Biology Test 2

Monophyletic

ALL descendants came from one common ancestor

Extremophile

Archaea that live in extreme environments.

Methanogens

Archaea that release methane, a greenhouse gas.

Thermophiles

Archaea that thrive in very hot environments, such as volcanic springs.

For the following clades of archaea, be able to describe the characteristics of the clade, the habitats of the clade, explain why the clade is important to humans and/or ecosystems: Crenarchaeota, Euryarchaeota, Nanoarchaeota.

Characteristics of clade: A clade consists of an organism and all of its descendants. The term "clade" comes from the Greek "klados," for "branch." It's useful to think of a clade as being one "branch" on the tree of life, where the common ancestor is the place that the branch split from the main trunk. Seeing how different species have descended from a common ancestor, and how they are similar or different, can help biologists to understand how different characteristics of life evolve. Habitats of clade: If we assume that competition leads to local replacement of species within clades, then we should expect clade members to never co‐occur even if they have similar habitat requirements. If no such competition occurred, and if dispersal was unlimited and survival in a new habitat never possible, then we should expect local co‐occurrence of clade members to depend entirely on the similarity of their habitat use: maximal co‐occurrence among species in all clades of highest habitat similarity, minimal or no co‐occurrence among species in all clades of lowest habitat similarity. Why clade is important to humans: According to a cladogram outlining the evolutionary history of humans and other primates:Humans, chimpanzees, gorillas, orangutans and gibbons all belong to a common clade - the Hominoids.The Hominoid clade forms part of a larger clade - the Anthropoids - which includes Old World and New World monkeys. Crenarchaeota: However, like all Archaea, Crenarchaeota are prokaryotic, and are bounded by ether-linked lipid membranes which contain isoprinoid side chains instead of fatty acids.Major characteristics of crenarchaeota, in terms of their membrane and chemical structure, the archaea cells share features with eukaryotic cells. Unique archaea characteristics include their ability to live in extremely hot or chemically aggressive environments, and they can be found across the Earth, wherever bacteria survive. Euryarchaeota: Euryarchaeota (Greek for "broad old quality") is a phylum of archaea. It is one of two phyla of archaea, the other being crenarchaeota.They are highly diverse and include methanogens, which produce methane and are often found in intestines, halobacteria, which survive extreme concentrations of salt, and some extremely thermophilic aerobes and anaerobes, which generally live at temperatures between 41 and 122 °C. Nanoarchaeota: The Nanoarchaeota, proposed as the fourth sub-division of the Archaea in 2002, are known from a single isolate, -Nanoarchaeum equitans", which exists in a symbiotic association with the hyperthermophilic Crenarchaeote, Ignicoccus hospitalis. The sequencing of both genomes has provided clues on their unusual and very specific association.

Name and describe the three major shapes of bacteria.

Cocci: Spherical prokaryotes. Bacilli: Rod-shaped prokaryotes Spiral: Spirilla spiral prokaryotes

ether linkage

Connects the glycerol molecule and the isoprene molecules found in lipid bilayers of archaea. The linkage is made of an oxygen atom attached to a carbon on one side and another carbon on the other side.

Describe the ecological and economic importance of protists with specific examples from lecture and lab.

Ecological and economic importance of protists 1. Source of food: Protists are a food source for many animals. Phytoplankton is one of the sole food sources for whales. Humans even harvest various protists for food. Seaweed is an algae, which is considered a plant-like protist. Many also eat spirulina and aphanizomenon flos-aquae in supplements for omega-3 fatty acids and other purported nutrients. Some protests such as kelps are edible and may be used to overcome shortage of food in world. 2. Source of mineral: Kelps are rich in sodium, potassium, iodine etc. They are good source of these minerals. 3. Biological research: Protists are also used in biological researches e.g. Chlorella is unicellular non-motile green alga. They can teach us about the origins of complex multicellular organisms like the plants and animals. 4. Pathogens: Several deadly diseases are caused by protist pathogens, such as malaria (Plasmodium), toxoplasmosis (Toxoplasma), and amoebic dysentery (Entamoeba histolytica). 5. Symbiotic Relationships: Some protists offer more direct benefits for animals in the form of symbiotic relationships. Trichonymphs live in the intestines of termites, feeding on the wood cellulose that termites eat and breaking it down into digestible components. These protists live in the digestive tracts of several cellulose eating organisms. Various protists and bacteria also live in the digestive tracts of ruminants, such as cows, and help them break down the food they eat for nutrients and energy. 6. Biofuel: Blue-green and brown algae is currently being grown for biofuel, which could eventually replace traditional fossil fuels. Living algae is 50 percent oil, and can be harvested and processed into usable oil, diesel and gas fuel. Additonally, the algae grows very fast, allowing producers to meetthe ever increasing demand. 7. Source of medicines: Sodium laminaria sulphate is used as a blood coagulant. Fucoidin and heparin are the algae products, which are also used as blood coagulants. Lyngbya produces an anticancer compound.

