Biology: Research Trivia

The questions are in the order of human anatomy, microbiology, then botany (plants, then fruits/vegetables (horticulture), then flowers, then trees).

%i. Can 2 people eat the same food, but 1 gets diarrhea, and the other does not? Yes.

%i. Human urine is salty. Eating more sugary foods does not make our urine sweeter, so sugars are excreted another route. How are salts and sugars separated in the body?

That is done in the stomach. Proteins and carbohydrates are broken down in the stomach and small intestines. Sucrose is broken by the enzyme sucrase, breaking into fructose and glucose, then absorbed in the small intestine. Salt is also absorbed in the gastrointestinal tract, bringing water along with it. The kidney has a filtration system that can separate small ions from larger molecules, and this allows for cations to pass through a lot better than anions. Glucose is filtered into primary urine and then re-absorbed in renal tubules, and sent back to the blood. If this didn't happen, as in if it didn't go back into the blood, we would rapidly lose blood glucose and slip into a coma very quickly.

No, because those are digestion. For food like energy drinks and the case of caffeine, the response is not a part of our immune system, but our receptors. When drinking energy drinks everyday for breakfast, lunch, and dinner, our receptors get used to it, so you need more amount to get the same effect.

%i. What are human bones and teeth made of? The primary mineral is hydroxyapatite (Ca₅(PO₄)₃OH).

About 1 in 10,000 people are born with Situs inversus, where the lungs and heart are rotated at 180 degrees.

Your red blood cells are replaced about every 4 months. The heme part of the hemoglobin molecule is broken down in the liver to bilirubin. Most of the bilirubin winds up in the intestines (it's a complicated path, through the gall bladder) where it makes the feces brown.

While it's in the intestines, some of the bilirubin is reduced into urobilinogen by bacteria. The urobilinogen is then oxidized into urobilin, again by bacteria. Urobilin gets into the bloodstream (through the intestinal wall) and is removed by the kidneys. It has a bright yellow color and it turns the urine yellow.

When ketones are discharged from your urine, they can cause it to have a foul smell. Ketones are produced when the body doesn’t use glucose properly. When the kidney tries to eliminate this, they can cause a significant smell in your urine.

%i. Is it possible to tell urine from a vegetarian? No, they consume the same 9 essential amino acids.

The 70% was estimated by the University of Cambridge. The answer is due to GDF15, which is a hormone produced in the placenta that increases substantially during pregnancy. A woman’s sensitivity to the hormone can determine the severity of her symptoms. It's also believed to act on the brain's vomiting center. The drug Metformin increases GDF15 levels. Some women, however, thought to be between 1-3% of pregnancies, suffer from HG (hyperemesis gravidarum), an even worse situation. HG can be life-threatening to the fetus and the mother. HG can also require IV fluids to prevent dangerous levels of dehydration.

%i. Is it possible for a woman to be pregnant with twins, and each twin has a different father?

Yes, this phenomenom is called heteropaternal superfecundation. This can only happen with fraternal twins (dizygotic) because identical twins result from the splitting of a single fertilized egg. The 1st confirmed cases did not happen until the 1990s due to DNA tests.

Most sugars do not directly cause tooth decay (glucose, sucrose, and fructose), but they feed bacteria that produce weak acids that cause tooth decay. But a sugar like citric acid, can cause tooth erosion directly, without bacterial effect. Which of those sugars are worse, is a matter of debate. Sugars like the 1st 3 cause more cavities, while citric acid causes more enamel erosion, which can lead to tooth decay over time.

The bacteria primarily responsible for causing tooth decay and producing acids that erode tooth enamel belong to a group known as cariogenic bacteria. The most notable among them are Streptococcus mutans and Lactobacillus, which produce weak acids as a byproduct of breaking down the sugar. The primary weak acids are lactic acid, which leads to enamel erosion. Those 2 bacteria also produce formic acid in smaller amounts. In addition, some strains of Lactobacillus produce acetic acid and propionic acid.

On the other hand, citric acid, is a powerful chelator for calcium. We use it to fight kidney stones because the citric acid binds to calcium. This makes diet sodas worse than regular sodas. The worst type of citric acid is trisodium citrate, usually labeled as sodium citrate. This is also worse if the pH is below 7. You can dissolve 2 xylitol mints in your mouth, as xylitol is a neutralizer to the effects of sugar.

