Lecture 2 Flashcards Preview

Microbiology > Lecture 2 > Flashcards

Flashcards in Lecture 2 Deck (71):
0

What is a flagellum?

Structure that allows for motility in some orgs

1

3 patterns of flagella distribution in a cell

Polar- at one end
Peritrichous- all over
Lophotricious- multiple at one end

2

Regardless of distribution, flagella use a lot of ________ which will cause what to happen?

H+, will deplete H+ that are in H+ gradient, decreases ability of cell to produce ATP

3

Describe the speeds of a flagellum

There are no speeds and you cannot turn it off

4

Because of massive H+ demand of flagella, what does cell do?

It can "drop" flagella

5

Spore details

Highly resistant to temp, desiccation, chemicals, etc.
Form of survival
Occurs in response to stress
Sporulating cell becomes the spore, 1 cell becomes 1 spore
No chromosomal replication, original chromosome gets packaged into the spore
Not metabolically active

6

Layers of prokaryotic spore

Exosporium
Spore coat
Cortex
Core wall and core

7

Exosporium

Sticky, more likely to be transported, helps with dispersion, can have different chemical compositions

8

Spore coat

Contains enzymes that will help with germination

9

Cortex

Thick layer of peptidoglycan
ONLY GRAM + can sporulate (not all do)

10

Core wall and core

-high conc. of Ca2+ and dipicolinic acid (not found in any other biological system) (help with resilience but don't know how)
- high number of ribosomes

11

Structure of flagellum

Basal body
Mot proteins
Fli proteins
Support rings embedded in cell layers, anchored in cell wall
Extending out from cell wall or outer membrane, a hook structure
Helical in shape

12

Basal body

Flagellum engine located just inside of cell membrane so it can turn flagellum itself and have access to H+

13

Mot proteins

Rotate flagellum

14

Fli proteins

Determines direction of rotation
Counter clockwise: forward (run)
Clockwise: tumble

15

Chemotaxis

Motile cells response to environmental cues
Mostly applies to flagellate motility
Response to enviro cues via series of runs and tumbles; length of runs increase in detection of nutrients

16

Examples of taxis

Chemotaxis: response to chemicals
Thermotaxis: response to temp
Phototaxis: response to light

17

Surface area to volume ratio

Based on sphere
3/r
Larger cells - less metabolically efficient
Prok. More efficient than euk. Metabolically

18

Definition of metabolism

All chemical processes in a cell
2 components:
1. Anabolism: biosynthesis (building cellular materials - requires energy
2. Catabolism - degradation (releases energy)

19

Energy molecules in a cell

ATP- assists for breakdown and work
NADPH- used in biosynthesis

20

ΔG

Amount of free energy associated with substrate
(-) exergonic - readily give up e
(+) endergonic
Example: ATP ΔG=-7.3 exergonic, used in endergonic reactions

21

Eo = reduction potential

(-) likely to release e
(+) likely to accept e

22

Energy source classifications

Chemoorganotroph- use organic C for energy (eg. Glucose)

Chemolithotroph- use inorganic electron donors for energy (eg. H, N, S, Fe

23

Carbon sources

Heterotroph- use organic C as carbon source (eg. Glucose)

Autotroph- use inorganic C as carbon source (eg. CO2)

24

What are the different parts of respiration

Glycolysis, pentose phosphate pathway (PPP), TCA cycle, electron transport chain (ETC)

25

Two forms of respiration

- aerobic: use O2 as terminal electron acceptor
- anaerobic: use something other than O2 as TEA (eg. N, S, Fe, etc.)

TEA other than O2 has slower growth

26

Total energy balance from glycolysis in aerobic respiration

2 ATP
2 NADH --> 6 ATP

8 total

27

Total energy balance from TCA cycle in aerobic respiration

8 NADH---> 24 ATP
2 FADH2---> 4 ATP
2 GTP ---> 2 ATP

30 ATP

28

Total ATP produced in aerobic respiration

38 ATP

29

Pathways in fermentation

Glycolysis, TCA cycle, PPP, fermentation steps

30

Fermentation steps

Use NADH
Use pyruvate from glycolysis
End products include alcohols and organic acids

31

Fermentation

Anaerobic metabolism
No ETC; no H gradient, no ATP production via oxidative phosphorylation

32

Limitations to fermentation

No oxidative phosphorylation so produce very little ATP
Make end products that are toxic to the cell that generated it
Reduction in bio synthetic intermediates

33

Glycolysis intermediates

Glucose-6-phosphate
Fructose-6-phosphate
Glyceraldehyde 3-phosphate
Pyruvate

34

TCA cycle intermediates and products

Intermediates:
Acetyl CoA
α-ketoglutarate
Oxaloacetate

Products
4 NADH/pyruvate
1 GTP
1 FADH2
Biosynthetic intermediates
CO2

35

Pentose phosphate pathway

Starting substrate is glucose-6-phosphate
Produces NADPH
Produces Biosynthetic intermediates

Intermediates
Glyceraldehyde-3-P
Fructose-6-P
Pyruvate

36

Quinone

Transport electrons

37

What happens as electrons move down the electron transport chain?

