Micro ch.1

What is the technique used to prevent contamination by unwanted microorganisms?

Aseptic technique

What is the rigid outer layer that provides shape and protection to a cell?

Cell wall

What is the process of obtaining energy by oxidizing inorganic chemicals?

Chemolithotrophy

What is the DNA molecule that contains genetic information?

Chromosome

What is a visible group of bacterial cells growing on a solid surface?

Colony

What is the difference between an object and its background that makes it easier to see?

Contrast

What is a group of microorganisms grown under controlled laboratory conditions?

Culture

What is the material inside the cell membrane that contains cellular components?

Cytoplasm

What is the selective barrier that controls what enters and leaves a cell?

Cytoplasmic membrane

What is the process in which cells become specialized?

Differentiation

What is one of the three highest levels of biological classification?

Domain

What is the process of copying DNA?

DNA replication

What is a culture designed to favor the growth of a specific microorganism?

Enrichment culture

What is a protein that speeds up chemical reactions?

Enzyme

What type of cell contains a nucleus and membrane-bound organelles?

Eukaryotic

What is the change in inherited characteristics over generations?

Evolution

What are organisms that live in extreme environmental conditions?

Extremophiles

What is all of an organism's genetic material?

Genome

What type of bacteria has a thin peptidoglycan layer and an outer membrane?

Gram-negative

What type of bacteria has a thick peptidoglycan cell wall?

Gram-positive

What staining method distinguishes bacteria as Gram-positive or Gram-negative?

Gram stain

What is an increase in the number or size of cells?

Growth

What is the community of microorganisms living in the digestive tract?

Gut microbiome

What is the transfer of genetic material between organisms rather than from parent to offspring?

Horizontal gene transfer

What is communication between cells using chemical or other signals?

Intercellular communication

What are the rules used to determine whether a microorganism causes a specific disease?

Koch's postulates

What are large biological molecules such as proteins, carbohydrates, lipids, and nucleic acids?

Macromolecules

What is the enlargement of an object's apparent size?

Magnification

What is a nutrient material used to grow microorganisms?

Medium (media)

What are all the chemical reactions that occur within a cell?

Metabolism

What is a group of different microorganisms living and interacting together?

Microbial community

What is the study of microorganisms and their interactions with the environment?

Microbial ecology

What is an organism too small to be seen clearly without a microscope?

Microorganism

What is the shape and physical form of a cell or organism?

Morphology

What is the ability of a cell or organism to move?

Motility

What is the region of a prokaryotic cell where its chromosome is located?

Nucleoid

What is the membrane-bound structure containing DNA in a eukaryotic cell?

Nucleus

What is a specialized structure inside a eukaryotic cell that performs a specific function?

Organelle

What is a microorganism capable of causing disease?

Pathogen

What is a diagram showing the evolutionary relationships between organisms?

Phylogenetic tree

What is the evolutionary history and relationships of organisms?

Phylogeny

What is a small circular DNA molecule separate from the bacterial chromosome?

Plasmid

What type of cell lacks a nucleus and membrane-bound organelles?

Prokaryotic

What is a culture containing only one species or type of microorganism?

Pure culture

What is the ability to distinguish two close objects as separate?

Resolution

What type of RNA forms part of the ribosome?

Ribosomal RNA

What cellular structure is responsible for protein synthesis?

Ribosome

What is the old idea that living organisms can arise from nonliving matter?

Spontaneous generation

What describes something that is completely free of living microorganisms?

Sterile

What is the process of making RNA from a DNA template?

Transcription

What is the process of using mRNA to make a protein?

Translation

In what ways are microorganisms important to humans?

Cause disease, Help digestion, Make food and medicines and Recycle nutrients

What is a bacterial colony and how is one formed?

A visible group of bacteria formed from cell division.

How can you get a pure culture of bacteria and why are pure cultures important?

Use a streak plate to isolate one type of bacteria for study.

Where do you find microorganisms and do they typically live in a pure culture?

They are found everywhere and usually live in mixed communities.

What cellular structures distinguish prokaryotic and eukaryotic cells?

Eukaryotes have a nucleus and membrane-bound organelles; prokaryotes do not.