Xylitol is a type of alcohol sugar that is not fermentable by oral bacteria. In some cases, xylitol can reduce the overall population of harmful bacteria in the mouth, as they effectively "starve" when they try to use xylitol as an energy source. Xylitol can be found in strawberries, plums, and cauliflower.

%i. Why does milk turn sour? Bacteria converts the carbohydrates into lactic acid.

Yes. But if they were slowly killed in a way that it caused them to produce exotoxins, then consuming that is dangerous.

%i. If all the viruses in the world died? Some viruses kill bacteria. And there could be good viruses out there that we don’t know about.

%i. Can there be a bacteria that produces endospores, and be Gram-negative and anaerobic? Yes, Sporomusa, which belongs to the class Negativicutes within the Firmicutes.

Generally kill Gram-positive better or equal to Gram-negative. Counter examples include 1st generation fluoroquinolones and 2nd and 3rd generation cephalosporins.

Copper (and its alloys) is the only metal that is naturally anti-bacterial, though a few others are weakly anti-bacterial.

%i. What are some examples of bacteria that 70% isopropanol kills better than 70% ethanol, and 70% ethanol kills better than 70% isopropanol?

The 1st bacteria-killing bacteria that scientists discovered is known as Bdellovibrio bacteriovorus. This bacterium is a small, predatory microorganism that preys on other bacteria by attaching to their cell walls, invading them, and consuming their contents. Bdellovibrio bacteriovorus was 1st described in the late 1960s and has since been studied for its potential applications in controlling bacterial infections and as a possible alternative to antibiotics.

%i. Many of the antibiotics that we use derive from streptomyces, which are bacteria. So perhaps that is the first example of bacteria killing bacteria?

You are correct that Streptomyces species are prolific producers of antibiotics, and they have been extensively studied for their antibiotic-producing capabilities. Streptomyces species have contributed significantly to the development of many antibiotics used in medicine today, such as streptomycin, tetracycline, and erythromycin, among others. And while Streptomyces species are indeed bacteria that produce antibiotics, they are not considered "bacteria-killing bacteria" in the same way that Bdellovibrio bacteriovorus is. Streptomyces species produce antibiotics as secondary metabolites, which are compounds they produce during specific stages of their growth cycle. These antibiotics are typically used to inhibit the growth or kill other bacteria, fungi, or even other microorganisms, but Streptomyces themselves do not typically attack and consume other bacteria like Bdellovibrio bacteriovorus does.

%i. (As Bdellovibrio are Gram-negative bacteria) What was the 1st Gram-positive bacteria killing bacteria discovered by scientists?

Lysinibacillus sphaericus. This bacterium is a spore-forming bacterium that produces toxins lethal to other bacteria, particularly those belonging to the genus Bacillus. Lysinibacillus sphaericus was 1st isolated and described in the 1960s and has since been studied for its potential as a biological control agent against disease-causing bacteria, particularly those responsible for mosquito-borne illnesses such as malaria and dengue fever. Its ability to produce insecticidal toxins has made it a subject of interest in the field of microbial control of vector-borne diseases.

%i. (As Bdellovibrio does not kill their own species) What about bacteria killing their same-species bacteria?

Bacteria killing their own species, or conspecific bacteria, is a phenomenon known as intraspecific killing or fratricide. This behavior can occur in various bacterial species and is often mediated by the production and release of toxins or bacteriocins, which are antimicrobial peptides or proteins.

1 well-known example of intraspecific killing in bacteria is observed in species of Bacillus, particularly Bacillus subtilis. B. subtilis can produce and release antimicrobial compounds such as subtilin, which can inhibit the growth of closely related strains or even kill them outright. This behavior is thought to contribute to competition for resources within bacterial populations and can influence the dynamics of microbial communities.

Another example is observed in some strains of the bacterium Escherichia coli, which can produce colicins, bacteriocins that target and kill other E. coli strains. These colicins are encoded by genes located on plasmids and are released by the producing strain to inhibit the growth of competing bacteria.

There are also many examples of bacteria killing their own species from type VI secretion systems. There, bacteria don't kill their kin, but will kill unrelated members of the same species that have different sets of type VI delivered toxins.

%i. If there's 5 g of dog poop vs. 10 g of dog poop, can we say the time it takes bacteria to convert 5 g of dog poop, to gas, is twice as fast for bacteria to convert 10 g of poop to gas?

