Microbiology Midterm Exam Study Guide

A collection of flashcards covering key terms and concepts from the Microbiology Midterm Exam Study Guide.

Microorganisms

Organisms that are too small to be seen without a microscope.

Bacteria

Single-celled prokaryotes with rigid cell walls containing peptidoglycan.

Viruses

Non-living infectious agents that require a host cell to replicate.

Fungi

Eukaryotic organisms that include yeasts and molds, often decomposers.

Protozoa

Single-celled eukaryotic organisms that may be motile.

Algae

Photosynthetic eukaryotic organisms found in aquatic environments.

Prokaryotes

Organisms without a nucleus or membrane-bound organelles; includes bacteria and archaea.

Eukaryotes

Organisms that have a nucleus and organelles; includes fungi, protozoa, and algae.

Endospores

Dormant, resistant cells formed by certain bacteria under stress conditions.

Gram-positive bacteria

Bacteria with thick cell walls that stain purple in the Gram staining process.

Gram-negative bacteria

Bacteria with thin cell walls and an outer membrane that stain pink in the Gram staining process.

Binary fission

Asexual reproduction in bacteria resulting in exponential growth.

Aerobic respiration

Process of producing ATP in the presence of oxygen.

Anaerobic respiration

Process of producing ATP without oxygen, using alternative electron acceptors.

Fermentation

An anaerobic process that breaks down glucose without an electron transport chain.

Hemolysis

The breakdown of red blood cells by bacterial enzymes.

Colonies

Visible clusters of microbial cells growing on solid media, originating from a single cell.

Culture

The growth of microorganisms in a nutrient medium.

Nutrient agar

A solid growth medium used to culture bacteria.

Optical density

A measure of how much a substance hinders the transmission of light through it.

Inoculation

The introduction of a sample containing microorganisms into a nutrient medium.

Incubation

Maintaining conditions that allow microorganisms to grow.

Catalysts

Substances that increase the rate of a chemical reaction without being consumed.

Enzymes

Proteins that act as biological catalysts in metabolic reactions.

Biochemical pathways

Series of chemical reactions occurring within a cell.

Metabolism

The sum of all chemical reactions in a biological system.

Peptidoglycan

A polymer that forms the cell wall of many bacteria.

LPS (lipopolysaccharide)

A component of the outer membrane of gram-negative bacteria, often toxic.

Thermophiles

Heat-loving microorganisms that thrive at high temperatures.

Psychrophiles

Cold-loving microorganisms that thrive at low temperatures.

Mesophiles

Microorganisms that grow best at moderate temperatures, typically between 20-45°C.

pH

A measure of how acidic or basic a solution is.

Osmosis

Movement of water across a semipermeable membrane from low to high solute concentration.

Flagella

Whip-like structures used for movement in some bacteria.

Fimbriae

Hair-like appendages that facilitate attachment to surfaces in bacteria.

Pili

Short, hair-like structures used for attachment and conjugation in bacteria.

Antibiotics

Substances that kill or inhibit the growth of bacteria.

Vaccines

Biological preparations that provide immunity to specific diseases.

Pathogen

Microorganisms that cause disease.

Extremophiles

Organisms that thrive in extreme environmental conditions.