What are some differences between a cell wall and a cell membrane?

The cell wall provides structure; the membrane controls what enters and leaves.

In what types of organisms would you expect to find cell walls and/or cell membranes?

All cells have membranes; bacteria, archaea, plants, and fungi have cell walls.

How has Earth changed over its history? How have microorganisms contributed?

Microbes changed Earth's atmosphere and nutrient cycles, especially by producing oxygen.

What are the three domains of life? Which contain eukaryotic life?

Bacteria, Archaea, Eukarya. Eukarya contains eukaryotes.

Why were cyanobacteria important? Give an example.

They produced oxygen through photosynthesis. Example: Anabaena.

How do microbes contribute to animal nutrition?

They help animals digest food and produce nutrients.

How are microorganisms important in food and agriculture?

They help make fermented foods, recycle nutrients, and improve soil.

What is wastewater treatment and why is it important?

It removes waste and harmful microbes from water.

What is the difference between magnification and resolution?

Magnification enlarges; resolution separates details.

What is the function of staining in light microscopy?

It increases contrast.

What color will Gram-negative and Gram-positive cells be? Why?

Gram-negative = pink/red. Gram-positive = purple. Their cell walls retain stains differently.

What are the steps of a Gram stain and the function of each reagent?

Crystal violet — Primary stain, Iodine — Mordant, Alcohol — Decolorizer, Safranin — Counterstain

What major advantage does phase-contrast microscopy have over staining?

It allows you to see living, unstained cells.

How can cells be made to fluoresce?

Using fluorescent dyes or antibodies.

What are the major differences between electron and light microscopes?

Electron microscopes have higher magnification and resolution but usually require dead specimens.

What microscope is used to view 3-D cell features? Internal parts?

SEM — surface/3-D features, TEM — internal structures.

How did Pasteur disprove spontaneous generation?

His swan-neck flask experiment showed microbes came from existing microorganisms.

What are Koch's postulates?

Rules used to prove a specific microbe causes a specific disease.

What advantages do solid media offer?

Solid media allow colonies to be isolated.

What is a pure culture?

A culture containing one type of microorganism.

What was Griffith's transformation experiment?

He showed that bacteria could acquire genetic material from other bacteria.

What is a phylogenetic tree and what does it tell you?

A diagram showing evolutionary relationships.

Robert Hooke

Observed cells.

Antoni van Leeuwenhoek

First observed microorganisms.

Louis Pasteur

Disproved spontaneous generation; germ theory.

Robert Koch

Koch's postulates; linked microbes to diseases.

Frederick Griffith

Discovered bacterial transformation.

Carl Woese

Developed the three-domain system using rRNA.

What does sterile mean in microbiology? How can media be sterilized?

Sterile means free of living microorganisms. Methods: autoclaving and filtration.

Why are Archaea more closely related to Eukarya than Bacteria are to Eukarya?

Archaea and Eukarya have more similar genetic machinery and rRNA sequences.

Why are viruses excluded from the ribosomal RNA-based tree of life?

They lack ribosomal RNA (rRNA).

What is a pure culture (population)?

A population of identical cells.

Who described the 'wee animalcules'?

Antoni van Leeuwenhoek.

In which domain(s) of life are microorganisms represented?

Archaea, Bacteria, and Eukarya.

Are most bacteria pathogenic?

False.

The structure that confers structural strength on the cell is known as what?

The cell wall.

A microbial cell's membrane is considered what, because its internal constituents are maintained within the cell while it also imports and exports molecules in response to its environment?

Semipermeable.

The process whereby microorganisms are used to help clean up pollution created by human activities is known as what?

Bioremediation.

The production of human proteins (e.g., insulin) by genetically engineered microorganisms is an example of what subdiscipline of microbiology?

Biotechnology.

Are most microorganisms pathogenic?

False

Who described the "wee animalcules"?

Antoni van Leeuwenhoek.

Who was the first to describe microorganisms, while who was the first person to see bacteria?

Robert Hooke / Antoni van Leeuwenhoek.

Whose work refuted the theory of spontaneous generation?

Louis Pasteur.

What are transparent double-sided dishes used for growing microbes most commonly called?

Petri dishes.