Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

microbes to medicine > Lecture 8 - principles of bacterial aerobic cellular respiration > Flashcards

Lecture 8 - principles of bacterial aerobic cellular respiration Flashcards

1
Q

Growing cells

A

new biomass dominates total energy requirements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Non growing cells

A

repair and replacement is all that is possible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Proton motive force

A

gradient of both concentration and charge that is required even during non growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

3 key molecules that participate and determine the majority of catabolic and anabolic reactions

A

ATP, NADH and NADPH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Active vs passive transport

A

Active transport accumulates substrates rapidly and against concentration gradient, but has a higher energy cost than passive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

3 transporters are

A

ABC family, MFS family, group translocation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Protein synthesis has the highest…

A

Protein synthesis has the highest energy requirement, making new amino acids monomers however would require more energy than protein synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do food sources get converted into NADH?

A

Amino acids, glucose, glycerol and fatty acid are monomers

Variety of different nutrient sources that cell can take up such as proteins, sugars and lipids. Idea behind cell metabolism in general is that we are trying to conserve backbones so that we can used conserved pathways to operate on because then you do not have to make millions of different proteins that are really hard to make so you want to make as few proteins as possible whilst still maintaining flexibility

Monomers are entered into various parts of glycolysis or the citric acid cycle//breakdown products ultimately enter the CAC and can be entered into different parts of this conserved pathway depending on the molecule or pathway used initially (see diagram)

Specialised pathways isolate the conserved carbon backbone from molecules to enter it into either glycolysis or TCA cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Monomers and how they are converted to NADH

A

Monomers are entered into various parts of glycolysis or the citric acid cycle//breakdown products ultimately enter the CAC and can be entered into different parts of this conserved pathway depending on the molecule or pathway used initially (see diagram)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Sugars/monosaccharides conversion

A

(6 carbon rings only)

Converted to glucose-6-phosphate or early precursors of glycolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Amino acids conversion

A

Amino (NH2) group must be removed. Variable entry into TCA

Primarily transaminate NH2 -> glutamate - key in CAC, example of how a specific amino acid can be entered into the CAC which means all the stuff that happened in glycolysis is missed and doesn’t happen and the alternative pathways need to be used

Glutamate alpha-ketoglutarate is tightly regulated by both TCA cycle and urea cycle. Deamination removes excess NH2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Fatty acids conversion

A

Glycerol can enter into glycolysis with only two enzyme reactions

Beta oxidation: flexibility removes acetyl-CoA or propionyl-CoA from any length fatty acids. Both enter into TCA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Two phases of glycolysis

A

Energy investment phase and the energy payoff phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Glycolysis define

A

Glycolysis is the first of the main metabolic pathways of cellular respiration to produce energy in the form of ATP. … Overall, the process of glycolysis produces a net gain of two pyruvate molecules, two ATP molecules, and two NADH molecules for the cell to use for energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Energy investment phase

A

Put in energy

ATP is used to phosphorylate sugar : unstable intermediate

6C sugar ring is broken into two 3C chains

Use ATP to further phosphorylate G6P and modify it into unstable intermediates, essentially glucose is split into two smaller things which go through the rest of the pathway twice

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Energy pay off phase

A

Oxidations and (eventual) removal of phosphate produced ATP and NADH

Subsequent oxidation and reduction reactions to essentially create ATP or NADH, can create ATP directly or can create NADH which is involved in some catabolic steps and then will be used by respiration later

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

For each molecule of glucose…

A

2 pyruvate are produced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What happens to the 2 pyruvate produced during glycolysis?

