Dr. Yesilkaya Lecture 2

Question 1

Who invented the first microscope and when?

Answer 1

In 17th century, Robert Hooke developed instruments with lower magnifications (30X).

Question 2

Who developed and improved the first microscope?

Answer 2

Anton van Leeuwenhoek (1632 – 1723): Developed and improved microscope (magnification: 200X),

Question 3

Describe some of the conceptual drawbacks of microbiology when it was first theorised?

Answer 3

1) life arises de novo from inanimate objects, if you leave a peice of meat maggots will appear, therefore this is where life comes from.
2) Proponents of the theory: Needham and Buffon around 1745, H. Charlton Bastian (d. 1915)

Question 4

Describe redis experiments

Answer 4

Microscopic vs Macroscopic (maggots)

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Question 5

Describe Pasteur’s experiments and what they showed

Answer 5

Swan necked flask

Question 6

Describe what Spallanzani experiments showed?

Answer 6

a sealed flask of meat broth sterlized by by boiling failed to grow microbes

Question 7

Describe and explain some of the tools and concepts of microbiology that helped the progression of microbiology

Answer 7

Further detail needed to be added from notes
Angelina and Walther Hesse>>agar
Julius Richard Petri
Hand Christian Gram
Pure culture and growth conditions
Robert Koch’s: germ theory of disease
Specific microbe causes a disease

Question 8

Outline some of the challenges of microbiology.

Answer 8

Challenges
Infectious diseases (antibiotic resistance, diagnostic, control of outbreaks)
Environmental issues (removal of pollution, recycling)
Industrial applications (creation of strains with high product yield and quality)

Question 9

Outline some of the opportunities of microbiology

Answer 9

Opportunities
Big data generation
Increased processing power
Single cell technologies
High power microscopy

Question 10

What is anabolism

Answer 10

To obtain the physical building blocks for the generation of cellular components

Question 11

What is Catabolism

Answer 11

To extract energy to do cellular work

Question 12

Are Catabolism and anabolism linked

Answer 12

Yes- when both work together- metabolism

Question 13

Why is it important to know nutritional needs of bacteria?

Answer 13

Optimise conditions to propagate them in vitro for research
To find out critical metabolic processes and target them for antibiotic and vaccine development
To improve product yield and quality relying on various metabolic pathways

Question 14

What nutrients do bacteria need to grow?

Answer 14

Macronutrients: Carbon, oxygen, hydrogen, nitrogen, sulfur, and phosphorus
Macronutrients are found in organic molecules: proteins, lipids, nucleic acids, and carbohydrates and form the large structural frame of a microbe
Other Macronutrients: Potassium, calcium, magnesium and iron: required for enzyme activity, ATP synthesis, membrane function
Micronutrients: Manganese, zinc, cobalt, nickel: support to growth, act as co-factor for enzymes, required for maintenance of proteins.

Question 15

What are the three main components for growth?

Answer 15

Energy source, Electron source and carbon source for biomass.

Question 16

What are the different types of Energy sources?

Answer 16

Photo-: Light absorption captures energy.

Chemo-: Chemical electron donors are oxidized

Question 17

What are the different types of electron sources?

Answer 17

Litho-: Inorganic molecules donate electrons.

Organo-: Organic molecules donate

Question 18

What are the different types of carbon sources?

Answer 18

Auto-: CO2 is fixed and assembled into organic molecules.

Hetero-: Preformed organic molecules are acquired from outside, broken down for carbon, and the carbon reassembled to make biomass.

Question 19

How are microbes classified

Answer 19

on the basis of their carbon and energy acquisition

Question 20

What do autotrophes do

Answer 20

. Build biomass by fixing CO2 into complex organic molecules. :

Photoautotroph. Photoautotrophs generate energy through light absorption by the photolysis (light-activated breakdown) of H2O or H2S.
Chemolithoautotroph. Produce energy from oxidizing inorganic molecules such as iron, sulfur, or nitrogen.

Question 21

What do heterotrophs do

Answer 21

Break down organic compounds from other organisms to gain energy and to harvest carbon for building their own biomass:

Photoheterotroph: Obtain energy from the catabolism of organic compounds and through light absorption.
Chemoheterotroph. Obtain energy and carbon for biomass solely from organic compounds, and is commonly called just heterotrophy.

Question 22

How do microbes build biomass through auto and heterotrophy ?

Answer 22

The carbon cycle requires both autotrophs and heterotrophs which builds biomass

Question 23

What are the environmental determinants of microbial growth?

Answer 23

Temperature
Pressure
pH 
Osmolarity 
Oxygen

Question 24

At what temperature is growth possible for a Hyperthermophile?

Answer 24

above 80°C

Question 25

At what temperature is growth possible for a Thermophile?

Answer 25

between 50°C and 80°C

Question 26

At what temperature is growth possible for a psychrophile?

Answer 26

below 15°C

Question 27

At what temperature is growth possible for a Mesophile?

Answer 27

between 15°C and 45°C

Question 28

How do microbes grow at low temperatures?

Answer 28

1) The proteins of psychrophiles are more flexible than those of mesophiles and require less energy (heat) to function. BUT at high temperature, they denature quickly.
2) Psychrophile membranes are more fluid at low temperatures due to a high unsaturated fatty acid content.
3) Bacteria and archaea that grow at 0°C in glaciers also contain antifreeze proteins and other cryoprotectants (such as trehalose) that can depress the freezing point by 2°C.

Question 29

How do microbes grow at high temperatures?

Answer 29

1) Enzymes do not unfold, hold their shape at higher temperatures, because they contain relatively low amounts of glycine, a small amino acid that contributes to an enzyme’s flexibility (glycines do not contain side chains, so they cannot form stabilizing intramolecular bonds).
2) The amino termini of proteins in thermophiles are “tied down” by hydrogen bonding to other parts of the protein, making them harder to denature.
Chaperone proteins that help refold other proteins as they undergo thermal denaturation.
3) Genomes are packed with DNA-binding proteins that stabilize DNA, and have tightly coiled DNA.
The membranes of thermophiles “glue” together parts of the two hydrocarbon layers that point toward each other, making them more stable. They do this by incorporating more saturated linear lipids into their membranes
4)The membranes are lipid monolayers, not bilayers» resist heat, because long hydrocarbon chains directly tether glycerophosphates on opposite sides of the membrane. The chains do not contain fatty acids, but are made of isoprene units bonded by ether linkages to glycerol phosphate.

Question 30

At what pH do Alkaliphiles grow?

Answer 30

growth above pH 9

Question 31

At what pH do Neutralophile grow?

Answer 31

growth between pH 5 and 8

Question 32

At what pH do Acidophiles grow?

Answer 32

growth below pH 3

Question 33

How can acid production be controlled?

Answer 33

by buffers, imfortant during fermentation and metabolism

Question 34

What can lead to faster rates of decline in bacterial growth?

Answer 34

high pH and low temp