Plasmids are circular, double-stranded DNA molecules found outside the nucleoid (extrachomosomal DNA). They can serve a variety of functions and code for traits that may vary within a single species, since different individuals may carry different plasmids.

Most notable are the plasmids related to antibiotic resistance and plasmids required for formation of the sex pilus in conjugation. Recall that antibiotic resistance is the ability of a bacterial cell to survive in the presence of antibiotics. This ability is facilitated by antibiotic resistant proteins that are coded by certain genes found on the plasmid of a bacterial cell.

The question states that a virus infects a host cell by integrating with the host cell’s genome; therefore, the virus integrates with the chromosomes inside the nucleus of the host cell. Recall that both plasmids and episomes are extrachromosomal DNA molecules (DNA molecules found outside the chromosomes), however, only episomes can integrate with the chromosomes inside the nucleus of a host cell. This means that a virus will only be able to infect host cells if it contains an episome. Plasmids are only found in bacteria and cannot integrate with chromosomal DNA.

A plasmid is a circular DNA molecule that is found outside the bacterial nucleoid (chromosomal DNA). DNA, or deoxyribonucleic acid, is a type of nucleic acid; therefore, a plasmid must contain substances that make up a nucleic acid. Recall that nucleic acids are made up of three main molecules per monomer: a pentose sugar, a phosphate group, and a nitrogenous base (adenine, thymine, uracil, guanine, or cytosine). Like the nucleoid DNA, plasmid DNA will be made of nucleotide monomers that contain a deoxyribose sugar, a phosphate, and a nitrogenous base.

Glycerol is the three carbon backbone for phospholipid and triglyceride structures. In triglycerides, a fatty acid chain is bound to each of the three glycerol carbons, whereas in phospholipids, two carbons are bound to fatty acids and the third is bound to a phosphate group. Glycerol is a chief structural component of lipid molecules, but will not be found in a nucleic acid plasmid.

Transformation is defined as the process by which bacteria can incorporate exogenous DNA from the environment into their genome via direct uptake. Transduction and conjugation are also processes by which exogenous DNA is incorporated, but involve other methods.

Prokaryotes lack a nuclear membrane, which allows translation to occur at the same time as transcription.

In eukaryotic cells the mRNA has to be exported to the cytoplasm before it can be translated. This transport requires post-transcriptional modification to protect the mRNA from degradation as it leaves the nucleus, a process unnecessary to prokaryotic cells. Both prokaryotes and eukaryotes can have cell walls and cytoplasts (cytoplasm). Prokaryotes do, in fact, generate proton gradients in order to complete cellular respiration. These gradients are created across the prokaryotic cell membrane, rather than across the mitochondrial membrane.

Transformation is the uptake of nucleic acid by competent cells, as was described in this question. Conjugation invovles cell-to-cell DNA transfer and transduction involves the use of a viral vector.

The use of bacteriophage viral vectors to transmit genetic information is transduction, an alternative form of genetic modification to transformation or conjugation. Transformation involves direct uptake of genetic material. Conjugation involves cell-to-cell transfer of DNA.

The question states that the antibiotic halts the bacterial cell division. Recall that mitosis is a form of asexual reproduction that produces two diploid daughter cells with identical DNA. Mitosis, however, is only found in eukaryotic cells. The analogous asexual reproduction in prokaryotic cells is called binary fission. In binary fission, bacterial cells replicate their circular DNA in such a way that the end products are two double-stranded, circular DNA molecules. Each DNA molecule migrates to opposite ends of the cell and the cell splits into two new daughter cells with identical DNA. The question asks about the effect of the antibiotic on mitosis; since the process doesn’t occur in prokaryotic cells, mitosis is irrelevant to this question.

Prokaryotic cells can reproduce either sexually and asexually. In a bacterial cell, sexual reproduction occurs via three different methods: conjugation, transformation, and transduction. Conjugation involves the exchange of genetic material (plasmids) between bacterial cells through a bridge called the sex pilus. Transformation involves the incorporation of extracellular DNA from the environment. Transduction involves the transmission of genetic material from one bacterial cell to another by a viral vector. These three processes are considered forms of sexual reproduction because all of them involve genetic recombination.

Prokaryotic cells can reproduce asexually only through binary fission. Binary fission is the process by which a bacterial cell splits into two identical daughter cells. This is a very fast process and contributes to the rapid growth and replication of bacteria.

Mitosis and meiosis are only found in eukaryotic cells. Mitosis is a form of asexual reproduction and meiosis is a form of sexual reproduction, since it involves genetically unique daughter cells. Binary fission is the prokaryotic analog of mitosis, but is a distinctly different process.

Endospores are produced by gram-positive bacteria and can lie dormant for years. Endospores are crucial to growth of gram-positive bacteria because they resist harsh conditions such as extreme temperatures, ultraviolet radiation, and many chemicals. Endospores are not used by fungi by any means. They are also uninvolved in the reproductive processes of bacteria.