CRISPR/Cas9

a revolutionary gene editing technique derived from the immune system of simple prokaryotes

ester linkage

a bond between a hydroxyl group and a carboxyl group

apical complex

a group of organelles specialized for entering host cells and tissues

Kinetoplast

a mass of mitochondrial DNA lying close to the nucleus in some flagellate protozoa.

exaptation

shaping of a useful feature of an organism by natural selection to perform one function and the later reshaping of it by different selection pressures to perform a new function

Halophile

"salt-loving" archaea that live in environments that have very high salt concentrations

Pyrococcus furiosus

sulfur reducing member of the Euryarchaeota that can grow in boiling water

Alternation of generations

the alternation between the haploid gametophyte and the diploid sporophyte in a plant's life cycle

Zygote

the fertilized egg; it enters a 2-week period of rapid cell division and develops into an embryo

macronucleus

the larger of a ciliate's two nuclei, contains multiple copies of most of the genes that the cell needs in its day-to-day existence

Haploid

(genetics) an organism or cell having only one complete set of chromosomes

Diploid

(genetics) an organism or cell having two sets of chromosomes or twice the haploid number

PCR

(polymerase chain reaction) multiple copies of a specific segment of DNA

Describe the following bacteria species and genera including clade, habitat, nutritional group (i.e. photoautotroph), and ecological and/or human significance: Bacillus anthracis, Mycoplasma, Mycobacterium tuberculosis, Deinococcus radiodurans, Anabaena, Borrelia, Chlamydia trachomatis, Rhizobium, Escherichia coli.

1. Bacillus anthracis- Species- Bacillus anthracis, Genera- Bacillus, Clade- Bacilli, Habitat- Soil, Nutritional group- heterotrophic(parasitic), human significance- causes anthrax disease in humans. 2. Mycoplasma- Species- not mentioned,many are known such as M. genitalium, M. hominis , Genera- Mycoplasma, Clade- Mollicutes, Habitat- Plants, animals, upper respiratory tract of humans, etc. Nutritional group- Heterotrophic(saprophytic or parasitic), Human significance- causes walking pneumonia and pelvic inflammatory disease. 3. Mycobacterium tuberculosis Species- M. Tuberculosis, Genera- Mycobacterium, Clade- Actinobacteria, Habitat- water and soil, Nutritional group- heterotrophs (parasitic), human significance- causes tuberculosis disease in human beings . 4. Deinococcus radiodurans Species- D. radiodurans, Genera- Dienococcus, Clade- Deinococci, Habitat- not known, can live anywhere, Nutritional group- Chemoorganoheterotroph; it uses chemical energy to obtain food from organic materials, Human significance- can be used to treat nuclear energy waste as it is extremely resistant to radiation. 5. Anabaena Species- many species are known such as A. aquaelis, A. affinis, etc. Genera- Anabaena, Clade- Cyanophyceae, Habitat- water ( as planktons), Nutritional group- Photoautotrophs, ecological significance- fixes nitrogen and symbiosis with other organisms. 6. Borrelia Species- B. afzelli, B. americana, B. burgdoferi etc. Genera- Borrelia, Clade- spirochaetes, Habitat- tissue of ticks, Nutritional group- Heterotrophs, Significance- causes Lyme disease in humans. 7. Chlamydia trachomatis Species- C. trachomatis, Genera- Chlamydia, Clade- Chlamydiae, Habitat- Genital tract of humans, Nutritional group- Heterotrophs, Significance- causes trachoma and sexually transmitted disease in humans. 8. Rhizobium Species- R. Leguminosarum, Genera- Rhizobium, Clade- Alphaproteobacteria, Habitat- root nodules of legumes, Nutritional group- Chemoautotroph, Significance- fixes nitrogen in root nodules of legumes. 9. Escherichia coli Species- E. coli, Genera- Escherichia, Clade- Gammaproteobacteria, Habitat- lower intestine of humans, Nutritional group- Heterotrophs (saprophytic), Significance- normally provides protection against harmful bacteria and keeps the gut of humans healthy, but some strains can cause diarrhoea and urinary tract infections.

Name and describe the 4 supergroups of protists covered in this chapter. Know which supergroups include plants (Archaeplastida), fungi (Unikonta), & animals (Unikonta). For the following groups know what supergroup they are in and the distinguishing characteristics of that group: Apicomplexans, Brown Algae, Ciliates, Diatoms, Dinoflagellates, Diplomonads, Euglenids, Foraminiferans (Forams), Green Algae, Kinetoplastids, Oomycetes, Radiolarians, Red Algae, Parabasalids, Plasmodial Slime Molds, Cellular Slime Molds. Know what supergroup the following organisms are in and what disease is associated with them (if applicable): Naegleria fowleri, Paramecium spp., Phytophthora infestans, Plasmodium spp., Euglena, Trypanosoma brucei, Giardia intestinalis, Entamoeba histolytica.

