histo L6 Flashcards
(32 cards)
what is Mitochondria ?
membrane-enclosed organelles with arrays of enzymes specialized for aerobic respiration and production of adenosine
triphosphate (ATP)
what is glycolysis ?
converts glucose anaerobically to pyruvate in the cytoplasm,
releasing some energy
. Mitochondrial enzymes yield 15 times more ATP
than is produced by glycolysis alone
.
do all the energy
released in mitochondria is stored in ATP ?
no , some of the energy is dissipated as heat that maintains body temperature
what is the diameters of the mitochondria ?
0.5 -1 μm
The number of mitochondria is related to what ?
to the
cell’s energy needs: cells with a high-energy metabolism (eg,
cardiac muscle, cells of some kidney tubules) have many
mitochondria, whereas cells with a low-energy metabolism
have few mitochondria
Where are mitochondria concentrated in cells?
concentrated in cytoplasmic regions where
energy utilization is more intense.
Mitochondria are large enough to be seen with a light microscope
.
mitochondrion is seen
to have two separated and very different membranes that
together create two compartments, what are they ?
the innermost matrix
a narrow intermembrane space
what is on the outer membrane ?
many transmembrane proteins called porins
what The inner membrane has ?
many long folds called
cristae
what is the function of the cristae ?
increase
the membrane’s surface area
The number
of cristae in mitochondria also corresponds to the energy
needs of the cell.
.
what make the inner membrane selectively
permeable to the small molecules ?
Integral proteins include transport proteins
Where are enzymes included in the mitochondria?
they are embedded in the inner membrane
Where does the oxidative phosphorylation take place?
inner membrane
what is the process that produces
most of the ATP in animal cells. ?
oxidative phosphorylation
oxidative phosphorylation
enzymes occurs by what ?
chemiosmotic process
How is ATP made in the mitochondria?
ATP is generated in the inner membrane by oxidative phosphorylation involving several membrane protein complexes
when NADH(high-energy electrons) used by the protein complexes to pump protons from the matrix to the intermembrane space and that creates a proton gradient which make the the protons re enter the matrix through the ATP synthase protein complex they catalyze the production of ATP
synthase complexes can produce more than 100 molecules of
ATP per second
.
when the another role for mitochondria occurs ?
at times of cell
stress when the protein cytochrome c is released from the
inner membrane’s electron-transport chain
what is the function of the cytochrome c ?
activates sets of proteases that degrade all cellular components in a regulated process called apoptosis which
results in rapid cell death
How do new mitochondria originate?
by growth and division of preexisting mitochondria
how is the mitochondria are partly autonomous of nuclear genes and activities.
The mitochondrial
matrix contains a small circular chromosome of DNA, ribosomes, mRNA, and tRNA similarities to the one in the bacteria
