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213 Cards in this Set
- Front
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Metabolism definition
|
the sum of all chemical reactions within a living organism
|
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catabolism
|
breaking down complex compounds into simple compounds/ molecules
- proteins into amino acids |
|
anabolism
|
building complex molecules from simple molecules
ex: amino acids into proteins |
|
5 things to know about enzymes
|
1. are biological catalysts
2. are specific for their substrates; usually 1 enzyme catalyzes only one reaction 3.All apoenzymes (main) are proteins 4. some enzymes need additional chemical components (cofactors) 5. the names of enzymes usually end in -ase |
|
2 types of metabolic reactions
|
1. catabolism
2. anabolism * both involve enzymes and energy |
|
T/F
a substrate can have many diff enzymes that can act on it- |
True
each reaction (and enzyme) may produce a diff product |
|
Different types of cofactors
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-organic cofactor- coenzyme (vitamins)
- inorganic cofactor- metal ions= Fe2+ and Ca2+ |
|
Factors influencing enzyme activity
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temperature, pH, substrate concentration
|
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Temperature- how does it influence enzyme activitiy
|
heat denatures protein- changes its 3D shape
when cold, substrate and enzyme have to move around to hook up. molecular movement slows when in cold temperatures. |
|
pH and enzyme activity
|
ions (H+, OH-) can change 3-D shape resulting in denaturation.
ions compete with chemical bonds in the enzyme |
|
Factors influencing enzyme activity
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temperature, pH, substrate concentration
|
|
holoenzymes (whole enzymes) consist of
|
apoenzyme, cofactor, and substrate
|
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which part of the enzyme is a protein?
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apoenzyme
|
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mechansim of enzyme action: steps
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1. substrate binds at active site
2. enzyme-substarte complex formed 3. leaves enzyme 4. products come off 5. enzyme with open active site |
|
substrate concentration: factor influencing enzyme activity
|
if saturated means: all active sites are filled with substrates.
|
|
to increase the reaction rate of a saturated enzyme..
|
the cell would have to make more enzyme for the excess substrate
|
|
what are the 2 types of inhibitors in regards to enzyme activity
|
1. competitive inhibitors
2. noncompetitive inhibitors |
|
competitive inhibitors
|
look like the substrate and compete with the substrate for enzymes active site
*no products from inhibitors* |
|
noncompetitive inhibitors
|
bind to another site on the enzyme (an allosteric site). binding changes the shape of the active site.
OR can bind to metal ion cofactors keeping them from helping the enzyme work |
|
5 things to know about energy
|
1. catabolic reactions release energy
2. anabolic reactions require energy |
|
5 things to know about energy
|
1. catabolic reactions release energy
2. anabolic reactions require energy 3. ATP is the principle energy molecule of the cell 4.ATP is generated in 3 ways from ADP (substrate-level, oxidative, and photophosporylation) 5. energy is released form food in a series of controlled reactions rather than in a simple burst |
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Oxidation
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loss of electrons
|
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reduction
|
gain of electrons
|
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to extract energy release from food in controlled series from one compound to another what type of reaction is used?
|
oxidation-reduction reaction
|
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when food is catabolized what happens/
|
chemical bonds are broken which release energy
|
|
when the third phosphate in ATP is removed what happens?
|
usable energy is released
|
|
substrate-level phosphorylation
|
ATP is generated when a high-energy phosphate is directly transferred from a phosphorylated metabolic intermediate too ADP
(glycolysis) |
|
oxidative phosphorylation
|
generation of ATP coupled with electron transport; electrons are passed from carried molecules to O2
(ETC) |
|
Photophosphorylation
|
generation of ATP coupled with electron transport in photosynthetic cells
+cells must have light-trapping pigments +converts light to energy into energy of ATP |
|
oxidation-reduction reactions are always coupled. T/F
|
TRUE
each time one substance is oxidized there is another substance which is reduced. |
|
what is it called when energy is released in a single burst?
|
combustion
|
|
Electron carrier molecules include
|
NAD and FAD
both coenzymes |
|
NAD nicotinmaide adenine dinucleotide
|
derivative of nicacin (b vitamin)
|
|
FAD flavin adenine dinucleotide
|
derivative of riboflavin
|
|
carbohydrate catabolism
|
produce energy from our food.
either by using cellular respiration and/or fermentation |
|
what is the first step for both fermentation and cellular respiration?
|
Glycolysis
|
|
cellular respiration is found where
|
some bacteria= anaerobically respire- dont us oxygen as a final acceptor in ETC
|
|
what is it called when energy is released in a single burst?
|
combustion
|
|
Glycolysis
|
Glucose (6 carbons)
(subst levl phosphorylation) 2 ATP (net)- ←--------------------→ 2NADH V V 2 Pyruvic Acid (3 carbons) |
|
Electron carrier molecules include
|
NAD and FAD
both coenzymes |
|
net ATP in glycolysis
|
2 ATP
2 used at beginning, 4 are made, net of 2! |
|
NAD nicotinmaide adenine dinucleotide
|
derivative of nicacin (b vitamin)
|
|
how is ATP made in glycolysis?
|
substrate level phosphorylation
|
|
FAD flavin adenine dinucleotide
|
derivative of riboflavin
|
|
carbohydrate catabolism
|
produce energy from our food.
either by using cellular respiration and/or fermentation |
|
what is the first step for both fermentation and cellular respiration?
|
Glycolysis
|
|
cellular respiration is found where
|
some bacteria= anaerobically respire- dont us oxygen as a final acceptor in ETC
|
|
Glycolysis
|
Glucose (6 carbons)
(subst levl phosphorylation) 2 ATP (net)- ←--------------------→ 2NADH V V 2 Pyruvic Acid (3 carbons) |
|
net ATP in glycolysis
|
2 ATP
2 used at beginning, 4 are made, net of 2! |
|
how is ATP made in glycolysis?
|
substrate level phosphorylation
|
|
In glycolysis 2, 3-carbon molecule are made which molecule are both converted to to go through?
|
glyceraldehyde 3-phosphate (GP)
|
|
Preparatory stage of glycolysis (KNOW ALL)
|
1. glucose
2. glucose 6-phosphate (phosph added from ATP) 3. fructose 6-phosphate + addition fo ATP 4. fructose 1,6 diphosphate 5. splits into: dihydroxyacetone phosphate (DHAP) adn Glyceraldehyde 3-phosphate --only Glyceradehyde are used to go through rest of process |
|
energy-conserving stage of glycolysis
|
2 GD oxidized to 2 pyruvic acid
- 4 ATP produced - 3 NADH produced |
|
transition step (glycolysis- kreb)
|
pyruvic acid is oxidized and decarboxylated (COOH is split off as CO2)
- 2 pyruvic acid per lucose result in 2 acetyl CoA per glucose |
|
what happens in the transition step
|
3 carbon molecule becomes a 2 carbon
|
|
T/F
Fermentation contains Krebs cycle but not an ETC? |
F
it doesnt use either! |
|
How many net ATP are made during Glycolysis?
And is that the same in all forms of fermentation and cellular respiration? |
2 NET ATP
YES! |
|
In fermentation what is oxidized/ reduced?
|
Oxidized: (lost e-) Glucose
Reduced: (gained e-) Pyruvic Acid Happens from the giving off of H+ from NAD |
|
wer does fermentation release energy from?
|
sugars or other organic molecules
|
|
Is fermentation anaerobic or aerobic?
|
it Does not require oxygen but can occur in its presence
|
|
If yeast is in an aerobic environment what does it produce? anaerobic?
|
aerobic: CO2
anaerobic: alcohol |
|
What is the final electron acceptor in fermentation?
|
it is ORGANIC!
ex: sulfate, nitrate |
|
why does fermentation produce less ATP than cellular respiration?
|
becase it doesn't get the 2 extra ATP from the Krebs cycle, nor does i get the multiple extra from the ETC
|
|
What is oxidized/reduced in lactic acid fermentation?
|
Lactic acid: reduced
NADH: oxidized |
|
Probiotics are what?
|
dried bacteria, usually lactobacillus
|
|
what accepts the H+ from NADH and is then changed to Ethanol
|
Acetaldehyde
|
|
Ethanol is reduced in alcohol fermentation? T/F
|
True
|
|
What are the 5 common end products of fermentation?
|
1. Lactic Acid- Streptococcus, Lactobacillus
2. Alcohol: ethanol, CO2 3. Propionic Acid and CO2- Propionibacterium 4. Acetone and Isopropyl Alcohol: Clostridium 5. Ethanol and Lactic Acid, Acetic acid and Succinic acid: E. Coli |
|
What are commercial product for each of the 5 common end products of fermentation?
|
1. Lactic Acid: yogurt
2. Alcohol: wine and beer 3. Propionic Acid + CO2: Swiss cheese 4. Acetone and Isopropyl Alc: Rubbing alcohol 5. Ethanol +lactic acid, Acetic acid, Succinic Acid: E. coli |
|
which form does Aerobic respiration use to generate ATP?
anaerobic? Fermentation? |
substrate-level and oxidative
-anaerobic: substrate-level adn oxidation -fermentation: substrate-level |
|
how many ATP are generated in each:
aerobic, anaerobic, and fermentation? |
aerobic: 36 (eu) 38 (pro)
anaerobic: btw (2-38) fermentation: 2 |
|
Lipids are composed of?
|
glycerol and fatty acid(s)
|
|
what does glycerol convert to?
|
glycerol converts to dihydroxyacetone phosphate
|
|
What does the dihydroxyacetone feed into?
|
glycolysis
|
|
Fatty acids convert to what?
|
Acetyl CoA which feeds into Krebs
|
|
what happens to Amino acids in Protein catabolism?
|
they must be deaminated (amine group removed)
|
|
what happens to the remainder of the amino acid after it has been deaminated?
|
its converted to pyruvate, acetyl CoA, or feeds into Krebs cycle directly
|
|
Transition step links glycolysis to what?
|
Krebs Cycle
|
|
During the transition step btw glycolysis and Krebs what happens to the pyruvic acid?
|
it is oxidized and decarboxylated (COOH is split off as CO2)
|
|
What does pyruvic acid turn into during the transition step btw glycolysis and krebs?
|
2 Pyruvic acid per glucose results in 2 Acetyl CoA per glucose
*a 3 carbon molecule becomes a 2 carbon mol |
|
What are the products of the Krebs cycle?
|
Acetyl CoA (2c)
Citric Acid (6c) 4 CO2 2 ATP 6 NADH 2 FADH2 Oxaloacetic acid (4 c) ** all #'s are for 2 spins of krebs cycle |
|
a 4c molecule (oxaloacetic acid) and a 2c (acetyl CoA) combine to for what?
|
a 6c molecule- citric acid
|
|
is FAD reduced or oxidized in Krebs cycle?
|
reduced because it's gaining H+
|
|
For every glucose molecule how many spins of the kreb cycle must you have?
|
2!
|
|
what are the other names of the Krebs Cycle?
|
Tricarboxylic acid cycle (TCA)
Citric Acid Cycle |
|
the 2 ATP are made through what process?
|
substrate level phosphorylation
|
|
What form of energy is made first in substrate level phosphorylation in krebs cycle?
|
GTP is made first, then broken down into GDP + Pi--> which creates energy
|
|
What is the energy from the break down of GTP into GDP +Pi used for?
|
Energy is used to put ADP + Pi to make ATP
|
|
What does the break down of Succinyl CoA to CoA and Succinate do?
|
creates energy to combine GDP + P
|
|
What is the ETC?
|
a series of carrier molecules that pass electrons given from NADH adn FADH2 via oxidation-reduction reactions
|
|
where do the NADH and FADH2 come from in the ETC?
|
theyre produced from glycolysis and Krebs cycle
|
|
where is most of the cells ATP made?
|
the ETC
|
|
how many ATP are produced per NADH? FADH2?
