Chapter 9 (Respiration and Fermentation) Flashcards
What are redox reactions?
transfer of electrons during chemical reactions aka one molecule gains electrons while the other molecule loses electrons
What happens in oxidation?
a substance loses electrons and increases the overall positive charge of a molecule
What happens in reduction?
a substance gains electrons and increases the overall negative charge of a molecule
What is a reducing agent?
influences other molecules to gain electrons
What is an oxidizing agent?
influences other molecules to lose electrons
What are the electron carriers in cellular respiration?
NAD+ and FAD+
How is NAD+ made?
the electrons from organic compounds like coenzyme Niacin from vitamin B3 (niacin) are transferred to make NAD+
What are dehydrogenase enzymes?
enzymes that take away hydrogens from organic molecules like NADH and FADH2 to make NAD+ + H+ and FAD+ + H+
What is the reduced form of NAD+?
NADH
What is the purpose of NADH?
stores energy and carries electrons
What does NAD+ stand for?
nicotinamide adenine dinucleotide
What is the structure of NAD+?
nicotinamide, ribose, phosphate group
adenine, ribose, phosphate group
What is NADPH?
has an extra phosphate group attached to ribose ring at bottom
What is the reduced form of FAD+?
FADH2
What is the purpose of FAD+?
stores energy and carries electrons
What does FAD+ stand for?
Flavin adenine dinucleotide
What is the structure of FAD+?
adenine (nitrogenous base), ribose, 2 phosphate group (ADP)
ribitol (the sugar chain)
flavin (nitrogenous base)
Where does energy come from in an ecosystem?
light, the sun
How does energy exit from an ecosystem?
thermal energy, heat
What materials does photosynthesis require for the process to happen?
energy + H2O + CO2
What does photosynthesis create?
O2 + organic molecules
Where does cellular respiration take place?
mitochondria
What materials does cellular respiration require for the process to happen?
organic molecules + O2
What does cellular respiration create?
energy + H2O + CO2
What is aerobic respiration?
consumes organic molecules AND O2 to yield ATP
What is anaerobic respiration?
consumes compounds that are NOT O2 to make ATP
What is fermentation?
anaerobic process, NOT RESPiRATION that takes partial degradation of sugars without O2
What type of reaction is cellular respiration with glucose?
redox reaction
How much ATP does glucose make?
about 32 ATP molecules
What are the stages of cellular respiration?
1) glycolysis
2) citric acid cycle
3) oxidative phosphorylation
What does glucose become in glycolysis?
glucose becomes 2 pyruvate molecules + 2NADH + 2ATP + 2H2O
6 carbon molecules to two 3 carbon molecules
Where does glycolysis happen?
outside the mitochondria, in the cytosol
What are the reactants and products of the citric acid cycle?
2 pyruvate becomes CO2 + ATP + NADH + FADH2
Where does the citric acid cycle happen?
mitochondrial matrix
What are the parts of oxidative phosphorylation?
electrons transport chain and chemiosmosis
What are the reactants of oxidative phosphorylation?
NADH, FADH2, O2, and ADP
What are the products of oxidative phosphorylation?
NAD+, FAD+, H2O, ATP
What step in cellular respiration generates the most ATP?
oxidative phosphorylation
Why does oxidative phosphorylation produce the most ATP?
because it is powered by redox reactions
Substrate level phosphorylation is used where?
glycolysis and krebs cycle
What are kinase enzymes?
enzymes that take phosphate group from one reactant and move it to the product
Is glycolysis anaerobic or aerobic?
anaerobic, doesn’t necessarily need oxygen to work
What organism did glycolysis probably evolve from?
prokaryotes
What are the phases of glycolysis?
the energy investment phase and the energy payoff phase?
What happens in the energy investment phase in glycolysis?
2 ATP invest to make 2 glyceraldehyde phosphate
How many steps does the energy investment phase in glycolysis have?
5 steps
What is the first step of the energy investment phase in glycolysis?
hexokinase enzyme uses 1ATP to attach phosphate to glucose
glucose becomes glucose 6-phosphate and gains energy by using 1ATP from being phosphorylated
What is the second step of the energy investment phase in glycolysis?
phosphoglucoseisomerase enzyme glucose 6-phosphate converted into isomer fructose 6-phosphate with more energy
What is the third step of the energy investment phase of glycolysis?
phosphofructokinase enzyme uses 1ATP to attach phosphate to fructose 6-phosphate
fructose 6-phosphate becomes fructose 1, 6-biphosphate with more energy
What is the fourth step of the energy investment phase of glycolysis?
aldolase enzyme splits fructose 1,6-biphosphate into dihydroxyacetone and glyceraldehyde phosphate (GAP)
What is the fifth step of the energy investment phase of glycolysis?
triosephosphate isomerase enzyme converts Dihydroxyacetone phosphate into glyceraldehyde 3-
phosphate (G3P)
What is the mnemonic for glycolysis?
Goodness Gracious! Father Franklin Didn't Go Buy Perfect Pumpkins to Prepare Pies
What is the mnemonic for glycolysis enzymes?