Not necessarily. The rate at which bacteria break down dog poop depends on a few factors, such as:

Surface area exposure: if the 5 g sample is in a single lump, bacteria may take longer to break it down compared to a spread-out sample. More surface area usually means faster decomposition.

Bacterial population growth: bacteria multiply as they feed. A larger amount of waste might allow bacteria to increase their population, accelerating the breakdown over time.

Dog poop can produce 50–100 mL of methane per gram of dry matter in anaerobic digestion over days or weeks. This suggests decomposition on the order of 0.01–0.05 g per hour per gram of active bacteria under good conditions.

Composting studies on animal waste show that about 30–50% of organic material can degrade in the first 1–2 weeks under high heat (~130°F or 55°C). In active composting, bacteria can break down 0.2–0.5 g of organic matter per hour per gram of bacteria, but this still varies widely.

Some plants can produce anti-bacterial compounds, such as phytoalexins. They are not defined by their chemical structure, but by the fact that they are synthesized by plants at sites of pathogen infections. Therefore, phytoalexins are chemically diverse, and are generally broad-spectrum inhibitors. Phytoalexins include terpenoids, glycosteroids, and alkaloids. Like humans, plants can also create reactive oxygen species such as hydrogen peroxide.

Some plants produce physical barriers such as waxy cuticles that prevent bacteria from penetrating the plant tissue.

Lignin is also a plant mechanism for defense from bacteria. It is different even within the same-species. It is a macromolecule rather than a biopolymer. Chemists have developed ways to remove lignin from plants, via protic ionic liquids, that have high lignin recovery and separation. Using dilute acid will remost some lignin and most hemicellulose.

The most common bacteria found in plants are species of the genus Agrobacterium. These bacteria are known for their ability to transfer DNA between themselves and plants, which can lead to the development of crown gall disease in some plant species. Agrobacterium is commonly found in soil and can infect a wide range of plants, including trees, shrubs, vegetables, and fruit crops. Other common plant-associated bacteria include species of Rhizobium, which are important for nitrogen fixation in legumes, and Pseudomonas, which can be beneficial or harmful to plants depending on the specific strain and context.

%i. How does adding sulfur to soil make the soil more acidic? Sulfur is not H⁺ ions.

Through the magic of Thiobacillus bacteria. Several species of Thiobacillus bacteria, will combine sulfur with oxygen and water to generate H₂SO₄, dissociating it into the (wet) soil. This is preferred over using diluted HCl because Cl^- is toxic to plants. When there are no sulfur in the soil, the Thiobacillus persist in a dormant state for extended periods without dying.

Once gases are inside the leaf, gases diffuse into intercellular spaces and may be absorbed by water films to form acids or react with inner-leaf surfaces. The removal of gas pollutants is more permanent than the removal of particulates because the gases are often absorbed and converted within the leaf interior.

%i. Is it true that certain plants can remove certain chemicals like benzene and formaldehyde?

Yes, they fall under the category of VOCs (volatile organic compounds). Unfortunately, these have almost no real applications, for 2 reasons. The 1989 test NASA did on indoor plants were placed in a small box, but in a large room or office environment, you would need hundreds of plants to produce the same effect. Benzene and formaldehyde are also not commonly found in indoor-air either.

%i. If I go to the Arctic and saw the plants were cold, and took them over to the tropical area where the weather is warm, will the plants be happier?

Unfortunately, most Arctic plants will now be exposed to different types of bacteria, viruses, and even fungi, and that alone they would not survive. Plants would also suffer water-loss, though big coniferous trees will be more adaptable.

(Since the answer is most plants prefer rain water, then what plants prefer DI water over rain water?). Mosses and liverworts.

Majority no, as plants have 1 pH-range they like, not several. So when plants have a pH range, look for the ones with the longest spanning pH range. It turns out plants having a pH range greater than 3 is rare.

Some plants with long-spanning pH ranges: the Tamarindus indica (a leguminous tree found in tropical Africa) has a pH range from 4.5 to 8.0. The Chrysopogon zizanioides, a bunchgrass, has a pH range from 3.3 to 8.0, but can also stand more basic soil.

Naturally no, plants that glow are too dim for the human eye, but there have been plants that have been genetically modified to fluoresce. Those genes were taken from bacteria. Scientists have also dipped plants in a liquid that contained nanoparticles, which reacted with the plants sugar to emit light.

