Microbiology Ch. 6
The three central metabolic pathways—glycolysis, the pentose phosphate pathway, and the tricarboxylic acid cycle (TCA cycle)—modify organic molecules to generate what three useful components for the cell?
-ATP -Reducing power -Precursor metabolites
The researchers were also able to grow Sulfurospirillum halorespirans using hydrogen gas as an electron donor and acetate as a source of carbon, using perchloroethylene (PCE) as an electron acceptor. When demonstrating growth in this manner, how would scientists classify this species?
-Chemoorganoheterotroph
Which of the following compounds can be generated from precursor metabolites produced during glycolysis?
-Glycerol, a component of lipids. -Some small amino acids like alanine, leucine, and valine. -Peptidoglycan, a component of bacterial cell walls.
A population of bacteria is breaking down some lipids to support microbial growth. Where do the products of lipid breakdown enter the central metabolic pathway?
-Glycolysis -TCA cycle
The breakdown products of proteins can enter which of the following metabolic pathways?
-Glycolysis -TCA cycle -Pentose phosphate pathway
What do you think the researchers included as part of their enrichment culture in order to isolate Sulfurospirillum halorespirans?
-Perchloroethylene -Lactate -Soil sample from a PCE-contaminated site
Which of the following compounds can be generated from precursor metabolites in the TCA cycle?
-Some amino acids like aspartate, glutamate, and proline. -Certain protein components.
Consider common human pathogens. Most of their enzymes likely function best under which of the following environmental conditions?
-Temperature around 37 degrees C -Low salt -Moderate pH around 7
______ refers to energy-requiring metabolic processes that result in the biosynthesis of macromolecules and cellular structures.
Anabolism
What is the most important point in the first paragraph?
Biologists thought that yeast cells multiplying in grape juice convert sugar into CO2 and alcohol.
Some enzymes require a cofactor or a coeznyme in order to be active. What is the difference between cofactors and coenzymes?
Cofactors are non-protein components that assist enzymes and are typically trace elements; coenzymes are organic cofactors that loosely carry molecules or electrons.
Which of the following contain a metal ion that can accept and donate electrons?
Cytochromes
Where does the TCA cycle take place in bacteria?
Cytoplasm
Where do NADH and FADH2 go after being produced in the TCA cycle?
Electron transport chain.
Consider the image you labeled showing a metabolic pathway under allosteric regulation. Which enzyme in this pathway is most likely under allosteric control?
Enzyme a
Identify which of the following are coenzymes.
FAD NADP NAD
In anaerobic respiration, the terminal electron acceptor would also be oxygen.
False
Most people who get Salmonella contract it from turtles.
False
True or false: In prokaryotes and eukaryotes, the TCA cycle takes place in the mitochondria.
False
How do chemolithotrophs acquire energy?
From inorganic compounds
When polysaccharides are broken down, their breakdown products can be oxidized for energy by entering which of the following metabolic pathways?
Glycolysis
Label the intermediates and products of glycolysis. Not all labels are used.
https://gyazo.com/0009c7ecce6c6e56939c20e2ba369c87
Label the components involved in the chemical reaction.
https://gyazo.com/044ad9f7e2cbdba4f57a68ddde23d724
The breakdown products of proteins can enter which of the following metabolic pathways?
https://gyazo.com/28bea42bd8059c7729d76cd520f91b59
Why would an organism use fermentation to generate ATP?
https://gyazo.com/34965dce68c4db3f6776a1b3bf112e96
Label the graphs demonstrating the effect of environmental factors on enzyme activity.
https://gyazo.com/35b633bf611d0e1927bdd5b117f5496b
Label the reactants and intermediates of the transition step and the TCA cycle. Not all labels are used.
https://gyazo.com/4edffb8f0525f23109a11e3b220b65c2
Consider the image you labeled showing a metabolic pathway under allosteric regulation. Imagine if the final enzyme in the pathway was under allosteric regulation instead of the first. What impacts would this have?
https://gyazo.com/5217e09ba90cb10379724cefa648265f
Label the overview of the central metabolic pathways and their associated components. Not all labels are used.
