Microbiology
60 flashcards covering Microbiology for the MCAT Biology & Biochemistry section.
Microbiology is the study of microorganisms, which are tiny living entities like bacteria, viruses, fungi, and parasites that are invisible to the naked eye. These organisms influence everything from human health and disease to environmental processes and food production. By understanding microbiology, you can grasp how infections spread, how the immune system responds, and how microbes are used in medicine and industry, making it essential for fields like healthcare.
On the MCAT, microbiology appears in the Biology and Biochemistry section, often through multiple-choice questions that integrate it with topics like genetics, immunology, and cell biology. You'll face questions on microbial structure, reproduction, pathogenesis, and antibiotic mechanisms, with common traps including confusing similar organisms or misinterpreting host-microbe interactions. Focus on key concepts such as bacterial vs. viral differences, microbial genetics, and epidemiology to handle these effectively and avoid errors.
Practice drawing microbial cell diagrams to solidify your understanding.
Terms (60)
- 01
Prokaryote
A single-celled organism lacking a nucleus and membrane-bound organelles, typically including bacteria and archaea, which have a simple cell structure with DNA in the cytoplasm.
- 02
Eukaryote
An organism with cells that contain a nucleus and membrane-bound organelles, such as fungi, protists, plants, and animals, allowing for more complex cellular processes.
- 03
Bacteria
A domain of prokaryotic microorganisms that can be beneficial or pathogenic, characterized by cell walls containing peptidoglycan and various shapes like rods or spheres.
- 04
Archaea
A domain of prokaryotic microorganisms distinct from bacteria, often found in extreme environments, with unique cell membranes and genetic machinery.
- 05
Virus
A non-living infectious agent that requires a host cell to replicate, consisting of genetic material in a protein coat, and can cause diseases in humans, animals, and plants.
- 06
Bacteriophage
A virus that infects and replicates within bacteria, often using a lytic or lysogenic cycle, and is studied for its role in bacterial genetics and potential therapeutic applications.
- 07
Fungi
Eukaryotic organisms that include yeasts, molds, and mushrooms, which obtain nutrients by absorbing organic matter and can act as decomposers or pathogens.
- 08
Protists
A diverse group of mostly unicellular eukaryotic microorganisms, such as amoebas and algae, that do not fit into other kingdoms and can be photosynthetic or heterotrophic.
- 09
Binary fission
The asexual reproduction process in prokaryotes where a single cell divides into two identical daughter cells after duplicating its DNA and cytoplasm.
- 10
Endospore
A dormant, tough structure formed by some bacteria, like Bacillus, to survive harsh conditions by enclosing the genetic material and essential proteins.
- 11
Gram staining
A laboratory technique that differentiates bacteria based on their cell wall composition, with Gram-positive retaining the crystal violet dye and Gram-negative not.
- 12
Peptidoglycan
A polymer in the cell walls of bacteria that provides structural support and is targeted by certain antibiotics, consisting of sugars and amino acids.
- 13
Cell wall
A rigid outer layer in bacteria and plants that maintains cell shape and protects against osmotic pressure, composed of materials like peptidoglycan in bacteria.
- 14
Capsule
A gelatinous layer surrounding some bacterial cells that helps evade the host immune system and aids in adherence to surfaces.
- 15
Flagella
Whip-like appendages on some bacteria and eukaryotes that enable movement by rotating or waving, propelling the cell through liquid environments.
- 16
Pili
Short, hair-like structures on bacterial surfaces used for attachment to host cells or other bacteria, and in some cases, for transferring genetic material.
- 17
Plasmid
A small, circular piece of DNA in bacteria that can replicate independently of the chromosomal DNA and often carries genes for antibiotic resistance.
- 18
Conjugation
A process in bacteria where genetic material is transferred between cells through direct contact via a pilus, allowing for horizontal gene transfer.
- 19
Transformation
The uptake and incorporation of foreign DNA from the environment into a bacterial cell's genome, a key mechanism in genetic engineering.
- 20
Transduction
The transfer of bacterial DNA from one cell to another by a bacteriophage, which accidentally packages host DNA during its replication cycle.
- 21
Lytic cycle
A viral replication process where the virus infects a host cell, replicates its genetic material, and causes the cell to burst, releasing new viruses.
- 22
Lysogenic cycle
A viral replication strategy where the viral DNA integrates into the host genome and replicates along with it without immediately killing the cell.
- 23
Retrovirus
A type of RNA virus, like HIV, that uses reverse transcriptase to convert its RNA into DNA, which then integrates into the host's genome.
- 24
Prion
An infectious protein particle without nucleic acids that can cause diseases by inducing normal proteins to misfold, such as in mad cow disease.
- 25
Antibiotic
A substance that kills or inhibits the growth of bacteria, often by targeting cell wall synthesis or protein production, but not viruses.
- 26
Penicillin
A beta-lactam antibiotic that disrupts bacterial cell wall synthesis by inhibiting peptidoglycan cross-linking, effective against Gram-positive bacteria.
