Introduction to Prokaryotic Cell Flashcards
State some examples for Prokaryotic Cells
- Bacteria
- Blue green Algae
- mycoplasma
- PPLO ( Pluero-Pnumeonia Like Organism.
what are the Basic Properties of Prokaryotic Cells?
- They are small
- multiply rapidly
- vary greatly in size
what are the basic Shapes of Bacterial Cell?
- Bacillus (Rod shaped)
- Vibrio (Comma shaped)
- Spirillium ( Spiral Shaped)
- Coccus (spherical Shaped)
comment on the organization of prokaryotic Cell
The organisation of prokaryotic cell, is fundamentally similiar even if it exhibits wide variety of shapes and function.
what are the outermost layers of a prokaryotic bacteria?
All prokaryotes have a cell wall being outermost layer and cell membrane within it, however mycoplasma is an exception.
comment about the Cytoplasm in Prokaryotic Cell
The fluid matrix, filling the cell is know as cytoplasm, there is no well defined nucleus
if prokaryotic cell doesnt have well defined nucleus does it mean it doesnt have any genetic material at all?
The genetic material in prokaryotic cell is usually naked , not enveloped by nuclear membrane
do we know the nature of genetic material, if yes elaborate more on it
Yes, its a single chromosome and circular in shape known as a genomic DNA.
What are Plasmids?
In addition to the genomic DNA there are small circular DNA outside the genomic DNA, known as Plasmid
List out the Functions of Plasmid
- Confer certain type of phenotypical characterstics, such as
Eg: resistance to antibiotics - Plasmid DNA is used to monitor bacterial transformation with Foreign DNA
Describe about the Special Inclusions in prokaryotic cell?
A specialised differentiated form of cell membrane, known as mesosomes. it has extensions of cell membrane, these extensions are in the form of vesicles, tubules and lamellae
Functions of Mesosomes
they help in
-DNA replication
- DNA formation
-distribution of daughter cells
- respiration
- secretion
- increase the surface area of
~ plasma membrane
~ enzymatic content
What is unique about Cyanobacteria?
In Cyanobacteria, their are membranous extensions into cytoplasm known as chromatophores which contain certain pigment
comment on Cell Envelope and Modifications
most prokaryotic cells, most particularly bacterial cells have a chemically complexed, tightly bound three layered structure known as cell envelope.
describe about the Layers
outermost is glycocalyx, followed by cell wall , followed by cell membrane
what are the common Functions of the layers
although each layer of cell are distinct function but together they act as a single protective unit.
Explain the Classification of Bacteria based on how they respond to the staining procedure developed by Gram Viz?
the cells which take up the stain are known as gram positive
the cells which do not take up the stain are known as gram negative
What is the Difference in composition and thickness of Glycocalyx in bacterias?
- It could be loose sheath called slime layer
-in some others it may be thick and tough known as capsule.
comment on the role of Cell wall?
Cell wall it helps in
determining the shape of cell
provides strong structural support to cell preventing it from bursting or collapsing
comment on the role of Plasma Membrane?
is selectively permeable in nature and acts with outside world
can cells be Motile or non motile?
Bacterial cells may be motile or non motile
What if they are motile?
if they are motile they have thin filamentous extensions from their cell wall called flagella
what are the three parts of flagella?
Bacteria show a range in number and arrangement of flagella. Bacterium Flagellum is composed of three parts
- Filament
- Hook
- Basal Body
what is a Filament? (in terms of flagella)
Filament is the longest portion of flagella, extends from cell surface to outside
What are Pili and Fimbriae
Besides Flagellum, Pili and Fimbriae are surface structures however they do not take role in motility.
What are Pili?
are long tubular structures made of special proteins
What are fimbriae?
Fimbriae, are tiny bristle like fibres sprouting from cell surface
what are the Functions of Fimbriae?
- they help the bacteria to attach to the rocks in steam
- to host tissues
what are Ribosomes
Ribosomes are associated with plasma membrane
What is the Size of Ribosomes?
15 nm by 20nm
comment on its Sub units?
They are made of 50S and 30S units when present together 70S
what is the Function of Ribosomes?
site of protein synthesis
What do ribosomes?
several ribosomes attach to single M(RNA) molecule to become polyribosomes or polysomes, the ribosomes Polysomes translate the RNA into proteins.
what are inclusion bodies?
Reserve material in prokaryotic cell are stored in cytoplasm in the form of inclusion bodies, these are not bound by membrane system and lie freely in cytoplasm
eg: phosphate granules
cyanophacean granules
glycogen granules
where are the gas vacuoles found?
gas vacoules are found in blue green and purple and green photosynthetic bacteria