https://gyazo.com/86c59646371c17e04fcf0b464669274a
Consider common human pathogens. Most of their enzymes likely function best under which of the following environmental conditions?
https://gyazo.com/a557c6f4bb6336d98166bc8f0e425a4e
The three central metabolic pathways—glycolysis, the pentose phosphate pathway, and the tricarboxylic acid cycle (TCA cycle)—modify organic molecules to generate what three useful components for the cell?
https://gyazo.com/ac2e3f6fb59018d0f20055361e4b5974
Which of the following compounds can be generated from precursor metabolites in the TCA cycle?
https://gyazo.com/ac31874f62279f464c14e4ccd47f8100
Label the diagram that shows the impact of enzymes on the energy level of chemical reactions.
https://gyazo.com/b2de1de397b6142e131598336ea94cbb
Label the diagram that shows the impact of enzymes on the energy level of chemical reactions.
https://gyazo.com/b8cba076f1b6543cea76c43f54d170c8
Identify which of the following are coenzymes.
NAD+ FAD NADP+
Hydrogen is transported from other reactions to the electron transport chain by ______
NADH and FADH2
Hydrogen is transported from other reactions to the electron transport chain by ______.
NADH and FADH2
Identify the final electron acceptor at the end of the tandem photosystems of cyanobacteria when non-cyclic photophosphorylation is used.
NADP
Place the labels to show the relationships between catabolic reactions and anabolic reactions.
https://gyazo.com/f0020c9da9ebed2e283f79ed90f0567c
Eventually Eduard Buchner showed that crushed (destroyed) yeast cells could convert sugar to ethanol and CO2. What did this experiment show?
Something was released frm the crushed cells that could still convert sugar to alcohol.
One of the methods used to identify S. enterica in the lab is growth in tetrathionate broth, a selective enrichment medium for this organism. What does this mean?
Tetrathionate broth inhibits the growth of non-Salmonella bacteria and encourages the growth of Salmonella.
Glycolysis takes place in the ______
cytoplasm
Glycolysis takes place in the ______.
cytoplasm
In prokaryotic cells, the electron transport chain (ETC) is located in the ______, whereas in eukaryotic cells, the ETC is located in the ______.
cytoplasmic membrane; inner membrane of mitochondria
Glycolysis makes products that feed into
electron transport chain, TCA cycle AND fermentation
Streptococcus pneumoniae lacks an electron transport chain. Therefore, S. pneumoniae generates ATP via ______.
fermentation
The rate of growth in flask 1 is slower than that in flasks 2 and 3, and you detect the production of lactic acid. The E. coli in this tube can be most accurately described as undergoing ______.
fermentation
In prokaryotic cells undergoing respiration, protons are pumped
from inside the cell to outside the cytoplasmic membrane.
In eukaryotic cells undergoing respiration, protons are pumped
from the mitochondrial matrix to the intermembrane space.
Glycolysis is the central metabolic pathway that involves the breakdown of ______
glucose
Glycolysis is the central metabolic pathway that involves the breakdown of ______.
glucose
The Tricarboxylic Acid Cycle (TCA cycle) occurs after ______
glycolysis
The Tricarboxylic Acid Cycle (TCA cycle) occurs after ______.
glycolysis
Hydrogen consists of
one proton and one electron.
The terminal electron acceptor in aerobic respiration is ______
oxygen
The terminal electron acceptor in aerobic respiration is ______.
oxygen
Removing the electron transport chain of E. coli would
prevent oxidative phosphorylation.
The main purpose of cellular respiration is to
produce energy.
The enzyme ATP synthase uses energy from ______ to make ATP.
protons re-entering the cell.
The electron transport chain is part of ______.
respiration
During the electron transport chain in bacteria, protons are
shuttled to the outside of the cell membrane.
During the electron transport chain, ATP will be made from
ADP + Pi
Consider how an aerobically respiring bacterial cell uses glycolysis, the TCA cycle, and oxidative phosphorylation to break apart and oxidize glucose. What are the three main benefits these central metabolic pathways yield to the cell
ATP, reduced electron carriers, and precursor metabolites.