1. Excavata: These are asymmetrical and have the presence of the feeding groove that has an excavation. These are the flagellates, in some the mitochondria is reduced and some lacks the mitochondria. Sub groups: Euglenids, plasmodial slime molds, cellular slime molds, Parabasalids, Diplomonads, Kinetoplastids. 2. Chromalveolata: These are known to have the defended from the red algae and bikont. Most of their plastids contain chlorophyll c in them, also presences of the cellulose in them. Subgroups: Diatoms, Dinoflagellates, Brown algae, Apicomplexans, and Ciliates. 3. Rhizaria: These are the amoeba that are thread like some of them are made up of the silica and some have shells. Subgroups: Foraminiferans and Radiolarians 4. Archaeplastida: These are basically the algae and land plants. They have presence of the chloroplast and they lack the centrioles and cell wall contain the cellulose. Subgroup: Green and red algae. 5. Unikonta: These include the fungi, animals and amoebazons, these are formed by the triple gene fusion and have single centrioles. Single flagella for locomotion. Subgroup: Oomycetes

Phagocytosis

A type of endocytosis in which a cell engulfs large particles or whole cells

Describe the role of endosymbiosis in the development of the mitochondria and chloroplast. Describe which prokaryotes are most closely related to the origins of the mitochondria (proteobacterium) and chloroplast (cyanobacterium). Describe primary, secondary, and tertiary endosymbiosis and know which taxa are associated with each type of endosymbiosis.

1. The endosymbiotic theory states that some of the organelles in eukaryotic cells were once prokaryotic microbes. Mitochondria and chloroplasts are likely evolved from engulfed prokaryotes that once lived as independent organisms. At some point, a eukaryotic cell engulfed an aerobic prokaryote, which then formed an endosymbiotic relationship with the host eukaryote, gradually developing into a mitochondrion. Evidence for the endosymbiotic hypothesis is the fact that both mitochondria and chloroplasts have double phospholipid bilayers. This appears to have arisen by mitochondria and chloroplasts entering eukaryotic cells via endocytosis. - Mitochondria & Chloroplasts have their own DNA which is circular, not linear. - Mitochondria & Chloroplasts are the same size as prokaryotic cells and divide by binary fission. 2. The nuclear genome of eukaryotes is related most closely to the Archaea, so it may have been an early archaean that engulfed a bacterial cell that evolved into a mitochondrion. Mitochondria appear to have originated from an alpha-proteobacterium, whereas chloroplasts originated as a cyanobacterium. 3. Primary endosymbiosis is the process which involves the engulfment of a prokaryote by another living cell. The engulfed organism may be used as an advantage, supplying the larger cell with its products. Ex: when a eukaryotic cell engulfs a prokaryotic cell. Secondary endosymbiosis is when a living cell engulfs another eukaryote cell that has already undergone primary endosymbiosis. Ex: When a eukaryotic cell engulfs another eukaryotic cell, chloroplast of brown algae is an example. Tertiary Symbiosis is when a cell is formed due to secondary symbiosis undergoes symbiosis. Ex: One unusual plastid acquisitions occur in Dino flagellates. The standard dinoflagellates plastid, which contains peridinin pigment, apparently originates from a secondary red algal endosymbiont.

Symbiosis

A close relationship between two species that benefits at least one of the species.

Nucleoid

A dense region of DNA in a prokaryotic cell.

binary fission

A form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size

Cytoskeleton

A network of fibers that holds the cell together, helps the cell to keep its shape, and aids in movement

F factor

A piece of DNA that confers the ability form a sex pili.

peptidoglycan

A protein-carbohydrate compound that makes the cell walls of bacteria rigid

Commensalism

A relationship between two organisms in which one organism benefits and the other is unaffected

Parasitism

A relationship between two organisms of different species where one benefits and the other is harmed

mutualism

A relationship between two species in which both species benefit

Plasmid

A small ring of DNA that carries accessory genes separate from those of the bacterial chromosome

Holdfast

A special structure used by an organism to anchor itself.

Gram stain

A staining method that distinguishes between two different kinds of bacterial cell walls.

Domain

A taxonomic category above the kingdom level. The three domains are Archaea, Bacteria, and Eukarya.

Conjugation

A temporary union of two organisms for the purpose of DNA transfer.

pseudopod

A temporary, foot-like extension of a cell, used for locomotion or engulfing food

Endosymbiosis

A theorized process in which early eukaryotic cells were formed from simpler prokaryotes.

Endospore

A thick-walled protective spore that forms inside a bacterial cell and resists harsh conditions.

Mitochondria

An organelle found in large numbers in most cells, in which the biochemical processes of respiration and energy production occur.

Chloroplast

An organelle found in plant and algae cells where photosynthesis occurs

Decomposer

An organism that breaks down wastes and dead organisms

Pathogen

An organism that causes disease

mixotroph

An organism that is capable of both photosynthesis and heterotrophy.

Chemoheterotrophs

An organism that must consume organic molecules for both energy and carbon.

Photoheterotrophs

An organism that uses light to generate ATP but that must obtain carbon in organic form.

Distinguish protists from other types of organisms. Explain why the term protist does not refer to a formal taxonomic group. Describe the different nutritional strategies of protists (autotroph/photoautotroph, heterotroph/chemoheterotroph, mixotroph).

