Biology Competitive Exam 2021-2022

Competitive Exams for the Academic Year 2021-2022

Question 1

• Chemoautotrophic microorganisms can use CO2 as a source of carbon and inorganic chemicals as a source of energy and electrons.
• Teichoic acid is a component that lacks phosphate in the cell wall of Gram-positive bacteria.
• Lipoteichoic acid is a component that lacks phosphate in the cell wall of Gram-positive bacteria.

Question 2

• Types of inhibitors that affect enzyme activity: uncompetitive, competitive, and noncompetitive inhibitors.

Question 3

• Nitrosomonas is a chemoautotrophic microorganism.
• The most responsible factor for the nature of the ulcers on the foot caused by Staphylococcus aureus is Exfoliatin.
• If the blood culture is negative, the best explanation is that there might be a problem with blood collection.

The Etiology of Sore Throat

• The best way to determine the etiology of a sore throat is through a throat culture.

Virulence

• Virulence is the ability of bacteria to cause disease when presented with favorable circumstances.

Lyme Disease

• The laboratory test that would confirm the diagnosis of Lyme disease is the Borrelia burgdorferi immunoassay.

Spore Formation

• The stages of spore formation: sporulation, engulfment, fore-spore formation, and spore maturation.

F-pilus

• An F-pilus is essential for plasmid transfer by conjugation.

Gene Expression

• False statement: Translation begins at a site called a promoter.
• True statements: More than one RNA polymerase can be transcribing a specific gene at a given time, More than one ribosome can be translating a specific transcript at a given time, Transcription stops at a site called a terminator, Some amino acids are coded for by more than one codon.

Eukaryotic Gene Expression

• False statement: The mRNA is often polycistronic.

Multiple Choice

• The nitrogen bases in DNA are bonded to the deoxyribose.
• Spliceosomes are present in eukaryotes but not prokaryotes, and simultaneous transcription and translation occur in prokaryotes but not eukaryotes.

Short Answer

• Conjugation: direct cell-to-cell contact, donor: F+ plasmid, recipient: F- plasmid. Transformation: uptake of free DNA, donor: any DNA source, recipient: competent cells. Transduction: virus-mediated DNA transfer, donor: bacteriophage, recipient: bacterial cells.
• Selective mediums for Salmonella: LJ medium, XLD agar, and SS agar.
• True or False: IgE is involved in Type I hypersensitivity reaction, Immune responses are controlled by exclusion of cells from the site of inflammation, Cytotoxic T cells kill targets via perforin and granzyme B, Antibodies activate the alternative complement pathway, Pattern recognition molecules distinguish self from pathogen.

Additional Questions

• Microbial activity level can be determined by measuring CO2 production, O2 consumption, or ATP production.
• Carbon cycle in land: photosynthesis, respiration, decomposition. Carbon cycle in microorganisms: photosynthesis, respiration, fermentation.
• No significant difference between the water cycle in land and the water cycle on the mainland because the water cycle is a continuous process.