Consider how an aerobically respiring bacterial cell uses glycolysis, the TCA cycle, and oxidative phosphorylation to break apart and oxidize glucose. What are the three main benefits these central metabolic pathways yield to the cell?
ATP, reduced electron carriers, and precursor metabolites.
Why would an organism use fermentation to generate ATP?
-The organism lacks an electron transport chain. -A suitable inorganic terminal electron acceptor is not available.
Consider the image you labeled showing a metabolic pathway under allosteric regulation. Imagine if the final enzyme in the pathway was under allosteric regulation instead of the first. What impacts would this have?
-There would be a buildup of intermediate b. -The reaction would be less efficient.
For each glucose molecule broken down by glycolysis, how many net ATP molecules are produced?
2
You are studying the metabolism of the phototrophic green sulfur bacterium Chlorobaculum tepidum and realize that it is running a reversed TCA cycle! How do you explain this observation?
C. tepidum is using the reversed TCA cycle to fix carbon dioxide.
Consider the growth of Sulfurospirillum halorespirans using lactate as a source of carbon and electrons, and perchloroethylene (PCE) as an electron acceptor. How would scientists classify this species based on its metabolism?
Chemoorganoheterotroph
Scientists isolated a new species of bacteria growing in sediments collected from a 63 meter deep site at the bottom of Lake Washington in Seattle This species, named Labrys methylaminiphilus, is capable of obtaining its carbon and energy needs from methylamine (CH3NH2), a derivative of ammonia (NH3) in which one H atom is replaced by a methyl (CH3) group. L. methylaminiphilus grows at a temperature range of 10-35°C, with optimal growth at 28-30°C, and a pH range of 4.0-9.5, with optimal growth at 5.0-7.0. Because methylamine is a single carbon compound resulting from the breakdown of decaying organic matter, methylotrophic ("methyl-feeding") bacteria like L. methylaminiphilus play an important role in carbon cycling in lake sediments and other environments.
Chemoorganoheterotroph
The researchers were also able to grow Sulfurospirillum halorespirans using hydrogen gas as an electron donor and acetate as a source of carbon, using perchloroethylene (PCE) as an electron acceptor. When demonstrating growth in this manner, how would scientists classify this species?
Chemoorganoheterotroph
What happens to carbon dioxide after it is released during reactions of the TCA cycle?
It diffuses out of the cell.
S. enterica can switch to anaerobic respiration in tetrathionate broth. What does this tell us about the organism?
It is a facultative anaerobe.
You set up a third test tube containing 8 mL water, 1 mL PTU, 1 mL potato juice, and 3 mL catechol. If this third test tube turned brown, this would suggest which of the following?
PTU is a competitive inhibitor of catechol oxidase.
You set up a third test tube containing 8 mL water, 1 mL PTU, 1 mL potato juice, and 3 mL catechol. If this third test tube showed no change, this would suggest which of the following?
PTU is a non-competitive inhibitor of catechol oxidase.
The results of your test tubes suggest which of the following?
PTU is an inhibitor of catechol oxidase.
Anabaena is a genus of filamentous cyanobacteria commonly found in aquatic environments, where it harvests energy from sunlight and fixes both carbon dioxide and nitrogen. Knowing this, how would you classify Anabaena?
Photoautotroph
Greenlake is a small lake in Seattle, WA that sometimes experiences blooms of cyanobacteria, photosynthetic nitrogen-fixing bacteria that typically grow as filaments. These blooms are especially likely to occur during warm summer weather and result in the production of large quantities of biomass that then dies off and decomposes, leading to unpleasant odors. In addition to the aesthetic problems, some strains make toxins that can be dangerous to ingest, leading to the closing of the lake. Treatment of the water with alum (aluminum sulfate) to remove phosphorus from the water has helped to limit growth of cyanobacteria.
Photoautotroph
You inoculate fern spores onto the surface of a growth medium in Petri dishes and wait for them to develop into gametophytes, a stage in the life cycle of a fern. The medium contains sources of nitrogen, phosphate, and a number of other macro- and micro-nutrients, but no carbon. After a few weeks, you see a contaminant growing on your plates. Assuming the organism is not digesting the agar itself, which of the following is most likely your contaminant?
