Ph 162A Lec 4: Prokaryotes

Front 1

prokaryotes consist of ____ and ____

Back 1

bacteria and archaea

Front 2

[Structure and Function of bacteria]

what is the size of bacteria?

Back 2

**size ranging from 0.2-2 microns (microscopic)

Front 3

There are four main shapes that bacteria have

Back 3

1. cocci (sgl. coccus) = round
2. bacilli = rod-shaped
3. spiral
4. square

Front 4

cocci has four different types of aggregates that they can form. what are they?

Back 4

1. diplococci = two cocci joined together
2. chains = severy cocci joined togehter at one point
3. tetrad = which consists of several cocci joined together (esp. 4 cocci arrangement in a square)
4. cluster = large number of cocci joined together (grape-looking)

Front 5

baccilli (rod-shaped) have two different types of aggregates:

Back 5

1. pairs (two bacilli joined)
2. chains (more than two joined)

Front 6

Bacteria can be pleomorphic, meaning

Back 6

they have several forms w/in the same culture

Front 7

a bacteria colony is a

Back 7

macroscopic mass of bacteria

Front 8

how do bacteria obtain thier nutrients?

Back 8

bacteria absorb the nutrients directly through their cell walls and plasma membrane

Front 9

Bacteria have the greatest diversity in types of metabolism, which can be used to classify bacteria into 4 nutritional types:

Back 9

**Autotrophs-- make thier own food by breaking CO2
**Heterotrophs

These two class are divided into four types:
1. photoautotrophs
2. photoheterotrophs
3. chemoautotrophs
4. chemoheterotrophs

Front 10

photoautotrophs or photoheterotrophs

Back 10

used light to make thier food

Front 11

chemoautotrophs and chemoheterotrophs

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use chemicals to make thier food

Front 12

which group contains most bacteria of public health concern?

Back 12

chemoheterotrophs

**the group that will learn the most

Front 13

Metabolic pathways of chemoheterotrophs depend on whether they are: (4 pathways)

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1. aerobic
2. microaerophilic
3.anaerobic
4. facultative

Front 14

aerobic

Back 14

they require oxygen for growth

Front 15

microaerophilic

Back 15

need reduced levels of oxygen for growth

Front 16

anaerobic

Back 16

they can grow in absence of oxygen

Front 17

facultative

Back 17

most flexible b/c they can survive either w/ or w/o oxygen

Front 18

Aerobic and anaerobic bacteria go through the process of _________

Back 18

glycolysis

Front 19

glycolysis

Back 19

the conversion of carbohydrates to pyruvate

Front 20

aerobic bacteria is more energy-rich process and generates ______ ATP and anaerobic bacteria generates ___ of ATP

Back 20

8

2

Front 21

Once you have pyruvate there are two different pathways that can happen. What are the pathway for aerobic bacteria and anaerobic bacteria?

Back 21

1. aerobic bacteria-- aerobic respiration and the Krebs cycle
**aerobic respiration generates 30 ATP

2. anaerobic bacteria-- fermentation **this patway lead to the production of carbon dioxide, alcohol, and hydrogen.
**energy poor pathway and 0 units ATP

Front 22

why is bacteria metabolism important to public health microbiologist?

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**different bacteria have diff. metabolic capacities-- can metabolic tests to identify what species of bacteria you have

**the end products of these bacteria can have industrial use

**biodegradation and bioremediation

Front 23

Bacteria aid their nutrition by secreting _______

Back 23

extracellular enzymes-- break down organic products in direct vicinity of the bacteria
**the breakdown of these substance allows the bacteria to absorb them

Front 24

Bacteria also generate _______ sustances

Back 24

antibiotic

Front 25

how does antibiotic substances help aid in nutrition?

Back 25

kill organisms around them so they are able to outcompete

Front 26

How do bacteria respond to their environment? or what are the sensory perception in bacteria?

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there are two ways:

1. chemotaxis-- involves chemoreptors this help aid the bacteria to move toward or away from a chemical.

2. phototaxis-- involves photoreceptors= moves toward or away from light

Front 27

Locomotion: name the 4 structures

Back 27

flagella, axial filaments, pilus (pl. pili), slime layer

Front 28

how are the bacteria flegella differ from eukaryotes (9+2)?