Bacteria are single celled microbes but protist are eukaryotic organism that does not comes under plant, fungi, or animals. Protists are eukaryotes mostly unicellular in nature protist have special organelles like true nucleus bounded by nuclear membrane. This is the difference between bacteria and protist. Protist are larger in size and can invest food or make their own food. Autotrophs- protist that make their own food and convert inorganic substances to organic. Photoautotrophs: If protist are using light energy from sunlight to make their food by photosynthesis. Ex: Diatoms Heterotrophs: protist that can not make their own food and have to depend on autotrophs for their nutrition. Ex: Amoeba; Paramecium Chemoheterotrophs: They use inorganic energy source and synthesize organic compounds with the help of carbon dioxide. Ex: Slime molds. Mixotrophs: Many protist act as both autotrophs and heterotrophs depending on the situtation. Ex: Euglena.

Denitrification

Conversion of nitrates into nitrogen gas

Capsule

Covers the cell wall in prokaryotes.

Compare and contrast the diversity of environments and nutritional categories of prokaryotes. Distinguish the four nutritional categories and know examples of prokaryotes in each category. Know which two nutritional categories are unique to prokaryotes.

Diversity of environments: The prokaryotes are found in moderate as well as extreme environmental conditions. They can be found in extreme heat conditions and also in frozen environments, present in environments deprived of oxygen, or in salty environments, they are also seen on skin and digestive systems of humans. A multilayered sheet of prokaryotes is known as a microbial mat. They grow near a hydrothermal vent- which is a fissure in the surface of the earth that causes the release the geothermal heated water. In extreme environmental conditions, the prokaryotes live together in colonies called biofilms. Nutritional Categories of Prokaryotes: Prokaryotes have different modes of nutrition and based on the energy and carbon source the mode of nutrition of prokaryotes are classified into four types. Photoautotrophs, Chemoautrotrophs, Photoheterotrophs, Chemoheterotrophs Chemoautrotrophs and Photoheterotrophs are the two nutritional categories that are unique to prokaryotes. Whereas the Photoautotrophs and chemoheterotrophs are mode of nutrition for eukaryotes.

Contrast Gram-positive and Gram-negative bacteria. Explain why Gram staining is of limited use in evolutionary studies.

Gram-positive bacteria have simpler walls with a relatively large amount of peptidoglycan in the cell which traps the violet dye in the cytoplasm. Gram-negative bacteria have less peptidoglycan and are structurally more complex, with an outer membrane that contains lipopolysaccharides. The violet dye is easily rinsed from the cytoplasm and the cell appears pink or red

Algae

Grow in soil, on trees and on the bodies of turtles and frogs; smallest of all green plants

Describe the mutualistic interaction between humans and Bacteroides thetaiotaomicron.

Gut mutualists, Bacteroides thetaiotaomicron, is a genome which includes a large array of genes involved in synthesizing carbohydrates, vitamins, and other nutrients needed by humans. Signals from the bacterium activate human genes that build the network of intestinal blood vessels necessary to absorb food. Other signals induce human cells to produce antimicrobial compounds to which B. thetaiotamicron is not susceptible. Keeping other competing bacteria out of the intestines benefits B thetaiotaomicron as well as its human host.

Cilia

Hairlike projections that extend from the plasma membrane and are used for locomotion

Carl Woese

He was a microbiologist who discovered the group of single-cell prokaryotic organisms known as archaea, which constitutes a third domain of life.

Describe the many ways humans and ecosystems benefit from prokaryotes as well as ways that prokaryotes harm humans. Define bioremediation. Describe two examples of bioremediation involving prokaryotes. Describe the potential benefits of CRISPR-Cas9 system. Describe how biofilms form. Describe examples of biofilms that impact humans.

Help: They help breakdown waste. They help in digestion of food and extraction of nutrients. Harm: These prokaryotes contain many disease causing agents in them which are harmful for both humans and animals. Release toxic chemicals which pollute water and soil. Bioremediation: the process of removal of pollutants and toxins present in soil, water, and other ecosystems by the use of living organisms including microbes and bacteria. Examples: Bacteria pseudomonas aeruginese is a prokaryote used in biomediation which converts toxic Hg2 into non-toxic elemental Hg0. Bacteria Alcanivorax borkumensis is another prokaryote which performs bioremediation which solubilige oil from oil spills. CRISPR- Cas 9 It provides simple and affordable ways of manipulating and editing DNA. It can create a revolution in treating diseases such as cancer and blindness. Biofilms: In the formation biofilms have major steps occurring. At first responsible microorganisms attach to the surface. The maturation phase in which microorganisms grow on the attached surface and start to produce extracellular polymers. Pseudemonas aeruginosa forms biofilms cause infection in skin and lungs. E.coli forms biofilms biofilms in urinary cathetors. Plaque is a biofilm formed on teeth.

. Describe the evidence that suggests that the dangerous E. coli strain O157:H7 arose through horizontal gene transfer.

Horizontal gene transfer can also spread genes associated with virulence, turning normally harmless prokaryotes into fatal pathogens. E.coli, for instance, is ordinarily a harmless symbiont in the human intestines, but pathogenic strains that cause bloody diarrhea have emerged. One of the most dangerous strains, called O157:H7, first came to the attention of microbiologists in 1982. In 2001, an international team of scientists sequenced the genome of O157:H7 and compared it with the genome of a harmless strain of E. coli called K-12. They discovered that 1,387 out of the 5,416 gees in O157:H7 have no counterpart in K-12. These 1,387 genes must have been incorporated into the genome of O157:H7 through horizontal gene transfer, most likely through the action of bacteriophages.