%i. Can there be some plants when dehydrated, their leaves turn the X color, and when have too much water, their leaves turn the Y color, and other plants that when they are dehydrated, their leaves turn the Y color, and when have too much water, their leaves turn to the X color?

Yes, as plants can turn yellow from either too much or too little water, as well as develop brown spots to mean too little water (and the leaves are dried to a crisp), or too much water (so there's a fungus attacking the leaves). Typically, a leaf will yellow first. Then, necrosis will set in. The necrosis (decayed tissue) can begin to occur before it has fully yellowed. This varies a lot depending on the succulence of the leaf. Some finer foliage may skip the yellowing and go fully necrotic.

Other colors are likely to have different causes. For instance, a thrips infestation can cause an orange tint.

A great dehydration test to do method is the finger test around the base of the plant into the soil: is it moist? Do soil particles stick to your finger? If not, it could use some water.

Generally most plants will turn yellowish if lacking nitrogen and will turn purplish when lacking phosphorus. Tropical houseplants tend to be the exceptions to a lot of those general rules though. The most common case of this is in late fall / early winter when cold temperatures inhibit plants ability to absorb phosphorus, known as cold-induced phosphorus deficiency.

No. Allergies are a result of maladaptive immune response in animals, particularly involving IgE antibodies, mast cells, and histamine release. Plants lack all 3, so they cannot have allergies. Plants do have defense mechanics, but they are not overreactive in nature. Examples of this are a hypersensitive response where infected plant cells die off to block pathogen spread.

%i. Fruits like cherries and nectarines only produce fruit in the summer. When summer ends, if you take it to the opposite hemisphere where summer starts, can it produce fruit year-round?

For cherries and nectarines no, because those fruits require a chilling period. That's requiring a winter chill hours, so moving them from hemisphere to hemisphere to get year-round summer won't work. Others that require a chilling period include raspberries, blueberries, and grapes. Examples that do not require a chilling period, include bananas, cherry tomatoes, bell peppers, cucumbers, leafy greens such as spinach, kale, Swiss chard, and lettuce, and certain herbs like basil, mint, rosemary, and thyme. However, certain examples like strawberries, apples, and oranges, can have certain varieties that have considerably less chilling hours required, and can almost produce year-round.

Also note that the part of the world that has the 4 seasons, are only between 23.5 and 66.5 degrees latitude (north and south). Less than 23.5, have essentially 2 wet and 2 dry seasons.

Yes and no. The no being sunlight does not directly involve the ripening or rotting process. But it does indirectly involve heat. For heat, that depends on the 2 types of fruits: climacteric and non-climacteric fruit. Climacteric fruit will continue to breathe in O₂, produce ethylene gas, and mature after plucked off the plant. Whereas non-climacteric fruits must stay on their plant to mature.

Climacteric fruit include apples, peaches, bananas, apricots, pears, and tomatoes and avocadoes.
Non-climacteric fruit include oranges, strawberries, raspberries, blackberries, blueberries, grapes, watermelon, cherries, plum, and pineapples.

Note that the shelf-life of blueberries is about 4x or more than that of strawberries and raspberries.

Both the sun and incandescent filament are essentially black body radiators. They both emit IR, usually more than they do visible light.

Apples contain an enzyme called polyphenol oxidase, which oxidizes phenols into melanin through a series of steps. (Melanin are more widespread in plant tissue than human tissue, and have a different purpose in plants than in humans). Plants secrete melanin upon damage.

%i. Why does blueberry juice have a longer shelf-life than strawberry juice and orange juice?

Blueberry juice may last longer than strawberry juice due to its higher levels of natural anti-oxidants, which can help to slow down the process of oxidation and spoilage. With orange juice, blueberry juice has a lower pH, which can help inhibit the growth of bacteria and others that cause spoilage.

%i. Who were the 1st seedless cherry and seedless watermelon? 1 of the early and notable seedless cherry varieties is the Stella cherry. Stella cherries are sweet cherries that are known for being self-pollinating and nearly seedless. The Stella variety was the result of a breeding program at the John Innes Institute in Norwich, England. That program developed 3 self-fertile seedlings, which were used in attempts to breed high-quality self-fertile cherry trees. 1 of the seedlings was crossed with the Lambert variety at the Summerland Research Station in Summerland, British Columbia in 1956 by K. O. Lapins (namesake of the Lapins cherry cultivar), and the resulting hybrid tree was named Stella in 1968.

