Molecular Biology And Diagnostic MLS312 Finals Mock Exam PDF

MOLECULAR BIOLOGY AND DIAGNOSTIC MLS312 3RD YEAR - SECOND SEMESTER FINALS MOCK EXAM 6. Which of the following components is involved in the...

MOLECULAR BIOLOGY AND DIAGNOSTIC MLS312 3RD YEAR - SECOND SEMESTER FINALS MOCK EXAM 6. Which of the following components is involved in the initiation of transcription? 1. Which of the following describes RNA? a. Terminator sequence a. RNA is usually double-stranded and contains the b. RNA polymerase base thymine c. Mature mRNA b. RNA is longer than DNA and uses five bases to d. Ribosome encode information RNA polymerase, an enzyme, is crucial for initiating c. RNA is usually single-stranded and contains the transcription, the process of copying DNA into RNA. The base uracil terminator sequence marks the end of the transcribed region. d. RNA is made in the nucleus of eukaryotic cells and stays there to carry out its functions 7. Which of the following types of RNA codes for a RNA (ribonucleic acid) is typically single-stranded, unlike DNA protein? (deoxyribonucleic acid) which is double-stranded. a. rRNA RNA uses uracil (U) instead of thymine (T) as a base to pair with b. tRNA adenine (A). c. mRNA d. snRNA 2. During RNA splicing, the 2'OH of the adenosine nucleotide attacks the: mRNA (messenger RNA) carries the genetic code from DNA a. Branch point cytosine and is used by ribosomes to build proteins during translation. b. Branch point thymine rRNA (ribosomal RNA) and tRNA (transfer RNA) are involved c. Branch point guanine in the translation process but don't code for proteins. d. Branch point adenine During RNA splicing, a specific adenine nucleotide in the intron 8. What is made during transcription? (non-coding region) attacks the phosphate group linked to the a. Protein 2'OH of a specific cytosine nucleotide in the intron, leading to b. RNA intron removal and exon (coding region) joining. c. DNA d. Carbohydrate 3. Alternative RNA splicing involves: Transcription utilizes DNA as a template to synthesize RNA. a. Removing introns and splicing the same exons together b. Removing introns and splicing different exons 9. When a base is inserted into a DNA sequence, it together will most likely cause: c. Removing exons and splicing different introns a. A silent mutation together b. A frameshift mutation d. Removing exons and splicing different introns c. No change together A base inserted into the DNA sequence disrupts the reading Alternative splicing allows a single pre-mRNA to be processed frame downstream, causing a frameshift mutation. This can into different mature mRNAs (messenger RNAs) by including lead to significant changes in the protein sequence. Silent or excluding different exons. This increases protein diversity 10. Which of the following enzymes is responsible for mutations don't affect the amino acid sequence. from a single gene. RNA synthesis in eukaryotes? a. DNA polymerase I b. DNA polymerase II 4. The protein and RNA complex that removes introns and connects exons is called the: c. RNA polymerase II a. Sigma factor d. RNA polymerase III b. RNA polymerase RNA polymerase II is the primary enzyme responsible for c. Cap and tail transcribing DNA into mRNA in eukaryotes (organisms with a d. Open complex nucleus). e. Spliceosome The spliceosome is a large protein complex that recognizes 11. Which of the following is the first step in RNA splice sites (intronic sequences) and facilitates intron removal isolation? and exon joining during RNA splicing. a. Washing of sample b. Cell lysis 5. Which of these genes is a tumor suppressor gene c. Blocking of contaminants commonly mutated in Wilms' tumor development? d. Precipitation a. WT1 c. HER2 Cell lysis is the initial step in RNA isolation. It breaks open the b. RB1 d. BRCA1 cells to release cellular contents, including RNA. WT1 is a well-known tumor suppressor gene frequently mutated in Wilms' tumor, a childhood kidney cancer. 