Microbiology Final

Lactis acid fermenters that form substantial amounts of products in addition to lactate, however, are ______________ fermenters

Heterolytic

Certain bacteria can produce proteins called ___________________ bacteriocins that kill closely related microbes by binding to specific sites on the target cell. They often affect __________________ integrity and function

Bacteriocins, plasma membrane

Ready-to-eat meats are being preserved by spraying a preparation of __________________ on the product prior to packaging. Phases that specifically target Listeria monocytogenes are the most used

Bacteriophages

The NADH and FADH2 formed by glycolysis and the TCA cycle are oxidized by a ______________, using oxygen as the terminal electron acceptor

Electron transport chain

Tuberculosis is a widespread deadly disease caused by _____________ tuberculosis

Mycobacterium

The TCA cycle plays an important role in energy conservation in cells by producing numerous _________ and FADH2, as well as precursor metabolites used for biosynthesis in the cell.

NADH

The electrons that are transferred through the electron transport system initially belonged to

NADH and FADH2

Respiration

NADH, FADH2, donate electrons to an electron transport chain, terminal acceptor is a different oxidized molecule such as nitrate, final electron acceptor is oxygen, proton motive force is generated and used to synthesize atp from adp and phosphate, can be either aerobic or anaerobic depending on the final electron acceptor

One preservative, ___________, is a small amphiphilic peptide produced by some strains of lactococcus lactis, and is the only widely used bacteriocins currently employed in food preservation

Nisin

The most common terminal electron acceptors used during anaerobic respiration are ___________, sulfate, and carbon dioxide, but metals and a few organic molecules can also be reduced.

Nitrate

Chemolithoautotrophs

Oxidize reduced inorganic compounds for energy and electrons; use carbon dioxide as carbon source

Choose the answer below that represents the correct sequence of events and mechanism during photosynthesis

Photo system 2 (atp production) to photo system 1 (nadph production)

When the atp and reducing power are sues to reduce and incorporate carbon dioxide, the process is called

Photosynthesis

Embden-Meyerhof pathway

Plants and animals

tricarboxylic acid cycle is linked to glycolysis through the intermediate molecule

Pyruvate

On the other hand low temperature is used in ___________________ or freezing inhibit the growth of most micro organisms but do not kill the microbes

Refrigeration

Another ancient method is the use of high ______________ when cooking to kill many microbes present in food

Temperature

Your friend tells you that she is lactose intolerant, but can eat yogurt without developing cramps and bloating that other dairy products trigger. What is the case?

The bacteria in yogurt ferment almost all of the lactose to lactate

Synthesis of ATP Steps

The flow of protons down the proton gradient through F0 subunit causes F0 and the gamma subunit to rotate, as the gamma subunit rotates rapidly within the F1, conformation changes occur in the beta subunits, betaE changing conformation to betaHC allows entry of ADP and Pi into the catalytic site, betaHC changes to betaDP and loosely binds ADP and Pi in the catalytic site, atp synthesized when betaDP conformation is changed to the betaTP conformation, atp is released when betaTP changes to the betaE conformation

During glycolysis, a 6 carbon sugar phosphate diphisphate molecule is split into two 3-carbon sugar phosphate molecules

True

Plastoquinone is the primary electron acceptor for electrons leaving photosystem II.

True

Pyruvate is converted to carbon dioxide via three separate decarboxylation reactions during the TCA cycle

True

The energy captured in the phosphorylation of adp to atp comes force created when energy is released following the oxidation of electron carriers

True

When food supplies, such as beef or pork, are gamma irradiated to kill pathogenic organisms, the food becomes temporarily radioactive. There is no harm to humans because the effects have worn off by the time the meat reaches grocery store shelves

True

When oxygen accepts electrons, water is produced as a byproduct.

True

At the site of infection, immune cells recruited to the area and form small nodules called ________________

Tubercles

Tubercles also may develop into _____________, which may allow the microorganisms to spread in the body and cause what is known as ___________ tuberculosis

Tuberculosis cavities, miliary

Canned food available for sale at grocery stores have been subjected to a commercial canning process. If you bought a can of peas from the local grocery store and found the peas to be spoiled, it could explained by ______. (Check all that apply.)