why? |
NADH: 3
FADH2: 2 difference bc FADH2 feeds in farther down the chain which is why you get less ATP production |
|
what is the importance of the ETC?
|
- it is a series of oxidation/reduction steps
-NADH adn FADH2: feed in a different locations (produce diff amounts of ATP) -Final electron acceptor is OXYGEN |
|
what is the final electron acceptor in the ETC?
|
oxygen
-aerobic respiration only -when it accepts the electrons, the combination with the H+ creates H2O. |
|
Every glucose produces 36-38 molecules of ATP
|
most come from ETC
2 from krebs 2 from glycolysis |
|
in chemiosmotic generation of ATP, for every NADH 6 H+ (protons) go through the ATP synthase pump what does that yield?
|
it yields 3 ATP
|
|
what is oxidative phosphorylation?
|
ETC coupled with ATP generation
|
|
photophosphorylation?
|
when sunlight hits clorophyl. it hits electrons and passes through a chain similar to the ETC
|
|
is oxygen the final electron receptor in anaerobic respiration?
|
no, usually nitrate or sulfate
|
|
in cellular respiration, glucose and oxygen combine with ADP +P to make what?
|
carbon and water dioxide, and ATP
|
|
can bacteria anaerobically respire?
|
some!
|
|
T/F ATP yield is always lower in anaerobic respiration than it is in aerobic respiration
|
TRUE
|
|
Does fermentation involve the Krebs Cycle?
|
No, it also does not involve the ETC in glycolysis
|
|
how many net ATP are produced form fermentation?
|
2!
|
|
In fermentation is glucose reduced or oxidized?
|
it is oxidized, oxygen gives up its electrons to pyruvate. (which then oxidates pyruvate)
|
|
T/F Pyruvic Acid is reduced in Fermentation?
|
TRUE! it gains electrons through the H+ given off from NAD-
|
|
HAVE YOU LOOKED UP FERMENTATION/ KREBS CYCLE/GLYCOLYSIS DIAGRAMS IN THE BOOK?
|
IF NOT DO IT!
|
|
Where does the energy released during fermentation come from?
|
sugars or other organic molecules
|
|
Does fermentation require oxygen?
|
no, but it CAN occur in its presence
|
|
What is produced from yeast during fermentation in both an anaerobic and aerobic environment?
|
anaerobic: alcohol
aerobic: CO2 |
|
How do the final electron acceptors differ in Krebs Cycle and fermentation?
|
in fermentation: its an organic molecule (sulfate, nitrate)
in krebs: always OXYGEN |
|
Which process produces more ATP?
|
Cellular respiration: bc of ETC
fermentation: only produces 2 |
|
HAVE YOU LOOKED UP LATIC ACID FERMENTATION AND ALCOHOL FERMENTATION DIAGRAMS IN BOOK?
|
GO DO IT NOW!
|
|
in lactic acid fermentation what is reduced? oxidized?
|
lactic acid (reduced)
Oxidized: 2 NADH + 2H --> 2 NAD+ |
|
what is the name of the "dried bacteria" that is formed during lactic acid fermentation?
|
probiotics
usually lactobacillus (Activia yogurt) |
|
What is the beginning of the Alochol fermentation process?
|
2 NADH (made from glycolysis) enter and are oxidized to form NAD+
|
|
what accepts the H+ that were removed from the NADH to form alcohol?
|
acetaldehyde
|
|
what is reduced in alcohol fermentation?
|
ethanol
|
|
what are the common end products for fermentation?
|
1. Lactic Acid: streptococcus, Lactobacillus (yogurt)
2. Alcohol: Ethanol + CO2 (wine/beer) 3. Propionic acid + CO2: propionibacterium (swiss cheese) 4. Acetone adn Isopropyl alc: Clostridium (rubbing alcohol) 5. ethanol +lactic acid, acetic acid, succinic acid: E.coli: micro test |
|
what are the components of household rubbing alcohol?
|
clostridium
(acetone and isopropyl alcohol) |
|
HAVE YOU LOOKED UP LATIC ACID FERMENTATION AND ALCOHOL FERMENTATION DIAGRAMS IN BOOK?