A

these are then entered into the CAC and essentially the idea is that it is going around in a forward (oxidative) direction and then adding in acetyl-CoA (can come from beta oxidation but pyruvate usually gets converted into acetyl-CoA) and this gets added into some of the conserved intermediates, essentially adding carbons on to the 4C molecule and then later removing carbons to generate NADH molecules

Full cycle operates twice per glucose in glycolysis

Many reactions are reversible

Aerobically the favourable direction is oxidative (forward running cycle)

Driven by dehydrogenases - enzymes that perform oxidation reactions that can produce lots of these energy currencies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

NET products produced during glycolysis

A

2 pyruvate, 2 ATP, 2 NADH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

ATP formed and used in glycolysis

A

4 ATP formed, 2 ATP used, therefore net gain of 2 ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Products produced from pyruvate dehydrogenase (PD)

A

1 NADH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Products produced during 1 full cycle of TAC

A

3 NADH
1 GTP (can be converted into 1 ATP)
1 FADH2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Total products from the entire process ( 1x glycolysis, 2 x PD, 2 x TCA)

A

10 NADH, 2 FADH2, 2 ATP and 2 GTP

24
Q

The two major routes of ATP production

A

Substrate level phosphorylation and oxidative phosphorylation

25
Q

Substrate level phosphorylation

A

Making ATP as a consequence of cytoplasmic reactions

Glycolysis and TCA possess such reactions

Low efficiency but simpler and not limited by electron acceptor

Eventually limited without regenerating NAD+ (e.g. fermentation) - linked to a lot of cytoplasmic reactions that need NAD+

Essentially it is any process in the cytoplasm of the cell that produces ATP, get very low amounts of ATP but can make smaller amounts of proteins in this process

26
Q

Oxidative phosphorylation

A

Oxidative phosphorylation is the process by which ATP is synthesized as the result of electron transport driven by the oxidation of a chemical energy source.

Using reducing power (combining NADH and FADH2) to generate ATP

Electron transport chain and ATP synthase

For ETC - oxidises our reducing power, takes the electrons off things like NADH and by taking these electrons down energy levels we make a proton pump, essentially the electron is put on oxygen and this is why we breathe oxygen as humans in order to power this process and get a proton gradient which is then used to power another enzyme called ATP synthase (enzyme that produces ATP)

High efficiency but complex and limited by electron acceptor
Very efficient system and is goof for organisms that require a lot of ATP or for organisms that need to use their carbon source efficiently so indeed persisters and cells that grow slow are found to rely on these processes therefore understand the importance of PMF in stressful environments

Regenerates NAD+ as part of its activity - allows catabolic reactions to continue which is a good way of dealing with the build up of too much reducing power

Linked by proton motive force

Also known as cellular respiration

27
Q

OXPHOS produces up to _____ times _____ ATP than SLP

A

10 times more

28
Q

ATP is required for

A

anabolic processes (polymer synthesis)

29
Q

Growth rate of bacteria depends on

A

ATP yields because you need ATP for anabolic processes

30
Q

Bacterial and archaeal ETCs vs mitochondrial ETC

A

Although some bacterial and archaeal ETCs resemble the mitochondrial chain, they are frequently very different. First, bacterial and archaeal ETCs are located primarily within the plasma membrane. Furthermore, some Gram-negative bacteria have ETC carriers in the periplasmic space and even the outer membrane. Bacterial and archaeal ETCs also can be composed of different electron carriers, employ different terminal oxidases, and be branched. That is, electrons may enter the chain at several points and leave through several terminal oxidases. Bacterial and archaeal ETCs also may be shorter, resulting in the release of less energy (and the transport of fewer protons across the membrane). Although microbial ETCs differ in details of construction, they operate using the same fundamental principles.

31
Q

Order used of reactions

A

from the first one used … aerobic respiration (oxygen at high pressure), micro aerobic respiration (oxygen at low oxygen pressure), anaerobic respiration (nitrate), anaerobic respiration (fumarate) and fermentation (acetyl-CoA)

32
Q

Aerobic respiration - Oxygen ( high pO2) - MAX YIELD

A

38

33
Q

Microaerobic respiration - oxygen (low pO2) - MAX YIELD

A

15

34
Q

Anaerobic respiration - Nitrate - MAX YIELD

A

15

35
Q

Anaerobic respiration - Fumarate - MAX YIELD

A

12

36
Q

Fermentation - acetyl-CoA - MAX YIELD

A

3

37
Q

Reactions that are oxidative phosphorylation and substrate level phosphorylation

A

aerobic respiration (oxygen at high pressure), micro aerobic respiration (oxygen at low oxygen pressure), anaerobic respiration (nitrate), anaerobic respiration (fumarate)

38
Q

Reactions that are only substrate level phosphorylation

A

Fermentation - acetyl-CoA

39
Q

Why is oxygen so important in OXPHOS?

