By the end of this section, you will be able to:Describe the evolutionary history of prokaryotesDiscuss the distinguishing features of extremophilesExplain why it is difficult to culture prokaryotes

By the end of this section, you will be able to:Identify the macronutrients needed by prokaryotes, and explain their importanceDescribe the ways in which prokaryotes get energy and carbon for life processesDescribe the roles of prokaryotes in the carbon and nitrogen cycles

By the end of this section, you will be able to:Describe the basic structure of a typical prokaryoteDescribe important differences in structure between Archaea and Bacteria

Biology is designed for multi-semester biology courses for science majors. It is grounded on an evolutionary basis and includes exciting features that highlight careers in the biological sciences and everyday applications of the concepts at hand. To meet the needs of today’s instructors and students, some content has been strategically condensed while maintaining the overall scope and coverage of traditional texts for this course. Instructors can customize the book, adapting it to the approach that works best in their classroom. Biology also includes an innovative art program that incorporates critical thinking and clicker questions to help students understand—and apply—key concepts.

How can you tell if harmful bacteria are in your food or water that might make you sick? What you eat or drink can be contaminated with bacteria, viruses, parasites and toxins—pathogens that can be harmful or even fatal. Students learn which contaminants have the greatest health risks and how they enter the food supply. While food supply contaminants can be identified from cultures grown in labs, bioengineers are creating technologies to make the detection of contaminated food quicker, easier and more effective.

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"Bogs are unique ecosystems, which have important ecological functions in carbon storage, climate stability, water quality, and biodiversity. The bog microbiome, composed mostly of bacteria that live in association with bog plants, plays key roles in these functions. However, the differences in associated bacteria between vascular plants and the non-vascular bryophytes that predominate in bogs remain unclear. Researchers recently used shotgun metagenomics to investigate the microbes associated with 12 representative bog species. Vascular plants tended to be colonized by specific bacteria, while bryophytes exhibited greater bacterial species richness and diversity. The two plant groups also had different marker species. The gene profiles of vascular plant- and bryophyte-associated microbes revealed functional differences, including differences in nitrogen cycling..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"Microbiomes are more than just prokaryotes and viruses; they also contain important eukaryotes, including fungi and protists. However, eukaryotes are difficult to study using ‘shotgun’ metagenomics, as their signal is often overwhelmed by the prokaryotes. Some methods use eukaryote-specific marker genes, but they can’t detect eukaryotes that aren’t in the reference marker gene set, and such methods are not compatible with web-based tools for downstream analysis. But CORRAL (Clustering Of Related Reference ALignments) is designed to close those gaps. CORRAL identifies eukaryotes in metagenomic data based on alignments to eukaryote-specific marker genes and Markov clustering. It can detect microbial eukaryotes that are not included in the marker gene reference set. The process is even automated and can be carried out at scale. A recent paper demonstrates CORRAL’s sensitivity and accuracy with simulated datasets, mock community standards, and human microbiome datasets..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"The skin is the interface between the human body and the environment, and the different features in distinct skin regions, such as different temperatures, humidity levels, gland densities, and pH values, create a variety of niches that can support a diverse skin microbiome. This microbiome includes bacteria, archaea, viruses, fungi, and even mites. A healthy skin microbiome helps maintain skin homeostasis, protects against pathogens, communicates with and trains the immune system, and affects wound healing. However, the skin microbiome can be influenced by many factors, including intrinsic factors like aging and extrinsic factors like cosmetic. Recent advances in molecular biology techniques and next-generation sequencing have drastically increased our understanding of the microorganisms that live on our skin, but the microbes are often still difficult to culture and study..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"Spaceflight affects the human body in numerous ways, but one underexplored area is the mouth. The mouth is home to rich populations of bacteria and fungi which, studies have hinted, can undergo shifts during long and even short space missions. For the first time, researchers have tracked changes in the oral microbiome during and after spaceflight and examined how those changes might reawaken dormant viruses — a phenomenon long known to affect astronauts. The team analyzed saliva samples from 10 male astronauts for microbial makeup and for the presence of Epstein-Barr, herpes simplex, and varicella zoster virus. Only Epstein-Barr virus counts appeared to track with changes in microbial composition during spaceflight. For example, increased virus counts coincided with increased numbers of bacteria of the genus Gracilibacteria, while low counts coincided with increased numbers of members of Oribacteria and Hemophilus..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"Bacteria and other microorganisms cover nearly every surface on earth, including the surfaces we build and maintain. Ocean piers are unique sites at the intersection of terrestrial, aquatic, and human-built environments. Saltwater spray, inclement weather, and pollutants make piers a harsh environment for bacteria. Together, these factors suggest that piers house a unique microbiome. Researchers recently conducted a study to characterize the microbiomes found on pier surfaces. On nine piers along the coast of Hong Kong, the researchers found diverse microbiomes that were rich in novel bacterial species. Surface material (metal versus concrete) was the strongest factor influencing the bacterial community structure. Although the overall abundance was low, corrosion-associated bacteria were more prevalent on metal surfaces, and high-touch surfaces like handrails and poles had more human skin-associated microbes than other surfaces..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"Built environment microbiomes are shaped by their occupants and the outside environment. These microbiomes can have a profound impact on the health of its occupants. The International Space Station (ISS) is a uniquely sealed environment, with only the arrival of crewmembers and supplies introducing new microbes. Monitoring the ISS microbiome is important to ensure astronaut health and spacecraft integrity. So, a recent study used samples from two long-term projects, Microbial Tracking 1 and 2, which sampled the same surfaces over two 14-month-long periods. The ISS surface microbiome was dominated by microbes associated with human skin. The most represented groups were Staphylococcus and Malassezia among bacteria and fungi, respectively. Community abundances shifted over time, but did not differ between surfaces. Overall, the metabolism genes tended towards amino acid utilization rather than carbohydrate metabolism..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"Bacteria and viruses are locked in a perpetual arms race. As bacterial viruses continuously try to penetrate and infect bacteria, bacteria are endlessly evolving anti-viral defense systems. Understanding how this struggle unfolds is critical, as bacteria are a vital component of many emerging biotechnologies and foods we eat. Scientists recently explored the battles that take place in cheese, where the presence of only a few species of bacteria makes an ideal, simple, and reproducible model system. The communities they analyzed harbored highly diverse defense mechanisms, even among nearly identical strains, suggesting rapid evolution. Additionally, the abundances of CRISPR spacers and their phage targets were correlated, suggesting that bacteria have genetic mechanisms for effectively defending against viral foes..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.

Students learn about a special branch of engineering called bioremediation, which is the use of living organisms to aid in the clean-up of pollutant spills. Students learn all about bioremediation and see examples of its importance. In the associated activity, students conduct an experiment and see bioremediation in action!

This includes materials to be used for a General Biology II course (or Introduction to Biology II course) for non-science majors.

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"Coral reefs are known to partner with a number of organisms for survival. including nitrogen-fixing microbes known as diazotrophs. A new study examined how these and other microbes vary among corals of different species and from different parts of the world— namely, Hawai’i, Curaçao, and Australia. The microbial makeup of the coral microbiome was found to vary with coral species, location, and ecological life history. For example, while diazotrophs of the order Rhizobiales were common to all coral microbiomes, they were 8 times as abundant in corals from Hawai’i than in corals from Curaçao or Australia. Interestingly, however, the factor contributing to the biggest differences in community structure was coral shape. Plate-like, branching, and solitary corals, for instance, showed communities that were genetically distinct from boulder-like corals. These findings confirm the known effects of coral shape and size on attributes such as light and food capture, gas exchange, and metabolism..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"Our mouths are a vast jungle of microbial life. Here, more than 700 distinct types of microbes make their home, but not everywhere all at once. Each region (the tongue, teeth, gums, etc.) hosts a unique community of microorganisms. To explore this complex living structure, researchers examined the community of bacteria found in the dental plaque of 14 healthy volunteers. Samples indicated the well-known formation of intricate corncob-like structures, where a central filament made of cells of Corynebacteria (magenta) is decorated with “kernels” of spherical Streptococcus bacteria (green). A closer look revealed that these kernels can be composed of a single species of bacteria or contain mixtures of different species. The major corncob species were common to all 14 donors. Corncob composition likely was dictated by the metabolic and binding interactions shared between corncob residents..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"The ribosomal RNA (rRNA) gene approach to sequencing genetic material has revolutionized microbiome science. But it isn’t perfect. The method relies on the assumption that counts of rRNA genes translate into microbial abundance. Exceptions to that rule, however, are known, such as the observation that rRNA gene counts can be higher in fast-growing microbes. Now, researchers report a new relationship between rRNA genes and cell volume that could help correct for biases inherent to microbiome studies. An analysis of previously reported data showed that the number of 16S or 18S RNA genes per cell follows an allometric power law of cell volume. Applying this relationship to a dataset for bacteria found in intertidal rocks allowed for more accurate biovolume and cell count distributions to be estimated for all taxa detected. The development of more comprehensive cell-size databases could help strengthen the bias-correcting relationship and boost the power of current microbiome analyses..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"Probiotic foods can help boost human health by promoting the growth of beneficial bacteria, but although probiotic bacteria can protect against infections with pathogens, little is known about the mechanisms underlying this interaction. In a new study, researchers evaluated the microbiome of a unique fermented kefir mixture. One of the predominant microbes found was the fungus Kluyveromyces marxianus, and a metabolite secreted by fungi – tryptophol acetate, which inhibits bacterial communication and virulence – was identified in the probiotic drink. Tryptophol acetate blocked the ability of the gut pathogen Vibrio cholerae to chemically sense bacterial density and form biofilms and altered the expression of genes associated with virulence. Although further studies are needed to fully understand the effects of probiotics on harmful gut bacteria, these results uncover a new cross-kingdom inhibition mechanism, where probiotic yeast prevent the growth of pathogenic bacteria..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.

Students design and conduct experiments to determine what environmental factors favor decomposition by soil microbes. They use chunks of carrots for the materials to be decomposed, and their experiments are carried out in plastic bags filled with dirt. Every few days students remove the carrots from the dirt and weigh them. Depending on the experimental conditions, after a few weeks most of the carrots will have decomposed completely.