Back 28

In bacteria it contains three protein fibrils

**protein fibrils form a triple helix. These structures move the bacteria by rotating like a screw

Front 29

There are four types of flagella:

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1. monotrichous = one polar flagellum
2. lophotrichous = a group of flagella at just one pole
3. amphitrichous = sets of two polar flagella
4. peritrichous = flagella all over the bacteria

***these flagella are very long in comparison to the bodies of the bacteria

Front 30

axial filaments

Back 30

**simalar to the flagella
**only found w/ spiral bacteria
**not exposed outside the environment of the bacterium; contained w/in the cell wall
**wraps around the bacterium
**gives bacterium spiral shape
**allows undulating corkscrew motion

Front 31

pilus

Back 31

**pili extend from the surface of bacteria
**shorter than flagella
**composed group of proteins called pilin
**main function = attachment
**structure important in disease causation b/c they may specify binding of a bacterium to a human or cell

Front 32

slime layer

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*compose of substance called glycocalyx

*function like glue-- allow attachment to surface
*protect bacteria from enviromental conditions

Front 33

glycocalyx

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*this substance is secreted by bacteria
*found exterior of the bacteria
*composed of polysaccharides as well as glycoproteins

Front 34

Bacteria: protection (3)

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1. capsule
2. endospores
3. cell wall

Front 35

What is CAPSULE?

Why is it important?

Back 35

**thicker more complex version of glycocalyx

**important b/c it can protect parasitic bacteria from the WBC of the human or animal that is infected
**keeps the bacteria from being engulfed and destroyed by WBC

Front 36

ENDOSPORE what is it? how is this structure important in protection?

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**thick wall and chemically diff. from bacterial cell wall
**protect bacteria from heating and drying; harsh environment

**e.g Bacillus anthracis-- the bacteria responsible for anthrax

Front 37

cell wall how does it protect bacteria?

Back 37

**surrounds the bacterium and protects it from osmotic stress

Front 38

Bacteria can be group into two different ways:

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1. gram positive-- the PM is surrounded by a thick layer of peptidoglycan

2. gram negative-- there's another membrane layer (outer membrane) of the thin layer of peptidoglycan

Front 39

what is peptidoglycan

Back 39

a carbohydrate unique to bacteria

**this carbohydrates consists of patterns and chains of N-acetylmuramic acid (NAM) and N-acetylglucosamine (NAG) sugars.
***these sugars are what make up the bacterial cell wall and they are differ for gram + and gram -

Front 40

[Classification] the bacterial technique was developed by ____ in 1890

Back 40

Hans Gram

Front 41

Give the steps of the bacterial staining technique:

Back 41

1. Stain-- crystal violet is added
2. Mordant (iodine) is added-- this reacts w/ stain to for insoluable precipitate-- fix stain w/in bacteria
3. decolorize the bacteria-- alcohol is added

**for gram negative the alcohol changes the lipids and loosens up bacterial cell walls loosing the purple color.

4. Counter stain-- safranin (red colored stain) is added. Gram negative becomes red

Front 42

Some bacteria will not stain with the gram stain what is another type of stain you can use?

Back 42

acid-fast stain

Front 43

why does some bacteria do not stain w/ Gram stain?

Back 43

because they have an exterior that is full of waxy lipids (extracellular waxy layer) that prevent the dye from entering

e.g Mycobacterium-- cause tuberculosis

Front 44

what is the heating process of the acid-fast staining

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1. Heating is done during the primary staining.
2. acid-fast if it retains the stain following decolorization. Non-acid-fast bacteria will wash free of the first dye and take on the counter-stain

Front 45

Bacteria reproduction methods: (5)

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1. binary fission
2. parasexual methods
3. transformation
4. conjugation
5. transduction

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binary fission

Back 46

**Asexual
**bacterium replicates its genetic information and divides in half
**no genetic diversity

Front 47

what is parasexual methods

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**increase genetic diversity
**bacteria contain circular chromosomes that contain their genetic material (can also contain plasmids)

Front 48

what is plasmid?