A

Redox (reduction) potentials

Molecules can inherently have high energy electrons within them

Main principle behind OXPHOS

Electrons in redox active molecules have an inherent energy, measured as a voltage

Tendency of a molecule to accept or release electrons

More negative = more likely to release electron. Electron in higher energy orbital/state (itself will be oxidised and it will reduce something else)

Energy release from transferring electrons can be used to do work, coupled to proton pumping

Oxygen is the lowest energy electron acceptor in biological systems

40
Q

Oxygen is the ______ _______ electron acceptor in biological systems

A

lowest energy

41
Q

Redox potentials

A

More negative = more likely to release electron. Electron in higher energy orbital/state (itself will be oxidised and it will reduce something else)

42
Q

Aerobic respiration

A

oxygen is used as terminal electron acceptor

43
Q

Anaerobic respiration

A

no oxygen available so bacteria use an alternative electron acceptor

44
Q

Electron transport chain

A

Series of membrane bound proteins AND cofactors

Catalyse the redox reactions that usually make a PMF

Bacteria = highly modular, but the mitochondrial configuration is the most efficient. Flexible

45
Q

Key features of ETCs

A

1 - A membrane = a physical barrier is needed to create a concentration gradient
2- Oxidative protein complexes that liberate electrons from reducing power and may pump H+
3 - Cofactors that transfer electrons between enzymes
4 - Reductive protein complexes that finally transfer electrons to a terminal electron acceptor and may pump H+

46
Q

Electron liberating complexes list

A 
Complex I 
Complex II 
Quinone 
Cytochrome C 
Complex III
Complex IV
47
Q

Complex I

A

Complex 1 - NADH dehydrogenase. Large multi-subunit enzyme

Oxidises NADH and reduced coenzyme q (ubiquinone)

Induces structural/conformational changes that pump proton
s
Electron liberating complexes

48
Q

complex II

A

Complex II - Succinate dehydrogenase (none protein pumping enzyme), the same enzyme from CAC

FAD is in fact covalently bound intermediate. Succinate oxidised and quoin directly reduced

Generally does not pump protons

Electron liberating complexes

49
Q

Quinone

A

Small lipophilic chemical with aromatic headgroup that accepts electrons

Small molecule that freely diffuses through the membrane at least by the standard model to fo to the terminal acceptors on the enzyme

Many types with different redox potentials
e.g. coenzyme Q / ubiquinone
E.g. vitamin K2/ Menaquinone

Called a quinol when reduced

Electron transferring cofactors

50
Q

Cytochrome C

A

Cytochrome = protein with heme

Small protein that contains a heme group that accepts electrons

Generally only associated with oxidase enzymes that perform oxygen reduction

Not to be confused with other heme containing enzymes like cytochrome P450, that perform reactions

Electron transferring cofactors

51
Q

Complex III

A

Cytochrome bcI. Transfer electrons between quinol and cytochrome C

Indirectly transfer protons using electron carrier acid/base chemistry (not a proton pump)

Linked to complex IV, in many bacteria they are a super complex

Electron donating complexes

52
Q

Complex IV

A

Cytochrome C oxidase. Electrons from cytochrome C used to terminally reduce oxygen

Protons taken up during catalytic intermediate and pumped

Electron donating complexes

53
Q

ETC features - a membrane

A

A membrane = a physical barrier is needed to create a concentration gradient

54
Q

ETC features - oxidative protein complexes

A

Oxidative protein complexes that liberate electrons from reducing power and may pump H+

55
Q

ETC features - cofactors

A

Cofactors that transfer electrons between enzymes

56
Q

ETC features - reductive protein complexes

A

Reductive protein complexes that finally transfer electrons to a terminal electron acceptor and may pump H+

microbes to medicine (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions