Unit 2: Metabolic Processes Flashcards
first law in thermodynamics
energy cannot be created nor destroyed–only converted from one form to another
activation energy
the amount of energy required to start a chemical reaction
difference between exothermic and endothermic reactions
exothermic–give off more energy than they take; release heat (e.g. wood)
endothermic–give off less energy than they take; absorbs heat (e.g. ice pack)
ATP
adenosine triphosphate; source of energy in living cells
difference between reduction and oxidation
reduction–gain of electrons
oxidation–loss of electrons
ATP and ADP can alternate through (___/___) reaction
hydrolysis/dehydration
NAD+
nicotinamide adenine dinucleotide; molecule that moves electrons
How does NAD+ become NADH?
It picks up 2 hydrogen atoms, takes a whole H + 1 e and releases a H+
difference between substrate level phosphorylation and oxidative level phosphorylation
substrate level: forms ATP through an enzyme catalyzed reaction that directly transfers a P to ADP (glycolysis and citric acid cycle)
oxidative level: forms ATP indirectly using energy transferred through a series of redox reactions (electron transport/chemiosmosis)
simple explanation of glycolysis
glucose molecule is broken down into 2 pyruvate molecules and energy is released
simple explanation of pyruvate oxidation
pyruvate is oxidized by NAD+, releasing NADH, CO2 is lost, and an acetyl group is formed
simple explanation of citric acid/Krebs cycle
series of reactions that transfer energy to ATP, NADH, FADH2, and releases CO2
simple explanation of electron transport
NADH and FADH2 are oxidized, water is released, H+ gradient allows ATP to be created
How is cellular respiration controlled? (list 3 ways)
- phosphofructokinase is inhibited by ATP (fructose 6 phosphate cannot turn into fructose 1,6-biphosphate) and stimulated by ADP
- phosphofructokinase also inhibited by citrate
- NADH inhibits enzyme pyruvate decarboxylase, reducing amount of acetyl-CoA produced
What does it mean when NADH levels are high?
electron transport chain is full and ATP production is at maximum
What is photosynthesis + describe the chemical process in words.
The process by which chlorophyll containing organisms use the sun’s energy to produce glucose
(carbon dioxide + water + energy = glucose + oxygen)
Where is the chlorophyll molecule usually found in the leaf?
Near the surface in the palisade layer
Describe a chlorophyll molecule.
Porphryn ring whose movement of electrons allows for absorption of radiant energy and a phytol tail for anchoring
Both mitochondria and chloroplasts contain their own ___, evidence that they once ____ _____.
Both mitochondria and chloroplasts contain their own DNA, evidence that they once existed separately.
List the 3 distinct parts/stages of photosynthesis.
- Capture light energy
- Convert light energy into chemical energy (ATP, NADPH)
- Storage of chemical energy in glucose (using ATP, NADPH)
How do plants obtain energy from the glucose they make? How do they obtain energy without sunlight (e.g. at night)?
Cellular respiration
light dependent reactions
first stage of photosynthesis where water is split as light energy is absorbed and transformed into chemical energy in ATP and NADPH
dark reactions (aka light independent reactions aka Calvin cycle)
second stage of photosynthesis where ATP and NADPH is used to convert CO2 to glucose
Where do light dependent reactions occur in photosynthesis?
thylakoid membranes
Where do dark reactions occur in photosynthesis?
Calvin cycle occurs in the stroma of the chloroplast
In what part of the mitochondria does each stage of cellular respiration occur?
Glycolysis - cytoplasm
Pyruvate oxidation and citric acid cycle - mitochondrial matrix
Electron transport - mitochondrial membrane
3 goals of cellular respiration
- Break bonds in glucose
- Move electrons from glucose to oxygen
- Trap free energy as ATP
Facultative anaerobes will produce more ATP in the ___ of oxygen.
presence
difference between alcohol fermentation and lactate fermentation
alcohol fermentation releases carbon dioxide, lactate fermentation does not
T/F: Anaerobic respiration relies on organic compounds other than oxygen to act as the final oxidizing agents in the production of ATP
False; they rely on INORGANIC compounds to act as final oxidizing agents
What are the products of pyruvate oxidation?
CO2, NADH, H+, acetyl Co-A
What anaerobic ATP producing process can occur in nearly all animals?
lactate fermentation
How does the folding of the mitochondria’s inner membrane benefit aerobic respiration?
Provides greater surface area for electron transport chain and ATP synthase = more copies of them = more ATP can be produced
What is ferredoxin?
An electron acceptor in PSI
____ have chloroplasts, and ____ have mitochondria.
Only green plant cells have chloroplasts, and all animal and plant cells have mitochondria.
What are the 2 important products of PSI?
ATP and NADPH
Out of the 6 glyceraldehyde 3 phosphate (G3P) molecules formed during the Calvin cycle, how many are turned into sugar?
One (but the cycle must repeat several times to make a carbon molecule because each turn only adds one carbon)
Describe the steps of the Calvin cycle.
- CO2 added to 5 carbon RuBP and the resulting 6 carbon molecule is unstable so it splits into 2, 3 carbon molecules called 3-phosphoglycerate.
- After going through a series of reactions with ATP and NADPH, 3-phosphoglycerate is converted into glyceraldehyde 3 phosphate.
Where does the Calvin cycle take place?
In the stroma of the chloroplasts
What is photorespiration?
A phenomenon that occurs during hot dry days, when oxygen competitively inhibits enzyme rubisco instead of carbon dioxide, reducing the production of glucose
How does an electron that has gained energy from light behave?
Three possible outcomes:
- Return to ground state, releasing thermal energy or fluorescence
- Transfer energy to neighbouring electron
- Electron is accepted by an electron-accepting molecule
p680 - PS II or I?
p700 - PS II or I?
PSII - p680
PSI - p700
How many turns of the Calvin cycle is required to produce one molecule of glucose?
6 (3 turns will give 1 G3P, which is half a glucose)
6 CO2 + 12 H2O + 12 NADP + 18 ADP = C6H12O6 + 6 H2O + 6 O2
correct equation for photosynthesis
