CELS 191 Lecture 6 Flashcards
how does ATP release energy
one of the three phosphate groups is released to create adenosine diphosphate ADP
why do cell require energy
for mechanical work
to make new materials
for transport
to maintain order
what are mitochondria and how many are in a cell
the organelles responsible for converting glucose and oxygen into energy - the number of mitochondria in a cell varies from 1-1000 depending on the cells energy needs
do mitochondria contain DNA and ribosomes
yes, this is part of the evidence for the endosymbiont theory. they can produce some (but not all) mitochondrial proteins
which of the mitochondria membranes if folded and why
the inner membrane is folded (folds are called cristae) to increase surface area
what is the matrix of a mitochondria composed of
proteins, water and ATP
what are the three steps involved in cellular respiration
glycolysis
pyruvate oxidation and citric acid cycle
oxidative phosphorylation
where and when does glycolysis occur
in the cytosol (the aqueous component of the cytoplasm) before the glucose even enters the mitochondria
what happens during glycolysis and what is produced
one glucose (six carbon molecule) is broken down into two pyruvate molecules (three carbons) - this produces 2 ATP and electrons are transferred to the high energy electron carrier NAD+ which makes NADH
where does pyruvate oxidation and the citric acid cycle occur
in the mitochondrial matrix
what and the reactants and products for pyruvate oxidation
the 2 pyruvate molecules from glycolysis are converted into 2 Acetyl CoA molecules - this produces 2 CO2 molecules which are released as waste products as well as 2NADH molecules
what are the reactants and products of the citric acid cycle
the 2 Acetyl CoA from pyruvate oxidation are used to produce 2 ATP molecules, 4CO2 molecules, 6 NADH molecules and 2 FADH2 molecules
where does oxidative phosphorylation occur
in the inner membrane of the mitochondrion
what are the 2 parts of oxidative phosphorylation
electron transport chain
chemiosmosis
what is the role of NADH and FADH2
to shuttle high energy electrons to the inner mitochondrial membrane
how do high energy electrons move through the electron transport chain
through a series of proteins embedded in the membrane
what is pumped across the membrane as the electrons move through the electron transport chain
H+ - protons
what is created by the electron transport chain
a high concentration of protons in the intermembrane space
how does the electron transport chain produce water
the electrons at the end of the chain (now low energy) are passed to an O2 (each O picks up a pair of electrons) at the last protein in the chain (4) which are joined by a pair of hydrogen ions (H2) from the aqueous solution to form water which is released as a waste product
do NADH and FADH2 join the electron transport chain at the same place
no - NADH enters at protein complex 1 and FADH2 (lower energy) enters at protein complex 2
NADH and FADH2 both donate the same number of electrons, do they provide the same amount of energy
no - the ETC provides about 1/3 less energy for ATP synthesis when the electron donor is FADH2 rather than NADH - FADH2 is lower energy
does the ETC produce energy directly
no - it eases the fall of electrons from food to oxygen, breaking a large free-energy drop into a series of smaller steps that release energy in manageable amounts
what is the protein used in chemiosmosis
ATP synthase
what is the function of ATP synthase
it allows the protons to move down their concentration gradient and into the matrix - this causes the enzyme to rotate and this mechanical energy is used to covert ADP and inorganic phosphate (Pi) into ATP