|
GO DO IT NOW!
|
|
in lactic acid fermentation what is reduced? oxidized?
|
lactic acid (reduced)
Oxidized: 2 NADH + 2H --> 2 NAD+ |
|
What is the form of ATP generation used in aerobic respiration?
how many ATP are made in this type of resp? |
substrate- level and oxidative phosphorylation
euk: 36 pro: 38 |
|
what is the name of the "dried bacteria" that is formed during lactic acid fermentation?
|
probiotics
usually lactobacillus (Activia yogurt) |
|
in anaerobic respiration what form of ATP generation is used?
how many ATP are generated? |
substrate- level and oxidative phosphorylation
variable ATP (2-38) |
|
What is the beginning of the Alochol fermentation process?
|
2 NADH (made from glycolysis) enter and are oxidized to form NAD+
|
|
what accepts the H+ that were removed from the NADH to form alcohol?
|
acetaldehyde
|
|
what is reduced in alcohol fermentation?
|
ethanol
|
|
what are the common end products for fermentation?
|
1. Lactic Acid: streptococcus, Lactobacillus (yogurt)
2. Alcohol: Ethanol + CO2 (wine/beer) 3. Propionic acid + CO2: propionibacterium (swiss cheese) 4. Acetone adn Isopropyl alc: Clostridium (rubbing alcohol) 5. ethanol +lactic acid, acetic acid, succinic acid: E.coli: micro test |
|
what is the components of household rubbing alcohol?
|
clostridium
(acetone and isopropyl alcohol) |
|
What is the form of ATP generation used in aerobic respiration?
how many ATP are made in this type of resp? |
substrate- level and oxidative phosphorylation
euk: 36 pro: 38 |
|
in anaerobic respiration what form of ATP generation is used?
how many ATP are generated? |
substrate- level and oxidative phosphorylation
variable ATP (2-38) |
|
What form of ATP generation is used in fermentation? how many ATP are generated?
|
substrate-level
2 ATP generated |
|
in Lipid and protein catabolism what is converted?
|
glucose
|
|
HAVE YOU LOOKED AT THE LIPID AND PROTEIN DIAGRAM IN THE BOOK??
|
DO IT NOW!
|
|
what are lipids composed of?
|
glycerol and fatty acids
|
|
What does glycerol convert to in Lipid Catabolism inorder to feed into glycolysis?
|
dihydroxyacetone phosphate
|
|
In Lipid catabolism what is converted into Acetyl CoA which feeds into the Krebs Cycle
|
fatty acids
|
|
Proteins are chains of amino acids
|
LOOK AT STRUCTURE OF AMINO ACID IN NOTES RIGHT NOW!
|
|
amino acids must be deaminated during what process? (amine group removed)
|
protein catabolism
|
|
what happens to the remainder of the molecule that is not the amino acid in protein catabolism?
|
converted to: pyruvate, acetyl CoA OR
feeds directly into Krebs |
|
What is the goal of metabolism?
|
so organisms can oxidize molecules to produce energy through aerobic respiration, anaerobic respiration and/or fermentation
|
|
T/F some energy is lost as heat during metabolism process?
|
TRUE
|
|
concluding that some energy from metabolic process is lost as heat what is the remaining energy used for?
|
1. active transport
2. locomotion 3. make cellular moleucles |
|
INTEGRATION OF METABOLISM DIAGRAM
|
LOOK AT IT
|
|
what is microbial growth?
|
growth of bacterial populations
|
|
T/F microbial growth refers to the number of cells?
|
true
|
|
how do bacteria reproduce
|
binary fission
|
|
generation time?
|
the time required for a cell to divide and its population to therefore double
can vary among diff organisms |
|
LOOK UP:::: PHASES: LAG, LOG, STATIONARY, DEATH
|
REMEMBER:
A COMES B4 O IN ALPHABET (LAG B4 LOG) |
|
chemical requirements for growth?
