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What two domains are prokaryotes divided into?
bacteria and archaea
Prokaryotes thrive ___
almost everywhere
Most prokaryotes are ___
unicellular
What are the three most common shapes (colonies)?
spheres (cocci), rods (bacilli), and spirals
spheres
cocci
rods
bacilli
An important feature of nearly all prokaryotic cells is their
cell wall
What is a cell wall made out of?
cellulose or chitin
What is the function of the cell wall?
maintains cell shape and protects the cell
Scientists use the ___ to classify bacteria by cell wall composition
gram stain
What color is a gram-positive bacteria?
Purple
Gram-positive bacteria have simpler walls with a
large amount of peptidoglycan
What color is a gram-negative bacteria?
Pink
Gram-negative bacteria have
less peptidoglycan and a toxic outer membrane
Many antibiotics target ____ and damage bacterial ___
peptidoglycan, cell walls
gram-negative bacteria are more likely to be
antibiotic resistant
Most motile bacteria propel themselves by
flagella
Many of the flagella’s proteins are
modified versions of proteins that perform other tasks in bacteria
exaptation
existing structures take on new functions through descent with modification
The prokaryotic genome has less DNA than the
eukaryotic genome
Most of the prokaryotic genome consists of a
circular chromosome
Where is the chromosome located?
nucleoid region
plasmids
smaller rings of DNA that some bacteria have
Key feature of prokaryotic reproduction (1)
They are small
Key feature of prokaryotic reproduction (2)
reproduce by binary fission
Key feature of prokaryotic reproduction (3)
have short generation times [1-3 hours]
What are the three factors that contribute to prokaryotic genetic diversity?
rapid reproduction, mutation, genetic recombination
Mutation rates during binary fission are low, but because of rapid reproduction
mutations can accumulate rapidly in a population
high diversity from mutations allows for
rapid evolution
Prokaryotic DNA from different individuals can be brought together by
transformation, transduction, conjugation
transformation
A prokaryotic cell can take up and incorporate foreign DNA from the surrounding environment
Transduction
the movement of genes between bacteria by bacteriophages (viruses that infect bacteria)
Conjugation
the process where genetic material is transferred between prokaryotic cells
genetic material is transferred through the
sex pilus
Prokaryotes can be categorized by how they obtain
energy and carbon
Phototrophs
obtain energy from light
Chemotrophs
obtain energy from chemicals
Autotrophs
require CO2 as a carbon source
Heterotrophs
require an organic nutrient to make organic compounds
Obligate aerobes
require O2 for cellular respiration
Obligate anaerobes
poisoned by O2
What processes do obligate anaerobes use?
fermentation or anaerobic respiration
Facultative anaerobes
can survive with or without O2
What led to the splitting of prokaryotes into bacteria and archaea?
Molecular systematics
Archaea share
certain traits with bacteria and other traits with eukaryotes
extremophiles
archaea that live in extreme environments
extreme halophiles
live in highly saline environments
extreme thermophiles
thrive in very hot environments
What does Chlamydia trachomatis cause?
Blindness
What does Borrelia burgdorferi cause?
Lyme disease
Plant chloroplasts likely evolved from
cyanobacteria
cyanobacteria
photoautotrophs that generate O2
Plant chloroplasts likely evolved from cyanobacteria by the process of
endosymbiosis
Prokaryotes play a major role in the ___ between the living and nonliving components of ecosystems
recycling of chemical elements
Chemoheterotrophic prokaryotes function as
decomposers
Symbiosis
ecological relationship in which two species live in close contact
prokaryotes often form symbiotic relationships with
larger organisms
mutualism
both symbiotic organisms benefit
commensalism
one organism benefits while neither harming nor helping the other in any significant way
parasitism
organism harms but does not kill its host
pathogens
parasites that cause disease
vectors
parasites that transmit disease
Prokaryotes are the principal agents in
bioremediation
bioremediation
the use of organisms to remove pollutants from the environment
The Romans thought the malaria was caused by
bad air from swamps
What did the Romans do to prevent malaria?
drain swamps
Malaria can be
asymptomatic
What are the classic symptoms of malaria?
fever, chills, sweating, headaches, muscle pains
What are the severe symptoms of malaria?
cerebral malaria, anemia, kidney failure
What factor affects the severity of symptoms? (1)
the species of Plasmodium
What factor affects the severity of symptoms? (2)
the victims genetic background
What factor affects the severity of symptoms? (3)
acquired immunity
Who discovered malaria?
Charles Laveran
Who discovered the mode of transmission of malaria?
Ronald Ross
What is the mode of transmission of malaria?
Anopheles mosquito
What are the four species of Plasmodium that causes malaria?
P. falciparum, P. vivax, P.ovale and P. malariae
P. falciparum cases are often
fatal and is responsible for most deaths
Both ___ and ___ can go dormant, hiding out in the liver
Plasmodium vivax, P. ovale
P. malariae causes a
long-lasting infection
Plasmodium has two hosts:
mosquitoes and humans
Where does sexual reproduction take place?
In the mosquito
When is malaria transmitted to humans?
when the mosquito takes a blood meal
In the salivary gland the parasite cuts off the mosquito’s
anticoagulant supply
What does cutting off the anticoagulant supply do?
this makes it harder for the mosquito to feed
As a result of the anticoagulant
an infected mosquito is twice as likely to bite two people in a single night as an uninfected mosquito
parasite is spread more widely
In humans, the Plasmodium helps the mosquito feed by
releasing chemicals that slow clotting
What does slowed clotting do?
increase the chances of the mosquito feeding successfully and sucking up the parasite
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