Mitochondria light

Figure 2 Partitioning SODl between the mitochondria and cytosol via the action of CCS. The double line represents the outer membrane of the mitochondria. Light arrows indicate maturation steps in the metallation of SODl, whereas heavy arrows indicate movement of SODl across the outer mitochondrial membrane. The apo or unmetallated form of SODl can readily traverse the membrane in either direction. Once copper is inserted via CCS, SODl can no longer cross the membrane and becomes trapped within the corresponding compartment, either the cytosol or intermembrane space (IMS) of the mitochondria as indicated. This model shows zinc loading of SODl prior to copper metallation, but the exact order by which this occurs in vivo is not clear...

C. If we assume that Equation 1.6 can adequately describe such motion, how long would it take on the average for a mitochondrion to diffuse 0.2 pm (a distance just discernible using a light microscope) How long would it take for the mitochondrion to diffuse 50 pm (the distance across a typical leaf cell) ... 

Figure 18.26. Testing the Chemiosmotic Hypothesis. ATP is synthesized when reconstituted membrane vesicles containing bacteriorhodopsin (a light-driven proton pump) and ATP synthase are illuminated. The orientation of ATP synthase in this reconstituted membrane is the reverse of that in the mitochondrion.

Translated from Greek, the word mitochondrion means thread-grain . This term was introduced many years ago by cytologists who used the light microscope. The first students of mitochondria always indicated that these organelles may exist in two basic forms ... 

There are analogies in structure and role between the mitochondrial matrix (Figure 15.2a) and the chloroplast stroma and also between the inner membrane of the mitochondrion and the thylakoid membrane of the chloroplast. Absorption of light and all of the light reactions occur within or on the thylakoid membranes. ATP and NADPH produced by these reactions are released into the surrounding stroma, where the synthetic dark reactions occur. 

Kinetoplast a structure at the base of the single flagellum of a trypanosome. The K. has a high affinity for basic dyes, and was first observed early in the 20th century by light microscopy. Electron microscopy shows that the K. is a disc-like structure in the matrix of the cell s single mitochondrion. The K. has attracted biochemical interest because it contains an unusual form of highly catenated DNA, known as kinetoplast DNA (kDNA). See Catenane. 

Yeast mitochondrial DNA occurs as double-stranded 26-/im closed circles, a molecular size corresponding to about 50 x 10 daltons. The number of circles per mitochondrion may range from zero to about five the total amount of cellular mtDNA per wild-type cell varies with the strain and accounts for 10-25% of the total cellular DNA. RNA-DNA hybridization studies indicate that yeast mtDNA contains one cistron of each of the 15 S and 21 S RNA species and probably 20 tRNA cis-trons. It has been reported that mitochondria from HeLa cells contain only 12 tRNA cistrons, 9 on the heavy DNA strand and 3 on the light strand. These authors suggested that since the proteins formed by mitochondrial ribosomes are enriched in hydrophobic amino acids, an array of 12 tRNAs may be sufficient for the complete synthesis of the inner-membrane proteins by mitochondria. Alternatively, some nuclear coded tRNAs may be available to the mitochondrial protein-synthesizing system. 

Fig. 1. Section through the center of the lower part of a chloroplast in a C. reinhardi y-1 cell, grown in the light. The chloroplast envelope (ce) surrounds the matrix occupied by numerous grana sectioned perpendicularly (g) or tangentially (gi). Some of the thylakoids interconnect different grana (T). Osmiophyllic globules (os) and ribosomes (r) are found in the stroma. A pyrenoid (py) surrounded by starch plates (s) occupies the center of the chloroplast. N, nucleus n, nucleolus V, vacuole cr, cytoplasmic ribosomes d, dicytisome p, plasma membrane m, mitochondrion cw, cell wall. (24,500x)...

Fig. 2 List of some of the most widely employed fluorochromes in FM with indication of their peaks of excitation and emission. On the right are indicated the main lines of emission of a mercury lamp (ML) and four common laser sources. According to the wavelength of emitted light, lasers can be indicated as UV lasers (350 nm), violet lasers (407 nm), Wue lasers (488 nm), and ref/lasers (635 nm). 7-A4D7-aminoactinomycin 0, APC allophycocyanin, CFP cyan fluorescent protein, Em emission (nm). Ex excitation (nm), EYFP enhanced yellow fluorescent protein, FAf fluorescence microscopy, F/ Pfluorescent reporter protein, 6FF green fluorescent protein, IMF immunofluorescence, mito mitochondrion/mitochondrial, ML mercury lamp, RFP red fluorescent protein, variant of YFP, KFFyellowfluorescentprotein...

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