Lecture 7 Flashcards
HD
Most microorganisms oxidize ________ as their primary source of cellular energy
carbohydrates
The breakdown of carbohydrate molecules to produce energy Glucose is the most common carbohydrate energy source used by the cells
Carbohydrate catabolism
To produce energy from glucose, microorganisms use two general processes which are what? Both processes start with the same first step which is what?
Cellular respiration and Fermentation. Glycolysis
The Embden-Meyerhof pathway is more commonly known as what?
Glycolysis
What is another pathway that many bacteria, including E. coli and Bacillus subtilis could use for glucose oxidation?
Pentose phosphate pathway
What are the 2 basic stages of glycolysis?
The Preporatory Stage and the Energy Conserving Stage
After glucose is broken down into pyruvic acid what are the next possible 2 steps?
Cellular respiration or fermentation
Respiration is defined as an ATP-generating process in which molecules are oxidized and the final electron acceptor is (almost always) a what?
an inorganic molecule
An essential feature of respiration is the operation of the what?
electron transport chain.
In the electron transport chain electrons are transferred from where to where?
higher-energy compounds to lower energy compounds
What are the two types of respiration?
Aerobic respiration
Anaerobic respiration
In aerobic respiration among prokaryotes, a total of ____ molecules of ATP can be generated from one molecule of glucose.
38
Aerobic respiration among Eukaryotes produces a total of only _____ molecules of ATP
36
Why are there fewer ATP in Eukaryotes?
Energy is lost when electrons are shuttled across the mitochondrial membranes that separate glycolysis in the cytoplasm from the ETC. Prokaryotes don’t have this separation.
In anaerobic respiration, the final electron acceptor is an what?
inorganic substance other than oxygen
Why is the ATP yield never as high as in aerobic respiration?
Not all carriers in the electron transport chain participate in anaerobic respiration. This is why anaerobes tend to grow more slowly.
During glycolysis, the ______ phase of lactic acid fermentation, a molecule of glucose is oxidized to two molecules of ________. This oxidation generates the energy that is used to form two molecules of ______. In the next step, the two molecules of pyruvic acid are reduced by two molecules of _______to form two molecules of ________. Because lactic acid is the end-product of the reaction, it undergoes no further oxidation, and most of the energy produced by the reaction remains stored in the lactic acid
first, pyruvic acid, ATP, NADH, lactic acid
Two important genera of lactic acid bacteria are?
Streptococcus and Lactobacillus.
Microbes that only produce lactic acid are referred to as what
homolactic or homofermentative
Two examples of homolactic bacteria?
Streptococcus and Lactobacillus.
Lactic acid fermentation can spoil food however it can be used to produce what?
yogurt from milk, sauerkraut from fresh cabbage and pickles from cucumbers
Alcohol fermentation also begins with the glycolysis of a molecule of glucose to yield two molecules of pyruvic acid and two molecules of ATP. In the next reaction, the two molecules of pyruvic acid are converted to two molecules of ____________. Then the two molecules of __________ are reduced by two molecules of _______ to form two molecules of ___________
acetaldehyde. acetaldehyde, NADH, ethanol.
Alcohol fermentation is also ________ process because most energy contained in the initial glucose molecule remains in the ethanol, the end-product.
low-energy-yield
The ethanol and carbon dioxide produced by the yeast ___________ are waste products for yeast cells but can be used in industry. Ethanol made by yeasts is the alcohol in alcoholic beverages, and carbon dioxide made by yeasts causes bread dough to rise
Saccharomyces
Organisms that produce lactic acid as well as other acids or alcohols are known as
heterolactic or heterofermentative.
Fermentation products of infectious microrganisms can be used in _________
diagnosis.
An intermediate in butanediol fermentation, helps to detect the bacterium Klebsiella pneumoniae (test)
Voges-Proskauer test for acetoin
The production of butyric acid by Clostridium perfringens is an important cause of the severe tissue damage of _________.
gangrene
Light energy is absorbed by chlorophyll molecules in the photosynthetic cell. The chlorophyll principally used by green plants, algae, and cyanobacteria is ________. Other bacteria use _____________
chlorophyll a, Bacteriochlorophylls.
What builds their organic compounds by fixing carbon dioxide in the Calvin-Benson Cycle. This requires both energy __________and __________
Autotrophs, (ATP), electrons (from the oxidation of NADPH).
What must have a ready source of organic compounds for biosynthesis
Heterotrophs
What is the name of the organisms that carry out photosynthesis, which is the capture of energy from light and the use of this energy to manufacture carbohydrates from carbon dioxide.
Photoautotroph
Photoheterotrophs are a small group of bacteria that can use energy from light but requires organic substances such as what 3 things?
alcohols, fatty acids, or carbohydrates as carbon sources.
