Unit 1: Chapter 1 Microbes Shape our History

Question 1

Microorganisms

Answer 1

Organisms that are too small to be seen with the naked eye; require microscope

Question 2

What are the two cell types?

Answer 2

Prokaryotic and eukaryotic

Question 3

Prokaryotes

Answer 3

• Free floating genetic material (cytoplasm)
• NO organelles, so NO compartment function
• Tend to be smaller

Question 4

T or F: Archaea causes disease

Answer 4

False

Question 5

Eukaryotes

Answer 5

• Has a nucleus (contains genetic material)
• Has organelles; allows for compartmentalized functions
• Generally larger
• Reproduce using mitosis and meiosis

Question 6

T or F: Viruses are acellular

Answer 6

True: viruses are NOT made up of cells

Question 7

What are virus encased in?

Answer 7

Protein coat

Question 8

What do viruses relay on?

Answer 8

They rely on a HOST CELL for things such as ATP, reproduction, etc

Question 9

Who built the first compound microscope?

Answer 9

Robert Hooke; came up with the term cells

Question 10

What did Anton Van Leeuwenhoek do?

Answer 10

He observed bacteria with a single lens microscope and was the first person able to see bacteria

Question 11

What are some roles of microbes in our life?

Answer 11

• Decompose organic waste
• Ecosystem producers by photosynthesis
• Produce things like ethanol and acetone
• Fermented foods; vinegar, cheese, bread
• Produce products used in manufacturing and disease treatment

Question 12

T or F: MOST microbes are pathogenic (disease causing)

Answer 12

False; there are very few microbes that are pathogenic

Question 13

Did the first prokaryotes that appeared use oxygen?

Answer 13

No. The first prokaryotes appeared ~ 3.8 billion years ago and they were anaerobic (did not use oxygen). This is because there was no oxygen around at the time.

Question 14

What happened when eukaryotes appeared 2.8 billion years ago?

Answer 14

Something called Cyanobacteria. This is oxygenic photosynthesis which is “oxygen produced photosynthesis”. This new oxygen killed a lot of previous organisms that were anaerobic.

After this, many things began to appear such as reptiles, bugs, mammals, and eventually humans.

Question 15

What did Lynn Margulis propose?

Answer 15

That the first energy-converting organelles of eukaryotic cells (mitochondria and chloroplasts) evolved as a result of endosymbiosis (inside mutualistic relationship); Endosymbitotic Theory

Question 16

Endosymbiotic Theory of mitochondria and chloroplast

Answer 16

Lynn Margulis proposed that eukaryotes evolved by merging with bacteria to form composite cells by intracellular endosymbiosis, in which one cell internalizes another that grows within it; a single organism who was formally independent is now incapable of existing independently

Respirng bacteria (Proteobacteria) ((similar to E. Coli)) was engulfed by pre-eukaryotic cells where they evolved into mitochondria, the eukaryotes energy-generating organelle.

A phototroph related to Cyanobacteria was taken up by a eukaryote, giving rise to chloroplast of phototrophic algae and plants.

Proved because the DNA sequence was very similar of the origin (respiring to mitochondria; phototroph to chloroplast); both organelles contain circular molecules of DNA which is similar to those of modern bacteria.

Question 17

How do you classify microorganisms?

Answer 17

Microbes are classified as members of a species according to a shared set of genes and traits

Question 18

How do you name microorganisms?

Answer 18

The genus is capitalized; the specific epithet is lowercase

After the first use, the scientific names can be abbreviated with the first letter of the genus and the specific epithet

Scientific names are italicized or underlined (if written)

Question 19

Spontaneous generation

Answer 19

The theory that living microbes can arise spontaneously WITHOUT parental organisms

Basically thought that life comes from thin air; was later proved wrong

Question 20

Biogenesis

Answer 20

The hypothesis that living organisms arise from preexisting life; the concept that cells do have parents

Question 21

Spallanzani’s sealed flask experiment

Answer 21

Opponents argued that since the flask was sealed, oxygen was not present and microbes could not grow; they believed that O2 is what caused microbes to grow.

