Term
How much more energy is released when pyruvate is converted to CO2 and H2O than when glucose is converted to pyruvate? |
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Definition
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Term
Why is a mitochondrion known as a "cell within a cell"? |
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Definition
(1) They have their own genome
(2) They synthesize their own proteins |
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Term
Mitochondria are present in all cells EXCEPT |
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Definition
RBCs and terminal keratinocytes |
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Term
Mitochondria are more numerous and concentrated in cells... |
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Definition
(1) with high E demands (e.g. striated muscle and cels involved in fluid and electrolyte transport)
(2) where E is needed (e.g. middle piece of sperm, adjacent to basolateral membrane of proximal convoluted tubule cells) |
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Term
Outer membrane mitochondrial structural components and function? |
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Definition
mitochondrial porins (voltage-gated anion channels) - make the outer membrane sieve like
receptors for porteins and polypeptides that translocates to intermembrane space
enzymes (1) phospholipase A2 (2) monoamine oxidase (3) acetyl Co-A synthase |
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Term
Inner membrane structure and functions? |
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Definition
cardiolipin - makes inner membrane impermeable to ions
cristae - numberous folds that increase surface area
inner membrane space- contains creatine kinase, adenylate kinase, cytochrome c (which can induce cell apoptosis)
matrix - Citric acid Cycle and fatty acid β-oxidation, dense matrix granules that store Ca2+, mtDNA, ribosomes, and tRNAs |
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Term
Relate changes in mitochondrial shape and appearance to its functions at the biochemical and cellular level.
Hint: morphological changes related to level of oxidation. |
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Definition
Mitochondria have two configurations:
(1) orthodox configuration- cristae are prominent and matrix occupies a large volume--assoc. w/ low levels of oxidative phosphorylation
(2) condensed configuration- matrix condensed and inner membrance space increases--assoc. w/ high levels of oxidative phosphorylation |
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Term
What is the difference between heterochromatin and euchromatin? What factors dictate each? |
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Definition
heterochromatin - condenced chromatin, predominantly found in metabolically inactive cells (lymphocytes,sperm).
w/in the nuc., marginal chromatin is found along the perimeter of nucleus , karyosomes--bodies of irregularsize and shape throughout the nuc., and nucleolar assoc. chromatin.
euchromatin -- lightly staining chromatin, chromatin "stretched out" so that DNA transcription can occur, metabolically active cells, |
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Term
| Explain the level of organization of chromatin |
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Definition
| 8 histones + loops of DNA (150 nt) --> nucleosomes (H1 is the clamp), 2 nm apart--> chromatin fibril (25-30 nm), 6 histones ea. -->chromatin fibers (loop domains anchored to c-some scaffold or nuclear matrix) --> chromosomes (condensation of chromatin), made of 2 chromatids, joined by centromere, doubled during S-phase |
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Term
Describe special features of chromosomes that protect the cell from aging and the relationship bet. these features and malignancy.
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Definition
telemorase adds regions of DNA to the telomers, thus immortalizing the cells--they can divide virtually forever |
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Term
What characteristics are unique to the nuclear envelope in comparison to the plasma membrane? |
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Definition
(1) 2 unit membranes sep. by perinuclear space
(2) outer membrance similar to and continuous with rER membrane
(3) Polyribosomes attached to outer nuc. membrane
(4) nuclear lamina support, formed of intermediate filaments (lamins and lamin-associated proteins)
(5) Nuclear pores- sites where inner and outer membranes fuse, nuclear pore complex, made of nucleoporins
(6) dense bodies-->found in the pore
(7) disassembles during cell division |
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