microbiology

chapter 1

aseptic technique

collection of practices that allow preparation and maintenance of sterile (no living organisms) media and solutions

cell wall

confer structural strength

chemolithotrophy

a type of metabolism where an organism gets its energy from inorganic chemical compounds (not from light and not from organic food)

chromosome

a long, organized structure of DNA and associated proteins that contain an organisms genes (genetic information)

colony

visible; contains millions or billions of cells

contrast

the difference in appearance between cells and the background when viewed under a microscope

culture

cells grown in/on nutrient medium

cytoplasm

gel like material inside the cell membrane that surrounds the cells internal components

cytoplasmic membrane

also called the plasma membrane is the thin flexible membrane that surrounds the cytoplasm

differentiation

is the process by which unspecialized cells become specialized in structure and function (Ex. a stem cell differentiates into a muscle cell)

domain

the highest and broadest form of biological classification, grouping organisms based on fundamental differences in cell type and genetics. the three major cell lineages are: bacteria, archaea, and eukarya

DNA replication

is the process by which a cell copies its DNA so each new cell recieves an identical genetic blueprint

enrichment culture

isolate microbes having particular metabolic characteristics from nature (used to increase the desired microorganism)

enzyme

is a biological catalyst and is usually a protein. it speeds up chemical reactions without being consumed

eukaryotic

linear chromosomes within nucleus, much larger/more DNA and up to billions of base pairs. refers to organisms that have a true nucleus and membrane bound organelles

evolution

genetic changes transfer to offspring over time

extremophiles

historically associated with extreme environments. live in habitats too harsh for other life forms

genome

a cells full set of genes

gram negative

do not retain crystal violet stain and appear pink/red afer staining

gram positive

will retain the crystal violet stain and appear purple after staining

gram stain

is a differential staining technique used to classify bacteria as Gram-positive or Gram-negative based on their cell wall structure.

growth

refers to an increase in the number of cells rather than the size of the cells

gut microbiome

digests complex carbohydrates in humans

horizontal gene transfer

process by which organisms, usually bacteria, exchange genetic material without reproduction

intercellular communication

process by which send and receive signals to coordinate their activities

Kochs postulates

definitively link cause and effect in infectious diseases- between microbes and infectious diseases

macromolecules

large, complex molecules essential for life, usually made by joining smaller subunits

magnification

the ability to enlarge an image

medium

a substance that allows microorganisms to grow

metabolism

the sum of all chemical reactions in an organism that provide energy and build up or break down molecules

microbial community

a group of different microorganisms that live in the same area

microbial ecology

the study of different microorganisms and how they interact with their environment

microorganism

a tiny organism that can only be seen by a microscope

morphology

the study of the shape structure and form of organisms or cells

motility

the ability of an organism to move by itself

nucleiod

the region of a prokaryotic cell where the DNA is located but it is not surrounded by a membrane

nucleus

a membrane bound organelle that is found in eukaryotes and houses the DNA and controls cell activities

organelle

a specialized structure within a eukaryotic cell that has a specific function

pathogen

these are organisms that cause disease

phylogenetic tree

depicts phylogeny (evolutionary history) of all cells. evolution along two paths to form bacteria and archaea

phylogeny

the evolutionary history

plasmid

a small, circular DNA molecule found in bacteria (and sometimes in archaea or eukaryotes) that replicates independently of the chromosomal DNA.

prokaryotic

lack of a true nucleus and membrane bound organelles

pure culture

a microbial culture that has only one type of microorganism

resolution

the ability to distinguish two adjacent objects as distinct and separate

ribosomal RNA

(rRNA) is a type of RNA that combines with proteins to form ribosomes, the cellular machines that synthesize proteins.

ribosome

a cellular structure where proteins are synthesized

spontaneous generation

is the discredited idea that living organisms can arise from non-living matter.

sterile

Sterile means completely free of all living microorganisms, including bacteria, viruses, fungi, and spores.

transcription

Transcription is the process by which DNA is copied into RNA.

translation

Translation is the process by which mRNA is used to build a protein.

in what ways are microorganisms important to humans

health and medicine (gut microbiome, probiotics, antibiotics, vaccines)

food and agriculture (nitrogen fixing in plants, fermented foods)

environmental roles (oxygen production, decomposition)

what is a bacterial colony and how is one formed

A bacterial colony is a visible cluster of millions of bacteria that all arose from a single cell. It appears as a small dot or circle on a solid growth medium, like agar.

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

A pure culture is a culture that contains only one type of microorganism, which is essential for studying the characteristics of that species without interference from others.

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

Microorganisms are everywhere in nature, but they rarely live in pure culture in the environment.

what cellular structures distinguish prokaryotic cells and eukaryotic cells

presence or absence of a nucleus and membrane-bound organelles.

what are some differences between cell wall and a cell membrane

• cell wall: Rigid, thick layer; made of peptidoglycan in bacteria, cellulose in plants, chitin in fungi

Distinguishes Gram-positive vs Gram-negative bacteria

Found in plants, fungi, bacteria, and some protists; not in animals

• plasma membrane: Flexible, thin phospholipid bilayer with embedded proteins

Site of energy production and transport in prokaryotes

Found in all cells