Under processing during canning, spoilage before canning, and the entrance of contaminated water through the can seams during cooling

In bacteria, when protons are pumped across the cell membrane, _________.

a proton motive force is created

Before entering the Krebs cycle, pyruvate is converted to

Acetyl CoA

process of fermentation

Glucose, glyceraldehyde-3-phosphate, pyruvate, lactate

Choose the major pathways that catabolize glucose to pyruvate.

Embden Meyerhof pathway, entner doudoroff pathway, pentose phosphate pathway

Chemoorganotrophs

Use reduced organic compounds as source of energy, electrons, and carbon

Heterotrophs

Use reduced, preformed organic molecules as their carbon source for growth

Fermentation

Uses an electron acceptor that is endogenous to the cell, does not involve an electron transport chain, atp synthesized almost exclusively by substrate-level phosphorylation

Many common methods of food preservation have been utilized since ancient times such as salting which lowers __________________ and inhibits microbial growth

Water activity

It is the activity of the electron transport chain that conserves most of the energy used to make ____________ during aerobic respiration.

ATP

Light energy is converted to chemical energy via

photophosphorylation

Some bacteria and fungi use proteins as their source of carbon and energy. They secrete enzymes called ___________________ that hydrolyze proteins to amino acids, which are transported into the cell and catabolized

proteases

Because mitochondrial ETC's consist of four complexes arranged in order, the strength of the ___________ generated is greater than that produced by bacterial and archaeal ETC's

proton motive force

At freezing temperatures, most bacteria

stop growing, but are not dead.

The catabolic pathways of greatest importance to chemoorganotrophs are the _________ pathways and the tricarboxylic acid cycle

Glycolytic

The tricarboxylic acid cycle is also known as the citric acid cycle or the

Krebs cycle

Prokaryotic ETC

Located in the plasma membrane, chain may be branched, protons are moved across the plasma membrane to the periplasmic space

Infection results when the bacteria are phagocytosed by _____________ in the lung

Macrophages

Entner-Doudoroff pathway

Major microbial groups, soil bacteria, enterococcus faecalis,

Classify the two types of fermentations

Mesophilic- performed at 20-30C, uses lactococcus lactis, process used to make sour cream, microbes make diacetyl Thermophilic- performed at 45C, microbes make diacetyl and acetaldehyde, uses streptococcus salivaruius thermophilus, uses lactobacillus, process used to make yogurt

Many bacteria convert pyruvate to numerous products simultaneously in the process of ___________________ fermentation

Mixed acid

The TCA cycle enzymes are located in the matrix of each ____________ in eukaryotic cells

mitochondria

Chemotrophs

obtain energy from chemicals

Phototrophs

obtain energy from light

The net yield of the TCA cycle for each acetyl-CoA molecule oxidized includes _________.

one ATP or GTP molecule

ATP synthase in fermenting microbes pumps protons _________ the cell, fueling this transport by the energy released when ATP is hydrolyzed to ADP and Pi.

out of

Anaerobic respiration is the process whereby an exogenous terminal electron acceptor other than ______ is used for ETC

oxygen

This process was advanced in the case of milk ______________ where slightly lower temperatures are applied yet still effective in killing potential pathogens

pasteurization

After the glycolytic pathway produces ______, the partially oxidized carbon is fed into the TCA cycle and oxidized completely to CO2 with the production of some GTP or ATP, NADH, and FADH2.

pyruvate

In glycolysis, glucose is converted to

pyruvate

The TCA cycle is linked to the Embden-Meyerhof and pentose phosphate pathways through the molecule _________.

pyruvate

The catabolism of glucose begins with one or more pathways that yield

pyruvate

The Krebs cycle

pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions and acetyl CoA

The process of decarboxylation involves

removing carbon

When chemoorganotrophs oxidize an organic energy source, the electrons released are accepted by electron carriers such as NAD+ and FAD. When these reduced electron carriers (e.g., NADH, FADH2) in turn donate the electrons to an electron transport chain, the metabolic process is called _________.

respiration

Foods can be spoiled by both intrinsic and extrinsic factors. Extrinsic factors can include things such as

storage temperature

Autotrophs

Use carbon dioxide as their source of carbon

Most of the energy used to make ATP during aerobic respiration is conserved by the activity of

electron transport chain

Organotrophs

obtain electrons from organic compounds

The main environmental factors that affect microorganism growth include chemical inhibitors, oxygen, pH, nutrients, moisture, and

temperature

Oxygen acts as

terminal electron acceptor

For one turn of the Krebs cycle, how many NADH are produced?