12. What is the purpose of guanidium thiocyanate during RNA isolation? a. It masks the DNA JMPM; Page 1 of 5 MOLECULAR BIOLOGY AND DIAGNOSTIC MLS312 3RD YEAR - SECOND SEMESTER b. It disrupts the secondary RNA structure 18. RNA synthesis during transcription proceeds in c. It precipitates proteins the: d. It stabilizes the RNA. Silent mutations are a. 5' to 3' direction mutations that: b. 3' to 5' direction Guanidium thiocyanate disrupts cell membranes and helps in c. Random direction protein denaturation during RNA isolation, allowing for better d. Bidirectional RNA extraction. RNA synthesis during transcription proceeds in the 5' to 3' direction, adding RNA nucleotides to the growing RNA chain at 13. Silent mutations are mutations that: the 3' end. a. Cause a change in the amino acid sequence b. Do not change the amino acid sequence 19. Which of the following RNA molecules is c. Cause a frameshift mutation transcribed by RNA polymerase I in eukaryotes? Silent mutations occur when a base change in DNA doesn't a. mRNA alter the amino acid sequence in the protein due to the b. tRNA redundancy of the genetic code (multiple codons encoding the c. rRNA same amino acid). d. snRNA RNA polymerase I in eukaryotes is responsible for transcribing 14. Which of the following genes is associated with ribosomal RNA (rRNA), a major component of ribosomes. Wilm's tumor development? a. RB1 20. Pre-mRNA refers to: b. HER2 a. It is the mature RNA molecule after splicing. c. BRCA1 b. It is the RNA molecule before splicing and d. WT1 processing. WT1 is a gene associated with Wilms' tumor development. c. It is the RNA molecule that codes for ribosomal proteins. 15. Sequence alignment in bioinformatics is used to: d. It is the RNA molecule involved in protein a. Determine the three-dimensional structure of a translation. protein Pre-mRNA (precursor messenger RNA) is the immature RNA b. Compare and find similarities between biological transcript before splicing and processing events in eukaryotes. sequences It contains introns and needs modifications to become mature c. Study the effects of mutations on gene mRNA. expression d. Predict the function of a gene 21. Which RNA polymerase is responsible for Sequence alignment tools in bioinformatics help identify transcribing most protein-coding genes in similarities and differences between biological sequences eukaryotes? (DNA, RNA, or protein) to understand evolutionary a. RNA polymerase I relationships, gene function, and mutations. b. RNA polymerase II c. RNA polymerase III 16. The purpose of using a phenol-chloroform d. RNA polymerase IV (doesn't exist in eukaryotes) extraction during RNA isolation is to: In eukaryotes, there are three main RNA polymerases with specific a. Remove proteins and other contaminants roles: b. Amplify the RNA molecules c. Precipitate the RNA for concentration RNA polymerase I: Transcribes ribosomal RNA (rRNA) genes. d. Stabilize the RNA for long-term storage RNA polymerase II: Transcribes most protein-coding genes and some non-coding RNA genes. Phenol-chloroform extraction separates RNA from proteins RNA polymerase III: Transcribes transfer RNA (tRNA) genes and other contaminants during RNA isolation. and other small non-coding RNA genes. 17. What is the purpose of including a DNase Therefore, RNA polymerase II is responsible for transcribing the majority of protein-coding genes. treatment during RNA isolation? a. To degrade DNA contaminants b. To stabilize RNA molecules 22. A point mutation describes a mutation where: c. To amplify RNA for downstream applications a. Insertion mutation d. To visualize RNA on a gel b. Deletion mutation c. Frameshift mutation DNase (deoxyribonuclease) is an enzyme that specifically d. A single nucleotide is substituted degrades DNA contamination during RNA isolation to ensure pure RNA samples. JMPM; Page 2 of 5 MOLECULAR BIOLOGY AND DIAGNOSTIC MLS312 3RD YEAR - SECOND SEMESTER A point mutation is a change in a single nucleotide base pair in 27. During translation, which tRNA anticodon would the DNA sequence. It doesn't involve insertion or deletion of bind to the mRNA codon UUU? nucleotides, but rather a substitution of one base for another a. AAG (e.g., A to T). b. CUU c. AAA 23. Frameshift mutations occur due to: d. GGG a. Point mutation During translation, tRNA molecules carry amino acids and bind b. Insertion or deletion of nucleotides to complementary codons on the mRNA strand. The anticodon c. Silent mutation on the tRNA is a triplet of nucleotides that base pairs with the d. Missense mutation mRNA codon. In this case, the mRNA codon UUU codes for the amino acid phenylalanine. The complementary anticodon Frameshift mutations occur when there's an insertion or