new cig |
1. carbon- CO2 OR organic (sugar)
2. nitrogen- needed for protein synthesis (amine gp of amino acid) 3. inorgainc ions (minerals)- cofactors for enzymes 4. growth factors- certain amino acids and coenzymes (vitamins) 5. water- needed for some enzymatic reactions 6. energy source- light or chemicals |
|
Which is more efficient in producing amino acids and vitamins? e. coli or humans?
|
E. Coli can make all of its own amino acid and vitamins while humans can only make about 1/2 of amino acids
|
|
what type of organisms use an energy source for food? light? chemicals?
|
light: phototroph
chemicals: chemotroph |
|
which organism uses a carbons source for food? CO2? Organic carbon?
|
CO2: autotroph
Organic carbon: hetertroph |
|
T/F microbial growth refers to the number of cells?
|
true
|
|
what type of organism uses both light for energy and CO2 for carbon (self feeders)
|
photoautotrophs
|
|
how do bacteria reproduce
|
binary fission
|
|
in photosynthesis: hydogens from water reduce/oxidize carbon dioxide to make food?
|
reduce
|
|
generation time?
|
the time required for a cell to divide and its population to therefore double
can vary among diff organisms |
|
LOOK UP:::: PHASES: LAG, LOG, STATIONARY, DEATH
|
REMEMBER:
A COMES B4 O IN ALPHABET (LAG B4 LOG) |
|
chemical requirements for growth?
|
1. carbon- CO2 OR organic (sugar)
2. nitrogen- needed for protein synthesis (amine gp of amino acid) 3. inorgainc ions (minerals)- cofactors for enzymes 4. growth factors- certain amino acids and coenzymes (vitamins) 5. water- needed for some enzymatic reactions 6. energy source- light or chemicals |
|
Which is more efficient in producing amino acids and vitamins? e. coli or humans?
|
E. Coli can make all of its own amino acid and vitamins while humans can only make about 1/2 of amino acids
|
|
what type of organisms use an energy source for food? light? chemicals?
|
light: phototroph
chemicals: chemotroph |
|
which organism uses a carbons source for food? CO2? Organic carbon?
|
CO2: autotroph
Organic carbon: hetertroph |
|
what type of organism uses both light for energy and CO2 for carbon (self feeders)
|
photoautotrophs
|
|
in photosynthesis: hydogens from water reduce/oxidize carbon dioxide to make food?
|
reduce
|
|
what is the formula for photosynthesis in green and purple sulfur?
|
CO2 + 2H2S --(light)--> (CH2O)n + H2O +2S
|
|
what is the difference btw green and purple sulfur photosyntheis and reg photosynthesis?
|
green/purple sulfur has an organic compound in the result (CH2O)
WHICH MEANS NO OXYGEN is produced -- but SULFUR is |
|
photoheterotrophs use which two sources to obtain energy?
|
light and organic carbon sources
|
|
Can photoheterotrophs convert CO2 to sugars?
|
NO! they must have an organic food source.
ex; green nonsulfur bacteria and purple nonsulfur bacteria |
|
Do photoheterorophs use light for food?
|
no they use it for energy, but need to be provided with outside sources of food
|
|
The light that is used for energy goes through what process?
|
the photosynsitive pigments attract the light and excite the electrons to go through the ETC
|
|
What source do Chemoatotrophs use for energy?
|
inorganic compounds= energy and CO2 as a carbon source
|
|
What is a function of chemoautotrophs/
|
they can leach minerals from an ore: extraction of copper from copper ore.
|
|
T/F ammonia is a common energy source in chemoautotrophs?
|
t/f some use it.
allows them to return nitrogen back to the environment. - found in soil, where they encounter nitrogen as waste product of animals |
|
Chemoheterotrophs are what form of organisms?
|
WE ARE CHEMOHETEROTROPHS!
|
|
what type of nutritional classification uses organic sources for energy and carbon?
|
chemoheerotrophs
(glucose may be used for both sources!) |
|
can chemoheterotrophs use light and/ or CO2 for energy?
|
NO! they must be fed!
|
|
is oxygen a requirement for all cell growth?
|
no, anaerobes do not need oxygen to grow
|
|
What is a free radical of oxygen and who produces it?
