanations! a-describe the structure of the trna molecule. Label its anticodon, too b-explain why specific base-paring is essential to the processes of transcription and translation. c-the structure (shape) and function (job) of a protein is determined by its sequence of what? 17. Big Picture Labeling 2 Label the following items on the diagram: a-trna b-amino acids attached to a trna c-ribosome d-growing protein chain e-mrna f-a codon g-an anticodon h-free-floating amino acids i-a trna that has just given up its amino acid and hasn t replaced it yet j-peptide bond (pick one) *What process is shown here? 5

6 Mutations! 18. Types of mutations ABOVE THE ARROWS each of these diagrams shows a strand of normal, plus the strand of mrna transcribed from it, and the protein strand made from that. BELOW THE ARROWS, a slightly mutated piece of is shown, along with the corresponding mrna and protein strands. Label which of the 3 examples represents which types of mutations A-substitution B-insertion C-deletion 19. Mutation Practice a-determine how the mutations below will affect each amino acid sequence. Use your translation chart to complete this table. In the space provided, write the names of the amino acids that correspond to each mrna sequence and mutation given. An example is provided for you. b-what kind of mutation occurred to the mrna sequence in item d? Explain. mrna Sequence Amino Acid sequence e.g. original UGU- CCG cysteine-proline mutated UGC-CGC cysteine-arginine a original GAA-CGU mutated GAU-CGU b original AUC-UGC mutated AUC-UGG c original UGU-CCU-CCU mutated UGU-UUC-CCU d original GGG-UUA-ACC mutated GGU-UAA-CC 6