Chapter 5- Microbial Metabolism Flashcards
Metabolism
The sum of all chemical reactions within a living organism
Metabolism is divided into two types of chemical reactions:
What’s the difference between these two?
Catabolic: breaks down large molecules into smaller products, exergonic (releases energy), ex: proteins –> a.a
Anabolic: turns smaller products into large molecules, requires energy to make bonds (endergonic), ex: a.a—> protein or fatty acid –> lipid
Is this anabolic or catabolic:
Starch (a polymer) is built from simple sugars (monomers)
Anabolic
Energy coupling
The energy that is released from the catabolic reactions can be used to drive an anabolic reaction that requires energy
Metabolic reactions usually involve the movement of electrons (which are ________ of _____). The molecule that is oxidized is the one to _____ the electron and involves _____. The molecule that is reduced ______ the electron and involves _____.
carriers of energy
oxidized: donates the electron and involves loss (OIL)
reduced: accepts the electron and involves gain (RIG)
To move the electrons around (for oxidation-reduction reactions), a carrier is often used. The important ones are:
The electron is usually associated with a _______ atom since it only has _____ ______. So the carriers pick up and drop off the _____.
NAD+
NADP+
FAD
The electron is usually associated with a HYDROGEN atom since it only has ONE ELECTRON. So the carriers pick up and drop off the HYDROGENS.
ATP is responsible for
mediating or carrying out energy coupling in cells
ATP is composed of
3 phosphorus groups
a sugar (ribose)
and a nitrogenous base (adenine)
How does ATP produce energy?
The terminal phosphate bond gets broken (just one out of the three)
When the _____ _____ bond is broken, the terminal phosphate ____ is ___ from ATP. We call this terminal phosphate _____ an _____ ________, abbreviated as ____.
When the TERMINAL PHOSPHATE BOND is broken, the terminal phosphate GROUP is REMOVED from ATP. We call this terminal phosphate GROUP an INORGANIC PHOSPHATE, abbreviated as Pi.
After the removal of the terminal phosphate group, ATP becomes _____ and ______ __ ____
ADP
energy is released
Phosphorylation
When ATP is regenerated/recycled from ADP and Pi (inorganic phosphate)
3 ways phosphorylation can be accomplished:
(basically, who provides the energy for the third phosphorus? ADP + P —> ATP
Substrate-level phosphorylation
Oxidative phosphorylation
Photophosphorylation
Substrate-level phosphorylation
transfers Pi from an organic molecule
(the bond gets broken)
Oxidative phosphorylation
Using energy from the redox reaction to add Pi
(there’s no bond to be broken)
Photophosphorylation
Using light energy to add Pi
(no bond broken)
ATP has ___ phosphate while ADP has ___
3
2
Enzymes
Speeds up chemical reactions by lowering the amount of activation energy needed
Requires energy
The amount of energy required by the reactant molecules for bond breaking is known as the
activation energy
Each enzyme can only bind to its own ____ ___ (they’re _____-______). The specificity of an enzyme is due to its _____ ___ ____.
Each enzyme can only bind to its own SPECIFIC SUBSTRATE (substrate-specific). The specificity of an enzyme is due to its UNIQUE 3D SHAPE.
What’s an active site?
the specific shape of the substrate (that matches with the specific shape of the enzyme)
Apoenzyme
The name of the protein portion when the enzyme is combined with other molecules
The apoenzyme is ____ if not bound to nonprotein ______
inactive
cofactors
Cofactors are ____ molecules, like ___ or ___. If the cofactor is an ______ molecule, it’s called a _____.
Cofactors are INORGANIC molecules, like Zn or Fe. If the cofactor is an ORGANIC molecule, it’s called a COENZYME
Important coenzymes:
NAD
FAD
CoA
Holoenzyme
Yields from when apoenzyme binds with its cofactors/coenzymes
Factors that influence the activity/action of an enzyme:
Temperature
pH
Substrate concentration
Inhibitors
If the temperature goes up too high, the rate of the reactions slows down as enzymes get _____. Enzymes are most active in ____ temperatures
denatured
warmer
Competitive inhibitors
bind to an active site
Noncompetitive inhibitors
binds to an allosteric site, distorting the active site (so it no longer matches with the enzyme)
Energy production is due to the
movement of electrons
Most microorganisms tend to break down carbohydrates to obtain their energy- specifically ____
Glucose
2 main pathways of energy production
cellular respiration
fermentation
The overall process of cellular respiration can be summarized as
Glycolysis
Krebs Cycle
Electron Transport Chain
General equation for cellular respiration:
Which is being oxidized and which is being reduced? Why?
C6H12O6 + 6O2 —-> 6CO2 + 6H2O + ATP
C6H12O6 is oxidized because the hydrogens are taken away and become 6CO2
6O2 is reduced because hydrogens are gained: 6H2O
Cellular respiration is a _____ reaction because ____________. All of the energy comes from the _____ ____
catabolic
energy gets released
glucose molecule
Glycolysis starting molecule:
ending molecule:
starting: Glucose
ending: Pyruvic Acid
What carrier molecule is used during Glycolysis and how many?
