Intro Flashcards
small organisms that usually require a
microscope to be seen
Microbes / Microorganisms
Germ actually comes from the Latin word ________
germen (to sprout; to germinate)
form the basis of the food chain in oceans, lakes, and
rivers
Marine and freshwater microbes
break down wastes and incorporate nitrogen gas from the air into organic compounds, thereby recycling
chemical elements among soil, water, living organisms, and air.
Soil microbes
enzymes from microbes can be manipulated to cause the microbes to produce substances they normally don’t synthesize, including:
-cellulose
-human insulin
-proteins for vaccines
-microbes that live stably in and on the human body
-humans and many other animals depend on these microbes to maintain good health.
Human microbiome / Microbiota
the population of microorganisms that inhabit the skin and mucous membranes of healthy normal persons
Normal Microbiota
microorganisms that are only temporarily found in the human body, and may include pathogenic microorganisms
Transient Microbiota
the movement of genetic information across normal mating barriers, between more or less distantly related organisms; process where microbes can swap genes with each other
horizontal gene transfer
Types of microorganisms
-bacteria
-virus
-archaea
-fungi
-protozoa
Why are bacteria called prokaryotes?
their genetic material is not enclosed in a special nuclear membrane
difference of cell wall between archaea and bacteria
archaea- no peptidoglycan
bacteria - has peptidoglycan
three main groups of archaea
- thermophiles
- halophiles
- methanogens
live in extremely salty environments such as the Great Salt Lake and the Dead Sea
halophiles
produce methane as
a waste product from respiration
methanogens
live in hot sulfurous water, such as hot springs at Yellowstone National Park
thermophiles
True or False
Archaea are known to cause disease to humans
False
True or False
Fungi cannot carry out
photosynthesis
True
True fungi have cell walls composed primarily of a substance called ______
chitin
unicellular forms of fungi that oval microorganisms that are larger than bacteria
yeasts
most typical fungi
Molds
Molds can form visible masses of ____ that are cottony growths sometimes found on bread and fruit
mycelia
the branching filaments that make up the mycelium of a fungus
hyphae
How do fungi obtain nourishment?
by absorbing organic material from their environment
Protozoa move by:
-pseudopods
-flagella
-cilia
Amebae move by using extensions of their cytoplasm called
Amebae is plural form of amoeba
pseudopods
microscopic hair-like structures involved in the locomotion of a cell
flagella
sing. flagellum
numerous shorter appendages for locomotion
cilia
singular. cillium
organisms that derive nutrients from living hosts
parasites
The cell walls of many algae are composed of a carbohydrate called ____
cellulose
most viruses can only be seen with this tool
electron microscope
a virus particle contains a core made of only one type of nucleic acid, either:
- DNA
- RNA
carbohydrate slimes exuded by bacteria; highly
amorphous
capsules
what happens if capsules reduce growth?
protect against predators, but makes it more difficult to obtain nutrients
2 types of bacteria
- Gram negative (G-)
- Gram positive (G+)
makes bacteria capable of withstanding huge
internal pressures
murein in cell wall
The space where the murein layer sits between the cytoplasmic inner & outer membranes
periplasm
these side chains are recognized by our immune system & are attached to a
“core”
O-specific side chains of Lipopoly Saccharides
membrane tunnels in bacteria which allow small molecules (600-700
Da) through.
porins
Periplasmic space
provides “additional reaction volume” for cell; often contains enzymes & binding proteins
proteinaceous filaments that help mediate attachment to surfaces & allow for the exchange of genetic material
fimbriae & pili
crystalline protein layers on cell surfaces, act as filters
S-layers
Flagellum can turn in both directions:
Counter Clockwise Rotation → runs forward →
Clockwise Rotation → tumbles backward
turn mRNA into proteins
this process is called translation
ribosomes
What happens if a cell lacks nutrients?
It eats its own ribosomes to survive (shrinks) because ribosomes make up much of all volume.
Ribosomal subunits
- Large (50 S): 23 S Ribosomal RNA (rRNA)
3,000 NT long, 5 S - Small (30 S): 16 S tRNA ~ 1,500 NT
NT = nanotesla
allows bacteria to last for tens of thousands of years
Endospores
rRNA gene copy number in genomes
gene copy numbers are aka operons
1-15 copies/genome
prokaryotes or eukaryotes present?
Plasmids
prokaryotes: +
eukaryotes: (rare)
prokaryotes or eukaryotes present?
Chromosome
prokaryotes: +
eukaryotes: +
prokaryotes or eukaryotes present?
Mitochondria, Chloroplast
prokaryotes: -
eukaryotes: +
prokaryotes or eukaryotes present?
Viruses (infect)
prokaryotes: +
eukaryotes: +
prokaryotes or eukaryotes present?
Transposable elements
prokaryotes: +
eukaryotes: +
CFU
Colony Forming Units
Prokaryote chromosomes
-Single (up to 3)
− haploid (1 copy)
− circular (some linear)
− supercoiled
− small & efficiently organized
~ 4.7 Mb ~ 3,000 genes
Eukaryote chromosomes
Multiple
− di → polyploid
− linear
− coiled around histones
− large & redundant
~ 40,000 genes
encodes several proteins and is characteristic of many bacterial and chloroplast mRNAs
Polycystronic mRNA
have adapted so well to high salt concentrations that they actually require
them for growth
obligate halophiles
do not require high salt concentrations but are able to grow at salt concentrations up to 2%
at 2% concentration the growth of many other organisms are inhibited
facultative halophiles
2 major groups of parasitic worms
-roundworms
-flatworms
parasitic worms are collectively known as ______
helminths
This scientist devised a system of classification based on the cellular structue of the organism
Carl Woese
3 domains of organisms based on cellular structure
- Bacteria
- Archaea
- Eukarya
Types of Eukarya
● Protists (slime molds, protozoa, and algae)
● Fungi (unicellular yeasts, multicellular molds, and
mushrooms)
● Plants (mosses, ferns, conifers, and flowering plants)
● Animals (sponges, worms, insects, and vertebrates)
were the first living cells to appear on Earth
Bacterial ancestors
the first to observe live microorganisms through the magnifying lenses of the more than 400 microscopes he constructed
Anton van Leeuwenhoek
archaic term referring to microorganisms
This word was invented by Leeuwenhoek
animalcules