Hungry Peter Pan And The Growling Pink Panther Eat Pies
How many steps are in the energy payoff phase in glycolysis?
5 steps
What is the sixth step of the energy payoff phase in glycolysis?
triose phosphate dehydrogenase enzyme converts glyceraldehyde phopshate to produce 1,3biphosphoglycerate and 2 NADH + H+ as the NAD+ picks up electrons as GAP is getting oxidized and phosphorylated
What is the seventh step of the energy payoff phase in glycolysis?
phosphoglycerokinase removes a phosphate group from 2 1,3 biphosphoglycerate molecules and adds it to ATP to make 2ATP and 3-phosphoglycerate
How many times does the energy payoff phase happen in glycolysis?
2 times
What is the eighth step of the energy payoff phase in glycolysis?
phosphoglyceromutase transfers remaining phosphate from 3-phosphoglycerate to the center carbon of the same molecule to make it less stable to make 2-phosphoglycerate
What is the ninth step of the energy payoff phase in glycolysis?
enolase removes a water molecule from 2-phosphoglycerate (2x from the 2 pyruvate) to form 2 phosphoenolpyruvate (PEP) molecules
What is the tenth step of the energy payoff phase in glycolysis?
pyruvate kinase transfers the 2 phosphates from the 2 PEP molecules to make 2 pyruvates and 2 ATP
What happens to pyruvate before it goes into the Krebs cycle?
pyruvate turn into acetal coA
What is the first step in the conversion of pyruvate to acetal coA?
decarboxylation
What happens in decarboxylation?
removal of CO2 from pyruvate to form acetaldehyde (toxic to cell)
What is the second step in the conversion of pyruvate to acetal coA?
transfer of electrons to reduce NAD+ to NADH to form acetate
What is the third step in the conversion of pyruvate to acetal coA?
coenzyme A (vitamin B5) is added to the molecule to produce acetyl CoA
What is the mnemonic for the steps in the Krebs cycle?
Anaheim, our city is kept safe and sound from malice obsession
During cellular respiration in general, what is being oxidized and what is being reduced?
glucose is oxidized to become CO2 and oxygen is reduced as it accepts electrons and recruits protons from proton gradient to form H2O
Is cellular respiration overall an exergonic or endergonic reaction?
exergonic
Does NAD+ function as an oxidizing agent or a reducing agent?
oxidizing agent because it accepts electron
What process directly harnesses the light energy from the sun?
photosynthesis
Where does photosynthesis take place?
chloroplasts
What is cellular respiration for?
the process that extracts the energy from the organic molecules produced from photosynthesis
What is the input molecule for cellular respiration?
glucose
Where does oxidative phosphorylation happen?
intermembrane space (space between the membrane of the matrix and the membrane of the mitochondria)
In which cycle do a small amount of ATP get produced?
glycolysis and Krebs cycle
What is substrate-level phosphorylation?
single enzymatic reaction will produce a single molecule of ATP
Which process occurs in nearly all eukaryotic and prokaryotic cells?
glycolysis
Glycolysis not needing oxygen to work, suggests what in terms of evolution?
probably developed before there was oxygen in the atmosphere
What happens in the energy payoff phase?
2 GAP turns into 2 pyruvates, 2 ATP, 2NADH, 2 H2O
How many ATP invested in the energy investment phase in glycolysis?
2ATP
How many ATP created in the energy payoff phase?
4 ATP but only count 2ATP because the 2ATP is used in the first stage of glycolysis
Why does the pyruvate have to turn into acetal coA?
to get into the mitochondria
How many times does the citric acid cycle happen?
2 times
How many ATP does citric acid cycle produce?
2 ATP in total (after 2 turns)
How many NADH is being made in citric acid cycle in total (after two cycles)?
6 NADH (3 per cycle)
How many FADH2 is being made in the citric acid cycle in total (after two cycles)?
2 FADH2 (1 per cycle)
Why is there more NADH being produced in the citric acid cycle than FADH2?
NADH carries more energy pent up in the molecular form that can donate more energy later
How many steps does the citric acid cycle take?
8 steps
What is the first step in the citric acid cycle? (irreversabile)
citrate synthase (IRREVERSABLE) oxaloacetate + acetal CoA ---> citrate
How much of the carbon from glycolysis stays at the end of the citric acid cycle?
no more carbon left
What is the final organic molecule created from the Krebs cycle?
oxaloacetate
What is the second step in the citric acid cycle?
isomerase converts citrate into isocitrate
What is the third step in the citric acid cycle? (irreversible)
isocitrate dehydrogenase adds hydrogen to NAD+ to form NADH+ and a-ketoglutarate with CO2 as a waste product
What is the fourth step in the citric acid cycle? (irreversible)
a-ketoglutarates dehydrogenase adds hydrogen to NAD+ to form NADH and succinyl coA with CO2 as a waste product
What is the fifth step in the citric acid cycle?
succinal coA synthase created succinate and ATP
What is the sixth step in the citric acid cycle?
succinate dehydrogenase creates fumarate and adds a hydrogen to FAD+ to make FADH2
What is the seventh step in the citric acid cycle?
