Chapter 27 - Mastering Biology

Conjugation, transduction, and transformation
Explanation: The three processes of genetic transfer in bacteria are:1. Transformation: This is the process by which bacteria take up naked DNA from their environment and incorporate it into their own genome. This can happen when bacteria are exposed to DNA that has been released from other bacteria through lysis (cell death).2. Conjugation: This is the process by which bacteria transfer DNA to one another via a physical connection (the conjugation bridge). This requires the presence of a specialised conjugation pilus on the surface of one of the bacteria.3. Transduction: This is the process by which bacteria transfer DNA to one another via a virus. The virus infects one bacterium and incorporates its DNA into its own genome. The virus then goes on to infect another bacterium, where it can incorporate the bacterial DNA into the new bacterium's genome.

conjugation: -involves the transfer of DNA from an Hfr cell to an F⁻ cell -requires cell-to-cell contact transduction: -involves bacteriophage transferring pieces of bacterial DNA from one cell to another transformation: -involves DNA from the environment being taken up into a bacterial cell All three: -involves recombination
Explanation: Genetic transfer in bacteria refers to the process by which genetic material is transferred from one bacterium to another. There are three main mechanisms by which this can occur: transformation, transduction, and conjugation.Transformation occurs when a bacterium takes up DNA from its environment and incorporates it into its own genome. This can happen when a bacterium comes into contact with DNA that has been released from another bacterium that has died. The DNA may be taken up by the bacterium and used to replace its own DNA.Transduction occurs when a virus infects a bacterium and inserts its own DNA into the bacterium's genome. The virus may then be able to replicate itself inside the bacterium.Conjugation occurs when two bacteria come into contact with each other and exchange DNA. This can happen when a bacterium produces a pilus (a type of appendage) that attaches to another bacterium. The two bacteria then exchange DNA through the pilus.

Bacteria can acquire new genes from the environment through transformation, by direct contact with another bacteria cell through conjugation, or by being infected with a bacteriophage through transduction.
Explanation: Bacteria can acquire new genes in a variety of ways, including horizontal gene transfer, which is the transfer of genetic material between two organisms that are not directly related. This can happen through mechanisms like transformation, where bacteria take up foreign DNA from their environment; transduction, where viruses carry DNA from one bacterium to another; and conjugation, where two bacteria are physically connected and DNA is transferred between them. Additionally, bacteria can acquire new genes through mutation, which is a random change in the DNA sequence.

when individual members from different species exchange DNA
Explanation: Horizontal gene transfer (HGT) is the transfer of genetic material between organisms that are not directly related. This process can occur between different species of bacteria, or between bacteria and other types of cells, such as eukaryotic cells. HGT is an important mechanism for the spread of antibiotic resistance and other traits between different strains of bacteria.

to help bacteria respond and adapt to their environment much more rapidly by acquiring large DNA sequences from another bacterium in a single transfer.
Explanation: Horizontal gene transfer (HGT) is the movement of genetic material between organisms that are not directly related to each other. This can happen either through direct contact between the organisms, or by indirect means such as viruses. HGT is an important mechanism for the spread of antibiotic resistance and other beneficial traits among bacteria. It can also lead to the emergence of new pathogens.

it aids in diversity
Explanation: The point of genetic recombination is to create new combinations of genes, which can lead to new traits in offspring. This process can help to increase the genetic diversity of a population, which can be beneficial in a number of ways. For example, a greater diversity of genes can make a population more resistant to disease, and it can also help to ensure that the population can adapt to changing environmental conditions.

gene transfer allows the transfer of antibiotic resistance genes to spread in a species of bacteria
Explanation: The main reason why gene transfer is so important for bacteria is because it allows them to rapidly adapt to their environment. For example, if a new strain of bacteria comes into an environment that is hostile to them, they can quickly acquire new genes that will help them survive. Additionally, if a bacteria is exposed to a new antibiotic, it can quickly acquire resistance genes that will allow it to survive. Gene transfer is thus a key mechanism that allows bacteria to rapidly evolve and adapt to their changing environment.

•Bacteria can acquire random mutations that allow them to grow in the presence of antibiotics. •Bacteria can gain an antibiotic-resistance gene by conjugating with another species of bacteria. •Bacteria can pick up an antibiotic-resistance gene from the environment through transformation. •Bacteria can acquire antibiotic-resistance genes by becoming infected with a virus that contains an antibiotic-resistance gene. Bacteria can acquire antibiotic resistance by a variety of methods, including random mutation and genetic transfer by transformation, transduction, or conjugation.
Explanation: Bacteria can acquire antibiotic resistance in a number of ways. One way is through mutation. As the bacteria reproduce, they may mutate in a way that makes them resistant to the antibiotic. Another way is through horizontal gene transfer. This is when bacteria exchange genetic material with other bacteria. This can happen when the bacteria are in close proximity to each other, such as in the same environment.

a.) The bacteriophage packages fragments of bacterial DNA into new phage particles During transduction, phages package fragments of bacterial DNA into new phage heads. This bacterial DNA can be transferred to another bacteria cell during the next phage infection.

