3. All cells have 3 main components:
Nucleoid
a region where DNA is located
Plasma membrane
limits access to the cell‟s interior
Cytoplasm
a place where all metabolic reactions occur
(e.g. protein synthesis, which occurs on the
ribosomes)
a gel-like structure composed mainly of water that
contains enzymes, salts, cell components, and
organic molecules
4. Bacteria also often have these features:
Cell wall
helps the cell retain its shape
made of peptidoglycan
Flagellum
plural: flagella
responsible for movement
Pili
are filamentous proteins that help cells
adhere to a surface or facilitate conjugation
5. Glycocalyx
sometimes called „capsule‟
a sticky layer composed of proteins or
polysaccharides that surround the cell wall
for protection
Plasmid
circles of DNA apart from the nucleoid
Ribosome
site for protein synthesis
8. Prokaryotes reproduce by BINARY FISSION,
an asexual process that replicates DNA and
distributes it and other cell parts into two
daughter cells.
9. Binary fission is an effective way for bacteria to
reproduce, however it does produce problems. Since
the cells produced through this type of reproduction
are identical, they are all susceptible to the same types
of antibiotics. In order to incorporate some genetic
variation, bacteria use a process called recombination.
Bacterial recombination can be accomplished through
conjugation, transformation, or transduction.
10. one bacterium connects
itself to another through
a protein tube structure
called pilus or sex pilus.
Genes are transferred
from one bacterium to
the other through this
tube.
sometimes called
“bacterial sex”
11. a prokaryote takes up naked DNA without
cell-to-cell contact. It occurs when prokaryotes
die and pieces of their DNA enter other cells.
12.
13. It is a type of recombination that involves the
exchanging of bacterial DNA through
bacteriophages.
14.
15. Bacteria are present in almost every
environment, e.g. in the soil, in the air, in
animals and plants. They are found all over our
bodies e.g. on our skin, in our mouth and in
our gut. Most are harmless and are even
beneficial.
16. Nutrition refers to how an organism obtains
energy and a carbon source. Phototrophs are
species that use light energy, and chemotrophs
obtain their energy from chemicals taken from
the surrounding environment. An autotroph is
an organism that only needs carbon dioxide as
its carbon source, and a heterotroph is an
organism that requires at least one organic
nutrient as a source of carbon for making other
organic compounds.
17. The four major modes of nutrition for prokaryotes are:
1. Photoautotrophs are photosynthetic organisms that
harness light energy to drive the synthesis of organic
compounds from carbon dioxide. All photosynthetic
prokaryotes use this mode of nutrition.
2. Chemoautotrophs only require carbon dioxide as a
carbon source. Instead of using light for energy, they
obtain energy by oxidizing inorganic substances. Only
certain prokaryotes use this mode of nutrition.
3. Photoheterotrophs may use light to make ATP but
must also obtain carbon in organic form. Only certain
prokaryotes use this type of nutrition.
4. Chemoheterotrophs consume organic molecules for
energy and carbon.
Prokaryotes, protists, fungi, animals and some plants
use this nutritional mode.
18. Most bacteria are heterotrophic, living off other
organisms. Most of these are saprobes, bacteria
that live off dead organic matter. The bacteria that
cause disease are heterotrophic parasites. There are
also many non-disease-causing bacterial
parasites, many of which are helpful to their hosts.
Autotrophic bacteria manufacture their own food
by the processes of photosynthesis and
chemosynthesis (see autotroph ). The
photosynthetic bacteria include the green and
purple bacteria and the cyanobacteria . Many of
the thermophilic archaebacteria are
chemosynthetic autotrophs.