fumarase creates malate by adding water
What is the eighth step in the citric acid cycle?
malate dehydrogenase creates NADH by adding H to NAD+ and also creates oxaloacetate
What can glycolysis produce if there is too much ATP produced by taking a different pathway called _____ synthesis?
glycogen
What else can the citric acid cycle produce?
before the citric acid, acetal coA can become urea, or fatty acids via beta oxidation (lipid breakdown), ketogenesis (lipid metabolism), and even lipid synthesis (palmitate)
Why do FADH2 and NADH donate electrons in oxidative phosphorylation?
electroneagtivity of the oxygen (electron acceptor that wants to hoard the H+)
What kind of energy does the proton pump generate?
potential energy
Where is the electron transport chain taking place?
intermembrane space (aka inner membrane)
What are cytochromes?
old family of enzymes that contain iron ions (called heme)
Does the electron transport chain generate energy?
NO
How many ATP does 1 NADH produce?
2.5 ATP
How many ATP does 1 FADH2 produce?
1.5 ATP
What are prosthetic groups?
areas of molecules and proteins that engage in redox reactions (cytochromes for example)
Is coQ a part of the 4 complexes of the etc?
no, it is not a protein component
Is CoQ lipid soluble or not?
yes, that means it is NOT protein based
Which two complexes don’t work sequentially?
complex I and complex II since the electron can either go to 1 or 2 (parallel system)
What two complexes work sequentially?
complex III and complex IV
What is the first step of the etc chain?
NADH donates proton (and electron) to complex I
FMN (flavin mononucleotide) gets reduced and passes electron to iron sulfur cluster as 4 H+ gets released into intermembrane space
What are iron sulfur clusters?
evolutionary old structural format system that allows electrons be moved (engage in redox reactions)
What is the second step of the etc chain?
electrons flow to coQ (non protein component)
coQ becomes reduced to coQH2
What is the third step in the etc chain?
if coQ picks up electrons, then it heads over to complex III
for complex II, its called succinate dehydrogenase
FAD+ integrated into it gets reduced into FADH electrons get picked up by iron sulfur cluster
What is the fourth step in the etc?
coQ picks up electrons to become coQH
What is the fifth step in the etc?
electrons go to cytochrome b , iron sulfur cluster picks up electrons and then those electrons get transferred to mobile water soluble cyt. c to release 4 H+
What is the is sixth step in the etc?
cyt.c shuttles electrons from complex III to complex IV
What is the seventh step in the etc?
cyt. c brings over the electrons and adds to copper (pump 2 H+ out) so that oxygen comes by as the final electron acceptor to make water as a waste product
What is the first step in chemiosmosis?
flow of ion gradient as potential energy, atp synthase converts the energy from the ion gradient and stores it in ATP
What is the “proton motor force”?
another term for chemiosmosis
Why would a cell choose to use fermentation?
accomplish the goal to regenerate electron carriers in the oxidative form (NAD+ and FAD+)
Is fermentation slow-acting or fast-acting?
slow-acting
What are the two options for fermentation?
alcoholic fermentation and lactate fermentation
What is the first step in alcohol fermentation?
glucose to pyruvate (glycolysis) that generate 2 net ATP and 2 NADH
What is the second step in alcohol fermentation?
pyruvate gets decarboxylated to 2 acetaldehyde (toxic) + NAD+ and 2 CO2 as a waste product
What is the third step in alcohol fermentation?
2 acetaldehyde gets converted into 2 ethanol as NADH gets converted back to NAD+ to give up electrons for ethanol to accept
Where is alcohol fermentation used?
yeast used in brewing, winemaking, baking
What is the first step in alcohol fermentation?
glycolysis (2 pyruvates, 2NADH, 2ATP)
What is the second step in lactate fermentation?
NO DECARBOXILATION NO CARBON DIOXIDE PRODUCED, pyruvates reduced (accepts electrons from NADH) and becomes 2 lactate
Which fermentation process doesn’t produce carbon dioxide as a waste product?
lactic acid fermentation
When is lactic acid fermentation used?
muscle cells use lactic acid fermentation to generate ATP when oxygen was scarce
What is the final electron acceptor in respiration?
oxygen
What is the final electron acceptor in fermentation?
the organic molecule (can either be ethanol or lactate)
How much ATP does cellular respiration usually produce per glucose molecule?
38 ATP
How much ATP does fermentation usually produce per glucose molecule?
2 ATP
What is the B2 vitamin?
FAD raw material
What is the B3 vitamin?
NAD raw material
What is the B1 vitamin?
giving raw material cofactors for efficiency of the cycle
What is the B5 vitamin?
pantothenic acid, building block for coA
What is the B6 vitamin?
pyridoxamine, breaks down glycogen to get sugar rings
What is the B9 vitamin?
folate/ folic acid, byproducts produce amino acids
What is the B12 vitamin?
with the help of B9, used for porphyrin rings (structure like heme) Fe in the middle = heme, Mg in the middle = chlorophyll
Where is heme located in the cell cycle?
cytochrome c