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51 Cards in this Set
- Front
- Back
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What is an endergonic reaction?
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A reaction in which energy is absorbed, such as photosynthesis.
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What is an exergonic reaction?
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A reaction in which energy is released,
such as cellular respiration. |
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What is anabolism?
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Building up
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What is catabolism?
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Breaking down
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What is metabolism?
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The sum of all anabolic & catabolic reactions in an organism or cell.
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What is an anaerobic process?
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A process that does not require oxygen.
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What is an aerobic process?
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A process that requires oxygen
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What are enzymes?
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Enzymes are protein catalysts that reduce the activation energy in a biological reaction. All chemical reactions require activation energy to break chemical bonds and begin the reaction.
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What conditions affect the function of enzymes?
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Very high temperatures may denature an enzyme due to the fact that enzymes are protein. Most pH levels will not affect the function of an enzyme.
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What is a substrate?
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A substrate binds to the active site of an enzyme to activate the enzyme so it can act as a catalyst.
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What is a competitive inhibitor?
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A competitive inhibitor is a substance that competes with an enzymes substrate for the active site on an enzyme.
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What is a non-competitive inhibitor?
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Non-competitive inhibitors do not compete at all. They bind to a site away from the active site, changing the shape of an enzyme so it no longer has an affinity for its substance.
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What is an allosteric site?
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A binding site some distance away from the active site that may bind to substances that may inhibit an enzymes activity.
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What is an activator?
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Activators bind to an allosteric site and stabilizes the protein conformation that keeps the active site available
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What is an allosteric inhibitor?
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An allosteric inhibitor binds to the allosteric site on an enzyme and activates the inactive form.
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What is feedback inhibition?
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A method of metabolic control when the product of a reaction comes back to an earlier part of a reaction and allosterically inhibits an enzyme.
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What is the function of dehydrogenase?
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Dehydrogenase removes hydrogen, electrons and energy. It is an exergonic process.
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What is the function of decarboxylase?
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Decarboxylase removes carbon dioxide and is an exergonic process
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What is the function of phosphorylase? Draw a diagram.
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Phosphorylase either adds/removes a phosphate or makes/uses ATP.
When ADP turns into ATP it is an endergonic reaction. |
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What are the 3 major steps involved in photosynthesis? Where do they occur?
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I) Capturing light energy in the thykaloid membrane
II)Light energy makes ATP + NADPH&H in the thykaloid membrane III) The calvin cycle making G3P in the stroma |
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Where does photosynthesis occur in prokaryotes?
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Photosynthesis occurs in the cell membrane folds in prokaryotes.
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Describe the structure of a chloroplast.
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Contained by an inner & outer phospholipid membrane
Material within called stroma Stroma is stacks of thylakoid disks Stacks are called grana Inside the disks is lumen Photosynthesis takes place in the thykaloid membrane, in the antenna complex with light absorbing pigments |
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Why is grass green? Explain the chlorophyll pigments.
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Chlorophyll A & B are the primary light absorbing pigments
They absorb photons of blue-violet and reg wave lengths Green is reflected |
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How does light energy travel?
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In wave packets called photons
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Explain the steps of the electron transport system.
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A group of photons strike photosystem II (p680)
A chlorophyll molecule gets excited and when it returns to ground state it releases energy The pathway is PQ > b6-f complex> PC > P 700 > fd > NADP reductase |
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How are electrons replenished?
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The Z protein breaks a water molecule
Electrons go into p 680 Oxygen is removed as waste H ions are released into the thykaloid membrane |
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What is the result of the H ions entering the thykaloid membrane?
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The H ions follow the concentration gradient and then move through ATP synthase which turns ADP + Pi = ATP
NADPH&H is created by 2 electrons 2 H ions moving through NADP reductase |
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What is non-cyclic phosphorylation?
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Involves both of the photosystems
As described "normally" |
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What is cyclic phosphorylation?
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Only involves photosystem I
Electrons are moved from the b6-f complex > PC > P700 > Fd > b6-f Generates ATP |
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Where does the calvin cycle occur and what are the three phases?
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Occurs in the stroma
I) Carbon fixation II) Reduction reactions III) RuBP Regeneration |
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Explain carbon fixation. What enzyme is involved?
