Microbiology Exam 3 Study Guide Overview

Staph

Catalase positive (catalase breaks down hydrogen peroxide)

E coli

Oxidase negative (part of electron transport chain)

Prokaryotes

Bacteria and Archaea, small cells (<5 mm), nucleus with no membrane (nucleoid), 1 haploid chromosome, circular DNA, coupled transcription & translation, no internal membrane-bound organelles, no cytoskeleton, peptidoglycan cell walls, and cell division by binary fission.

Eukaryotes

Algae, Fungi, Protozoa; larger cells (>10 mm), nucleus with membrane, 2 diploid chromosomes, linear DNA associated with histone proteins (chromatin), transcription & translation not directly linked, membrane-bound organelles (e.g., mitochondria), cytoskeleton, no peptidoglycan cell walls, and cell division by mitosis or meiosis.

Capsule

Slime/sugar layer/coating that has a white halo around it.

Lysosomes

Formed from Golgi Complex, single membrane, enzymes for digestion.

Mitochondria

Bilayer outer layer, inner layer has cristae (folds), center has a matrix (semifluid substance), proteins that help make ATP.

Rough endoplasmic reticulum

Synthesis and transport with ribosomes.

Smooth endoplasmic reticulum

Synthesis and transport without ribosomes.

Golgi complex

Works with the ER to sort and transport.

Bacterial Cell Wall

Polymeric mesh-like structure that provides rigidity and structure; peptidoglycan is a monomer and a repeating disaccharide with peptides.

Gram-positive

Purple, thick peptidoglycan wall (penicillin can prevent its growth), long bacilli.

Gram-negative

Pink, thin peptidoglycan wall, example E-coli.

Beta-lactam drugs

Interact with peptidoglycan synthesis; can be bactericidal (kills the microbe directly) or bacteriostatic (prevents the microbes from growing).

Narrow-spectrum

Range of different microbial types affected by the drug.

Broad-spectrum

A large range of gram-positive/negative bacteria affected by the drug.

Selectively Toxic

Kills the microorganism but not the host.

Differential stain

Stains that help distinguish between organisms.

Negative Stain

Shows capsules.

Malachite Green Stain

Used to identify endospores.

Gram Stain

Used to identify how thick the peptidoglycan cell wall is.

Acid Fast Stain

Used to identify the mycotic acid on the cell wall; differentiates bacteria with high content of mycolic acids.

Carbolfuchsin Stain

Used for flagella; also the primary stain in an acid-fast stain.

Citrate test

Tests the use of citrate as a carbon source.

Coagulase test

Tests for the production of coagulase which causes fibrinogen in the blood to clot.

Catalase test

Differentiates between staph(+) and staph(-) by the decomposition of hydrogen peroxide to H2O and oxygen.

Active Transport

Movement across the proton gradient with the use of ATP.

Passive Transport

Movement from high to low concentration without the need for ATP.

Facilitated Transport

A form of passive transport of molecules along their concentration gradient, guided by membrane proteins.

Lag phase

No increase in cell number; cells are synthesizing proteins and enzymes needed for nutrient uptake.

Exponential phase

Cells are balanced in growth; antibiotics work best here.

Stationary phase

Population is stable but unequal growth.

Decline/death phase

Cells die.

Innate immunity

Non-specific immunity with no immunological memory.

Adaptive immunity

Specific immunity with immunological memory.

Lymphocytes

Directly destroy other cells, especially virus-filled cells through the release of perforins and other cytolytic chemicals.

Macrophages

Specialized cells involved in detection, phagocytosis, and destruction of bacteria and other harmful organisms.

Neutrophils

Highly phagocytic white blood cells that are early responders in the innate defense against infection.

Eosinophils

Granulocytes that possess phagocytic properties and play an important role in the destruction of parasites.

Natural killer cells

Capable of directly destroying other cells, especially virus-infected cells and tumor cells.

CD8+ T cells

Primarily involved in the destruction of cells infected by foreign agents.

CD4+ T cells

Mediate the response by directing other cells to perform cytotoxic and phagocytic activity.

Plasma cells

Secrete soluble enzymes.

Memory B cells

Long-lived cells that respond quickly during a second exposure.

Dendritic cells

Messengers between innate and adaptive immunity.

Basophiles

Granulocytes that can control mechanisms associated with allergy and asthma.

Mast cells

Function as immune sentinel cells and are early producers of cytokines in response to infection or injury.

Phagocytes

Cells that perform phagocytosis.ingestion of a microorganism or any particulate matter by a cell; CELL EATS MICROORGANISM!).