Lecture 7 Flashcards Preview

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Flashcards in Lecture 7 Deck (71):
1

Metabolism

sum of all chemical reactions that occur within an organism

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Hope for metabolism is that..

catabolic NRG covers anabolism NRG

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2 classes of metabolism

-catabolism
-anabolism

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Catabolism

reactions that GENERATE energy. breakdown of complex organic compounds into simpler ones

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Anabolism

reactions that REQUIRE energy. biosynthesis or building of complex molecules from simpler ones

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Energy is stored in the form of..

adenosine tri-phosphate (ATP)

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The bonds between each of the 3 phosphate groups of ATP are..

very high energy (all NRG is stored here)

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______ is key reason ATP stores so much NRG.

negative; negative oxygen wants to leave

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What type of reactions generate ATP

catabolic

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ATP ---->
ADP ----->
ATP ----->

ADP + Pi
AMP + Pi
AMP + PPi

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What is waste product lost to form ATP

heat energy

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Oxidation reduction reactions reffered to as..

redox reactions. re= reduction ox= oxidation

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Oxidation..

is the loss of an electron from a molecule

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Reduction..

is the gain of an electron by a molecule

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LEO says GER

loss e- oxidation; gain e- reduction

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Oxidation and reduction always occur...

simultaneously

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In a redox reaction one molecule is...... and another molecule is...

oxidized (provides electrons) ; reduced (receives the electrons from the oxidized molecule)

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Nicotinamide adenine Dinucleotide (NAD+)

Acts as an electron carrier. oxidized form, only room for 2 electrons

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NADH + H

reduced form

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NAD + 2e- + 2H ---->

NADH + H

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To get NAD reduced..

2 electrons are removed from the donor molecule and added to the recipient molecule

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A + B are...

reactants

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AB are..

products

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Reaction rate

speed at which the chemical reaction proceeds

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3 things can can be done in order to increase reaction rate

-increasing temp
-increasing pressure
-adding an enzyme

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Catalysts

lower the activation energy of a particular reaction

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Enzymes

catalysts, cause more effective collisions, acts on a specific substrate

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A particular enzyme catalyzes..

only on reaction

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How does the enzyme lower the activation energy...

by positioning the substrate such that there is a greater probability that the reaction will take place

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With an enzyme present reactions can occur..

up to 10 billion times faster than without an enzyme

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Carbohydrate catabolism

breakdown of carbohydrates in order to release energy

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Most common carbohydrate used by cells for energy is

glucose

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2 processes can be used to catabolize glucose

-cellular respiration
-fermentation

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Cellular respiration

occurs when oxygen is present, much more effective than fermentation

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How many ATP are released in cellular respiration

32 ATP

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Fermentation

occurs when oxygen is absent, less effective

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How many ATP are released in fermentation

2 ATP

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3 main stages of cellular respiration

-glycolysis (intermediate stage)
-krebs cycle (citric acid cycle)
-electron transport chain

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Glycolysis

splitting of sugar into smaller molecules, this reaction can occur in presence or absence of oxygen.

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Gylcolysis occurs in a sequence of..

10 reactions

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During glycolysis

one glucose is converted into 2 molecules of pyruvic acid. only a small amount of NRG is released, 2 ATP and 2 NADH

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Intermediate step

2 molecules of pyruvic acid are prepared for entry into Krebs, oxygen is needed to produce this step

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Intermediate step process

one carbon dioxide is removed from each (2) pyruvate, a CoA group is added to each of the 2 new formed carbon sugars. total of 2 NADH are formed

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Krebs cycle

2 molecules of acetyl CoA are broken down into 4 CO2, requires oxygen

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Where does the Krebs cycle occur

in the cytoplasm of bacterial cell and the mitochondria of eukaryotic cell

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Total per glucose after krebs

10 NAPH, 2 FADH2, and 4 ATP

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Electron transport chain

last step of aerobic respiration, occurs in the bacterial membrane, electrons from the NADH are transported through a series of electron carriers

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Process of the electron transport chain

During each transfer of electrons, NRG is released and used to make ATP, 2-3 ATP are produced for each NADH that pass through the chain, end of the chain electrons are deposited to on oxygen forming water

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The entire process of cellular respiration produces approximately..

32 ATP per glucose molecule\

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Fermentation

occurs to produce NRG when oxygen is absent, produces much less NRG than aerobic respiration

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Fermentation has... but no..

glycolysis; no krebs or ETC

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How man ATP produced per glucose

2 ATP

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2 main types of fermentation

-alcohol fermentation
-lactic acid fermentation

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Alcohol fermentation

carried out by yeast/fungi and some bacteria. waste products of reaction are ethanol and carbon dioxide. 2 ATP are produces

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Lactic acid fermentation

Pyruvic acid is converted into lactic acid, performed by many bacteria, can cause food spoilage and food production. 2 ATP are produced

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Although glucose is the primary energy source used in bacteria they also use... (3 food catabolism)

-carbohydrates
-lipids
-proteins

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Carbohydrates

polysaccharides such as starch are broken down into component sugars which are converted into glucose, the glucose then enters metabolic cycle beginning w/ glycolysis

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Lipids

lipids are broken into components (FA and glycerol) by the enzyme lipase, components then enter metabolic cycle via glycolysis or krebs

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Proteins

proteins are broken into component amino acids by enzymes (proteases), then enter into the metabolic cycle via glycolysis or krebs

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Anabolism =

biosynthesis

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The components of glycolysis and krebs usually serve as the..

starting point for the production go amino acids, lipids, and nucleotides

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Components of glycolysis and krebs are referred to as..

precursor metabolites

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Precursor metabolites can be..

one of carbon backbones in glycolysis like pyruvate, can used then to do glycolysis

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Organisms can be classified based on their nutritional needs as..

-source of energy
-source of carbon

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Energy sources...

-Chemical energy - chemotrophs -organic OR unoriginal
-Light energy - phototrophs

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Carbon sources..

-organic - heterotrophs (sugars)
-inorganic - autotrophs (CO2)

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Most medically relevant bacteria are..

chemoheterotrophs

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Photoautotrophs

these organisms use light energy ti produce ATP and CO2 as carbon source through photosynthesis, includes some bacteria, all algae and plants

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Photoheterotrophs

these organisms use light energy to produce ATP and obtain organic carbon from food, includes some bacteria

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Chemoautotrophs

these organisms use chemical reactions to obtain energy and CO2, the chemical reactions involve reduced inorganic molecules (H2, H2S, CO), only done by some bacteria

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Chemoheterotrophs

these organisms use chemical reactions to obtain energy and organic molecules as carbon source, involve reduced organic molecules (very diverse) this group includes all animals, fungi, protozoa, and most bacteria