Biotechnology: Principles and Processes Questions and Answers

According to the operon model, for the synthesis of an inducible enzyme such as lactose permease to occur, the A. end-product must not be in excess. B. substrate must bind to the enzyme. C. allolactose must bind to the repressor and inactivate it D. repressor must bind to the operator. E. repressor must not be synthesized.

10. A culture of Escherichia coli is heated at 60°C and a series of samples taken at intervals to determine the numbers of survivors. From the data we can calculate the D-value for this strain. The D-value: A. Tells us how long we need to heat the bacteria at 60°C to achieve the SAL B. Tells us how long the bacteria needs to be heated at 60°C to achieve a 10-fold reduction in viable counts C. Allows us to predict how quickly the E. coli would die at 60°C D. Allows us to predict how quickly E. coli would multiply at 60°C E. Tells us the relationship between temperature and rate of killing

How was bacterial contamination prevented in tissue cultures?

Quorum sensing can regulate the production of O a. Biofilms O b.Bioluminescence O c. Toxins, Biofilms, and Bioluminescence O d. Toxins

The unpaired nucleotides produced by the action of restriction enzymes are referred to as A. sticky ends. B. base sequences. C. single strands. D. restriction fragments.

Southern blot hybridization is based on hybrization/annealing between: A. DNA and RNA. B. DNA and DNA. C. RNA and RNA. D. RNA and protein.

A scientist prepares a smear with bacteria but forgets to heat fix the smear and uses methylene blue to do a simple stain. Do you think that this error would affect the results? Why? A. No, it would not affect the results but the bacteria will be still alive B. Yes, it will affect the results because the heat fix is necessary for an effective staining of bacteria C. Yes, it will affect the results because the bacterial smear will be washed away during the staining D. No, it will not affect the results. The results will be better than expected because heat-fixing causes distortion of the cell shape

Tumor suppressor genes normally code for proteins that inhibit cell division. True False

How does the field of science gain knowledge and understanding? through the testing of hypotheses through deductive reasoning by using the latest technologies by making value judgments

The technique called fluorescence in situ hybridization (FISH) uses DNA probes with attached fluorescent molecules that indicate specific DNA sequences. lures to pull out specific sequences from their chromosomes. stains to sort chromosomes into general size classes, designated A through G. stains that distinguish AT-rich from GC-rich sequences.

A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the tRNA that binds the mRNA codon is UUA UUU TTT AAA either UAA or TAA, depending on first base wobble.

If transporting a substrate across an intracellular membrane is the limiting factor for an enzyme-catalyzed reaction, then the regulatory process would most likely be altering the number of enzymes regulation by sequestering an enzyme into a subcellular organelle binding the enzyme to a regulatory protein binding of an enzyme to a substrate

You are interested in obtaining Staphylococcus aureus for a study investigating the prevalence of methicillin-resistant Staphylococcus aureus in the general population. You have received several samples and are ready to start your isolation procedures. Describe the personal protective equipment that would be needed and three different culturing techniques that can be used to obtain organisms to produce pure cultures. State if you use general or selective media and which specific media you would choose. How would you determine if the culture was contaminated? What is the first step you would take if you detected contamination?

Why is it possible for human genes to be expressed in bacteria for manufacturing pharmaceutical products such as insulin? Point mutations change a single nucleotide base pair All organisms use the same basic genetic code Norisense mutations introduce STOP codons into the sequence RNA viruses can reverse transcribe RNA into DNA The reading frame groups codons into the correct triplet codes

In Eukaryotic gene regulation, which of the following is part of the transcription initiation complex? General transcription factors RNA polymerase II START codon Specific transcription factors RNA polymerase III

In agarose gels, DNA travels depending on the nucleotide content of the fragment faster for the large molecules than the small ones from the positive to the negative electrode faster for the small molecules than the large ones from the negative to the positive electrode

Sean is thinking about using seawater to water his plants. Sean places 10 spider plants near a window for 20 days. Each day he waters five plants with 10ml of seawater and five plants with 10ml of fresh water. By measuring the height of the plants Sean collected: unreliable data quantitative data qualitative data control data

tRNAs carrying the correct amino acid recognize the proper codons on the mRNA because the amino acid binds to the anticodon of the mRNA and brings the correct tRNA with it. the codon of the mRNA binds the correct amino acid, and the tRNA stabilizes this interaction. the codon of the tRNA binds to the anticodon of the ribosome by complementary base pairing. the anticodon of the tRNA binds to the codon of the mRNA by complementary base pairing.

The discovery of restriction endonucleases was crucial to the development of recombinant DNA technology because these enzymes Always cut DNA at either end of a gene Always cut DNA leaving unpaired lengths of bases that have a charge. This is the basis of gel electrophoresis Tag DNA so that individual fragments can be identified Cut DNA at specific and predictable sequences of nitrogen bases

What is a key characteristic of a restriction endonuclease? They join broken strands together There are many copies of these enzymes in human cells They prevents viral DNA entering the nucleus They cut DNA in the interior instead of at the ends

Bacterial transformation is the process in which A recessive gene becomes dominant Eukaryotic cells are altered O Foreign DNA is taken up and assimilated Many copies of a gene accumulate

You have 2 copies of a small gene that you wish replicated by PCR. After 4 replication cycles, how many double-stranded DNA molecules do you have? 32 8 2 64 16

During Gram stain, the alcohol... Select all the correct answers decolorizes Gram-positive bacteria dehydrates the thick peptidoglican and close the pores in Gram-negative bacteria dissolves the outer membrane in Gram-negative bacteria fails to decolorize Gram-positive bacteria removes the CV-I complex from Gram-negative bacteria

How many times is magnified an image observed using a compound microscope with a 10X ocular and a 40X objective? 50 times 40 times 400 times 1000 times

Which of the following mutation is the least lethal form? O Insertion mutation O missense mutation O nonsense mutation O deletion mutation

"After the amount of a specific DNA sequence is increased several fold, DNA can then be analyzed by a procedure that produces a readable pattern of DNA fragments called PCR gel electrophoresis (e.g. RFLP) gene probes (e.g. Southern blot) DNA sequences

Gene transfer in bacteria by transformation has the following characteristics: a majority of the donor genes are transferred it involves a plasmid it depends on phage infection of the recipient cell it can be carried out using free DNA extracted from the donor

The Ames test is a screening test used to predict whether a chemical is likely to result in O "spontaneous mutation, cancer" O "spontaneous mutation, antibiotic resistance" O "induced mutation, cancer" O "induced mutation, antibiotic resistance" cell membrane and causes in human cells.

Gene silencing involves all of the following EXCEPT a. small interfering RNAs. b. small interfering RNA binding to mRNA. c. small interfering RNA binding to a gene promoter. d. RNA-induced silencing complex.

The process of discovering gene function from a genetic sequence is a. reverse genetics b. proteomics c. bioinformatics d. metagenomics e. forensic microbiology

What is the purpose of high salt concentration in the mannitol salt agar medium? a. Staphyloccoci ferments the salt in the medium. b. It serves as an indicator. c. It inhibits staphylococci. d. It selects for staphylococci.

What are fastidious microorganisms? a. Organisms that are self sufficient. b. Organisms that do not need enriched medium for growth. c. Organisms that grow at a fast rate. d. Organisms that need enriched medium for growth