Crafoord Prize

It is an annual science prize established in 1980. The prize is awarded in four categories: astronomy, mathematics, geosciences, and biosciences. It is awarded to one person every year. It is only awarded when special committee decides that substantial progress in the field has been made.

protist

Kingdom composed of eukaryotes that are not classified as plants, animals, or fungi

Describe different types of life cycles found in protists. Describe the different stages of alternation of generations. Explain why animals do NOT have an alternation of generations even though they have both haploid and diploid stages. Describe and distinguish the different types of asexual reproduction found in protists. Explain why conjugation is a sexual process, but not a reproductive process. Describe the process of conjugation in Paramecium.

Life cycle of plasmodium: Malaria infection begins when an infected female Anopheles mosquito bites a person, injecting Plasmodium parasites, in the form of sporozoites, into the bloodstream. The sporozoites pass quickly into the human liver. The sporozoites multiply asexually in the liver cells over the next 7 to 10 days, causing no symptoms. In an animal model, the parasites, in the form of merozoites, are released from the liver cells in vesicles, journey through the heart, and arrive in the lungs, where they settle within lung capillaries. The vesicles eventually disintegrate, freeing the merozoites to enter the blood phase of their development.* In the bloodstream, the merozoites invade red blood cells (erythrocytes) and multiply again until the cells burst. Then they invade more erythrocytes. This cycle is repeated, causing fever each time parasites break free and invade blood cells. Some of the infected blood cells leave the cycle of asexual multiplication. Instead of replicating, the merozoites in these cells develop into sexual forms of the parasite, called gametocytes, that circulate in the blood stream. When a mosquito bites an infected human, it ingests the gametocytes, which develop further into mature sex cells called gametes. The fertilized female gametes develop into actively moving ookinetes that burrow through the mosquito's midgut wall and form oocysts on the exterior surface. Inside the oocyst, thousands of active sporozoites develop. The oocyst eventually bursts, releasing sporozoites into the body cavity that travel to the mosquito's salivary glands. The cycle of human infection begins again when the mosquito bites another person.

Chemoautotrophs

Organisms that use hydrogen sulfide or other chemicals as energy source instead of light.

Photoautotrophs

Organisms that use light as a source of energy to synthesize organic substances.

Taxis

Movement toward or away from a stimulus.

Distinguish among mutualism, commensalism, and parasitism. Provide an example of a prokaryote partner in each type of symbiosis.

Mutualism(+/+): Both symbiotic organisms benefit. Example of a prokaryote partner- Human intestines are home to an estimated 500 to 1,000 species of bacteria; their cells outnumber all human cells in the body by as much as ten times. Many of these species are mutualists, digesting food that our own intestines cannot break down.- Bacterial "headlights" of bioluminescent bacteria Commensalism(+/0)one organism benefits the other is unaffected. Example of a prokaryote partner: Bacteria that live on our body's surface which provides provide them with food, such as the oils that exude from our pores Parasitism- one organism benefits and the other is harmed. Example of a prokaryote partner: Various diarrheal diseases causing causing 2 million human deaths per year

nitrogen fixation

Process of converting nitrogen gas into ammonia

Describe the cell surface structural features that allow prokaryotes to thrive. Explain why prokaryotes are unable to grow in very salty or sugary foods, such as cured meats or jam.

Prokaryotes often have appendages on their surface. Flagella and some pili are used for locomotion, fimbriae help the cell stick to a surface, and sex pili are used for DNA exchange. In a hypertonic environment, most prokaryotes lose water and shrink away from their wall (plasmolyze), like other walled cells. Severe water loss inhibits the reproduction of prokaryotes, which explains why salt can be used to preserve certain foods, such as pork and fish.

In general terms, describe the role prokaryotes in the cycling of chemical elements. Describe the roles of bacteria in the nitrogen cycle and why nitrogen metabolism is vital to other organisms. Describe the specializations for nitrogen fixation in a filamentous colony of the cyanobacterium, Anabaena.

Prokaryotes play several roles in the nitrogen cycle. Nitrogen-fixing bacteria like Azobacter convert nitrogen gas in the atmosphere to ammonia nitrates. Denitrifying bacteria (Thiobacilis) converts back to nitrogen gas. Nitrogen enters the living world by way of bacteria and other single-celled prokaryotes, which convert atmospheric nitrogen(N2) into biologically usable forms in a process called nitrogen fixation. Nitrogen-fixing microorganisms capture atomospheric nitrogen by converting it to ammonia which can be taken up by plants and used to make organic molecules. Forms filamentous colonies with specialized cells to carry out nitrogen fixation. Photosynthesis produces O2, which inactivates the enzymes involved in nitrogen fixation. Most cells in the filament are photosynthetic, which a few specialized cells called heterocysts carry out only nitrogen fixation.

Describe the characteristics that distinguish prokaryotes from eukaryotes. Describe the relative abundance of prokaryotes on Earth.

