Chapter 7 Flashcards
what is the basic formula for cellular respiration
c6h1206 + 6O2 –> 6 Co2 + 6 H20
is cellular respiration exergonic or endergonic? Catabolic or anabolic?
cellular respiration is a catabolic; exergonic reaction meaning that there is more energy in the reactants than in the products
what constitutes as a loss of energy or as a gain of energy in regards to adenosine triphosphate alone?
if adp gains an inorganic phosphate to make atp that makes it gained energy and is therefore an endergonic reaction; if atp loses an inorganic phosphate to make adp and an inorganic phosphate making that an exergonic reaction
why do cells need atp? why not use energy directly from glucose?
atp is the energy currency of the cell; glucose releases too much energy in the form of heat and barely stores any where as atp only releases a small amount of energy in the form of heat making atp the more efficient form of energy
what is atp composed of
3 phosphate group, nitrogenous base adenine, and 5-carbon ribose
what are the four stages of respiration and where do they take place
1) Glycolysis (Cytoplasm)
2) Pyruvate oxidation (in mitochondria - inner membrane space)
3) Krebs cycle/TCA/citric acid cycle/tricarboxylic acid - mitochondrial matrix
4) Electron transport chain - inner mitochondrial matrix
based on the location of the krebs cycle what is the exception within the cycle
during the krebs cycle, despite its location being in the mitochondrial matrix, FADH2/FAD is found on the memrane in the etc in the second complex and so is succinate dehydrogenase (the enzyme used to reduce FAD into FADH2)
what are the two main phases of glycolysis
the first five phases are known as the investment phase and the last five steps are known as the payoff phase; this is because during the investment phase we are “investing” two molecules of atp to phosphorylate molecules glucose and fructose 1-6 biphosphate in steps one and three and in the steps 7 and 10, pyruvate and phosphoglycerate become phosphorylated to produce atp
how much atp and Nadh get produced as a resultof glycolysis
glycolysis alone technically produces 4 atp molecules but because of the fact that two need to be used in steps 1 and 3, glycolysis produces a net total of 2 atp molecules. In step 6, 1-3biphosphoglycerate gets oxidized with the help of the enzyme dehydrogenase and loses an H proton to give to NAD which gets reduced to NADH
what are the most frequent enzymes used in glycolysis
Kinase which is involved in the transfer of a phosphate group, Isomerase which is involved in the catalyzation of of rearranging molecules, and dehydrogenase which is involved in the removal of a hydrogen proton from a substrate
what are the cofactors used in gylcolysis
Mg2+ in most of the steps but in the last step Mg2+ and K
EXTRA FOR MCAT** what are the differences in the delta g values and what do they mean
if the delta g value is negative that means that there is more energy on the product side, if the delta g value is positive then there is more energy on the reactant side
what happens in glycolysis
a molecule of glucose gets broken down into two pyruvate molecules
where does glycolysis occur
glycolysis occurs in the cytoplasm
what is being oxidized and reduced in glycolysis
Nadh is being reduced and 1-3 biphosphoglycerate is being oxidized
what is pyruvate oxidation
the molecules of pyruvate generated combine with CoA to produce acetyl coA
what is being reduced and what is being oxidized during pyruvate oxidation
Nad is getting reduced and pyruvate is getting oxidized
what is produced as a result of pyruvate oxidation
2 Nadh and 2 Co2 molecules
how are two molecules of co2 produced
pyruvate undergoes decarboxylated
what is decarboxylation
decarboxylation is the removal of a carboxyl group from a molecule to generate a molecule of co2
where does pyruvate oxidation occur
in the mitochondria/inner membrane space
what happens to the acetyl coA made during pyruvate oxidation
Acetyl CoA enters the Krebs cycle as a 2 carbon molecule and combines with the 4 carbon molecule oxaloacetate to create the 6 carbon molecule citrate. During this step another molecule of CoA-SH is released to go back to the inner memebrane space where pryuvate oxidation occur. Citrate then enters the citric acid cycle.
where does Nadh find the get the h molecule to get reduced from during pyruvate oxidation
in order for acetyl coA to actually form, CoA which has a sulfur and hydrogen group attached to it need to combine with pryuvate; therefore the H group attached to coA is given to Nad to create NADH
identify the products of the citric acid cycle
3 Nadh molecules, 2 co2 molecules, 1 fadh molecule, and 1 atp molecule but because the cycle turns twice, 6 Nadh molecule, 4 Co2 molecules, 2 Fadh2 molecules, and 2 Atp molecules