Photoautotrophic species of bacteria, archaea, or protists.
Pasteur set up the following experiment: he prepared a solution of sugar, ammonia, mineral salts, and trace elements, and added some yeast cells to it. He then measured the number of yeast cells as well as the sugar and alcohol levels over time. He noted that as the yeast cells multiplied, sugar levels decreased and alcohol levels increased, suggesting that the yeast cells were converting the sugar to alcohol. What do think would be an appropriate control for this experiment?
Preparing a solution of sugar, ammonia, mineral salts, and trace elements, but not adding any yeast cells to the solution.
Which of the following is not a catabolic process?
Protein synthesis
The two 3-carbon molecules that glucose is split into during glycolysis are converted through a series of steps ending in what 3-carbon molecule?
Pyruvate
The TCA (Krebs) cycle takes place in the mitochondria of eukaryote cells. Where does it take place in prokaryote cells?
The cytoplasm
When bacteria such as S. enterica infect the intestinal tract, inflammation results. This is one of the body's immune defenses. Researchers have recently discovered that tetrathionate is produced in the intestinal tract as a result of inflammation. Why is this important?
The presence of tetrathionate gives the Salmonella a competitive advantage over the normal microbiota such as E. coli.
When setting up the reaction in tube 1, you measure the rate of product (brown pigment) formation upon adding the catechol substrate. If you set up another tube but instead add twice the amount of substrate, what do you think would be the effect on the rate of product (brown pigment) formation compared to the first test tube? Assume that the enzyme is not saturated with substrate.
The rate of the second tube would be faster than that of the first tube.
How many molecules of NADH are generated for each turn of the TCA cycle?
Three
In this case, a person who contracted Salmonella from a turtle was classified as having a primary infection. A person who acquired Salmonella by person-to-person transmission from a person with a primary infection would be classified as having a secondary infection.
True
For each glucose molecule that enters glycolysis, how many times does the TCA cycle "turn"?
Two
How many ATP molecules are produced in the TCA cycle for each glucose molecule that enters glycolysis?
Two
The electron carrier proteins in the electron transport chain shuttle electrons to
a terminal electron acceptor
The electron carrier proteins in the electron transport chain shuttle electrons to
a terminal electron acceptor.
The energy released during the reactions of glycolysis is used to form ______
adenosine triphosphate
The rate of growth in flask 3 is substantially faster than that in flask 1 and somewhat faster than that in flask 2. The E. coli in this tube can be most accurately described as undergoing ______.
aerobic respiration
A culture of E. coli is growing on glucose salts agar (GSA), a chemically defined medium that contains glucose as its sole carbon source. E. coli utilizes the glucose for both its energy and carbon needs. During metabolism, it uses precursor metabolites of its central metabolic pathways and ATP to build up the biological macromolecules needed to make cell components. These biosynthetic reactions are best described as ______.
anabolism
The rate of growth in flask 2 is substantially faster than that in flask 1, but somewhat slower than that in flask 3. You detect the production of nitrite. The E. coli in this tube can be most accurately described as undergoing ______.
anaerobic respiration
As bacteria grow in broth, oxygen becomes depleted. At that point, most bacteria switch to fermentation to continue growing. In tetrathionate broth however, S. enterica can switch to anaerobic respiration. This gives the organism a growth advantage because
anaerobic respiration yields more ATP per glucose molecule than fermentation.
The coenzyme NADH is generated by
by oxidation reactions in glycolysis and the Krebs cycle.
A culture of bacteria is breaking down sugars to yield energy. This is best described as ______.
catabolism
In bacteria, the electron transport chain is located in
the cytoplasmic membrane
Cells prefer to use carbohydrates as energy sources because
they are such good donors of hydrogen and electrons
In aerobic respiration, the last carrier protein in the electron transport chain transfers
two electrons to oxygen.
What is a synonym for the word "employed" which we see in this sentence: Pasteur studied the relationship between yeast and alcohol production using a strategy commonly employed by scientists today?
used