three

The catabolic pathways of greatest importance to chemoorganotrophs are the glycolytic pathways and

tricarboxylic acid (TCA) cycle

For each glucose molecule that enters glycolysis, how many times does the Krebs cycle turn

two

How many net ATPs can be made from one molecule of glucose in glycolysis?

two

Lithotrophs

use inorganic molecules as a source of electrons

photolithoautotroph

- use light for energy and carbon dioxide for carbon; use water or other inorganic molecules for electron source - include the purple and green sulfur bacteria

photoorganoheterotroph

- use light for energy and organic matter as their electron donor and carbon source

Arrange the electron acceptors in order from highest to lowest energy. 1 = Cytochrome C 2 = Oxygen 3 = Cytochrome C oxidase

1, 3, 2

One of the three products made by organisms through the fueling reactions is _________, the primary molecule used to conserve the energy supplied by an energy source.

ATP

A single "turn" of the Krebs cycle will yield

1 ATP, 3 NADH, 1 FADH2

The NET products from the oxidation of glucose to pyruvate in the Emden-Meyerhof pathway are

2 NADH and 2 ATP

Following the formation of acetyl-CoA, the initial reaction of the Krebs cycle involves the addition of

2-carbon molecule to a 4-carbon molecule.

Choose the answer below that is an end product of aerobic respiration

ATP

Many microbes that can carry out anaerobic respiration will preform ________ respiration instead if oxygen is available

Aerobic

Pathogenesis of tuberculosis in order

Airborne mycobacterium tuberculosis are inhaled from respiratory droplets most often spread when an infected person coughs, alveolar macrophages engulf the bacteria but the bacteria survive and even multiply within macrophages, infected macrophages spread throughout the body to locations cub as the kidney, brain, and lymph nodes (bacteria are released in these locations, an inflammatory reaction occurs whenever m tuberculosis are located (macrophage and lymphocytes surround the bacteria and growth of bacteria cases in latent cases of tuberculosis, in active cases of tb, the inflammatory response cannot contain the growth of m tuberculosis and the organisms spread throughout the lungs and are released through coughing

Pentose Phosphate Pathway

All organisms

Gamma radiation is used on a variety of foods to extend their shelf life. Some of the characteristics of radiation are

An effective way to sterilize food, the process must be used with moist foods

dark reactions

Atp hydrolized, co2 is fixed, nadph is oxidized

light reactions

Atp is produced by phosphorylation, an ETC is utilized, nadph is generated, a proton motive force is created

Yet another use of heat is the sterilization of closed anaerobic containers in the _____________ process

Canning

The disease can become latent at this point, but in time nodules may develop into cheese like ___________ lesions

Caseous

What term describes organisms that obtain their energy by oxidizing organic compounds made by autotrophs

Chemoorganoheterotrophs

Microbial growth can be controlled by both intrinsic and extrinsic factors. Classify each characteristic by category.

Extrinsic factors- storage temperature, humidity, packaging Intrinsic factors- amount of carbohydrates, presence of a rind, oxidation-reduction potential, water activity

The Krebs cycle occurs in the mitochondrion of eukaryotes and the cytoplasm of bacteria and archaea

False

The formation of ATP as a result of the activity of the electron transport system is termed substrate-level phosphorylation.

False

The high-energy electrons of photosystem 1 are directly passed on to

Ferrodoxin

Nisin was added to the __________ list by the FDA IN 1988. It is nontoxic to humans and affects ___________ bacteria by binding to lipid 2 during _______________ synthesis and forms pores in the plasma membrane. The product is added directly to foods such as packaged meats, cheese, eggs, and canned vegetables.

GRAS, gram-positive, peptidoglycan

These lesions may calcify over time, forming __________ complexes that appear clearly on an X-ray

Ghon

Microorganisms employ several metabolic pathways to catabolize _____________ to pyruvate to produce energy and metabolites.