- 27
Microbial growth curve
A graph showing the phases of bacterial population growth in a culture, including lag, exponential, stationary, and death phases based on nutrient availability.
- 28
Generation time
The time required for a bacterial population to double in number under optimal conditions, influenced by factors like temperature and nutrients.
- 29
Pasteurization
A heat treatment process that kills pathogens in food and beverages, such as milk, by heating to a specific temperature for a set time without sterilization.
- 30
Vaccination
The administration of a vaccine to stimulate an immune response and provide immunity against a specific pathogen, such as viruses or bacteria.
- 31
Innate immunity
The nonspecific defense system present at birth, including physical barriers like skin and cellular responses like phagocytosis, that responds quickly to pathogens.
- 32
Adaptive immunity
The specific immune response that develops over time, involving T cells and B cells, which provides long-term memory and targeted defense against pathogens.
- 33
Antibody
A Y-shaped protein produced by B cells that binds to specific antigens on pathogens, neutralizing them or marking them for destruction by the immune system.
- 34
Antigen
A molecule or molecular structure on a pathogen that triggers an immune response by being recognized by antibodies or T cells.
- 35
T cell
A type of lymphocyte that plays a central role in cell-mediated immunity, including helper T cells that activate other immune cells and cytotoxic T cells that kill infected cells.
- 36
B cell
A lymphocyte that produces antibodies in response to antigens, maturing in the bone marrow and differentiating into plasma cells upon activation.
- 37
Phagocytosis
The process by which immune cells, like macrophages, engulf and destroy pathogens or debris, a key mechanism in innate immunity.
- 38
Complement system
A group of proteins in the blood that enhances the ability of antibodies and phagocytic cells to clear pathogens from an organism.
- 39
HIV
A retrovirus that attacks CD4 T cells, leading to acquired immunodeficiency syndrome (AIDS) by weakening the immune system and increasing susceptibility to infections.
- 40
Tuberculosis
A bacterial disease caused by Mycobacterium tuberculosis, primarily affecting the lungs and spread through airborne droplets, requiring long-term antibiotic treatment.
- 41
Microbial ecology
The study of interactions between microorganisms and their environment, including how they influence nutrient cycles and community structures.
- 42
Symbiosis
A close and long-term interaction between different biological species, which can be mutualistic, commensal, or parasitic in microbial contexts.
- 43
Mutualism
A symbiotic relationship where both organisms benefit, such as nitrogen-fixing bacteria providing nutrients to plants in exchange for a habitat.
- 44
Parasitism
A relationship where one organism, like a pathogen, benefits at the expense of the host, often causing disease or harm.
- 45
Biofilm
A community of microorganisms embedded in a self-produced matrix attached to a surface, making them more resistant to antibiotics and immune responses.
- 46
Quorum sensing
A system used by bacteria to communicate and coordinate behavior based on population density, such as triggering virulence factors when numbers are high.
- 47
Nitrogen fixation
The process by which certain bacteria convert atmospheric nitrogen into ammonia, making it available for plants and other organisms.
- 48
Fermentation
An anaerobic metabolic process where microorganisms like yeast convert sugars into acids, gases, or alcohol to generate energy without oxygen.
- 49
Aerobic respiration
A metabolic pathway in which microorganisms use oxygen to break down organic molecules, producing more energy than anaerobic processes.
- 50
Anaerobic respiration
A form of respiration in some bacteria that uses electron acceptors other than oxygen, such as nitrate, to generate energy from organic compounds.
- 51
Endotoxin
A lipopolysaccharide component of the outer membrane of Gram-negative bacteria that can trigger a strong immune response and fever when released.
- 52
Exotoxin
A toxin secreted by certain bacteria, like Clostridium, that can cause damage to host cells and tissues even before the bacteria invade.
- 53
Koch's postulates
A set of criteria used to establish that a specific microorganism causes a disease, involving isolation, culturing, and reinfection of a host.
- 54
Epidemiology
The study of how diseases spread in populations, including factors like transmission routes and incidence rates for microbial infections.
- 55
Pathogenesis
The mechanism by which a microorganism causes disease, involving steps like attachment, invasion, and evasion of the host immune system.
- 56
Virulence factors
Molecules produced by pathogens that enable them to colonize hosts and cause disease, such as adhesins or toxins.
- 57
Immune evasion
Strategies used by microorganisms to avoid detection or destruction by the host immune system, such as altering surface antigens.
- 58
Hypersensitivity
An exaggerated immune response to antigens that can lead to tissue damage, categorized into types like immediate allergic reactions.
- 59
Autoimmunity
A condition where the immune system mistakenly attacks the body's own cells, potentially triggered by microbial mimicry of self-antigens.
- 60
Immunization
The process of inducing immunity through vaccines or exposure, leading to memory cells that provide rapid response upon future pathogen encounters.