Reproduction in Bacteria
The majority of time, prokaryotes reproduce _________ by a process known as
______________. Sexual reproduction is not very common in prokaryotes, but does
occur in some, such as Escherichia coli, by a process known as ___________.
Asexual Reproduction (Binary Fission)
Asexual reproduction is the formation of a new individual from a ____ organism. It
results in a genetically ___________ offspring. In favourable conditions, a bacterium
can grow and divide through binary fission in as little as ___ minutes.
Binary fission is prokaryotes can be broken down into stages:
1. DNA replicate (____________
________), resulting in identical
copies of genetic material
2. The two strands of DNA will then
___________
3. A new ____________ and _____
______ will develop through the
midsection of the prokaryote
4. The cells will eventually become
two _________________, which
may separate or remain attached
Sexual Reproduction (Conjugation)
Sexual reproduction is a process involving ___ organisms and results in offspring that
are genetically ____________ from both parents.
Conjugation in prokaryotes can be broken down into stages:
1. Two bacteria join together by forming a specialized structure called a _______.
2. Genetic information (_____________) is ________ through the pilus, resulting
in an altered set of characteristics.
3. Following the transfer, the two bacteria separate and can then undergo binary
fission.
The result of the uptake of a new piece of DNA by conjugation can have many effects
including:
1)
2)
In both cases, if the piece of DNA is inserted into the chromosome, then the process is
called ______________________.
This produces a permanent change in the DNA of the cell, which is ___________ to the
________________ of that cell.
During unfavourable conditions, some prokaryotes survive by forming dormant or resting
cells, called _________, which can withstand harsh environments such as ______ and
______. When suitable conditions return, the prokaryote will re-emerge and begin
_______________.
Bacterial Growth
Bacterial growth curves take on a particular pattern, which shows the rate
at which bacteria will reproduce when conditions are optimal. A typical
growth curve consists of 4 different phases:
Lag phase –
Exponential growth phase –
Stationary phase –
Death phase –
Bacterial Growth Curve
 The maximum number of organisms a particular environment can
support is termed the _____________________
 Growth rate is the time it takes for a population of bacteria to
__________ in number
 Like all organisms, bacteria thrive under __________ conditions
 The primary reason that our planet isn’t buried under a thick layer of
bacteria can be attributed to the fact that conditions are rarely
______ for the bacteria to grow. Scientists who study bacteria try
to create the optimal environment in the lab: culture medium with the
necessary ___________, _________, ___, and
________________, in which bacteria grow predictably
Generation times for some common bacteria under optimal conditions of
growth
Bacterium
Medium
Escherichia coli
Glucose-salts
Bacillus megaterium
Sucrose-salts
Streptococcus lactis
Milk
Streptococcus lactis
Lactose broth
Staphylococcus aureus
Lactobacillus acidophilus
Rhizobium japonicum
Mycobacterium tuberculosis
Treponema pallidum
Heat infusion broth
Milk
Mannitol-salts-yeast
extract
Synthetic
Rabbit testes
Growth Rate
(minutes)