for UUU would be AAA. deletion of nucleotides in the DNA sequence that is not a multiple of three. This disrupts the reading frame, shifting the grouping of nucleotides by one or two bases. This can lead to significant changes in the amino acid sequence downstream 28. Which of the following statements about the from the mutation. genetic code is true? a. It is redundant, meaning some amino acids have 24. Mutagens are agents that: multiple codons. a. They induce changes in DNA replication. b. It is ambiguous, meaning a single codon can b. They repair mutations in the DNA sequence. code for multiple amino acids. c. They protect DNA from mutation-causing agents. c. It is not universal, meaning the code differs d. They promote errors in DNA replication and between different organisms repair processes. d. It is all degenerate, with each amino acid having Mutagens are physical or chemical agents that can cause a single codon. changes in DNA during replication. These changes can be The genetic code is a set of rules that translates the nucleotide errors in copying the DNA or damage to the existing DNA sequence in mRNA into a sequence of amino acids in a structure. Mutagens don't repair mutations; they promote their protein. This code is redundant, meaning most amino acids formation. have multiple codons that can code for them. This redundancy helps to minimize the effects of point mutations, as some 25. Quality control in sequence assembly aims to: mutations might not change the encoded amino acid. a. Remove low-quality sequencing reads b. Verify the accuracy of the assembled sequence 29. What is the main function of the ribosome during (performed later) protein synthesis? c. Identify structural variations in the genome a. To synthesize mRNA from a DNA template (performed later) b. To transport amino acids to the growing d. Annotate the genes present in the genome polypeptide chain (performed later) c. To catalyze the formation of peptide bonds d. To proofread the mRNA sequence for errors Sequencing reads are short fragments of DNA sequences obtained from high-throughput sequencing technologies. Ribosomes are cellular machines responsible for protein Some reads may be of low quality due to errors. Quality control synthesis. They move along the mRNA strand, reading the aims to remove these low-quality reads before assembly to codons and catalyzing the formation of peptide bonds between ensure a more accurate final sequence. Verifying the amino acids brought in by tRNAs. This process continues until assembled sequence's accuracy, identifying structural a stop codon is reached, and the newly synthesized protein is variations, and gene annotation are typically performed later in released. the analysis pipeline. 30. What is the role of operator sequences in gene 26. BLAST stands for: regulation? a. Basic Local Alignment Search Tool a. They bind RNA polymerase to initiate b. Biotechnology Laboratory for Analysis of transcription. Sequence Transcripts b. They bind repressor proteins to block c. Bioinformatics Link for Annotation and Sequence transcription. Tagging c. They bind activator proteins to enhance BLAST is a bioinformatics tool widely used to compare a query transcription. sequence (DNA, RNA, or protein) against a database of known d. They mark the termination site of transcription. sequences. It helps identify sequences with significant similarity to the query, allowing researchers to infer potential functions or evolutionary relationships. JMPM; Page 3 of 5 MOLECULAR BIOLOGY AND DIAGNOSTIC MLS312 3RD YEAR - SECOND SEMESTER The operator sequence is a regulatory region on the DNA that b. Prenatal FISH probe can be bound by repressor proteins. When a repressor binds c. Split gene FISH probe to the operator, it blocks RNA polymerase from initiating d. Telomere FISH probe transcription of the downstream genes. This helps control gene e. Whole chromosome FISH probes expression based on cellular needs. 