---A--c---------b-d The relative location of genes on the bacterial chromosome can be determined by the frequency at which they cotransduce. Genes that are closely linked on the bacterial chromosome are more likely to be cotransduced -- 10 cells contained the cotransduced a and c genes, which means these two genes are close together on the bacterial chromosome. Genes that are not linked will only rarely (or never) cotransduce -- no cells contained contransduced a and b genes or a and d genes, which means that a must be far away from both b and d on the bacterial chromosome. Then, using the cotransduction data for the c and b genes (2 cells) and the c and d genes (0 cells), you can determine that gene b is closer to gene c than is gene d.

gram-positive bacteria: •have a thick peptidoglycan layer •appear purple after Gram staining •alcohol rinse does not remove crystal violet Gram-negative bacteria: •have a thin peptidoglycan layer •appear pink after Gram staining •alcohol rinse easily removes crystal violet •have an outer membrane as part of their cell wall structure both: •have a plasma membrane

http://www.chegg.com/homework-help/questions-and-answers/label-diagram-show-relationship-nutritional-modes-bacteria-drag-labels-appropriate-locatio-q10745827 From left to right: autotroph - heterotroph chemoautotroph - photoautotroph - photoheterotroph - chemoheterotroph phototrophs chemotrophs Some bacteria obtain energy from light (phototrophs), whereas other bacteria obtain energy from chemicals (chemotrophs). Autotrophs (literally "self-feeders") require only an inorganic substance, such as carbon dioxide, as their carbon source; heterotrophs (literally "other-feeders") require at least one organic nutrient as their carbon source.
Explanation: heterotrophs (literally "other-feeders") require at least one organic nutrient as their carbon source."

-They are shaped like rods -They have a relatively thin layer of peptiodglycan in their cell wall -They can convert atmospheric nitrogen to ammonia -They use O₂ for cellular respiration
Explanation: The four statements that are true for bacteria in the genus Azotobacter are: They are bacilli, they are gram-negative, they are obligate aerobes, and they can fix nitrogen.

Proteobacteria: •photosyntheic •nitrogen fixing •disease-causing Chlamydias: •parasitic •disease causing Spirochetes •flagellum •corck-screw motion •disease-causing •digests wood Gram-positive bacteria: •disease causing •food production •lost cell wall •smallest Cyanobacteria: •photosynthetic •aquatic producer/nitrogen fixers
Explanation: The five major groups of bacteria are Gram-positive bacteria, Gram-negative bacteria, Firmicutes, Actinobacteria, and Proteobacteria. Gram-positive bacteria are bacteria that stain purple when exposed to a Gram stain. Gram-negative bacteria are bacteria that stain red when exposed to a Gram stain. Firmicutes are a group of bacteria that includes the genera Clostridium and Bacillus. Actinobacteria are a group of bacteria that includes the genera Streptomyces and Mycobacterium. Proteobacteria are a group of bacteria that includes the genera Escherichia and Salmonella.

cyanobacteria
Explanation: Prokaryotic cells are classified as bacteria. The bacteria that built stromatolites are thought to be cyanobacteria, which are a type of bacteria that gets its energy from photosynthesis.

cyanobacteria which are aerobic photosynthesizers
Explanation: The prokaryotic cells that were the first to add significant quantities of oxygen to Earth's atmosphere are classified as cyanobacteria. Cyanobacteria are a type of bacteria that are able to photosynthesize, and they are thought to be responsible for the rise in oxygen levels on Earth.

gram-positive bacteria
Explanation: Streptococcus pyogenes is classified with other streptococcal bacteria. These bacteria are classified together because they share similarities in their structure and function.

chlamydias
Explanation: Organisms that can cause nongonococcal urethritis (NGU) are classified with a number of different terms, including: chlamydia, Mycoplasma genitalium, Trichomonas vaginalis, and Ureaplasma urealyticum.

spirochetes
Explanation: Spiral-shaped bacteria are likely to be placed with other spiral-shaped bacteria. This is because they share a similar shape, and this similarity can help to indicate that they are of the same or similar species. Additionally, spiral-shaped bacteria are often found in the same environments, such as in soil or water, which can also help to indicate that they are related.

Euryarchaeota ... Crenarchaeota
Explanation: The most recent common ancestor of the two prokaryotic subgroups at the bottom of the phylogenetic tree is likely the one that is most closely related to each other. This is because they share more characteristics with each other than with any other prokaryotic subgroup on the tree.