BISC 1005- LECTURE 5 - Organisms that are Your Food: Prokaryotes and You

What is the definition of "Food"?

A nutritious substance that organisms ingest to maintain life.

Prokaryotes

Unicellular organisms that lack a membrane-bound nucleus or any other membrane-bound organelles.

What are the two main types of prokaryotes?

Bacteria and Archaea.

Describe Bacteria based on the slides

Among the first organisms ever, found nearly everywhere, and difficult to quantify the total number of species.

Fermentation

A biochemical process that gets energy from carbohydrates that does not require oxygen (anaerobic).

What types of organisms are mostly responsible for fermentation?

Bacteria and fungi, often together.

What does SCOBY stand for?

Symbiotic colony of bacteria and yeast.

What is the primary function of Lactic Acid Fermentation?

Takes glucose to make lactic acid to get energy without oxygen.

What is a natural characteristic of acid that results from lactic acid fermentation?

It has a naturally sour taste.

What historical human activity first harnessed lactic acid fermentation?

Early cheesemakers.

How does lactic acid fermentation occur in the human body?

Muscles produce lactate as a result of anaerobic metabolism during strenuous exercise.

What was a false belief regarding lactate production in muscles?

it causes soreness and cramping

What is another function of lactic acid fermentation in the body?

Maintains pH in the vagina.

Name an important common fermenting bacteria.

Lactobacillus (Lacto = lactic acid).

List other common fermenting bacteria mentioned besides Lactobacillus.

Lactococcus and Streptococcus.

Name some foods produced through Lactic Acid Fermentation.

Pickles, Yogurt, Cheese, Sour cream, Kimchi, Sauerkraut.

What common disease is associated with Streptococcus?

Strep throat (also meningitis, pneumonia, and necrotizing fasciitis).

Define "Disease."

A disorder of structure or function in an organism, especially one that has a known cause and a distinctive group of symptoms.

What types of organisms can cause disease?

Viruses, bacteria, fungi, protists, animals, plants.

Describe "Extracellular Bacterial Pathogens."

Multiply outside of your cells, excrete a substance (toxin) that causes harm, and can cause an imbalance in our microbiome.

Give an example of an Extracellular Bacteria.

Escherichia coli (E. coli).

How is E. coli commonly transmitted?

Raw or undercooked ground beef, unpasteurized beverages and dairy.

Describe "Intracellular Bacterial Pathogens."

They enter cells to survive, can excrete harmful substances, and kill your cells by causing them to burst (apoptosis).

Give an example of an Intracellular Bacterial Pathogen and associated foods.

Salmonella, associated with undercooked eggs, poultry, meat, contaminated fruits and vegetables, unpasteurized milk and other dairy products, and reptiles.

What are the two types of toxins discussed, and how do they differ in composition and release?

  ◦ Endotoxins: Mostly based on lipids and sugars, only released into the host if the bacterial cell ruptures (lysis).

    ◦ Exotoxins: Mostly proteins, produced and secreted as a defense.

What effect can endotoxins cause?

They can cause septic shock.

Give an example of an exotoxin.

Botulinum toxin.

What is the definition of an Antibiotic?

An antimicrobial substance active against bacteria.

What is an example of an antibiotic and its impact?

Penicillin, one of the most impactful discoveries in human history, which increased the life-expectancy of humans immensely.

What is a Microbiome?

A collection of microbes that live in or on your body.

How does the body contribute to microbiomes?

The body creates favorable environments for microbes, for example, the stomach develops a thick mucus for bacteria to insert into.

How do microbiomes contribute to digestion?

They are responsible for major aspects of digestion, such as the breakdown of the protein tryptophan, and make a molecule called IPA which protects neurons.

Name at least three ways to protect yourself from disease.

    ◦ Wash hands (after using the bathroom, public transportation, before preparing food).

    ◦ Never drink unpasteurized milk (or other dairy products).

    ◦ Take antibiotics only with bacterial infections and complete the regimen.

    ◦ Prepare food appropriately.

    ◦ Maintain a healthy gut biome to outcompete pathogenic bacteria (plenty of fruits/vegetables, fermented foods).

Name three methods for safely preparing food.

Pickling, canning, drying, salting, and using preservatives.

How does pickling help preserve food?

Vinegar kills microbes.

How does canning help preserve food?

Heat kills bacteria, and then the food is sealed.

How does drying help preserve food?

Microbes die without water.

What is an example of a food provided by prokaryotes, besides fermented foods like yogurt or cheese?

Soy sauce, which is a fermented soybean paste made with many species of bacteria.

How does salting help preserve food?

High salt concentrations prevent microbial growth.

You find a new bacteria, which you name Jeffgoldblumillus, within red blood cells. What kind of bacteria is this?

Intracellular bacteria.

You find a new bacteria, which you name Lauradernocus, free-floating in the blood. What kind of bacteria is this?

Extracellular bacteria.

Endotoxins

Mostly based on lipids and sugars, only released into the host if the bacterial cell ruptures (lysis).

Exotoxins

Mostly proteins, produced and secreted as a defense.

fermentation formula

glucose —> ethanol + carbon dioxide + energy