Bacterial Metabolism (BE #1) Flashcards
catabolic reactions
- breaking down reactions
- are often hydrolytic reactions (use water to break bonds)
- produce 3 things
- small precursor molecules
- reducing power
- ATP
anabolic reactions
- building up reactions
- usually dehydration synthesis reactions
- uses ATP
- use the 3 things produced in catabolism to build larger molecules in the cell
- 3 steps in anabolism
- biosynthesis - building blocks to monomers
- polymerization - monomers join to create polymers
- assembly - polymers assemble into biological structures (peptidoglycan forms the cell wall)
metabolism
all biochemical reactions that take place in the cell
enzymes
proteins that catalyze chemical reactions
substrate
specific molecules that enzymes act upon
What determines if an enzyme can catalyze a particular chemical reaction?
Specificity - The enzyme must fit with their substrate.
Name 3 coenzymes used by cells.
NAD+
FAD
CoA - acetyl choline
Coenzymes like NAD+ and FAD function as _______ .
electron carriers
What does OIL RIG stand for?
O - oxidation
I - is
L - loss (of an electron)
R - reduction
I - is
G - gain (of an electron)
Redox reactions involve the loss and gain of _______, which can be tracked by looking for the loss and gain of ___________ .
electrons
hydrogens
Which is in it's oxidized form? Which is in its reduced form? NAD+ NADH FAD FADH2
NAD+ - oxidized
NADH - reduced
FAD - oxidized
FADH2 - reduced
What is “reducing power?”
Reduced coenzymes (NADH, FADH2) will carry electrons/hydrogen to the electron transport system to make lots of ATP.
What does ATP stand for?
adenosine triphospate
What is a molecule of ATP composed of?
nitrogenous base adenine + ribose sugar + 3 phosphates
Why do we call ATP the “energy molecule”? - How does it supply energy to run chemical reactions?
Phosphorylation - ATP transfers high energy phosphates to other compounds so they can enter into chemical reactions.
Name 3 ways that ATP can be generated.
- substrate level phosphorylation (SLP)
- oxidative phosphorylation (OP) - involves electron transport system
- photophosphoylation (photosynthesis)
In general, catabolic reactions transform raw materials into:
- small precursor molecules
- reducing power (NADH, FADH2)
- ATP
What’s the chemical for glucose?
C6H1206
Glycolosis
- splits glucose (6 C) into two molecules of pyretic acid (3 C)
- does not produce a lot of ATP
- uses substrate level phosphorylation (SLP) to make ATP
- part of aerobic & anaerobic metabolism
Kreb’s cycle
- requires acetyl CoA;
- produces a lot of reducing power
- does not produce a lot of ATP
- uses substrate level phosphorylation to make ATP
- produces a lot of carbon dioxide
- part of aerobic and anaerobic metabolism
How many ATP are required to get glycolysis started?
2
What are the two other names for the Kreb’s Cycle?
Citric Acid Cycle
Tricarboxylic Acid Cycle
How many times does the Kreb’s Cycle turn for each glucose molecule?
2 times
Kreb’s cycle - major outputs for 1 glucose:
NADH
FADH2
ATP
6 NADH
2 FADH2
2 ATP
Pyruvic acid oxidation - major outputs for 1 glucose:
NADH
acetyl CoA
CO2
2 NADH
2 acetyl CoA
2 CO2
Lots of reducing power can be turned into _______ in the electron transport system. Where does all of that reducing power come from?
ATP
glycolysis, pyruvic acid oxidation & Kreb’s cycle
Why is a glucose molecule great for producing lots of ATP?
It’s highly reduced (it has lots of H’s)
What is the final electron acceptor in the electron transport chain for aerobic respiration?
What’s it reduced to?
Oxygen
Water
The creation of a H+ concentration across a membrane to create ATP is referred to as _____.
chemiosmosis
How many ATP are generated for each NADH?
3
How many ATP are generated for each FADH2
2
Why does FADH2 generate fewer ATP than NADH?
It drops electrons/hydrogens further down the electron transport chain, so fewer H’s will be pumped through ATP synthase, generating fear ATP.
How many ATP are generated by bacteria in aerobic respiration?
38
What are three final electron acceptors in the electron transport chain for anaerobic respiration? What are they reduced to?
- nitrate - nitrite, ammonia, or nitrogen gas
- sulfate - hydrogen sulfide gas
- carbonate users - methane gas
Generally, anaerobic respiration generates approx. _______ % of that generated by aerobic respiration.
50%
Why does anaerobic respiration generate fewer ATP than aerobic?
The Kreb’s Cycle is shortened - still goes around twice, but it has a smaller number of redox reactions which means a smaller number of reduces coenzymes - fewer ATP generated.
What are the 4 major steps in anaerobic respiration?
- glycolysis
- pyruvic acid oxidation
- Kreb’s cycle
- electron transport system
What is a final electron acceptor in the electron transport chain for fermentation?
There is no electron transport chain, so N/A
What catabolic pathways do aerobic respiration, anaerobic respiration, and fermentation have in common?
glycolysis (some types of fermentation also include Pyruvic Acid Oxidation)
Where does the electron transport system occur in prokaryotic cells?
plasma membrane
Name 3 major differences between fermentation and respiration.
- fewer ATP produced in fermentation (2 vs 19 in respiration)
- no electron transport system in fermentation
- oxygen not used
- sugars are the only substrate that can be used in fermentation
- substrate (glucose) must be abundant for fermentation
Why are some cells able to survive using fermentation?
small size & unicellular
Name/describe the 2 types of fermentation.
- Lactic Acid:
Glycolysis: 2 molecules of pyruvic acid + 2 ATP + NADH
pyruvic acid + NADH -> lactic acid (uses up the reducing power produced in glycolysis) - Alcoholic Fermentation:
Glycolysis: glucose -> pyretic acid + 2 ATP + NADH
Pyruvic Acid -> acetyl + carbon dioxide
acetyladehyde + NADH -> ethanol (uses up the reducing power produced in glycolysis)
poylmerization
joins building blocks to make macromolecules (proteins, nucleic acids, polysaccharides)
assembly
joins macromolecules to make cell structure (cell walls, flagella, ribosomes)
biosysnthesis
converts precursor molecules into building blocks (amino acids, monosaccharides)
Why do fats yield more ATP than glucose?
They are more highly reduced. Lots of H’s means lots of reducing power. Long fatty acid chains of carbons can be chopped up into acetyl groups (2 C’s) & fed into the Kreb’s cycle for the production of lots of reducing power. Reducing power goes into the electron transport system to make lots of ATP.
What 3 things does anabolism get from catabolism to build in the cell?
- precursor molecules
- ATP
- reducing power (NADH, FADH2)
strict anaerobe
cannot survive in the presence of oxygen
strict aerobe
cannot survive without oxygen
facultative anaerobe
can switch their metabolism between aerobic & anaerobic
aerotolerant anaerobe
does not use oxygen, but is not harmed by its presence