Prokaryotes: 1. They do not have nuclear membrane around nucleus 2. Cell size is less than a micrometer and 5 micrometer. 3. Organism is usually single celled. 4. Ribosomes are small 5. Membrane bound organelles are absent. Eukaryotes: 1. They have nuclear membrane around nucleus. 2. Cell size is 10 to 100 micrometer. 3. Organism is multicellular 4. Ribosomes are large 5. Membrane bound organelles are present.

Describe reproduction in prokaryotes. Explain how their high reproductive potential is related to their success. Explain how rapid reproduction, mutations, and genetic recombination promote high levels of genetic diversity in prokaryotes even though they reproduce asexually.

Prokaryotic cells reproduce by a process called binary fission. Reproduction in prokaryotes is asexual they can also exchange genetic material by transformation, transduction, and conjunction. The reproductive process start with a replication of chromosome. The new chromosome attaches itself to the plasma membrane & two chromosomes migrate to opposite ends of the cell. The plasma membrane in the middle of the cell grows inward until it closes to separate the cell into two compartments, each with a full complement of genetic material. The cell then "fission" at the center forming two new daughter cells. Reproductive success is defined as an individuals production of offspring per breeding event or life time. Reproductive success is different from success is not necessarily a determinant for adoptive strength of a genotype since the effects of chance and the environment have no influence on those specific genes. - Prokaryotic divine by binary fission and have the potential to reproduce very rapidly. - Some prokaryotes can produce endospores which allow them to survive through long periods of unfavorable conditions. Methanogens are poisoned by oxygen and live in places like swamps and the gut of animals. Genetic variation refers to diversity in gene frequencies. Genetic variation can refer to differences between individuals or the differences between population. Mutation is the ultimate source of genetic variation, but mechanism such as sexual reproduction and genetic drift contribute as well. Horizontal gene transfer , the transfer of genetic material from one organism to another organism within the same generation, is an important way to promote genetic diversity.

For the following clades of bacteria, be able to describe the characteristics of each clade, explain why the clade is important to humans and/or ecosystems, and give examples of bacteria in each clade: Proteobacteria, Spirochetes, Cyanobacteria, Chlamydias, Gram-Positive Bacteria, Deinococcus-Thermus.

Proteobacteria is a major phhlum of gram negative bacteria. Examples of proteobacteria escherichia, salmonella. Betaproteobacteria are a type of proteobacteria which play a very important role in nitrogen fixation. It works as oxidizing agent ammonium for production of nitrite which is very important chemical for functioning of plants. These bacteria are also found in waste water or soil. In case of increased gut disease in humans proteobacteria number also increases and instable microbiota. Spirochetes can be either gram negative or gram positive and most of these have long, helically coiled rings. Examples are spirochaeta, treponema etc. They can be observed in gut of animals and can be causal agent for many diseases like syphillis, lyme disease. They are also found as free living microbe in nature. Cyanobacteria are a type of bacteria which includes photosynthetic bacteria and also as endosymbiotic in plastids of archaeplastids of autotrophic eukaryotes. Examples are nostoscales, gleobacterales. Very important for growth of many plants convert inert nitrogen into organic compounds, detoxify harmful chemicals, catalyze nutrient cycling, supress growth of bacteria in water and soil. Chlamydias are intracellular obligate bacteria, can behave as pathogenic to symbionts of ubiquitous protozoa. Ecamples include chlamydia trachomatis, chlamydia pneumoniae. They are known to cause respiratory diseases. Gram positive bacteria important components of freshwater ecosystem. They are easier to kill as theri wall absorbs antibiotic. Examples include staphylococci, streptococci etc. Important in soil ecology, some species are pathogenic to humans. Dienococcus thermus as the name is depicting higly resistant to environmental hazards and termed as extremophiles having thick walls. They can be used for treatment of nuclear energy waste.

Describe the causes and impacts of coral bleaching. Describe symbiotic relationships (mutualism, commensalism, parasitism) involving protists mentioned in the textbook and lecture. Describe the role of dinoflagellates in red tides. Describe how Forams can be used to estimate past environmental conditions.

Q2. Describe the causes and impacts of coral bleaching. Coral bleachng is a phenomenon which occurs when water is too warm, corals will expel the algae (zooxanthellae) living in their tissues causing the coral to turn completely white. When a coral bleaches, it is not dead. Corals can survive a bleaching event, but they are under more stress and are subject to mortality. CAUSES: Increases in seawater temperature (upto 2 degree celsius), particularly when associated with elevated levels of solar irradiance (e.g., ultraviolet radiation). Changes in seawater chemistry (e.g., due to ocean acidification or pollution) Increased levels of sediment in seawater Coral's exposure to sodium cyanide (a chemical used in the capture of coral reef fish). * As a result, under such conditions the zooxanthellae may lose substantial amounts of their photosynthetic pigmentation, which decreases rates of photosynthesis and produces bleaching. IMPACTS: WILDLIFE: Coral reefs support some of the most biodiverse ecosystems on the planet. Marine animals depend on coral reefs for survival,shelter and protection from predators including some species of sea turtles, fish, crabs, shrimp, jellyfish, sea birds, starfish, and more. They also support organisms at the base of ocean food chains. As reef ecosystems collapse, already at-risk species may face extinction. HUMANS: Coral bleaching impacts peoples' livelihoods, food security, and safety. Coral reefs are natural barriers that absorb the force of waves and storm surges, keeping coastal communities safe. Bleached coral also compounds the overfishing crisis by removing links in the food web. Coral reef tourism brings in billions of dollars each year and supports thousands of jobs.

heteromorphic

Referring to a condition in the life cycle of plants and certain algae in which the sporophyte and gametophyte generations differ in morphology.

