Microbiology Study Guide Exam 1

These flashcards cover key concepts, definitions, and historical milestones in microbiology as per the provided lecture notes.

What are the main categories of microbes?

Bacteria, viruses, fungi, algae, and protozoa.

How are microbes classified?

They are classified based on their characteristics such as cell structure, metabolism, and genetic makeup.

Where can microbes be found?

Microbes are found in various environments including soil, water, and on living organisms.

What is a pathogen?

A pathogen is an organism that causes disease.

What is a parasite?

A parasite is an organism that lives on or in a host and benefits at the host's expense.

What milestone discovery was made in the mid 1600s regarding microbiology?

The invention of the microscope, which enabled the study of microorganisms.

How high can compound light microscopes magnify?

Up to 1000 times.

What is biochemistry?

The study of the chemical processes within and related to living organisms.

What is the modern day tree of life?

A phylogenetic tree that illustrates the evolutionary relationships among various biological species.

What is 16S rRNA?

A component of the small subunit of ribosomal RNA used for bacterial classification and phylogeny.

What is the typical size of bacteria?

Bacteria typically range from 0.5 to 5 micrometers.

What is a micrometer?

A micrometer is a unit of length equal to one millionth of a meter.

What is the typical size of a virus?

Viruses typically range from 20 to 300 nanometers.

What discovery in the 1940s changed the practice of medicine?

The discovery of antibiotics, specifically penicillin.

Who was well known for the discovery of penicillin?

Alexander Fleming.

What molecular structure was discovered in the 1950s?

The double helix structure of DNA.

Who were involved in the discovery of the DNA structure?

James Watson and Francis Crick.

What is the field of study called molecular biology?

The branch of biology that deals with the molecular basis of biological activity.

What does cell theory state?

All living things are composed of cells; the cell is the basic unit of life; all cells come from pre-existing cells.

What is the endosymbiotic theory?

The theory that mitochondria and chloroplasts were once free-living prokaryotes that were taken inside another cell.

Who is Lynn Margulis?

A biologist known for her endosymbiotic theory regarding the evolution of eukaryotic cells.

What is germ theory?

The theory that specific diseases are caused by specific microorganisms.

What are microorganisms?

Microorganisms are microscopic organisms that can exist as single cells or in colonies.

What are eukaryotic microorganisms?

Microorganisms that have complex cells with a nucleus; examples include fungi, protozoa, and algae.

What are prokaryotic microorganisms?

Microorganisms that have simpler cells without a nucleus; examples include bacteria and archaea.

What is taxonomy?

The science of classifying organisms.

What is phylogeny?

The evolutionary history and relationships among species.

What is binomial nomenclature?

A system for naming species using two names, the genus and the species identifier.

What is a cladogram?

A diagram that shows the evolutionary relationships among organisms.

What is a phylogenetic tree?

A branching diagram that represents the evolutionary relationships among various species.

What is a micrograph?

An image taken with a microscope.

What is the difference between TEM and SEM?

TEM (Transmission Electron Microscopy) provides detailed images of the internal structure, whereas SEM (Scanning Electron Microscopy) provides 3D images of the surface.

What is magnification in microscopy?

Magnification is the increase in apparent size of an object.

How do you calculate total magnification with a compound microscope?

By multiplying the magnification power of the ocular lens by that of the objective lens.

What are the visual differences between SEM and TEM images?

SEM images are 3D and show surface details, while TEM images are 2D and show internal details.

What is gram staining?

A method of staining bacteria to distinguish between two broad classes based on their cell wall structure.

Do Gram positive bacteria stain dark purple or pink?

Gram positive bacteria stain dark purple.

How do Gram positive bacteria differ from Gram negative bacteria structurally?

Gram positive bacteria have a thick peptidoglycan layer, whereas Gram negative bacteria have a thinner layer and an outer membrane.

What is peptidoglycan?

A polymer that makes up the cell wall of bacteria.

What is an organic molecule?

A molecule that contains carbon and is found in living organisms.

What is a polymer?

A large molecule made up of repeating subunits called monomers.

What is a polar covalent bond?

A type of bond in which electrons are shared unequally between two atoms, resulting in partial charges.

What is a hydrogen bond?

A weak bond between a hydrogen atom with a partial positive charge and another electronegative atom.

What is a redox reaction?

A chemical reaction involving the transfer of electrons between two species.

Which biomolecules are formed by dehydration synthesis?

Carbohydrates, proteins, and lipids.

Give an example of a slightly acidic pH.

A pH of around 6.

Is glucose a monosaccharide?

Yes, glucose is a monosaccharide.

How many carbons does glucose have?

Six carbons.

What are examples of polysaccharides?

Starch, glycogen, and cellulose.