Glucose

Steps of Entner-Doudoroff Pathway (5)

Glucose 6-phosphate, 2-keto-3-deoxy-6-phosphogluconate (KDPG), substrate-level phosphorylation

Steps of Embden-Meyerhof pathway

Glucose, glucose 6-phosphate, fructose 6-phosphate, fructose 1,6-biphosphate, glyceraldehyde 3-phosphate, pyruvate

It is transferred to humans through the ____________ route through droplet nuclei

Respiratory

Correctly identify the steps that can lead to food borne illnesses by Salmonella/Campylobacter and E.Coli

Salmonella/Campylobacter- incomplete cooking of poultry and fruits and vegetables fails to kill all pathogens, live salmonella or campylobacter bacteria are ingested, pathogen multiplies in the intestinal tract for 2-48 days, diarrhea/abdominal pain/nausea can result Ecoli- incomplete cooking of raw hamburger fails to kill all pathogens, live ecoli bacteria are ingested , a shiga-like toxin is produced, bloody diarrhea and hemolytic uremic syndrome can result.

Bacterial and archaeal electron transport chains may be ____________ than mitochondrial ETC's, resulting in the release of less energy and the transport of fewer protons across the membrane

Shorter

Johnny buys a package of ham and places it in the refrigerator. There are 10,000 E.Coli cells on the ham. Predict the amount of E.Coli cells that would be on the ham three days later.

Slightly more than 10,000 because refrigeration slows microbial growth.

Various chemicals are used to preserve food and prevent microbial spoilage. If you wanted to prevent clostridium botulinum spore germination in your sausage meat it would be best to use

Sodium nitrite

Identify the steps that might occur leading to a food intoxication by staphylococcus aureus and clostridium botulinum

Staphylococcus aureus- other bacteria in the food are killed/inhibited by cooking/salty conditions, a food handler carries the pathogens in their nasal cavity and transfers it to the food via their hands, the pathogen produces an enterotoxin when the food is held at room temperature for several hours, a person ingests the toxin-containing food, resulting in staphylococcal enteritis in two to six hours Clostridium botulinum- bacterial endospores contaminate many different foods, endospores survive inadequate canning processes (canned foods are anaerobic), surviving endospores germinate, grow, and produce toxin in canned foods, a person ingests the toxin containing food, symptoms of botulism begin in 12-36 hours

The pyruvate is oxidized to form _______, which is fed into the TCA cycle and oxidized completely to _________

acetyl CoA and carbon dioxide

Another common fermentation carried out by many yeasts is ___________ fermentation, a process in which sugars are converted to ethanol and carbon dioxide

alcoholic

Numerous soil microbes use nitrate as an electron acceptor in ____________ soils.

anoxic

Above 100° C (212°F) most bacteria

are destroyed

Protons received from NADH

are pumped across the membrane

Methanogens use ____ as a terminal electron acceptor.

carbon dioxide

The low yield of atp means that _______________ must oxidize a large quantity of inorganic material grow and reproduce

chemolithotrophs

In eukaryotes, glycolysis takes place in the

cytoplasm

The first step in amino acid catabolism is ____________, the removal of the amino group from an amino acid

deamination

Anaerobic reduction of nitrate is called ________ nitrate reduction because it makes the nitrogen unavailable for use in constructing N-containing molecules such as amino acids and nucleotides.

dissimilatory

With ideal environmental factors, the reproduction rate of bacteria is

extremely rapid

Under aerobic conditions, the end product of glycolysis is further reduced to yield more ATP

false. Under aerobic conditions, the pyruvate is further oxidized to yield ATP. Under anaerobic conditions, the pyruvate is converted into lactic acid.

In addition to generating atp during respiration, in bacteria the pmf is also used to rotate the bacterial __________ motor

flagellar

In addition to its role in atp synthesis, in bacteria the pmf provides energy to drive

flagellar rotation and nutrient uptake

In glycolysis, glucose is phosphorylated at the expense of one ATP, producing

glucose-6-phosphate

Lactic acid fermenters that reduce almost all of their pyruvate to lactate are _____________ fermenters

homolactic

The movement of protons through atp synthase in eukaryotes occurs from the

intermembrane space to the matrix.

Where does carbon dioxide go when it is released during reactions of the Krebs cycle

it diffuses out of the cell

Under anaerobic conditions, the end-product of glycolysis is converted to

lactic acid

Eukaryotic ETC

located in the mitochondrial membrane, always consists of four complexes, protons are moved across the inner membrane of mitochondria, forming a proton gradient