Question

Describe the 4 major modes of nutrition. Which ones are used by bacteria?

Distinguish between the 3 mechanisms by which bacteria can transfer DNA to one another.

Describe the various beneficial and harmful roles that bacteria play on Earth.

Answer 1

I. 4 Major modes of nutrition are

Chemohetrotroph- Gets energy from chemicals and carbon from different sources.
Photohetrotroph- Gets energy from light and carbon from different sources.
Chemoautotroph- Gets energy from chemicals and produces its own carbon.
Photoautotroph- Gets energy from light and produces its own carbon.

The mode of the nutrition of bacteria is sometimes each autotrophic as well as heterotrophic. they're characterized by the presence of chlorophyll-a that is similar to green plants and so will build their own food, e.g., blue-green algae whereas some show heterotrophic mode of nutrition which needs an organic carbon supply for growth and perhaps parasites, saprophytes or symbionts, e.g., streptococci, clostridia.

II. three mechanisms by that microorganism will transfer DNA to at least one another.

Normally, genes and therefore the characteristics they code for are passed down from parent to offspring. this can be known as vertical gene transfer and is why you've got half the characteristics of your mother and half your father. bacteria and a few lower eukaryotes are distinctive in this they will pass DNA from one cell of identical generation to another.
There are 3 ways for bacteria to transfer their DNA horizontally:

Conjugation-

Conjugation is the transfer of DNA directly from one cell to a different through cell-cell contact. The DNA transferred by conjugation typically involve plasmids. Plasmids are circular pieces of DNA that may replicate within the bacterial cell, severally of the body. The conjugative transfer of plasmids is carried out by cell surface structures that act like syringes, injecting the plasmid into near cells.

Transformation-

Unlike humans, bacteria are capable of absorbing DNA directly from their environment and incorporating it into their genomes. This method is understood as a natural transformation. This DNA sometimes comes from dead bacteria lysing (splitting open) and releasing their genetic contents into the encompassing area.

Transduction-

Transduction is the transfer of polymer from one cell to a different by a virus. These viruses are called bacteriophage and that they specifically infect bacteria. phage haven't got the machinery to duplicate their own genomes or express their own genes, so instead, they hijack the bacterial machinery to try to to therefore. Host cells can still express phage proteins and replicate the phage genome forming new virus particles. This method continues until the cell is so full of phage particles that it splits open (lyses), releasing phage into the encompassing area. this can be called the lytic cycle. Some viruses will switch between this life cycle and a state of lysogenicity, wherever they mix their genome with the microorganism body and stay silent for several generations. once lysogenic phage removes (excise) their genomes from the host chromosome, they sometimes take tiny sequences of bacterial DNA with them. phage genome containing bacterial DNA is then packaged into phage coat proteins to create a whole, recombinant virus particle. once these phages lyse the bacterial cell and re-infect a new host, they take bacterial DNA with them.

III. helpful and harmful roles that bacteria

Bacteria and Humans

Bacteria and humans have several necessary relationships. bacteria build our lives easier in number of way. In fact, we couldn't survive without them. On the opposite hand, bacteria may also build us sick.

Benefits of bacteria

Bacteria give very important scheme services. they're necessary decomposers. they're conjointly required for the carbon and chemical element cycles. There are billions of bacteria within the human intestines. they assist digest food, build vitamins, and play different necessary roles. Humans conjointly use microorganism in several different ways that, including:

making product, like fermentation alcohol and enzymes.
creating medicine, like antibiotics and vaccines.
creating biogas, like alkane series.
improvement up oil spills and noxious wastes.
Killing plant pests.
Transferring traditional genes to human cells in gene medical care.
ferment foods

Bacteria and illness

You have 10 times as several bacteria as human cells in your body. Most of those bacteria are harmless. However, bacteria may also cause malady. examples of bacterial diseases embody tetanus, syphilis, and food poisoning. bacteria could spread directly from one person to a different. as an example, they will spread through touching, coughing, or reflex. they will conjointly spread via food, water, or objects.

Another way bacteria and different pathogens will spread are by vectors. A vector is an organism that spreads pathogens from host to host. Insects are the foremost common vectors of human diseases.