Question 22

Pasteur’s “swan neck” flask

Answer 22

Pasteur’s “swan neck” flask allowed for oxygen to enter, but the curves in the flask trapped bacteria and dust which kept the boiled contents free of microbes.
When you break the swan neck and expose the contents to the open air, you will notice that microbial growth will occur. This proves that oxygen is not the cause for microbial growth rather its whatever contents is in the air.

This was the experiment that proved spontaneous generation to be false.

Question 23

Who is considered the “Savor of the Mothers”?

Answer 23

Ignaz Semmelweis

Question 24

What did Ignaz Semmelweis (1847) do?

Answer 24

Semmelweis ordered doctors to wash their hands with chlorine.

Question 25

How did Semmelweis find that washing hands lowered mortality rate?

Answer 25

He separated two wards to deliver babys to see if mortality rates change. The first ward was doctors and the 2nd ward was midwives. He noticed that with **doctors, they had a higher mortality** rate compared to midwives, and one big difference he noticed is that **doctors did autopsies** while midwives did not. Doctors would do autopsies and go straight to delivering babies without changing their clothing or washing their hands and this would cause disease to spread. Once doctors started washing hands, mortality rate dropped.

Question 26

Did doctors listen to Semmelweis when he ordered doctors to begin washing their hands with chorline?

Answer 26

**NO**; many doctors still refused and thought he was crazy, so he was shunned and sent to a mental institution

Question 27

Who began to use antiseptic agents (ie. carbonic acid) to treat wounds and surgical instruments after noting that half of his amputee patients died of sepsis?

Answer 27

Joseph Lister (1867) (this is when cleaning began to catch on)

Question 28

What did Robert Koch do?

Answer 28

He developed the first scientific method for establishing the microbial cause of a disease The first to connect a specific disease with a specific microbe; diagnosis for a patient requires evidence that a given microbe causes that disease so this is huge for the world of medicine

Question 29

The Koch Postulate

Answer 29

1. The microbe is found in all cases of the disease, but is absent from healthy individuals. 2. The microbe is isolated from the diseased host and grown in pure culture. 3. When the microbe is introduced into a healthy susceptible host, the same disease occurs. 4. The same strain of microbe is obtained from the newly diseased host.

Question 30

Is the Koch Postulate still used today?

Answer 30

Yes and no. What he found is not always the case with all diseases. Ex. *E. coli* is part of our natural microbiome, but if it gets in the wrong place, then it become bad. Ex 2. In many cases, you can't grown microbes in a lab. Ex 3. The same disease doesn't always occur when the microbe is introduced to other individuals (ie. covid and flu) **Nowadays we look at the genetic material of the virus rather than growing it.**

Question 31

Variolation vs Vaccination

Answer 31

Variolation is when the same pathogen is introduced into the person in small amounts. Vaccination is when an attenuated (weak) version of the pathogen is introduced into the body.

Question 32

Who deliberately infected patients with matter drawn from cowpox lesions and is known as the “Father of Vaccines”?

Answer 32

Dr. Edward Jenner

Question 33

What is an antibiotic?

Answer 33

A “magic bullet" that only kills the microbe, but leaves the host unharmed

Question 34

Who discovered the first antibiotic and how?

Answer 34

Alexander Fleming He came back from vacation and found mold growing on a petri dish of Staphlyococcus bacteria. He noticed the mold was preventing surrounding bacteria from growing, and identified that the mold produced a self-defense chemical that can kill bacteria. He made this observation, but stopped there with it

Question 35

What did chemist Florey and Chain do?

Answer 35

They took Flemings observations and purified the chemical the mold produced and used it to treat patients who were dying of bacterial infections. (penicillins) Mass production of penicillins gave birth to the pharmaceutical industry