CHAPTER 1- EXPLORING THE MICROBIAL WORLD Flashcards
also called microbes, life forms too small to be seen by the naked eye
Microorganism
microorganisms typically live in complex ________, their activities are regulated by interactions with each other, with their environment, and with other organisms
Microbial communities
those microbes that causes diseases
pathogens
is a collection of cells that have been grown in or on a nutrient medium
microbial culture
is a liquid or solid nutrient mixture that contains all of the nutrients required for a microorganism to grow
medium
refers to the increase in cell numbers as a result of cell division
growth
a single microbial cell placed on a solid nutrient medium can grow and divide into millions of cells that forms a visible ______
colony
seperates the insides of a cell, the cytoplasm, from the outside
cytoplasmic membrane
is a mixture of macromolecules, small organic molecules, varios inorganic ions and ribosomes
cytoplasm
example of proteins, lipids, nucleic acid, and polysaccharides
macromolecules
are the structures responsible for protein synthesis and are found in all cells
ribosomes
lends structural strenght to the cell, relatively permeable structure located outside the cell membrane and is much stronger layer than the membrance itself
cell wall
animal cells have cell wall, true or false?
false
plant cell and most microorganism have cell wall, true or false?
true
two major structural classes of cells
prokaryotic cells and eukaryotic cells
found int the phylogenetic domain eukarya, includes plants and animals also microbial eukaryotes such ah algae, protozoa, and fungi
eukaryotic cells
eukaryotic cells contain an assortment of membrane-enclosed cytoplasmic structures.
organelles
all cells also possess a DNA genore, true or false?
true
complement of all genes in a cell
genome
a segment of DNA that encodes a protein or an RNA molecule
gene
in eukaryotes, DNA is present as several linear molecules within the membrane-enclosed ______
nucleus
a mass visible in the electron microscope
nucleoid
small circles of DNA distinct from that of the chromosome, typically contain genes that are not essential and confer some special property on the cell
plasmids
the genomes or ______ and ______ are typically small and compact and most contains 500 and 10,000 genes encoded by 0.5 to 10 million base pairs
Bacteria and Archaea
microcial cell typically live in groups called _______
microbial communities
taking up nutrients from the environment and transforming them into new cell material and waste product.
metabolism
those proteins that have catalytic activity, are required to carry out reactions that supply the energy and precursors necessary for the biosynthesis of all cell component
enzymes
process by which the information on DNA is copied into an RNA molecule
transcription
process whereby the information on an RNA molecule is used by a ribosome to sythesize a protein
tranlation
microbial growth requires replication of the genome through the process of _____
DNA replication
result in the formation of modified cells specialized for growth, dispersal, and survival
differentiation
typically by self- propulsion, allows cells to relocate in response to environmental conditions
motility
cells respond to chemical signals in their environment, including those produced by other cells of either the same or different species, and these signal offen trigger new cellular activities.
microbial cells exhibit ________;they are “aware” of their neighbors and can respond accordingly.
intercellular communication
is a structure found in bacteria that makes it more resistant to inoculation.
spore
many prokaryotic cells can also exchange genes with neighboring cells, either of the same or different species, in the process of __________
horizontal gene transfer
results when genes in a population of cell change sequence and frequently over time, leading to descent with modification
evolution
how old is earth?
4.6 billion years old
when did microbial cells first appear?
3.8 and 4.3 million years ago
organisms that harvest energy from the sunlight
prototrophic microorganisms
early prototrophs lived in structures called
microbial mats
3 major lineage of microbial cells are
bacteria, archaea, eukarya
the 3 major cell lineage are called _______, and all known cellular organisms belong to one of there 3 ______
domains
