Lecture 1

Question 1

What is microbiology?

Answer 1

Study of organisms too small to see with the naked eye
(bacteria, archaea, fungi, protozoa)

(some can be seen with the naked eye)

Question 2

What are the 3 main domains of life according to Whittaker?

Answer 2

Monera: archaea and bacteria

Protista: eukaryotes

Crown taxa: very little of total diversity

Question 3

What are microbes?

Answer 3

Bacteria: very small 1-6um in size

Archaea: none pathogenic

Fungi

Protists: very diverse, most eukaryotes

Question 4

Where are microorganisms found?

Answer 4

Everywhere where temperature is less than 140 degrees

Question 5

How many microbial cells are there estimated to be on Earth?

Answer 5

4-6 X 10 ^30 cells

Question 6

Why are there so many microbes?

Answer 6

Rapid growth rate

Many chances of speciation through random mutation

Long evolutionary history

Every available niche is occupied with them

Question 7

How long ago was the estimate for multi-cellular organisms?

Answer 7

6-7 million years ago

Question 8

Through what 3 ways are nutritional categories based on?

Answer 8

Energy, electron donor and cell carbon

Question 9

What is a phototroph?

Answer 9

Gets energy from light

Question 10

What is a chemotroph?

Answer 10

Energy from chemical bonds

Question 11

What is an organotroph?

Answer 11

Organic compounds as e- donors

Question 12

What is a lithotroph?

Answer 12

Inorganic compounds as e- donors

Question 13

What are autotrophs?

Answer 13

CO2 as carbon source

Question 14

What are heterotrophs?

Answer 14

Organic carbon as carbon source

Question 15

What are prototrophs?

Answer 15

Synthesise all their own cellular components

(including ALL amino acids, nucleotides, vitamins)

Question 16

What is fastidious bacteria?

Answer 16

Need organic components, such as vitamins

Need organic components

(Humans)

Question 17

What are the primary nutrients of all organisms to survive?

Answer 17

Macronutrients: C, H, O, N, S, P, K, Mg, Na, Ca, Fe

Micronutrients: B, Cr, Co, Cu, Fe, Zn

Question 18

What is the carbon and energy source in E. Coli?

Answer 18

Glucose

Question 19

How is bacteria grown?

Answer 19

Asexual reproduction by binary fission

Cells double in size and split into 2

Exponential growth as 1 cells becomes 2, becomes 4

Question 20

What limits bacterial growth?

Answer 20

The environment

Cells too close together stop growing = carrying capacity

Question 21

How do microbes grow?

Answer 21

Assimilating and cell division

1. Lag phase: adapting to new conditions
2. Log phase: exponential growth
3. Stationary phase: limitation by nutrients, build up of waste that inhibits growth
4. Death

Question 22

How are the growth of microbes measured?

Answer 22

Cell number

Optical density

Fresh/ dry weight

Protein

DNA

Question 23

How can microbes be counted using total viable count?

Answer 23

Count colony forming units

Plate serial dilutions onto solidified media

Based on how dilute the sample is calculate total viable count

Question 24

What is the problem with the identification of microorganisms?

Answer 24

Limited morphological diversity

Most microbes look similar down a microscope

Must use range of methods for identification

Question 25

What are ways of identifying microorganisms?

Answer 25

Microscopy and staining

Growth on selective media

Testing substrate spectrum supporting growth

Testing of enzyme activities

Question 26

What is selective media when growing colonies of organisms?

Answer 26

Allows the growth of only some types of organisms

Question 27

What is differential media when growing colonies of organisms?

Answer 27

Allows the identification of organisms based on growth and appearance on that medium

Identify based on colour, shape etc.

Question 28

How can enzymes be tested using ApiZym?

Answer 28

1. Culture of organism grown
2. Cells resuspended in a buffer
3. Test wells are inoculated
4. Resulting colour in test strip is compared against database