Then the 1st seedless Stella cherry variety was reportedly developed by Dr. Raymond D. C. Findlay at the Summerland Research Station in British Columbia in the late 1960s.

Seedless watermelons were developed through breeding efforts. The 1st seedless watermelon varieties were developed in the 1950s by scientists Charles Fredric Andrus and his student Charles LaRue at the USDA Vegetable Breeding Laboratory in Charleston, South Carolina.

%i. What makes strawberry juice strawberry juice, and what makes raspberry juice raspberry juice?

We can rephrase that question to "What are some chemicals found in the juice of strawberries that are not found in the juice of raspberries, and what are some chemicals that are found in the juice of raspberries that are not found in the juices of strawberries?"

Chemicals found in strawberries but not raspberries include: Furanones (Furan-2(5H)-one and Furaneol (4-Hydroxy-2,5-dimethyl-3(2H)-furanone)), pelargonidin (main anthocyanin in strawberries, responsible for their bright red color), Ellagitannins (Sanguiin H-6 and Agrimoniin), linalool, and methyl butanoate (ester).

Chemicals found in raspberries but not in strawberries include: a lot more ellagic acid, raspberry ketone ((4-(4-Hydroxyphenyl)-2-butanone), which contributes to the raspberry flavor), alpha-Ionone and beta-Ionone, cyanidin glycosides ((Cyanidin-3-glucoside and Cyanidin-3-rutinoside), responsible for the color), and geraniol.

What they have in common, is water, sugars (fructose, glucose, and sucrose), organic acids (primarily citric acid and malic acid), then vitamin C.

They are to proteins founds in the latex of rubber trees (latex-fruit syndrome), which commonly associates with bananas, kiwi, avocado, chestnuts, and passionfruit. Outside of that, according to the Institute of Agriculture and Natural Resources, Food Allergy Reserch and Resource Program, lists apple, peach, and kiwi.

Vegetable allergies are less common. Celery, specifically celery root (celeriac). Others include carrots.

It would not be by color, but by the ones with the thickest skin, so dark blue grapes.

Depending on your nutritional needs, red onions have quercetin, and more anti-oxidants, whereas yellow and white onions have more fiber and sulfur.

%i. A quick mouseover scan on Wikipedia's Flora of the Arctic category, produced majority white-flowers, and half as much yellow flowers, with traces of light purple, blue, and pink flowers. No red flowers. Why aren't there any red flowers in northern latitudes?

The answer is pollination, and hummingbirds. Hummingbirds are big pollinators of red flowers, so if hummingbirds don't exist in cold climates, red flowers won't exist either. In other parts of this website, mentions most birds cannot see red, they can only see in the orange-ultraviolet spectrum instead of red-violet like humans do. Hummingbirds are examples of few birds that can see red.

Similarly, yellow flowers are pollinated by bees, purple flowers by bumblebees (whom also cannot see red), and white flowers by bats.

According to Wild Flowers at a Glance, by Dorothy Fitchew Carey, the U.K. lacks big red wild flowers (with an obvious exception of the field poppy), while having lots of pink and purple ones.

Note: the taiga is defined as 50 N. latitude to 70 N. latitude, Arctic at 66 N. latitude and plus, the tundra at 70 N. latitude and plus.

Yes, this is possible for some non-white Hydrangea species, particularly Hydrangea macrophylla and Hydrangea serrata. For soil pH less than 5.5 will produce blue flowers, pH between 5.5 to 6.5 produce pink flowers, and pH greater than 6.5 produce purple flowers. This is largely determined by aluminum ions.

Yes, such is the case for Satsuki azalea. Flower colors vary from white to pink, yellowish pink, red, reddish-orange and purple. Color patterns include solids, and stripes, flakes, lines, and margins of color on a lighter background. The complete range of color patterns can appear on the same plant, differently each year.

Apparently flowers with extended roots. Examples include coneflowers, red columbine, butterfly weed, asters, coreopsis, purple prairie clover, black-eyed susan and brown-eyed susan, standing cypress, prairie blazing star, and lemon mint.

%i. Flowers 101: what’s the difference between violas, pansies and petunias, hydrangeas and hyacinth, and tulips?