How are disaccharides held together?

By glycosidic bonds formed during dehydration synthesis.

What is a fatty acid?

A carboxylic acid with a long hydrocarbon chain.

Where is cholesterol found?

Cholesterol is found in eukaryotic cell membranes.

Where are proteins made in the cell?

In ribosomes.

What is the subunit of proteins?

Amino acids.

What is a peptide bond?

A bond formed between two amino acids during protein synthesis.

What is the function of proteins in the cell?

Proteins perform various functions including catalyzing reactions, providing structure, and regulating processes.

What is a polypeptide?

A chain of amino acids linked by peptide bonds.

What is a prokaryote?

An organism that lacks a membrane-bound nucleus and organelles.

Are the domains Bacteria and Archaea both prokaryotes?

Yes, both Bacteria and Archaea are prokaryotes.

Give an example of a Gram positive prokaryote.

Staphylococcus aureus.

Give an example of a Gram negative prokaryote.

E. coli.

How is a virus defined?

A virus is an acellular infectious agent that can only replicate inside a host cell.

Are viruses considered prokaryotes or eukaryotes? Why not?

Neither, because viruses lack cellular structures and cannot reproduce independently.

What are distinguishing structures of eukaryotic cells?

Nucleus, membrane-bound organelles, and cytoskeleton.

What are the differences between prokaryotic and eukaryotic cell structures?

Prokaryotes lack a nucleus and organelles while eukaryotes have both.

Do any eukaryotes have cell walls?

Yes, plants and fungi have cell walls.

What is selective permeability?

The ability of a cell membrane to allow some substances to pass while restricting others.

What is phagocytosis?

The process by which cells engulf solid particles.

What is a protozoan?

A single-celled eukaryotic organism.

What are helminths?

Multicellular parasitic worms.

What are nematodes?

A type of roundworm, which is a common helminth.

What cell structures are found in eukaryotic cells and not in prokaryotic cells?

Nucleus, mitochondria, and Golgi apparatus.

What is endosymbiotic theory and its supporting evidence?

It posits that mitochondria and chloroplasts originated from free-living prokaryotes that were engulfed.

What are fungi and molds?

Eukaryotic organisms that absorb nutrients and can be decomposers; molds reproduce via spores.

Are fungi photosynthetic?

No, fungi are heterotrophic.

What is yeast?

A type of fungus used in fermentation.

What is Candida albicans?

A yeast that can cause infections in humans.

Describe several eukaryotic pathogens.

Examples include Giardia sp. and Plasmodium falciparum.

What are basic prokaryotic cell structures?

Nucleoid, plasmids, ribosomes, inclusions, plasma membrane, and cell wall.

What is cell morphology?

The study of the shape and structure of cells.

What are some shapes of bacteria?

Coccus (spherical), bacillus (rod-shaped), and vibrio (comma-shaped).

What does cell arrangement mean?

The way that cells are organized in relation to each other.

What does the term strepto- mean?

A prefix indicating a chain or grouping of bacteria.

What is chemotaxis?

The movement of an organism in response to a chemical stimulus.

Describe Proteobacteria (Example E.coli) in terms of their cell wall structure?

Proteobacteria are Gram negative, meaning they have a thin peptidoglycan layer and an outer membrane.

What are phototrophic bacteria?

Bacteria that obtain their energy from sunlight.

What are cyanobacteria?

Photosynthetic bacteria often referred to as blue-green algae.

Are cyanobacteria the same thing as algae?

No, cyanobacteria are prokaryotic while algae are eukaryotic.

Describe the shape and arrangement of Staphylococcus aureus cells. Is it a “Firmicute”?

Staphylococcus aureus is round and forms clusters; it is classified as a Firmicute.

Describe the unique cell characteristics of Archaea.

They have unique lipids in their membranes and potentially pseudopeptidoglycan in their cell walls.

Why do we know much less about Archaea species compared to Bacteria species?

Many Archaea are extremophiles found in harsh environments that are difficult to sample.

What is microbiota?

The community of microorganisms living in a particular environment.

What is a microbiome?

The collective genomes of the microbiota.

What are the differences between commensalism and mutualism?

In commensalism, one species benefits while the other is unaffected; in mutualism, both species benefit.

Are bacteria found in air, soil, and water?

Yes, bacteria can be found in all these environments.

What does define sterile mean?

Free from all living microorganisms.

What are prions?

Infectious proteins that can induce abnormal folding of normal proteins in the brain.

What are the basic structures of viruses?

Viruses consist of nucleic acid surrounded by a protein coat.

How do viruses reproduce?

Viruses replicate by hijacking the cellular machinery of host cells.

How are viruses named?

Viruses are often named based on the disease they cause, the location they were discovered, or a specific characteristic.