Isomorphic

Referring to alternating generations in plants and certain algae in which the sporophytes and gametophytes look alike, although they differ in chromosome number.

Pilus/Pili

Short, filamentous protein projecting above cell wall to help it adhere to surfaces.

Describe the significance of methanogens and halophiles and know to which clade they belong.

Significance of methanogens and halophiles Methanogens are microorganisms that produce methane as a metabolic byproduct in hypoxic conditions. They are prokaryotic and belong to the domain of archaea. Like other members of the archaea domain, methanogens are extremophiles, living in the guts of animals, the cracks of undersea volcanoes and deep in swamps and wetlands. Methanogens have a cell wall, providing them with a rigid cell structure and protecting them from the effects of harsh environments. Methanogenic archaea, or methanogens, are an important group of microoraganisms that produce methane as a metabolic byproduct under anaerobic conditions. Methanogens belong to the domain archaea, which is distinct from bacteria. Halophiles play an important part in ecosystems. For example, halophiles often support entire populations of wild birds. Halophiles are useful for cleaning up polluted environments. Waste water with salt concentrations more than 2% is ideal for halophiles to remove organic pollutants from. They are microorganisms that require high levels of salt in order to be able to complete all of their life functions and survive.Most of the halophiles that have been discovered are simple prokaryotic organism, while others are eukaryotes.

Compare and contrast the two prokaryotes domains—bacteria and archaea. Describe what makes the membranes of archaea unique. Describe what makes bacteria cell walls unique.

Similarities: These are unicellular organisms that lack a nuclear membrane. The genetic material is naked and coiled with the help of non-histone proteins. All double membrane-bound cell organelles such as mitochondria, golgi bodies, endoplasmic reticulum are absent. Reproduction is also asexual mostly by binary fission. They don't show the process of exocytosis and endocytosis. Differences: Bacteria: 1. Bacteria have a cell wall made up of peptidoglycan 2. Bacteria include microorganisms such as Streptococcus, Escherichia, Lactobacillius. 3. The initiation of transcription is bacterial type. Archaea: 1. The cell wall of archaea ranges from proteinaceous to peptidoglycan-like. 2. Archaea include microorganisms such as methanogens, thermoacidophiles, and, halophiles. 3. The initiation of transcription is eukaryotic type. The cell wall of bacteria is a tough and rigid membrane and is granular in appearance. The 3 main constituents that make up the cell wall of bacteria are N-acetyl-glucosamine(NAG) N-acetyl muramic acid (NAM) A peptide chain of four or five amino acids. The bacterial cell wall can withstand an osmotic pressure of eight atmospheres per square centimetre.

Describe how prokaryotes carry out photosynthesis and cellular respiration without compartmentalized organelles such as mitochondria.

Some prokaryotic cells have specialized membranes, usually inholdings of the plasma membrane, that perform metabolic functions. The infoldings of the plasma membrane, reminiscent of the cristae of mitochondria, function in cellular respiration in some aerobic prokaryotes. Photosynthetic prokaryotes called cyanobacteria have thylakoid membranes, much like those in chloroplast

Explain the problem faced by Dictyostelium aggregates of constraining "cheaters" that never contribute to the stalk of the fruiting body. Discuss how research on this topic may lead to insights into the evolution of multicellularity

Some studies have found that some individuals of Dictyostelium cells have gone through mutation which turn them "cheaters." These "cheaters" never become part of Dictyostelium aggregate stalk. Mutation causes lack of a protein of the cell of surface of "cheaters" which help non cheaters in separating themselves from cheaters. Non-cheaters aggegrate only with non-cheaters depriving cheaters of the opportunity to exploit them. By the cheaters (mutants) gain a strong reproductive advantage over non-cheaters. Evolution of Multicellularity: The central role of CAMP in regulation of cell movement and cell differentiations. Helps in encystation Research shows that cell aggregate to form fruiting body with multiple side branch. Dictostelium is commonly called slime mold. It is a species of soil dwelling amoeba. It is a eukaryote that show transition from a collection of unicellular amoeba to a multicellular slug and then into a fruiting body. These occur within a lifetime.

contractile vacuole

The cell structure that collects extra water from the cytoplasm and then expels it from the cell

Lateral gene transfer

The transfer of genes from one species to another, common among bacteria and archaea.

lateral gene transfer

The transfer of genes from one species to another, common among bacteria and archaea.

Describe the two types of nuclei found in ciliates. Know which group of green algae is most closely related to land plants (Charophytes).