H+ pumped into periplasmic space

38

What is the terminal electron acceptor in aerobic respiration?

O2

39

What is the terminal electron acceptor in anaerobic respiration?

Something other than O2

40

What is the initiator of the electron transport chain in respiration?

NADH dehydrogenase- releases H+ and electrons

41

Where is the ATPase?

In the cell membrane, has 30 degree rotations

42

Fermentation steps

Purpose: recycles NADH into NAD+
Unless genetically modified orgs have several pathways
Toxic end products eg. Ethanol, lactic acid, propionate
Uses pyruvate

43

Organisms that use chemolithotrophy are

Chemolithoautotrophs: use inorganic source of electrons and CO2 as source of C

44

Do all chemolithotrophs use chemolithotrophy?

No, some use photosynthesis

45

Where does the inorganic e donor donate it's es to in chemolithotrophy?

Directly to the ETC, don't need to be shuttled

46

How are Biosynthetic intermediates made in chemolithotrophy?

Turn CO2 into organic C by the Calvin cycle or reverse TCA cycle

47

Reverse TCA cycle

3CO2---> pyruvate
Requires energy from NADH or NADPH

48

Calvin cycle

6CO2 ---> fructose-6-PO4
Requires 12 NADPH and 18 ATP per cycle

49

A species will use _____ reverse TCA or Calvin to fix CO2

Either, they do not flip flop

50

Calvin cycle produces _____, which can go into:

Fructose-6-PO4---> glycolysis--->pyruvate--->TCA cycle

Fructose-6-PO4--->glucose-6-PO4--->PPP--->NADPH

51

Reverse TCA cycle produces _____, which can go into:

Pyruvate---> TCA cycle

Pyruvate--->reverse glycolysis--->glucose-6-PO4--->PPP--->NADPH

52

Chemolithotrophy components

Glycolysis, TCA, PPP, ETC, and Calvin or reverse TCA to fix CO2

53

In aerobic chemolithotrophy what is the TEA?

O2

54

In anaerobic chemolithotrophy what is the TEA?

Something other than O2

55

What is the enzyme responsible for incorporation of CO2 into the Calvin cycle?

RubisCO

56

Calvin cycle input needs

6CO2
12 ATP
12 NAD(P)H
6ATP

57

Calvin cycle product

Fructose-6-phosphate

58

In oxygen if photosynthesis what is each photo system?

An electron transport chain

59

What is the electron donor in oxygenic photosynthesis?

H2O

60

What role does light play in photosynthesis?

Stimulator, does not provide energy; it drives energy production

61

Oxygenic photosynthesis has what that makes it have a stronger gradient?

Photo system I is a second pathway that makes NAD(P)H; producing twice as strong of a gradient

62

Where are the photosystems located?

Cell membrane because goal is to build H+ gradient

63

There are more gram ___ that use photosynthesis, why?

Negative because cell wall doesn't retard light as much as a gram positive cell wall would

64

Anoxygenic photosynthesis uses what as an electron donor and where is it donated to?

Something other than H2O eg. H2S, Fe2+ and to a cytochrome

65

Anoxygenic photosynthesis uses what to drive the reverse e flow to make ____?

ATP, NADPH

66

In anoxygenic potosynthesis, NAD(P)H is:

Made but is not the TEA

67

What organisms use photosynthesis for metabolism?

Chemolithoautotrophs: use inorganic e donor (H2O) and CO2 as C source

68

How do orgs that use photosynthesis fix CO2?

Reverse TCA
Calvin cycle

69

What are the 2 types of photosynthesis?

Oxygenic: produces O2; uses H2O as donor
Anoxygenic: O2 not produced; H2O not e donor but stil inorganic donor (can only be bacteria and archea)

70

What pathways do all of the metabolisms include?

Glycolysis, PPP, TCA and all but fermentation have an electron transport chain