Microbiology

Cards (24)

• 1
  Front

  What is the key structural difference between prokaryotic and eukaryotic cells?

  Back

  Prokaryotic cells lack a membrane-bound nucleus and membrane-bound organelles; eukaryotic cells have both.

• 2
  Front

  Which type of cell contains 70S ribosomes?

  Back

  Prokaryotic cells contain 70S ribosomes (composed of 50S and 30S subunits).

• 3
  Front

  What is the function of the bacterial cell wall in gram-positive bacteria?

  Back

  It provides structural support and protection; gram-positive cell walls have a thick peptidoglycan layer that retains crystal violet dye in the Gram stain.

• 4
  Front

  How does the gram-negative cell wall differ structurally from gram-positive?

  Back

  Gram-negative bacteria have a thin peptidoglycan layer plus an outer membrane containing lipopolysaccharide (LPS); they stain pink in the Gram stain.

• 5
  Front

  What are the four phases of bacterial growth in a closed system?

  Back

  Lag phase, exponential (log) phase, stationary phase, and death (decline) phase.

• 6
  Front

  During which phase of bacterial growth is the rate of cell division at its maximum?

  Back

  The exponential (log) phase.

• 7
  Front

  What is generation time in bacterial growth?

  Back

  The time required for a bacterial population to double in number; it varies by species and environmental conditions.

• 8
  Front

  What is the basic structure of a virus?

  Back

  A virus consists of a nucleic acid genome (DNA or RNA) enclosed in a protein coat called a capsid; some viruses also have a lipid envelope.

• 9
  Front

  What is the difference between a lytic and a lysogenic viral infection cycle?

  Back

  In the lytic cycle, the virus replicates and lyses the host cell. In the lysogenic cycle, viral DNA integrates into the host genome and replicates with it without immediately destroying the cell.

• 10
  Front

  What is a bacteriophage?

  Back

  A bacteriophage is a virus that specifically infects bacteria.

• 11
  Front

  What is the role of reverse transcriptase in retroviruses?

  Back

  Reverse transcriptase converts the viral RNA genome into DNA, which can then be integrated into the host cell's genome.

• 12
  Front

  What is the difference between obligate aerobe and obligate anaerobe microorganisms?

  Back

  Obligate aerobes require oxygen for growth; obligate anaerobes cannot tolerate oxygen and grow only in its absence.

• 13
  Front

  What is fermentation in microbial metabolism?

  Back

  Fermentation is anaerobic catabolism in which organic molecules serve as both electron donors and acceptors, producing ATP without an electron transport chain.

• 14
  Front

  What is the net ATP yield from glycolysis alone?

  Back

  2 ATP molecules per glucose molecule.

• 15
  Front

  What is the difference between autotrophs and heterotrophs in microbiology?

  Back

  Autotrophs synthesize organic compounds from inorganic carbon sources (CO2); heterotrophs must obtain organic carbon from other organisms.

• 16
  Front

  What are the two main branches of the immune system?

  Back

  The innate immune system (non-specific, immediate response) and the adaptive immune system (specific, involves B and T lymphocytes).

• 17
  Front

  What is the function of B lymphocytes in adaptive immunity?

  Back

  B lymphocytes differentiate into plasma cells that produce antibodies (immunoglobulins) specific to an antigen.

• 18
  Front

  What is the role of cytotoxic T cells (CD8+) in the immune response?

  Back

  Cytotoxic T cells directly kill infected, cancerous, or foreign cells by inducing apoptosis upon recognizing antigen presented on MHC class I molecules.

• 19
  Front

  What is an antigen?

  Back

  An antigen is any molecule (usually a protein or polysaccharide) that elicits a specific immune response, particularly antibody production.

• 20
  Front

  Which major pathogen causes tuberculosis, and what is its key characteristic?

  Back

  Mycobacterium tuberculosis causes tuberculosis; it is acid-fast due to a waxy, mycolic acid-rich cell wall that resists standard Gram staining.

• 21
  Front

  What disease does Clostridium tetani cause, and what is its mechanism of action?

  Back

  C. tetani causes tetanus by releasing tetanospasmin, a toxin that blocks inhibitory neurotransmitter release, leading to spastic paralysis.

• 22
  Front

  What is the causative agent of malaria, and to what microbial group does it belong?

  Back

  Malaria is caused by Plasmodium species (P. falciparum, P. vivax, etc.), which are eukaryotic protozoan parasites transmitted by Anopheles mosquitoes.

• 23
  Front

  What type of pathogen is Candida albicans, and what kind of infection does it commonly cause?

  Back

  Candida albicans is a fungus (yeast) that commonly causes opportunistic infections such as oral thrush and vaginal candidiasis, especially in immunocompromised individuals.

• 24
  Front

  What is the significance of MHC (Major Histocompatibility Complex) molecules in immunity?

  Back

  MHC molecules present antigen fragments on cell surfaces for recognition by T lymphocytes; MHC class I presents to cytotoxic T cells, MHC class II presents to helper T cells.