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A CO2 molecule is added to a 5 carbon RuBP to form a 6c
Ribulose biphosphate carbolxylase splits the 6 carbon molecule into two 3 carbon molecules of PGA Occurs 6 times to make 1 glucose |
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Explain the reduction reactions.
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PGA is then phosphorylated into BPG using ATP
BPG is then reduced to G3P by using NADPH&H For every 1 G3P that leaves the cycle, 5 go on 2 x G3P = 1 glucose |
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Explain RuBP Regeneration.
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5 molecules of G3P must be converted back to 3 molecules of 5 carbon RuBP
There are 5 phosphates, 1/G3P & must end with 6, 2/RuBP 2 Pi are removed & 3 ATP are added 2 water molecules are added for the H & OH groups |
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What are the reactants & products of the electron transport system?
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Reactants: Light energy and water
Products: ATP + NADPH&H |
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What are the reactants and products of carbon fixation?
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Reactants: CO2 & a five carbon RuBP
Products: PGA (3-phosphoglycerate) |
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What are the reactants and products of
the reduction reactions? |
PGA + ATP > BPG & NADPH+H > G3P
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What are the reactants and products of RuBP regeneration?
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5 G3P, 3 ATP, Pi removed and water
Products: 3 five carbon RuBP's |
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What is cellular respiration?
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Cellular respiration is the conversion of energy trapped within glucose to energy available to do work within the cell in the form of ATP
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What is glycolysis and where does it occur?
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Glycolysis occurs in the cytoplasm
Glucose is broken down into 2 molecules of pyruvate by the addition of 2 ATP The breakage released 4 ATP NADH&H is also produced |
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What is the fate of pyruvate and why does this occur?
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NAD must be returned to the cell
This is done by removing pyruvate from NADH |
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What is ethanol fermentation?
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Ethanol fermentation is an anaerobic process and occurs in bacteria and yest cells.
pyruvate + NADH&H -> ethanol + CO2 + NAD |
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What is lactic acid fermentation?
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This is an anaerobic process and occurs in animal cells
pyruvate + NADH&H <-> lactic acid _ NAD When oxygen is available again, lactate is converted back into pyruvate so cellular respiration can continue |
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Explain oxidation of pyruvate.
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This is an aerobic process and occurs in the mitochondrial matrix of eukaryotic cells.
pyruvate + NAD + CoA-SH -> acetyl-CoA + NADH&H + CO2 occurs twice per cycle |
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What is the krebs cycle and where does it occur? Why is it cyclical?
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This process is aerobic and occurs in the mitochondrial matrix.
This process is cyclical because oxaloacetate is both a reactant and product 2 acetyl-CoA are produced/glucose |
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What happens if acetyl-CoA levels are high? Low?
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High: goes onto produce lipids
Low: Goes into the krebs cycle to produce more ATP |
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What is the ETC and where does it occur?
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This occurs in the inner membrane of the mitochondria. A set of oxidation-reduction reactions convert energy in FADH2 + NADH&H into ATP
NADH&H passes its electrons onto FADH2 because it cant fit in the membrane NADH dehydrogenase > Protein Q > cytochrome complex > cytochrome c > cytochrome oxidase complex > oxygen As the chain goes the molecules become more negative |
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What is chemiosmosis?
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Proton accumulate in the intermembrane space, creating an electrochemical gradient.
Protons want to move back across the inner membrane but cant due to the phospholipid by layer Enzyme ATP synthase distorts its shape to allow protons to move through it Once it goes back to its normal shape it is able to convert ADP + Pi > ATP |
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What is the ATP yield for NADPH, FADH2 and glucose
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NADPH: 3 ATP
FADH2: 2 ATP Glucose: 36 ATP |
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What steps of cellular respiration are aerobic?
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pyruvate oxidation
krebs cycle ETC |
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What steps of cellular respiration catabolic?
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glycolysis
pyruvate oxidation krebs cycle |
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What steps of cellular respiration are anabolic?
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The light reactions
The calvin cycle Glycolysis pyruvate oxidation krebs cycle ETC..kind of |
