Prokaryotic Cells Flashcards
examples of prokaryotic cells
bacteria, blue-green algae, mycoplasma, pplo (pleuro pneumonia-like organisms)
most prokayotes have a what surrounding their cell membrane
a cell wall
what is the fluid matrix filling the cells of prokaryotes
cytoplasm
do prokaryotes have a well-defined nucleus
no
what are plasmids
in addition to the genomic dna, many bacteria have small circular DNA outside the genomic DNA.
these smaller DNA are called plasmids
an example of a unique phenotypic character given to bacteria by plasmids
resistance to antibodies
what is plasmid dna used for
monitoring bacterial transformation with foreign dna
which organelle is found in eukaryotes and prokaryotes both
ribosomes
what does cell envelope of prokaryotes consist of
a tightly bound three-layered structure i.e. glycocalyx, cell wall and plasma membrane
two types of glycocalyx
slime layer and capsule
slime layer glycolayx structure
it’s a loose sheath
capsule glycocalyx structure
thick and tough
what does the cell wall do
determines shape of the cell
provides a strong structural support to prevent the bacterium from bursting or collapsing
gram staining is developed by
christian gram
what is gram staining
a technique used to classify bacteria into two groups
gram positive which take up the gram stain
gram negative which do not take up the gram stain
what is mesosome and how is it formed
it is a membranous structure that is formed by the extensions of plasma membrane into the cell
mesosome can be in form of
vesicles
tubules
lamellae
what do mesosomes help in
cell wall formation
dna replication and distribution to daughter cells
respiration
secretion process
to increase the surface area of plasma membrane and enzymatic content
photosynthetic prokaryotes
cyanobacteria
purple bacteria
other membranous extensions found in photosynthetic bacteria into the cytoplasm
chromatophores which contain pigments
what is flagella
in motile bacteria, thin filamentous extensions from cell wall
three parts of flagella are
filaments, hook, basal body
longest portion of flagella
filament
extends from cell surface to outside
other surface structures like flagella
pili and fimbriae
do pili and fimbriae play a role in motility like flagella
no
structure of pili
elongated tubular structure
structure of fimbriae
small bristle-like fibres sprouting out of the cell
function of fimbriae
in some bacteria they help in attaching to rocks in streams and also to host tissues
in prokaryotes, ribosomes are associated with _______ of the cell
plasma membrane
size of ribosomes
15 nm by 20 nm
which two subunits are ribosomes made up of
50S and 30S units which when present together form 70S prokaryotic ribosomes
site of protein synthesis
ribosomes
several ribosomes may attach to a single mRNA and form a chain called
polyribosome or polysome
ribosomes of a polysome translate ______ into _____
mRNA into proteins
reserve material in prokaryotic cells are stored where in form of what
in cytoplasm in form of inclusion bodies
are inclusion bodies bounded by any membrane system
no
where do inclusion bodies lie
free in cytoplasm
examples of inclusion bodies
phosphate granules
cyanophycean granules
glycogen granules
gas vacuoles are found in
blue-green algae
purple and green photosynthetic bacteria
size of PPLO
about 0.1 micrometre
size of a typical bacteria
1 to 2 micrometre
size of a typical eukaryotic cell
10 to 20 micrometer
size of viruses
0.02 to 0.2 micrometer
rod like bacteria
bacillus
spherical bacteria
coccus
comma shaped bacteria
vibrio
spiral bactera
spirillum
four basic shapes of bacteria
rod like
comma shaped
spherical
spiral