Pansies are a genetic hybrid of violas, to be lower in pollen, both being majority annuals. Hyacinth produces both pollen and nectar, while hydrangeas produce nectar, but low pollen, both being perennials. Petunias are annuals while tulips are perennials, and they both produce low pollen and low nectar.

The 3 main types are all coniferous evergreens: fir, spruce, and pine. Fir and spruce trees have their needs attached individually to branches, whereas for pine trees, the needles are attached to branches in clusters of 2 (red pine), 3 (yellow pine), or 5 (white pine). Most conifers are evergreens. Most tropical rainforest plants are evergreens. Palm trees are evergreens, but are not conifers. Note that palm trees are not technically considered to be trees, but as woody herbs.

Apparently deciduous conifers. There’s about 20 species out there, with the best known being larches. So deciduous conifers, they form cones and sprout needles like conifer trees, but they also change colors in the fall and lose their needles every year like deciduous trees.

Note: there is no overlap between deciduous and evergreen plants, and almost all conifers are green. Deciduous plants lose all their leaves for part of the year, evergreen do not.

In the context of fruits and vegetables, evergreen plants include citrus trees (such as oranges, lemons, limes, and grapefruits), avocado trees, olive trees, fig trees, and guava trees. Deciduous plants includes cherries and blueberries.

%i. Is there a correlation between how expensive wood is, to whether they came from deciduous or evergreen tree?

Cheap wood includes pine. Expensive wood includes mahogany, teakwood, bloodwood, and padauk. It appears wood from deciduous trees are more expensive. The expensive woods, such as teakwood, are also water-resistant, and used on boats.

The most expensive wood in the world is considered to be Agarwood or Oud, which is found in Southeast Asia, particularly in Thailand, Cambodia, Vietnam, and Laos. This wood is valued for its distinctive and aromatic fragrance, which is produced when the wood is infected by a particular type of mold. The cost of Agarwood varies depending on the grade, quality, and age of the wood, but it can reach up to 10s of thousands of dollars per kilogram. Other expensive wood species include Ebony, Sandalwood, and Pink Ivory.

Examples are polyurethane, mineral oil, automotive UV-inhibitors, and tung oil (which is 82% alpha-eleostearic acid). In Australia, cedar homes are painted with used motor oil, which soaks in.

Cocoa prices have been rising for nearly a year and hit an all-time high of $10,080 per metric ton in the 1st week of April 2024. Crop production has been hurt by black pod disease and swollen shoot virus, particularly in Ivory Coast and Ghana, which account for 60% of global cocoa production.

There’s a supply deficit of 374,000 tons for the 2023-2024 season, according to the International Cocoa Organization, and the industry has said consumers could see more noticeable price increases for chocolate toward the end of 2024 as a result.

%i. I'm interested in buying organic food, but am conservative on spending. What are some lesser-important foods that to not need to be organic?

Foods that have a strong peel (like bananas) and foods with a strong shell (like walnuts) would not as importantly need to be organic. Some of the most importantly-necessary organic health foods are therefore mushrooms, berries, cruciferous vegetables, leafy vegetables, flour and grains, and olive oil. (Pesticides are even used on olive trees.). You do not need to buy organic cabbage (just peel the outer layer) but you do need for peanuts.

1. Culture-Based Methods: in this approach, water samples are spread or diluted onto specific growth media that provide the necessary nutrients for bacteria to grow. The samples are then incubated at an appropriate temperature, allowing bacteria to multiply and form visible colonies. After incubation, scientists can identify and count the colonies to determine the presence and concentration of bacteria.

2. Polymerase Chain Reaction (PCR): a molecular biology technique used to amplify specific DNA sequences. Scientists can extract genetic material (DNA) from water samples and use PCR to target and amplify bacterial DNA. By comparing the amplified DNA with known bacterial sequences, they can identify the presence of specific bacteria in the sample. This method allows for the detection of even small amounts of bacteria and can provide rapid results.

3. Flow Cytometry: a technique that involves the detection and characterization of individual cells based on their physical and chemical properties. In water analysis, samples are stained with fluorescent dyes that specifically bind to bacterial cells. The stained samples are then passed through a flow cytometer, which uses lasers to detect and measure the fluorescence emitted by the stained cells. This method allows for rapid detection and enumeration of bacteria in water samples.

