This question involves the concept of generation time, which is the time it takes one colony to double. Therefore, there will be 2 cells in 25 minutes, 4 cells in 50 minutes, 8 cells in 75 minutes, 16 in 100 minutes, 32 cells in 125 minutes, 64 cells in 150 minutes, 128 cells in 175 minutes, and 256 cells in 200 minutes. Note that it is very rare for a single bacterium to be isolated, thus a bacterial colony grows exponentially over a short period of time. Note that 200 minutes represents 8 generation times. The number of bacteria, when starting with a single cell, can be calculated as  where  is the number of generation (doubling) times. Here, we have .

Students should possess the knowledge that the Clostridium genus produces endospores. This fact makes them extremely virulent. Heating alone will not kill the spores. Only heat, accompanied by pressure, will penetrate spores. This method is obtained either by an autoclave or pressure cooker.

This question requires that the student recognizes that the process illustrated is recombinant DNA (deoxyribonucleic acid) technique. It requires the understanding that the process of producing protein from RNA (ribonucleic acid) is termed translation. Replication is the process by which DNA is synthesized from DNA. Transcription proceeds translation and involves synthesizing RNA transcripts of specific sections of DNA. Transduction is one way bacteria exchange genetic information. Specifically, transduction involves the transfer of bacterial DNA via bacteriophage. Note that this is one way that a group of bacteria can become resistant to antibiotics without ever having been exposed to the antibiotic to which they are resistant.

The question requires the knowledge of pili and that pili are of two types: attachment and conjugation. Conjugation is a way that bacteria become resistant to antibiotics. In this process, a circular piece of deoxyribonucleic acid (DNA) (plasmid) is exchanged through a conjugation pilus. Transformation is genetic alteration caused by direct uptake of naked genetic material from a bacteria's surroundings. A prophage is a bacteriophage that has inserted itself in the genome or plasmid of its host via the lysogenic cycle is latent. Transduction is the movement of genetic material due to bacteriophage that digest host DNA and accidentally package it inside their own capsids. These phage then go on to infect other bacteria, and insert the newly borrowed DNA into the new host cell's genome/plasmids. Translation is the process in which RNA (ribonucleic acid) is converted to protein.

The TB skin test has different thresholds for positive values based on the size of induration. In an HIV-positive individual (low CD4+, immunocompromised), a test is considered positive if it is > 5 mm (not cm). A positive result takes 24 to 48 hours to reveal itself.