Photoautotrophs include what organisms?
nonsulfur, purple, or green bacteria
What can extract energy from inorganic substances?
chemoautotrophs
What is the name of the bacteria that increase the quantity of usable nitrogen compounds available to plants and replace nitrogen that plants remove from the soil.
nitrifying bacteria
What extracellular enzymes can break fats down into fatty acid and glycerol components and then each component is metabolized separately.
lipases (catabolic reaction)
Many bacteria that hydrolyze fatty acids can use the same enzymes to degrade _______ products.
petroleum. Bad in fuel tanks good on oil spills.
Microbes produce extracellular _________ and _________ and these enzymes break down proteins into component amino acids, which are then enzymatically converted to other substances that may enter the Krebs cycle
proteases, peptidases
Microbes use ______ to provide energy for the transport of substances across plasma membranes.
ATP
Most microbes use the majority of their energy in the production of new _______ __________
cellular components
Is the process of cellular production faster in prokaryotic cells or eukaryotic cells?
Prokaryotic cells
A polymer of glucose and is a storage depot for carbon and energy.
Glycogen
Glycogen is produced when carbon is _______ in the environment and is consumed when carbon is _________
in excess, limited
In order for bacteria to synthesize glycogen, a molecule of ATP is added to_________ to form __________ Once that is synthesized, it is linked with similar units to form glycogen.
glucose 6phosphate, adenosine diphosphoglucose (ADPG).
UDPNac is formed from _______, and the reaction uses a nucleotide called ___________as a source of energy.
fructose 6-phosphate, uridine triphosphate (UTP)
UDPNAc is a key starting material in the biosynthesis of ____________
peptidoglycan
Microbial cells synthesize fats by joining _____ to fatty acids
glycerol
The most important role of lipids is the formation the structural components of ____________ (most membrane lipids are phospholipids)
biological membranes
The two most important components of the cell wall of acid fast bacteria are
waxes and lipids
Example of an acid fast organism
mycobacterium
Acid fast organisms are; once stained with an Acid-fast stain, cannot be decolorized by mineral acids or by mixtures of acid and ethanol. Other lipids, such as __________, provide the red, orange, and yellow pigments of some
microorganisms. Some lipids form portions of __________
carotenoids, chlorophyll molecules.
One important source of the precursors (intermediates) used in amino acid synthesis is the
Krebs cycle
Adding an amino group to pyruvic acid or to an appropriate organic acid of the Krebs cycle converts the acid into an amino acid. This process is called _________. If the amine group comes from a preexisting amino acid, the process is called _____________
amination, transamination
Many bacteria synthesize _____ and _______ and other polymers associated with cell walls.
peptidoglycan, lipopolysaccharide,
Some bacteria form capsules. Capsules usually consist of polymers of one or more __________
monosaccharides.
Some organisms, such as the aerobe Acetobacter, synthesize cellulose, which is ordinarily found in plants. As strands of cellulose reach the cell surface, they form a mat that traps ____________ and keeps the cell afloat. Because these organisms must have oxygen, the mat contributes to their survival by keeping them near the water surface, where oxygen is plentiful.
carbon dioxide bubbles
Bacterial transport systems are operated by membrane proteins, also called carriers or
permeases
Most solutes in bacteria are transported by _________
active transport systems
Trans-membrane carrier proteins called ________ form channels through the outer membrane. ______ allow entry of ions and small hydrophilic metabolites via facilitated diffusion
porins, Porins
Most motile bacteria move by means of flagella, but some move by _______or _______ in a corkscrew motion.
gliding or creeping
Flagellated bacteria move by rotating their flagella. The mechanism for rotation appears to involve a proton gradient, as in __________. As the protons move down the gradient, they drive the rotation.
chemiosmosis
Gliding bacteria move only when in contact with a ___________, such as decaying organic matter.
solid surface
Most studied gliding bacterium
Myococcus
Myococcus uses energy to secrete a substance called ________, which lowers surface tension at the bacterium’s posterior end. The difference in surface tension between the anterior and posterior ends causes Myxococcus to glide.
surfactant
_______ expand energy for both creeping and thrashing motions. On a solid surface they creep like an inchworm by alternately attaching front and rare ends. Suspended in a liquid medium, they thrash (twist and turn).
Spirochetes
Bioluminescence, the ability of an organism to emit light, appears to have evolved as a by-product of __________ exhibited by bacteria
aerobic metabolism
Two types of bioluminescent bacteria
Photobacterium and Achromobacter.
What enzyme do light emitting microorganisms have with other components of the electron transport system?
Luciferase
Luciferase catalyzes a complex reaction in which molecular oxygen is used to oxidize a long chain aldehyde or ketone to a carboxylic acid. At the same time, FMNH2 from the electron transport chain is oxidized to an excited form of ____________, a carrier molecule derived from riboflavin that emits light as it returns to its unexcited state. In this process, phosphorylation reactions are bypassed, and no ________ is generated. Instead, energy is released as light
flavin mononucleotide (FMN), ATP