Back 48

independent structures, usually circular, that are not a part of the chromosomes but contain genetic material

Front 49

What are the three methods for parasexual?

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1. transformation
2. conjugation
3. transduction

Front 50

transformation

Back 50

**direct uptake of DNA by the bacteria. How this works?

1. as a bacteria is dying it releases its genetic material: chromosomes and plasmids.
2. This material can then be taken up by neighboring bacteria.
**If it is a piece of chromosome, it will replace the portion that is similar in the bacterium that it enters.

Front 51

Conjugation

Back 51

**you have an exchange of genetic material b/w two living cells: a donor and a recipient bacteria

1. the donor bacterium makes a structure know as a sex pilus
2. the genetic material (chromosome or plasmid) can be passed through the sex pilus from the donor to the recipient cell.
3. During this transfer, the material is usually replicated so that the donor would not lose any of its own generic material

Front 52

transduction

Back 52

**viral DNA from a bacteriophage into the bacterial chromosome
**how does it works?

1. bacteriophage attaches to the bacterium and injects its genetic material, which can then be integrated into the bacterial chromosome.
2. When the bacterial chromosome replicates, it is now also replicating viral DNA. This allows the bacterium to make more bacteriophages if that is what the DNA codes for.

** Sometimes the DNA can be taken up by the virus, and when they infect a new bacterium, they not only inject viral material, but also material from the other bacterium.

Front 53

bacteriophages

Back 53

are viruses that specifically infect bacteria

Front 54

what are sterols?

Back 54

organic compound w/ alcohol, like glycerol

Front 55

[effects of bacteria on Humans] Beneficial

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**they are metabolizers: these pathways can recycle elements and release important compound like N and C

**important for the processes of biodegradation and bioremediation

**bacteria can be endosymbiotic-- that is when they are living w/in another cell e.g mitochondria and chloroplasts (originally bacteria)

Front 56

what is bioremediation?

Back 56

improvements in the environment

Front 57

biodegradation

Back 57

breaking things down, like garbage

Front 58

endosymbiosis

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bacteria can live in our gut. they help us break down food or protect us from pathogenic bacteria

Front 59

what are the industrial uses of bacateria? (5)

Back 59

1. antibiotics
2. food processing e.g yogurts for example u see Lactobacillus, probiotics
3. research and clinical reagents
4. useful in recombinant DNA-- simple organism simple to study
5. food sources

Front 60

What is another good aspects of bacteria to human?

Back 60

disease prevention
**the bacterial inside us help to outcompete dangerous bacteria that might be introduced

Front 61

Bacteria: Detrimental

Back 61

1. food spoilage-- food contamination and outbreaks
2. disease causation-- most human infectious diseases are caused by bacteria

Front 62

[prokaryotes] What are the three bacteria division we have to know?

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1. Gracilicutes
2. Firmicutes
3. Tenericutes

Front 63

what is one Archaea group we have to know?

Back 63

mendosicutes

Front 64

Division: Gracilicutes

1. cell wall/membrane
2. morphology
3. nutrition
5. examples of bacteria in this division

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1. Gram +/no membrane sterols
2. cocci, bacilli, spiral
3. photoautotrophic, photoheterotrophic, chemoheterotrophic
4. all photosynthesizing bacteria; many human pathogens including Chlamydia, Rickettsia

Front 65

Division: Firmicutes

1. cell wall/membrane
2. morphology
3. nutrition
5. examples of bacteria in this division

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1. Gram +/no membrane sterols
2. cocci, bacilli
3. chemoheterotrophic
4. many human pathogens

Front 66

Division: Tenericutes

1. cell wall/membrane
2. morphology
3. nutrition
5. examples of bacteria in this division

Back 66

1. no cell wall membrane has sterols
2. pleiomorphic
3. chemoheterotrophic
4. human pathogens (genus Mycoplasma)

Front 67

Division: Mendosicutes

1. cell wall/membrane
2. morphology
3. nutrition
5. examples of archaea in this division

Back 67

1. cell walls w/o peptidoglycans/ nomembrane sterols
2. cocci, bacilli, square
3. chemoautotrophic, chemoheterotrophic
4. no human pathogens; most members are environmental, living in extreme conditions