4. ATP (Adenosine Triphosphate) Testing: based on the measurement of ATP, which is present in all living cells, including bacteria. The water sample is mixed with a reagent that releases ATP from the bacteria, and then a luminometer is used to measure the emitted light. The amount of light detected is proportional to the concentration of bacteria in the sample. So, the bacteria do not emit light naturally. Instead, a chemical reaction is used to generate light when ATP is present in the sample. The ATP testing method involves the use of a reagent called luciferin-luciferase, which reacts with ATP to produce light. The reaction occurs when the reagent is added to the water sample, and if ATP is present (indicating the presence of living bacteria), the reaction generates a luminescent signal.

So, in summary, the ATP testing method relies on the chemical reaction between luciferin-luciferase reagent and ATP to generate light, which is then measured to determine the presence and concentration of bacteria in the sample.

#1 is the easiest to setup at home, #2 the hardest. #2 is the only 1 that tells you the specific bacterial species. In addition to the other 3, you can do a Gram-stain testing to detect whether it is Gram-positive or Gram-negative bacteria. #2 and #3 can also be used to detect viruses.

In a undergraduate biology major, #1 is typically done in general biology lab, #2 in genetics lab, and #3 in microbiology lab.

%i. Can a snake be poisoned by a snake of the same species, and can a frog be poisoned by a frog of the same species?

It is possible for a snake to be poisoned by a snake of the same species, but rare. Frogs however, cannot be poisoned by other frogs of the same species (unless they are poisoned by themselves).

That appears to depend on the species, and not all combinations are known. The most poisonous frog by far is the poison dart frog of South America, because of batrachotoxins. While a frog can have multiple chemical poisons on its skin, batrachotoxins are by far the most dangerous. But frogs don't actually manufacture batrachotoxins. They get that from their diet, from the beetles they eat. So frogs as pets loose their poisons, and frogs in other continents don't have them. In 2004, it was reported that Melyrid beetles (Choresine) were known to contain large amounts of batrachotoxin.

Around 136 µg is the lethal dose for a person weighing 150 pounds. On average 1 frog packs 1100 µg of batrachotoxin.

How does the toxin work? The batrachotoxin increases the permeability of the outer membrane of nerve and muscle cells to sodium ions. Thus it stops these channels within muscle fibers from closing normally, allowing a big inflow of sodium ions into the cell. This causes an irreversible electrical depolarization, blocking the nerve signals that would normally cause the muscle to relax, the muscle remaining contracted. Certain cells within the heart are very sensitive to this, resulting in heart arrhythmias, fibrillation and ultimately cardiac failure.

Why are the frogs immune to their poison? It seems that they have a modified sodium channel protein in their nerves and muscles, so the batrachotoxin cannot bind to a receptor.

The only natural predator of most of the poison dart frog family is the fire-bellied snake (Leimadophis epinephelus), which has developed a resistance to the frogs poison.

There have been cases, where a green tree frog ate a venomous coastal taipan snake (the 3rd most venomous snake in the world, Oxyuranus scutellatus), and the frog still survived, Feb. 2020.

Keelback snakes carry a genetic tolerance to cane-toad toxin, at least in small doses. In Australia, there are species of ants are among a few unaffected by the cane toads toxins. Grass snake (Natrix natrix) has been able to eat a green frog completely.

2 answers to this are the uromastyx and bearded-dragon (pogona). But not turtles. Turtles can be smelly. For example, can turtles be happy to see you when you come home? Generally no, unless you control their food supply and cause them to associate seeing you, with receiving food. So if they have excess food, then no. So what reptiles make the best pets? 2 factors I associate with this question, the 2nd being when it comes to their droppings, are any intelligent enough to do it in 1 place, or bury it with sand? And most importantly, if you're holding them, would they try to hold dropping it on you? Well, there's 2 sure things to say about that, and it's all reptiles/amphibians are ectotherms, so they don't eat much, and don't do droppings much, like once every 2 days or so. And the other is, if it is a factor, some reptiles can be herbivores. So no turtles are herbivores, and no alligators/crocodiles are herbivores, but some lizards are herbivores. So 1 of the 2 earlier mentioned, the uromastyx, are herbivores. Regarding alligators/crocodiles, for something that is a smaller version of them, are caiman, but still don't make good pets. Komodo dragons are not a type of alligator/crocodile, but are a type of lizard.

