Lect 11&12 PDF - Biology Past Paper

Lect 11 1. Which of the following statements is true about body cells in an organism? Answer: B) All body cells have the same set of DNA, but can perform different functions. 2. If the DNA in every body cell is the same, how can cells be so different? This is due to: Answer: B) Gene regulation a...

Lect 11 1. Which of the following statements is true about body cells in an organism? Answer: B) All body cells have the same set of DNA, but can perform different functions. 2. If the DNA in every body cell is the same, how can cells be so different? This is due to: Answer: B) Gene regulation and differentiation. 3. True or False: An individual starts out as a single cell called a zygote, which divides by mitosis to form identical copies. Answer: True 4. In eukaryotes, most genes are typically: Answer: B) Turned "off" by default. 5. Which of the following processes is NOT a method of gene regulation in eukaryotes? Answer: C) Reverse transcription 6. True or False: The lac operon in E. coli allows the bacteria to utilize lactose when it is present in the environment. Answer: True 7. The lac operon consists of a promoter, operator, and which of the following? Answer: C) Genes with related functions 8. Which of the following statements about transcriptional factors is true? A) They inhibit the binding of RNA polymerase. B) They bind to enhancers and promoters to activate multiple genes. C) They only work in prokaryotic cells. D) They are not involved in gene regulation. Answer: B) They bind to enhancers and promoters to activate multiple genes. 9. True or False: Homeotic genes are master control genes that regulate the expression of other groups of genes during embryonic development. Answer: True 10. Cloning refers to which of the following? Answer: A) The process of making identical copies of cells, organisms, or DNA. 11. Which type of cloning involves replacing an egg's DNA with that from a somatic cell? Answer: B) Reproductive cloning 12. True or False: "Dolly" the sheep was the first mammal to be cloned in 1997. Answer: True 13. What is the primary purpose of therapeutic cloning? Answer: B) To generate embryonic stem cells for medical treatment. 14. True or False: Oncogenes are normal genes that, when mutated, can lead to cancer. Answer: True 15. Which of the following is considered a carcinogen? Answer: B) Tobacco smoke 16. True or False: Embryonic stem cells are derived from adults and are less controversial than adult stem cells. Answer: False (Embryonic stem cells are derived from embryos and are more controversial than adult stem cells.) 17. Which type of stem cells can differentiate into any type of cell and are derived from embryos? Answer: C) Embryonic stem cells 18. What role do microRNAs play in gene regulation? Answer: B) They degrade target mRNA or block its translation. 19. True or False: Carcinogens are substances that cause mutations to DNA that can lead to cancer. Answer: True 20. Compounds found in fruits and vegetables can help reduce cancer risks due to their role as: Answer: B) Antioxidants Lec 12 1. What technology allows genes from different sources to be combined? C) Recombinant DNA technology 2. Which of the following is an example of a genetically modified food? A) “Bt” corn 3. True or False: Genetically modified crops have been widely used in the US since 1996. Answer: True 4. What is the purpose of bacterial plasmids in genetic engineering? B) To act as vectors (gene carriers) 5. How do restriction enzymes work? B) They cut DNA at specific nucleotide sequences. 6. True or False: The staggered cuts made by restriction enzymes create "sticky ends." Answer: True 7. Which method is commonly used to edit genes in living cells? B) CRISPR-Cas9 system 8. What role does the Cas9 protein play in gene editing? C) It identifies and cuts viral DNA. 9. DNA fingerprinting is used in forensics to: B) Compare DNA samples 10. True or False: A DNA fingerprint is unique to every individual because of variations in DNA fragments. Answer: True 11. Which process is used to amplify DNA samples before generating a DNA fingerprint? B) Polymerase Chain Reaction (PCR) 12. What are Restriction Fragment Length Polymorphisms (RFLPs)? B) Differences in the size of DNA fragments produced by restriction enzymes 13. True or False: Gel electrophoresis separates DNA fragments based on their charge and size. Answer: True 14. What is the purpose of using primers in PCR? B) To amplify specific DNA sequences 15. How many markers are typically analyzed in standard STR analysis in forensics? C) 13 16. True or False: The chance of two individuals being identical at all 13 STR markers is very high. Answer: False (It is very low, estimated between 1 in a billion to 1 in several trillion.) 17. Which of the following is a common application of recombinant DNA technology? A) Developing vaccines B) Creating genetically modified crops C) Both A and Bra D) None of the above 18. What is the main function of DNA ligase in genetic engineering? B) To join DNA fragments together 19. The first transgenic dog was created by inserting a gene from which organism? B) Sea anemone 20. What is a significant challenge when using genetic engineering in crops? B) Public acceptance and regulatory issues