Module 1: Topic 4-5 Flashcards Preview

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Flashcards in Module 1: Topic 4-5 Deck (24)
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1

What are Properties of ALL cells?

- Metabolism (take up nutrients, transform and then expel waste)
- Growth (nutrients taken up - converted to new cell materials to form new cells)
- Evolution (Cells evolve to display new properties)

2

What are Properties of SOME cells?

- Differentiation (some cells form new cell structures e.g. spores)
- Communication (via chemical messengers(
- Genetic Exchange
- Motility (self propulsion)

3

Differences between Prokaryotes and Eukaryotes

Prokaryotes
- No Nucleus
- Nearly all have cell wall
- No organelles

Eukaryotes
- Some have cell walls, some don't
- Membrane bound nucleus
- Generally larger than prokaryotes

4

What are the different shapes Prokaryotic cells form?

- Cocci - sphere-shaped
- Rod/Bacilli - cylinder shaped
- Spiral/Spirilla - curved rods to tightly coiled bacteria
- Appendaged Bacteria - cells have extensions like stalks or hypha
- Filamentous - connected chains of cells (usually cocci or bacilli)
- Other: square/star sharped, are very rare

5

Most common prokaryotic shape

Bacilli/Rod shaped

6

How do Cocci cells arrange themselves to be easier to ID?

Arrange over varying numbers of planes
- Dip- is 1 planes
- Strep- 1 planes in a chain
- Tetrad - 2 planes
- Some are random such as staphylococci

7

Normal measurements of prokaryotes

0.5-2 um diameter and 1-5 um in length

8

What is the advantage of smaller size?

Microbes absorb nutrients through their cell membrane - smaller cells have a greater surface to volume ration and therefore absorb more nutrients proportional to their demand

9

Where do Microbes Live?

Everywhere
(water, land, extreme environments and in gut flora of animals)

10

Describe the properties in water that different prokarotes thrive in

Bacteria - more prevalent close to surface where O2 and Temperature are higher

Archaea - deeper where there is lower temp/O2, use H2S for energy instead of heat/light

11

Where are microbes found in land?

In sediments and deep subsurface
- esp in organic material in fertile soil and sediments
- Near Groundwater usually

12

What role do microbes play in normal gut flora?

Important for immune development, behaviour, health and disease prevention

13

How do we know where microbes live?

Sample testing

14

Microbes live in communities and undergo symbiotic interactions - describe these interactions

Positive:
- Mutualism
- Synergism
- Commensalism

Negative
- Parasitism
- Predation

15

Describe the symbiotic relationship: Mutualism

Both require and benefit

e.g. lichen, gut microbiom

16

Describe the symbiotic relationship: Synergism

Both benefit but don't require
e.g. skin microbiota

17

Describe the symbiotic relationship: Commensalism

Only one benefits

e.g. cross-feeding

18

Describe the symbiotic relationship: Predation

E.g. protozoa/bacteria
Absorbs other microbe for nutrients, killing it

19

Describe the symbiotic relationship: Parasitism

E.g. viruses/pathogens
Uses host cell for functions

20

When did first prokaryotic micro organisms evolve?

3.8 billion years ago

21

What did the Miller-Urey experiment demonstrate?

That early earth atmosphere (reducing and lacking O2) was an environment that organic molecules (amino acids, sugars, nucelotides and fatty acids) could be synthesised in
- In presence of heat and electricity (high energy)

22

What is the RNA theory for the origin of Life?

First self-replicating organisms thought to be made of RNA

23

Describe the RNA theory for the origin of life (sequence of events)

RNA formed from pre-biotic compounds --> riboenzymes could self-replicate and carry out reactions (catalysis) --> became enclosed in lipid vesicles
--> Amino acids entered vesicles that enclosed RNA --> Proteins synthesised --> carry out catalytic activity in early cells --> more proteins --> more reactions
--> RNA eventually developed into DNA

24

What is the subsurface hypothesis or the origin of life?

Life likely developed subsurface