NADH, 2
How much ATP is used in Glycolysis? How much is produced? Net amount?
2 ATP is used
4 ATP is produce, 2 net
Penicillium is a ____ that leads to antibiotics
Streptomyces is a _____ that leads to antibiotics
mold
bacteria
Only ____ leads to fermentation, not ____
yeast,
not bacteria
Tetrapeptide cross bridges hold together..
NAM and NAM molecules
Outer cell/cytoplasmic membranes are made up of a cholesterol-like molecule called a
Hopanoid
Each molecule of pyruvate coming from glycolysis must first be converted to another chemical called_______
acetyl coenzyme A (acetyl CoA)
The preparation stage
2 NADH
2 CO2
2 acetyl CoA
2 points about the Krebs Cycle
It occurs in the cytoplasm of prokaryotes
A great amount of energy remains in the bonds of acetyl CoA
Key concepts of the Krebs Cycle:
Starting molecule?
How many molecules of ATP?
What method of phosphorylation?
How many molecules of FADH2?
How many molecules of NADH?
How many molecules of CO2?
Starting molecule?
Acetyl-CoA
How many molecules of ATP? 2
What method of phosphorylation? Substrate level phosphorylation
How many molecules of FADH2? 2
How many molecules of NADH? 6
How many molecules of CO2? 4
The Electron Transport Chain is the most _____ ____ in aerobic respiration because it will generate the most number of ____ ___
important stage
ATP molecules
The Electron Transport Chain:
During aerobic respiration, there is a lot of transferring of electrons (aka oxidation-reduction reactions) going on. Glucose _____ its electrons to form ____. This reaction is called ______. Oxygen ____ the electrons given away from glucose to form ____. This is called a ______.
During aerobic respiration, there is a lot of transferring of electrons (aka oxidation-reduction reactions) going on. Glucose LOSES its electrons to form CO2. This reaction is called OXIDATION. Oxygen GAINS the electrons given away from glucose to form WATER. This is called a REDUCTION.
Electron Transport Chain:
-There is a series of _____ ____ that pass electrons from one to another to a _____ ____ ____
-Energy from electrons used to pump protons (H+) across the membrane, establishing a ______ ______. These protons return through a channel protein attached to the enzyme ___ ____
- Occurs in the ___ ____ of ______
Electron Transport Chain:
-There is a series of CARRIER MOLECULES that pass electrons from one to another to a FINAL ELECTRON ACCEPTOR
-Energy from electrons is used to pump protons (H+) across the membrane, establishing a CONCENTRATION GRADIENT. These protons return through a channel protein attached to the enzyme ATP SYNTHASE
- Occurs in the CELL MEMBRANE of PROKARYOTES
In aerobic respiration, ____ is the final electron acceptor. In anaerobic respiration, it’s an ______ _____ that acts as the final electron acceptor
Oxygen
Inorganic molecule
What method of phosphorylation occurs in the Electron Transport Chain?
Oxidative phosphorylation
Electron Transport Chain:
Each NADH creates __ __
Each FADH creates __ __
In total, there are ___ ATP molecules that can be generated from one ____ ____
3 ATP
2 ATP
34 ATP
glucose molecule
Summary of Metabolic Stages:
Glycolysis:_______—> ______
The Preparation stage: _____—> ______
The Krebs Cycle: _______—> ______
The Electron Transport Chain: once ______ _____ electrons, it is _____ to form ____
Glycolysis: 1 glucose molecule –> 2 pyruvate molecules
The Preparation stage: each pyruvate molecule—> acetyl CoA molecule
The Krebs Cycle: each acetyl CoA —> CO2
The Electron Transport Chain: once oxygen accepts electrons, it is reduced to form H20
Summary of Energy Yielded:
Glycolysis:
The Preparation Stage:
The Krebs Cycle:
The Electron Transport Chain:
Total:
Glycolysis: 2 ATP, 2 NADH
The Preparation Stage: 2 NADH
The Krebs Cycle: 2 ATP, 2 FADH2, 6 NADH
The Electron Transport Chain: 34 ATP
Total: 38 ATP molecules per glucose molecule
In anaerobic respiration, some commonly used inorganic molecules (that act as final electron acceptors) are..
Sulfate and Nitrate
In anaerboic respiration, what’s the ATP yield?
between 2 and 36 ATP molecules
End products of fermentation
Lactic acid and ethanol
How much ATP does fermentation produce?
2
When does fermentation occur?
When there is an absense of final electron acceptors (no oxygen, no inorganic molecule)
3 points about fermentation-
-_____ is ______ ____
-________ ____(or other organic molecule) acts as a ________ ______ ______
-__________ _____
- Glucose is partially oxidized
- Pyruvic acid acts as a final electron acceptor
- Regenerates NAD+
The ability to ferment carbohydrates is a common way in helping _____________ and determining its _______. A ______ ______ is what determines whether the microbe ferments the carb or not. Fermentation can also detect ______ _____ ___
identify a particular microorganism and determining its classification
pH indicator
CO2 gas production
