Molecular Biology Quiz

Flow of Genetic Information in Cells

• DNA to RNA to protein is the correct sequence of genetic information flow
• The other options are incorrect

Synthesized Sequence

• The correct synthesized sequence is 3'-AGGCTTGAC-4'

Ribosomal Site

• During elongation in translation, an incoming charged tRNA molecule binds to the A site of the ribosome

Bacterial Transcription Stage

• The sigma subunit of the RNA polymerase is involved in the initiation stage of bacterial transcription

Transcriptional Control

• Negative transcriptional control represses gene expression, whereas positive transcriptional control activates gene expression
• Both types of control can regulate inducible and repressible genes

Immunity

• Innate immunity is the first defense and is antigen-independent
• Thymus is the site for maturation of T cells, but not B cells
• Peyer patch is a mini lymph node
• Macrophages are not the only source of interleukin-6 (IL-6)
• Ig M antibodies play a role in protection against helminth infection

Immune Response

• The site where immune response is initiated is the thymus
• Natural killer cells are the source of Interferon-y (IFN-y)
• Macrophages activated to produce oxygen-dependent compounds produce nitric oxide
• The first immunoglobulin produced after antigen exposure is Ig A
• Antigen is the substance capable of eliciting a specific immune response

Antibiotics

• Benzylpenicillin is the chemical name for Penicillin G
• A common feature among the antibiotics like penicillin, cephalosporins, carbapenems, and monobactams is that they all have a β-lactam ring as a part of their biological interaction
• Aerobic fermentation is used in the production of penicillin
• Long-term use of broad-spectrum antimicrobials can contribute to the development of a superinfection

Fermentation

• Spherooplast and protoplast cells can live in a medium containing a high concentration of sucrose solution
• RNA POLYMERASE enzyme is an ideal target for antibiotics such as REFA, which leads to the killing of bacteria

Genetics

• The F plasmid is involved in the process of conjugation
• The formation of pyrimidine dimers results from exposure to ultraviolet radiation
• Ligase is not involved in the initiation of replication
• The conditions for maximal expression of the lac operon are lactose present and glucose absent
• A deletion of a codon is an example of a frameshift mutation
• The promoter is involved in the initiation of transcription

Biology Exam

• Transferases are the enzymes that do not need water for reactions
• Mg is the important nutrient for bacterial techoic acid
• Thermophel is the bacterial group that cannot grow at less than 55°C
• The Enter-Doudoroff pathway is used by bacteria but not by eukaryotes
• Carboxysomes are an example of storage inclusions

Antibiotics

• Most penicillins only cross the blood-brain barrier when the meninges are inflamed
• Penicillins inhibit the cross-linkage of peptidoglycans in the cell wall
• Piperacillin is a penicillin active against pseudomonas
• Only about 5 to 10% of people with a past history of penicillin allergy have a reaction on re-exposure
• Norfloxacillin, Chloramphenicol, Trimethoprim, and Rifampicin are all antibiotics that inhibit nucleic acid synthesis
• Sulfasalazin is not an antibiotic that inhibits nucleic acid synthesis
• Concerning toxicity of antibiotics, enamel dysplasia is common with aminoglycosides, Grey Baby Syndrome occurs with rifampicin use, a disulfiram-like reaction can occur with macrolides, and haemolytic anaemias can occur with sulphonamide use
• Chloramphenicol is a bacteriostatic antibiotic
• Metronidazole is used to treat giardia, causes a metallic taste in the mouth, inhibits alcohol dehydrogenase, and is used to treat gardnerella and trichomonas vaginalis
• Tetracycline is an antibiotic that functions as a protein synthesis inhibitor