36. These bind to a different sequence along the 31. Operons are groups of genes under the control of length of a given chromosome: a single: a. Alphoid FISH probe a. Promoter sequence b. Prenatal FISH probe b. Terminator sequence c. Split gene FISH probe c. Operator sequence d. Whole chromosome FISH probes d. Coding sequence e. None of the above (these probes hybridize to the An operon is a cluster of genes under the control of a single entire chromosome) promoter sequence. The promoter acts as a binding site for These probes are designed to bind to two separate sequences RNA polymerase to initiate transcription of all the genes in the within the same gene. This allows for the detection of deletions operon. or rearrangements within a gene that might be associated with birth defects. 32. The lac operon in E. coli codes for the enzymes needed to utilize: a. Amino acids 37. Generated from repetitive sequences found in the b. Lactose middle of each chromosome: c. Fatty acids a. Alphoid FISH probe d. Glucose b. Prenatal FISH probe The lac operon in E. coli is a well-studied example of operon c. Split gene FISH probe regulation. These genes code for enzymes involved in lactose d. Telomere FISH probe (a sugar) metabolism. When lactose is present, the repressor e. Whole chromosome FISH probes protein detaches from the operator, allowing RNA polymerase to transcribe the lac operon genes and produce the enzymes These probes are generated from repetitive DNA sequences needed to utilize lactose. called alpha satellite DNA. This repetitive DNA is found at the centromeres of chromosomes, which are the regions where sister chromatids are attached during cell division. MCQ: FISH & PROBES 33. Used for identification of break-apart of a gene: 38. What is the purpose of FISH? a. Alphoid FISH probe a. To localize specific nucleic acid sequences within b. Prenatal FISH probe intact cells c. Split gene FISH probe b. To visualize proteins within cells d. Telomere FISH probe c. To study the structure of chromosomes e. Whole chromosome FISH probes d. To study the function of organelles within cells FISH uses fluorescent probes to target specific DNA sequences. Split gene probes are designed to bind to two FISH (Fluorescence In Situ Hybridization): This technique separate regions within the same gene. These probes can be uses fluorescent probes to target specific DNA or RNA used to detect breakpoints in the gene, which might be sequences within a cell. These probes bind to their associated with genetic disorders. complementary sequences on the chromosomes, allowing researchers to visualize their location in the nucleus. 34. Attaches to the end regions of the chromosome: 39. What is the difference between FISH and Southern a. Alphoid FISH probe blotting? b. Prenatal FISH probe a. FISH uses radioactive probes, while Southern c. Split gene FISH probe blotting uses fluorescent probes d. Telomere FISH probe b. FISH uses fluorescent probes, while Southern e. Whole chromosome FISH probes blotting uses radioactive probes Telomeres are the protective caps at the ends of c. FISH is used to study RNA, while Southern chromosomes. Telomere FISH probes are designed to bind blotting is used to study DNA specifically to these regions. This allows researchers to study d. FISH is used to study DNA, while Southern telomere. blotting is used to study RNA 35. Multiple color FISH probes to determine birth Both FISH and Southern blotting can utilize either fluorescent or radioactive probes depending on the researcher's defects: preference and the specific application. a. Alphoid FISH probe JMPM; Page 4 of 5 MOLECULAR BIOLOGY AND DIAGNOSTIC MLS312 3RD YEAR - SECOND SEMESTER 40. What is the difference between FISH and karyotyping? a. FISH is used to study individual chromosomes, while karyotyping is used to study the entire genome b. FISH is used to study the entire genome, while karyotyping is used to study individual chromosomes c. FISH is used to study RNA, while karyotyping is used to study DNA d. FISH is used to study DNA, while karyotyping is used to study RNA FISH (Fluorescence In Situ Hybridization): Focuses on specific DNA or RNA sequences within intact cells. Uses fluorescent probes to target these sequences and visualize their location in the nucleus. Can be used to detect chromosomal abnormalities like deletions, duplications, or translocations that affect specific genes or regions. Karyotyping: Analyzes the entire set of chromosomes in a cell. Involves preparing and staining chromosomes to visualize their structure and number. Provides a complete picture of chromosomal abnormalities like aneuploidy (missing or extra chromosomes) or structural rearrangements. JMPM; Page 5 of 5