WGU C785 OA Biochem Final Exam 2023

WGU C785 OA Biochem Final Exam 2023 1. What is the complementary sequence to 3’ ATG CGA ATA 5’? * 1/1 3’ TAT TCG CAT 5’ 3’ TAC GCT TAT 5’ 3’ GAT AGC ATA 5’ 5’ ATA AGC GTA 3’ Feedback The correct answer is 3' TAT TCG CAT 5'. Remember complementary means “Matching or Pairing” You have to remember to pay attention to your numbers as well as your letters (A-T, G-C, 5'-3'). The correct answer is 3’ ATG CGA ATA 5’ (original sequence) 5’ TAC GCT TAT 3’ (complementary sequence) But we asked for it in the 3’ direction, so mirror answer to give correct answer: 3’ TAT TCG CAT 5’ 2. Which amino acid sequence would result from this Coding DNA strand? 3’ ATG CAG ATA 5’? * 1/1 Tyr Val Tyr Ile Gln Ile Ile Asp Val Leu His Lys Feedback The correct answer is Ile Asp Val. We are starting at the coding strand, and have to remember the relationship between coding DNA and mRNA. These two strands are non-complementary and parallel. So we copy the coding strand , change T ---> U, and then write the mRNA sequence: 3’ ATG CAG ATA 5’ coding 3’ AUG CAG AUA 5’ mRNA Mirror by changing orientation: 5’ AUA GAC GUA 3’ Read chart Ile Asp Val (chart is in direction of 5' ---> 3') 3. Which amino acid sequence would be made from this template DNA strand? 5’ TAT TAC CGA 3’? * 0/1 Tyr Tyr Arg Ile Met Ala Ser Val Ile Ser His Gln Correct answer Ser Val Ile Feedback The correct answer is C because 5’ TAT TAC CGA 3’ template is complementary and antiparallel so 3’ AUA AUG GCU 5’ but it is in the wrong orientation, so mirror 5’ UCG GUA AUA 3’ and read the chart Ser Val Ile 4. Which of the following are the correct components for a PCR reaction? * 1/1 dNTPs, Primer, RNA Polymerase, template RNA dNTPs, Primer, DNA Polymerase, template DNA ATP, Primer, mRNA polymerase; template mRNA Acetyl CoA, RNA primer, DNA Ligase, Template phosphate Feedback The correct answer is b 5. If you had a mother who is homozygous for a recessive disease, and a father who is a heterozygous carrier, what percentage of children will have the disease? * 1/1 0% 25% 50% 75% 100% Feedback The correct answer is c 50% Homozygous recessive: aa Heterozygous: Aa 6. Which of the following would represent a silent mutation if this is the original sequence: 5’ AUC GUA ACA 3’? * 1/1 5’ AUC GGA ACA 3’ 5’ AUA GUA ACA 3’ 5’ AUC GUA UAA 3’ 5’ AUC CUC ACA 3’ Feedback The correct answer is B AUC GUA ACA Ile Val Thr Ile Gly Thr Missense Ile Val Thr Ile Val STOP nonsense Ile Leu Thr Missense 7. If the original coding sequence is 5’ CGA TAC TTC AGA 3’ and it is mutated to 5' CGA TAT TTC AGA 3', what type of mutation would have taken place? * 1/1 Silent Missense Nonsense Insertion Feedback The correct answer is A: silent mutation. The nucleotide sequence changes, but it codes for the same amino acid 8. Huntington's is an autosomal dominant disorder. Which of the following chromosome pairs would be inherited by a person with Huntington's Disease? (Yellow box = Dominant allele, Green box = Recessive allele) * 1/1 Option 1 Option 2 Option 3 Option 4 Feedback The correct answer is A because an autosomal dominant disorder would be inherited on numbered chromosomes, not sex chromosomes X or Y. Also, at least one dominant allele (yellow box) needs to be present for the individual to have the dominant disease. 9. The pedigree below tracks Duchenne Muscular Dystrophy (DMD) through several generations. What type of inheritance does DMD express? * 0/1 Autosomal dominant Autosomal recessive X-linked Dominant X- Linked recessive Correct answer X- Linked recessive Feedback The correct answer is x- linked recessive because parents do not have it (II-5-6) but a child does III- 5 10. Rett syndrome is a brain disorder that occurs almost exclusively in females, causing severe deficits in language, learning, coordination and other brain functions. Decreased expression of the MECP2 gene causes Rett syndrome. Which of the following scenarios correctly describes how Rett syndrome could be developed? * 1/1 A DNA-binding protein blocks RNA Polymerase from binding to the promoter sequence, facilitating the transcription of the MECP2 gene. Transcription factors are unable to bind to the transcription start site of the MECP2 gene because nucleosomes are tightly packed together. Transcription activators cause nucleosomes to separate, exposing the MECP2 gene. RNA Polymerase binds to the MECP2 gene and begins translation. Feedback The answer is B. Gene expression is increased when nucleosomes are widely spaced and transcription factors and RNA Polymerase are able to bind to the transcription start site of the gene. 11. Which of the following strands are complementary and anti- parallel? * 1/1 Coding and Non-template Template and mRNA Coding and mRNA Template and tRNA Feedback The correct answer is B. The template and mRNA strands are complementary to each other. 12. What is the correct order of the Central Dogma? * 1/1 Translation, Replication, Transcription Transcription, Replication, Translation Translation, Transcription, Replication Replication, Transcription, Translation Feedback The correct answer is D 13. What happens when the incorrect base is added during the synthesis of a DNA strand in DNA replication? * 1/1 The homologous chromosome is used to replace the incorrectly added base with the correct one. DNA Polymerase removes the incorrect base and adds in the correct base. Thymine dimers occur. Distortion of the double helix occurs and is repaired by RNA Polymerase. Feedback The correct answer is B. DNA Polymerase repairs mismatch errors that occur during DNA replication. 14. What is the correct definition of nucleotide excision repair? * 1/1 Removal of a single damaged nucleotide Damage to a few or several nucleotides are identified, then many nucleotides are removed and all are replaced to repair the DNA segment Required when there are breaks in the double stranded DNA strand which causes discontinuity in both strands Insertion of a thymine dimer Feedback The correct answer is B, several nucleotides are removed where in BER a single nucleotide is removed 15. What type of interactions would be affected in a patient with diabetic ketoacidosis? (select all that apply) * 0/1 Hydrogen bonds Ionic bonds Hydrophobic interactions Disulfide bonds Correct answer Hydrogen bonds Ionic bonds Feedback B and A are affected by a change in pH 16. On a hot summer's day, I was cleaning my garage. My cat Sophie was out with me, and got into a bottle containing a strong reducing agent. Of course I took her straight to the vet. What type of amino acid bonds would be disrupted by exposure to the strong reducing agent? * 1/1 Hydrophobic interactions Hydrogen bonds Disulfide bonds Ionic bonds Feedback The correct answer are covalent (disulfide) bonds C 17. What type of bond can the amino acids below form to stabilize the tertiary structure of a protein? * 1/1 Ionic bond Hydrophobic interaction Hydrogen bond Disulfide bond Feedback The correct answer is hydrogen bonds C 18. What type of reaction forms the primary structure of a protein? * 1/1 Activation energy Enzymes Dehydration Hydrolysis Feedback The correct answer is a dehydration reaction C 19. Myoglobin is an oxygen storage protein and exhibits a hyperbolic curve in an oxygen saturation graph. What is the highest level of protein structure exhibited by myoglobin? * 1/1 Primary Secondary Tertiary Quaternary Feedback Tertiary, myoglobin is a single subunit protein C