The two types of nuclei are the micronucleus and macronucleus. The micronucleus is diploid; that is, it contains two copies of each paramecium chromosome. Forney notes that the micronucleus contains all of the DNA that is present in the organism. The large nucleus is called the macronucleus which controls cell activities such as respiration, protein synthesis and digestion. Smaller micronucleus is used only during reproduction. Reproduction in paramecium involves the exchanging of DNA within the micronucleus. In order to do this, two paramecium lie side by side and join at the mouth pore. This process is called conjugation and is a method of sexual reproduction in other microorganisms. The charophytes (Streptophyta,Virideplantae) are the extant group of green algae that are most closely related to modern land plants. Approximately 450-500 million years ago, an ancestral charophyte emerged onto land and ultimately gave rise to terrestrial plants, an event of profound significance in the natural history of the planet. Green algae contain the same carotenoids and chlorophyll a and b as land plants, whereas other algae have different accessory pigments and types of chlorophyll molecules in addition to chlorophyll a. Both green algae and land plants also store carbohydrates as starch. Cells in green algae divide along cell plates called phragmoplasts and their cell walls are layered with cellulose in the same manner as the cell walls of embryophytes. Consequently, land plants (embryophytes) and closely-related green algae ( Charophyta ) are now part of a new monophyletic group called Streptophyta.

Describe three processes that produce recombinant DNA in prokaryotes.

Transformation: the uptake of DNA from the environment Transduction: the transfer of new DNA through pages(virus) Conjugation: the exchange of plasmid through a sex pilis.

Explain why some trypanosomes are able to evade the human immune system. Describe the life cycle of malaria.

Trypanosome brucei is a hemoflagellate of the family Trypanosomatidae, with a digenetic life cycle that develops in a vertebrate host and invertebrate host. The mammal becomes infected when the tsetse fly injects into its skin the metacyclic parasites along with the saliva, which multiply at the entry site and sometimes produce a lesion known as chancre. Subsequently, some of them are transformed to the long and slender blood-stream trypomastigotes, takes place the process of division and they become in shorter, stumpy blood-stream form of parasite. trypanosomes modify their surface membranes in order to evade host immune systems, multiplying with every surface change in a process known as antigenic variation. The parasite can even elude acquired immunity during infection because of the rate at which they multiply. The innate immune system is the first barrier of mammals to defend themselves against trypanosomes.rypanosome brucei is subject to the lytic action of two serum human complexes, denominated trypanosome lytic factor (TLF) (TLF 1 and TLF 2), containing apolipoprotein L1 (APOL1) which is endocytosed via the haptoglobinhemoglobin parasite surface receptor. Both parasites evade the destruction by APOL1 producing certain proteins that give them resistance.The complement activation can start through two pathways: the alternative pathway (independent of antibody) and the classical pathway (dependent of antibody). The turn on of the alternative pathway is supremely important in the destruction of the parasite during the beginning of the disease. Life cycle of Malaria: The malaria parasite(Plasmodium) life cycle involves two hosts. During a blood meal, a malaria-infected female Anopheles mosquito involves two hosts. During a blood meal, a malaria-infected female Anopheles mosquito inoculates sporozoites into the human host. Sporozoites infect liver cells and mature into schizonts, which rupture and release merozoites.

Explain how R plasmids confer antibiotic resistance in bacteria.

When a bacterial population is exposed to an antibiotic, individuals with the R-plasmid survive and increase in the overall population. Because R-plasmid has genes encoded for sex pili, they can be transferred from one cell to another by conjugation

Kelp

any of various large, tough, brown seaweeds

Describe how lateral gene transfer complicates evolutionary studies

ateral gene transfer (LGT) is the transmission of qualities, at times across species obstructions, outwith the exemplary vertical inheritance from parent to offspring.LGT is perceived as a significant wonder that has formed the genomes and science of prokaryotes. Prokaryotes were once viewed as equivalent on the grounds that there was no framework to analyse the qualities of various prokaryotes. when qualities engaged with sidelong exchange occasions are sequenced phylogentically, the subsequent quality.trees won't coordinate the phylogeny. Lateral gene transfer is the exchange of qualities between two unrelated species and accordingly, complicates the basic tree model.

facultative anaerobes

can live with or without oxygen

Plasmodium

causes malaria

Fimbriae

finger or fringe like projections at the end of the fallopian tubes

primary producer

first producer of energy-rich compounds that are later used by other organisms

Coenocyte

fungal species that have hyphae lacking septa

Plastid

group of plant organelles that are used for storage of starches, lipids, or pigments

heterocysts

nitrogen-fixing cells

obligate aerobe

organism that requires a constant supply of oxygen in order to live

obligate anaerobes

organisms that cannot live where molecular oxygen is present

Transformation

process in which one strain of bacteria is changed by a gene or genes from another strain of bacteria

Endotoxins

released only when bacteria die and their cell walls break down

rRNA

ribosomal RNA; type of RNA that makes up part of the ribosome

micronucleus

the smaller of a ciliate's two nuclei; contains a "reserve copy" of all of the cell's genes

Alveoli

tiny sacs of lung tissue specialized for the movement of gases between air and blood

Exotoxins

toxic substances that bacteria secrete into their environment

Transduction

transforming one form of energy to another