No. 1st and foremost, all pythons and cobras lay eggs (oviparous), while majority of snakes lay eggs, and some snakes give live birth (viviparous). So no oviparous can breed with viviparous.

Some examples of snakes that lay eggs are rat snakes, king snakes, and milk snakes.
Some examples of snakes that give live birth are garter snakes and boas (including anacondas).
Some examples of vipers that lay eggs are Bush vipers.
Some examples of vipers that give live birth are rattlesnakes and the European adder.

When they lay eggs, most snakes abandoned them beforehand, but most pythons and some cobras remain with the eggs until they hatch.

%i. Do most plants pollinated by animals, get pollinated by multiple species, or 1 species?

The idea that 1 species of plant only being pollinated by 1 species of an animal is rare. Examples of those include.

-The phlox flower in Texas, about 88% of the time are pollinated by a single butterfly species, battus philenor.
-The Chilean tomato Solanum chilense, found in the deep canyons of the Andean hills near the Atacama desert, are mainly pollinated by female solitary bee species Centris buchholtzi.

Flowers don't tend to be pollinated by different animal species. For example, bees tend to pollinate open-flowers, hummingbirds tend to pollinate tubular flowers, and moths tend to pollinate flowers with a narrow opening and wide tube.

-It's still not known who pollinates Greigia, in the South American Andes, though they are visited by wasps, as of 2024.

Both, but more commonly with low HDL. When triglycerides are high, HDL tends to decrease because triglyceride-rich particles interfere with HDL production and clearance. High triglycerides can cause the formation of small, dense LDL particles, which are more dangerous and atherogenic than larger LDL particles.

%i. If I eat fatty meat, will some of that fat become LDL, HDL, or triglycerides?

Yes, eating fatty meat can contribute to your LDL, HDL, and triglyceride levels, but the exact effect depends on the type of fat in the meat and how your body processes it. The fat in meat (mostly saturated fat) is broken down into fatty acids and glycerol during digestion. If you consume more calories than you burn, especially from fatty and carbohydrate-rich meals, these fatty acids can be converted into triglycerides and stored in fat cells or circulate in the blood.

Saturated fats found in fatty meats can raise LDL cholesterol levels by altering how your liver processes and clears LDL from the bloodstream. Saturated fats can also modestly increase HDL cholesterol in some individuals. However, the overall cardiovascular benefit of this increase is debated because the rise in LDL often outweighs the benefit of higher HDL.

Unsaturated fats (e.g., from fish, nuts, avocados, or and olive oil) improves HDL and lowers LDL, and generally helps decrease triglycerides, especially when it replaces saturated fat or refined carbohydrates in the diet. Unsaturated fats, particularly those high in omega-3s, are effective at lowering triglycerides and improving overall heart health.

Yes, when the body metabolizes excess sugar, it converts it into fat, which is stored as triglycerides in the blood. (High triglyceride levels are associated with an increased risk of heart disease.)

Sugar also decreases the good, HDL cholesterol. Because HDL cholesterol removes the bad LDL cholesterol, having less HDL is not good, so eating a lot of sugars increases the bad LDL cholesterol.

Fructose decreases HDL cholesterol more significantly than glucose. Studies comparing the effects of fructose and glucose on lipid profiles have consistently found that fructose consumption leads to greater increases in triglycerides and decreases in HDL cholesterol than glucose, particularly when consumed in large amounts.

Fructose increases triglycerides more significantly than glucose. This is due to differences in how these sugars are metabolized in the body: the liver converts excess fructose into fatty acids through a process called de novo lipogenesis. These fatty acids are then packaged into triglycerides and released into the bloodstream, leading to elevated plasma triglyceride levels.

%i. Is the glucose and fructose in ice cream and chocolate, different than the glucose and fructose found in fruit?

Fruit contains dietary fiber, which slows the digestion and absorption of sugars. This prevents rapid blood sugar spikes and reduces the load on the liver. Unlike fruit, ice cream and chocolate lack fiber, leading to rapid absorption of glucose and fructose into the bloodstream. Additionally, ice cream and chocolate contain saturated fats and, in some cases, trans fats, which can worsen the impact of the added sugars on cholesterol levels and triglycerides.

Saturated fats can raise LDL cholesterol and may contribute to higher triglycerides, especially if consumed in excess.