Week 1/2 Flashcards
What are Microbial Cells
living compartments that interact with the environment and with other cells in dynamic ways
Cytoplasmic Membrane
All cells have a permeability barrier that separates the inside of the cell, the cytoplasm, from the outside.
Cytoplasm
An aqueous mixture of macromolecules (e.g.proteins, lipids, nucleic acids, and polysaccharides), small organic molecules (mostly the precursors of macromolecules), various inorganic ions, and ribosomes.
Ribosomes
The structures responsible for protein synthesis.
Cell wall
The cell wall is a relatively permeable structure located outside the cytoplasmic membrane and is a much stronger layer than the membrane itself.
Cell types based on cellular organization
- Eukaryotic cell structure
- prokaryotic cell structure
Eukaryotic Cell (where are they found?)
Are found in a group of organisms called the Eukarya.
a) plants
b) animals
c) diverse microbial eukaryotes
* Algae
* Protozoa
* Fungi
Organelles
Eukaryotic cells contain an assortment of membrane-enclosed cytoplasmic structures called organelles
Prokaryotic Cell (where are they found)
- Is found within two different groups of organisms
- Bacteria
- Archaea
Genome
The genome is the living blueprint of an organism; the characteristics, activities, and very survival of a cell are governed by its genome. The full set of genes in a cell
Gene
*a segment of DNA that encodes a protein or
an RNA molecule.
Chromosomes:
(organization)
*The genomes of prokaryotic cells and eukaryotic cells are organized into structures called chromosomes.
Metabolism
- Nutrients are acquired from the environment and transformed
into new cellular materials and waste products.
Energy is used to support synthesis of new structures
Cell division
- Production of these new structures culminates in the division
of the cell to form two cells. - Microbial growth results from successive rounds of cell
division.
Proteins
- Genes are decoded to form proteins that regulate cellular processes.
Enzymes
- Those proteins that have catalytic activity, carry out reactions that supply energy and perform biosynthesis within the cell.
Gene expression
- Enzymes and other proteins are synthesized during gene expression in the sequential processes of transcription and translation.
Transcription
- The process by which the information encoded in DNA sequences is copied into an RNA molecule
Translation
- The process whereby the information in an RNA molecule is used by a ribosome to synthesize a protein.
DNA replication
- Microbial growth requires replication of the genome through the process of DNA replication, followed by cell division.
- All cells carry out the processes of transcription, translation, and DNA replication.
Responsiveness
- Microorganisms have the ability to sense and respond to changes in their local environment.
Motility
- Many microbial cells are capable of motility, typically by self-propulsion
- Motility allows cells to relocate in response to environmental conditions.
Differentiation
- Some microbial cells undergo differentiation, which may result in the formation of modified cells specialized for growth, dispersal, or survival.
Cell signaling
- Cells respond to chemical signals in their environment, including those produced by other cells of either the same or different species, and these signals often trigger new cellular activities. Microbial cells thus exhibit intercellular communication; that is, they are “aware” of their neighbour’s and can respond accordingly.
Horizontal gene transfer
- Many prokaryotic cells can also exchange genes with neighbouring cells, regardless of their species.
Evolution
*results when genes in a population of cells change in sequence and
frequency over time, leading to descent with modification.
What do pathogens do?
ALWAYS cause disease
What fabric components of life and MO’s woven into?
- infectious diseases
- food we eat
- water we drink
- fertility of our soils
- health of our animals
- fuel we put in automobiles
Biosphere
activity of the biosphere depends on microorganisms actions
Microbial culture
a collection of cells that have been grow in or on a nutrient medium
A medium
A liquid or solid nutrient mixture that contains all of the nutrients required for a MO to grow
Growth in Bacteria
the increase in the number of cells as a result of cell division
Colony
a single microbial cell placed on a solid nutrient medium can grow and divide into millions or even billions of cells that form a visible colony
- formation makes it easier to see and grow MO’s
Environment
MO’s abound in any natural environment that will support life INCLUDING many environments that are too hostile for higher life forms
Microbial communities & what they are regulated by
MO’s live in these complex communities regulated by:
- Interactions with each other
- with their environment
- with other organisms
Microorganisms
Life forms too small to be seen by the human eye
Describing MO’s
Undifferentiated single cell organisms
Form complex structures
Even multicellular
Microbiology
Science of Microbiology is all about MO’s
WHO they are
HOW they work
WHAT they do
Why are viruses excluded from the microbial discussion?
- Viruses are excluded in most of this discussion because although they resemble cells in many ways, viruses are not cells
- Viruses are a special category of microorganisms.
where are cell walls typically found?
Cell walls are typically found in plant cells and most microorganisms but are not found in animal cells.
What are prokaryotic characteristics
- Few internal structures
- They lack a nucleus
- They lack organelles
How is the DNA present in eukaryotic cells?
DNA is present as several linear molecules (each one formed into its own chromosome)
Where is the genome located in eukaryotic cells
within the membrane-enclosed nucleus
where are the genomes in Prokarytotic cells?
typically closed circular chromosomes
How many chromosomes do most prokaryotic cells have?
have only a single chromosome
What are plasmids
what many prokaryotic cells contain, one or more small circles of DNA distinct from that of the chromosome
What do plasmids typically contain
- Plasmids typically contain genes that are not essential but often confer some special property on the cell (such as a unique metabolism, or antibiotic resistance).
How many pairs does a human cell have
A human cell, for example, contains approximately 3 billion base pairs, which encode about 20,000–25,000 genes.
How many genes do Prokaryotic cells contain
most contain between 500 and 10,000 genes encoded by 0.5 to 10 million base pairs of DNA
Gene
Contain information that is used by the cell to perform the work of metabolism.
Gene
Contain information that is used by the cell to perform the work of metabolism.