|
free radical: highly reactive particle with an unpaire electron:
superoxide O2-. (organisms who go through aerobic respiration produce superoxide) |
|
why is superoxide harmful to cells?
|
steals electrons away from neighboring molecules-- which will in turn become a free radical itself
|
|
aerobic cells neutralize superoxide by which enzymes?
|
superoxide dismutase and catalase enzymes
|
|
LOOK AT REACTION OF NEUTRALIZING SUPEROXIDE
|
the very end components are water and oxygen
|
|
can anaerobes experience free radicals of oxygen?
|
no they cannot make catalase or superoxide dismutase
w |
|
why do strict anaerboes die in the presence of oxygen?
|
they lack superoxide dismutase and usually catalas
(ex: clostridium) |
|
how is superoxide produced?
|
if the O2 accepts 1 electron at the end of the ETC
|
|
why are hydrogen peroxide and superoxide bad for the cell?
|
they attack unsaturated fatty acids in membrane lipids and can cause the membrane to lyse
|
|
what is prevented through the control of microbial growth?
|
1. contamination
2. spoilage 3. transmission of infection and disease |
|
Does controlling microbial growth always mean killiing the bacteria?
|
NO! they can also be used to stop the growth: bacteriastatic
|
|
what is sterilization?
|
is killing or removal of all life forms in a given area.
ZERO bacteria |
|
UV light is a form of which form of which type of radiation?
|
nonionizing radiation
|
|
what does UV light effect in the cell?
|
causes mutations in DNA-
pyrimidines (thymine or cytosine) bind together instead of with with the cells across on the other strand |
|
what are two examples of pyrimidines?
|
thymine or cytosine
*hint: all have "y's" in the name! |
|
do you need to have direct exposure to UV rays for them to be effective?
|
yes!
|
|
ionizing radiation consists of what forms of radiation?
|
gamma rays, x-rays, and electrons beams
|
|
what do ionizing radiation beams ionize?
|
water inside the cell to form a highly reactive free radical
|
|
what are hydroxyl radicals?
|
they steal electrons away form cellular components especially DNA- causes mutations/possible death
(cancer) |
|
What are the physical methods of controlling microbial growth?
ch ford |
heat
filrtration cold desiccation osmotic pressure radiation |
|
What is the most effective form of heat for controlling microbial growth?
|
autoclaving- bc it also ensures death of endospores, unlike boiling, pasteurization or dry heat
|
|
what are the 3 forms of dry heat?
|
direct flaming (loops in lab)
incineration (animals in lab) [both ^ burn to ashes] hot- air sterilization (old labs- in oven) |
|
Is pasteurization considered sterilization?
|
no, only stopped growing not killed
|
|
are all 3 forms of Dry heat sterilization?
|
yes! and are all very effective
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why is heat an effective method of controlling microbial growth?
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because heat denatures proteins which in turn denatures enzymes. w/o enzymes the cell cannot grow and function effectively
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Why does being cold effect the growth of bacteria?
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it slows down molecular mvmt, which leads to less enzymatic activity= less growth.
also there can be possible changes in proteins |
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deep freezing works in controlling growth bc?
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there is lots of H2O in ells which create ice crystals w/ jagged edges when frozen. these crystals can disrupt and injure the cell membrane
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what is the main focus of desiccation?
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removal of water.
which disrupts the metabolism bacteriostatic |
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why does desiccation work for controlling growth?
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bc many metabolic reactions require H2O and w/o it the reactions cannot happen
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osmotic pressure is revolved around what ideal?
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cell wall theory.
plasmolysis occurs- cell shrinks |
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what is osmotic pressure most commonly used in
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salt cured or sugar cured food. results in loss of water from cells.
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which is better suited for inhibiting the growth of living organisms? antiseptics or disinfectants
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antiseptic
a disinfectant cleans non living surfaces |
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how do chemical agents work?
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destroying the cell membrane and/or denaturing proteins
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concentration, time, temperature, and the surrounding environment are all variables for what?
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they are all things to consider in chemical controls of microbial growth
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