B. how is it possible to contaminate a subculture

For a majority of cell cultures, the medium change is usually done after days, and sub-culturing after 7 days. The purpose for which the cells are required is another important criteria for consideration of sub-culturing.

Generally, if the cells are to be used for any specialized purpose, they have to be sub-cultured more frequently. However for a new culture, subculture has to be started at a high concentration and gradually reduced. Majority of continuous cell lines grow as monolayers.

Some of the cells which are non- adhesive e. The transformed cells are sub-cultured by this method. Subculture by suspension is comparable to culturing of bacteria or yeast. The criteria adopted for suspension subculture are the same as that already described for monolayer subcultures.

Any particular social class, age span, gender, or ethnicity could conceivably dominate membership, although sociological studies of subcultures have often focused on those composed of white, male, working class youths.

In a pluralistic and highly differentiated society, cultural identifications do not all wield the same influence or share equal status; rather, they are unevenly ranked in terms of power, so it is broadly possible to identify cultural clusters that stand in mutual relationships of domination and subordination.

The assumption is that subcultures are inherently oppositional in that they are necessarily predicated on some form of disorder, delinquency, or deviance. The concept of subculture has therefore more typically been applied to those groups, arising from a subordinated parent class culture, whose position vis a vis the dominant culture is less clearly articulated or overtly politicized than those of the countercultures.

Various forms of social inquiry into a range of subcultural groups had taken place long before the concept itself had begun to gain currency in academic circles from the late s onwards; but the pioneering, institutional research in this respect was that conducted by members of the sociology department at the University of Chicago in the period between the two world wars.

It also surfaced during this time in a slightly different strain of American sociological research into subcultures, one influenced by anomie theory, which suggests that certain groups, having internalized dominant success goals, find it impossible to realize their aspirations due to their structural position in society. This paradigm was to dominate US subcultural theory throughout this period, albeit with various attempts at modification including an analysis of the differential opportunities for illegitimate as well as legitimate means for success.

See Answer. Best Answer. Study guides. Q: How is it possible to contaminate a subculture? Write your answer Related questions. Is Amish a subculture? Is racism a subculture? In sociology is the KKK a subculture or conterculture? Will you contaminate your baking if baking with cold or flu? Is hip hop a subculture or dominant culture? What is the meaning of subculture using word parts? Are the grunge movement and the Amish community examples of a subculture?

What is the adjective of contaminate? Is it possible for a subculture to be the dominant culture in an organization? What is occupational subculture? What is a legal subculture? Why are Amish considered subculture and not counterculture?

What are the subculture group in the Philippines? Will conventional vegetables contaminate organic compost with pesticides? A pure culture contains only one single type; a mixed culture contains two or more different bacteria. If a bacterial culture is left in the same media for too long, the cells use up the available nutrients, excrete toxic metabolites, and eventually the entire population will die. Thus bacterial cultures must be periodically transferred, or subcultured , to new media to keep the bacterial population growing.

Microbiologists use subculturing techniques to grow and maintain bacterial cultures, to examine cultures for purity or morphology, or to determine the number of viable organisms. In clinical laboratories, subculturing is used to obtain a pure culture of an infectious agent, and also for studies leading to the identification of the pathogen.

Because bacteria can live almost anywhere, subculturing steps must be performed aseptically , to ensure that unwanted bacterial or fungal contamination is kept out of an important culture. In microbiology, aseptic techniques essentially require only common sense and good laboratory skills. First, consider that every surface you touch and the air that you breathe may be contaminated by microorganisms. Then think about the steps you can take to minimize your exposure to unwanted invisible intruders.

You should also be thinking about how to prevent contamination of your bacterial cultures with bacteria from the surrounding environment which includes you. To maintain an aseptic work environment, everything you work with should be initially free of microbes.

Thus, we begin with pre-sterilized pipettes, culture tubes, and glassware. Inoculating loops and needles made of metal wire can be used to transfer bacteria from one medium to another, such as from the surface of an agar plate to a broth. Metal tools may be sterilized by heating them in the flame of a Bunsen burner.

Standard aseptic techniques used for culturing bacteria will be demonstrated at the beginning of lab. One very important method in microbiology is to isolate a single type of bacteria from a source that contains many. The most effective way to do this is the streak plate method, which dilutes the individual cells by spreading them over the surface of an agar plate see Figure 2.

Single cells reproduce and create millions of clones, which all pile up on top of the original cell. The piles of bacterial cells observed after an incubation period are called colonies. Each colony represents the descendants of a single bacterial cell, and therefore, all of the cells in the colonies are clones.

Therefore, when you transfer a single colony from the streak plate to new media, you have achieved a pure culture with only one type of bacteria. Different bacteria give rise to colonies that may be quite distinct to the bacterial species that created it. Therefore, a useful preliminary step in identifying bacteria is to examine a characteristic called colonial morphology , which is defined as the appearance of the colonies on an agar plate or slant. Ideally, these determinations should be made by looking at a single colony; however, if the colonial growth is more abundant and single colonies are absent, it is still possible to describe some of the colonial characteristics, such as the texture and color of the bacterial growth.

By looking closely at the colonial growth on the surface of a solid medium, characteristics such as surface texture, transparency, and the color or hue of the growth can be described. Texture —describes how the surface of the colony appears. Common terms used to describe texture may include smooth, glistening, mucoid, slimy, dry, powdery, flaky etc. Transparency —colonies may be transparent you can see through them , translucent light passes through them , or opaque solid-appearing.

Color or Pigmentation —many bacteria produce intracellular pigments which cause their colonies to appear a distinct color, such as yellow, pink, purple or red. Many bacteria do not produce any pigment and appear white or gray. As the bacterial population increases in number, the colonies get larger and begin to take on a shape or form.

These can be quite distinctive and provide a good way to tell colonies apart when they are similar in color or texture. The following three characteristics can be described for bacteria when a single, separate colony can be observed.

It may be helpful to use a magnifying tool, such as a colony counter or dissecting microscope, to enable a close-up view of the colonies.

Colonies should be described as to their overall size, their shape or form, what a close-up of the edges of the colony looks like edge or margin of the colony , and how the colony appears when you observe it from the side elevation.

Figure 4 shows a close-up of colonies growing on the surface of an agar plate. In this example, the differences between the two bacteria are obvious, because each has a distinctive colonial morphology. Using microbiology terms, describe fully the colonial morphology of the two colonies shown above.

A full description will include texture, transparency, color, and form size, overall shape, margin, and elevation. A culture medium must contain adequate nutrients to support bacterial growth.

Minimally, this would include organic compounds that can provide the building blocks necessary for cellular reproduction. In many cases, predigested protein, such as hydrolyzed soy protein, serves this purpose and will support the growth of many different bacteria. These media formulations are generally referred to as complex media , to indicate that it is a mixture with many components.