Where is the location of bacterial DNA?
Where is the location of bacterial DNA?
nucleoid
The DNA of most bacteria is contained in a single circular molecule, called the bacterial chromosome. The chromosome, along with several proteins and RNA molecules, forms an irregularly shaped structure called the nucleoid. This sits in the cytoplasm of the bacterial cell.
How is bacterial DNA transferred?
In conjugation, DNA is transferred from one bacterium to another. After the donor cell pulls itself close to the recipient using a structure called a pilus, DNA is transferred between cells. In most cases, this DNA is in the form of a plasmid. An F+ donor cell contains its chromosomal DNA and an F plasmid.
What shape is the DNA in bacteria?
In many bacteria the DNA is present as a single circular chromosome, although some bacteria may contain two chromosomes, and in some cases the DNA is linear rather than circular. A variable number of smaller, usually circular (though sometimes linear) DNA molecules, called plasmids, can carry auxiliary information.
Where does DNA transformation take place?
Transformation results in the genetic alteration of the recipient cell. Exogenous DNA is taken up into the recipient cell from its surroundings through the cell membrane (s). Transformation occurs naturally in some species of bacteria, but it can also be affected by artificial means in other cells.
What structure do some bacteria use to move?
flagella
Most motile bacteria move by means of flagella. The structures and pattern of movement of prokaryotic and eukaryotic flagella are different. Eukaryotes have one to many flagella, which move in a characteristic whiplike manner. The flagella closely resemble the cilium in structure.
Where does DNA replication start in most bacteria?
the origin of replication
In bacteria, the initiation of replication occurs at the origin of replication, where supercoiled DNA is unwound by DNA gyrase, made single-stranded by helicase, and bound by single-stranded binding protein to maintain its single-stranded state.
Why do bacteria use horizontal gene transfer?
Horizontal gene transfer enables bacteria to respond and adapt to their environment much more rapidly by acquiring large DNA sequences from another bacterium in a single transfer. Horizontal gene transfer is a process in which an organism transfers genetic material to another organism that is not its offspring.
Where are plasmids located in a bacterial cell?
A plasmid is a small, extrachromosomal DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently. They are most commonly found as small circular, double-stranded DNA molecules in bacteria; however, plasmids are sometimes present in archaea and eukaryotic organisms.
What is the shape and structure of DNA?
DNA is made of two linked strands that wind around each other to resemble a twisted ladder — a shape known as a double helix. Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups.
How does bacterial transformation occur?
Bacterial transformation is a process of horizontal gene transfer by which some bacteria take up foreign genetic material (naked DNA) from the environment. It was first reported in Streptococcus pneumoniae by Griffith in 1928. DNA as the transforming principle was demonstrated by Avery et al in 1944.
How do bacteria move from cell to cell?
Many bacteria move using a structure called a flagellum. The flagellum is a long, corkscrew-like appendage that protrudes from the surface of the bacterium and can extend for a distance longer than the bacterial cell itself. A typical flagellum may be several thousand nanometers long and only 30 nanometres wide.
