Plastids generally contain pigments or can store nutrients. Photosynthesis occurs in the chloroplasts; specifically, in the grana and stroma regions. The individual discs are called thylakoids. It is here that the transfer of electrons takes place. The empty spaces between columns of grana constitute the stroma. Like mitochondria, chloroplasts are also thought to have originated from primitive bacterial cells through the process of endosymbiosis.
In their article, Chan and Bhattacharya make the point that the formation of secondary plastids cannot be well explained by endosymbiosis of cyanobacteria, and that the origins of this class of plastids are still a matter of debate.
Pigment molecules are associated with proteins, which allow them the flexibility to move toward light and toward one another. A large collection of to 5, pigment molecules constitutes "antennae," according to an article by Wim Vermaas , a professor at Arizona State University. These structures effectively capture light energy from the sun, in the form of photons.
Ultimately, light energy must be transferred to a pigment-protein complex that can convert it to chemical energy, in the form of electrons. In plants, for example, light energy is transferred to chlorophyll pigments. The conversion to chemical energy is accomplished when a chlorophyll pigment expels an electron, which can then move on to an appropriate recipient.
The pigments and proteins, which convert light energy to chemical energy and begin the process of electron transfer, are known as reaction centers. The "electron hole" in the original chlorophyll pigment is filled by taking an electron from water. What is the final concentration of the solution if it is diluted to 3. How much water must be added to How much water must be added to 1.
What Is the Fibonacci Sequence? | Live Science
Dilutions and Concentrations by Jessie A. Skip to content Increase Font Size. Chapter Learning Objective 1. Learn how to dilute and concentrate solutions. Example 9 If Solution It does not matter which set of conditions is labelled 1 or 2, as long as the conditions are paired together properly. Using the dilution equation, we have 2. Test Yourself A 0. Answer Medical personnel commonly must perform dilutions for IV solutions. Key Takeaways Calculate the new concentration or volume for a dilution or concentration of a solution.
Exercises What is the difference between dilution and concentration? Previous: Some Definitions. Next: End-of-Chapter Material.
Someone answered the buzzer almost immediately. Is it something important—bad news for him, or something? When he comes in, get him to the transmitter as soon as you possibly can. Is there anything else I can do? He turned the volume to an inaudible minimum, an act that would not affect the functioning of the signal buzzer, and unclipped the pad of paper from the control board. He tore off the sheet containing his flight instructions and handed the pad to her, together with pencil.
She began to write, her fingers still clumsy and uncertain in the way they handled the pencil, and the top of it trembling a little as she poised it between words. He turned back to the viewscreen, to stare at it without seeing it. She was a lonely little child trying to say her last goodbye, and she would lay out her heart to them.
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She would tell them how much she loved them and she would tell them to not feel bad about it, that it was only something that must happen eventually to everyone and she was not afraid. The last would be a lie and it would be there to read between the sprawling, uneven lines: a valiant little lie that would make the hurt all the greater for them. Her brother was of the frontier and he would understand. He would not hate the EDS pilot for doing nothing to prevent her going; he would know there had been nothing the pilot could do.
He would understand, though the understanding would not soften the shock and pain when he learned his sister was gone. But the others, her father and mother—they would not understand. They were of Earth and they would think in the manner of those who had never lived where the safety margin of life was a thin, thin line—and sometimes nothing at all.
What would they think of the faceless, unknown pilot who had sent her to her death? He would never see them, never know them. He would have only the memories to remind him; only the nights of fear, when a blue-eyed girl in gypsy sandals would come in his dreams to die again …. He scowled at the viewscreen and tried to force his thoughts into less emotional channels. There was nothing he could do to help her. She had unknowingly subjected herself to the penalty of a law that recognized neither innocence nor youth nor beauty, that was incapable of sympathy or leniency.
Regret was illogical—and yet, could knowing it to be illogical ever keep it away?
She stopped occasionally, as though trying to find the right words to tell them what she wanted them to know; then the pencil would resume its whispering to the paper. It was when she folded the letter in a square and wrote a name on it.
She began writing another, twice looking up at the chronometer, as though she feared the black hand might reach its rendezvous before she had finished. It was when she folded it as she had done the first letter and wrote a name and address on it.
She held the letters out to him. She glanced at the chronometer, then back to him.europeschool.com.ua/profiles/besyzasa/chicas-canarias-desnudas.php
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She began to roll the pencil back and forth between her palms. I never did feel like this before; like I was all by myself and there was nobody to care what happened to me. Always, before, there were Mama and Daddy there and my friends around me. I had lots of friends, and they had a going-away party for me the night before I left. Friends and music and laughter for her to remember—and on the viewscreen Lotus Lake was going into the shadow. I always thought danger along the frontier was something that was a lot of fun; an exciting adventure, like in the three-D shows.
Her glance flicked from the chronometer to the door of the air lock, then down to the pad and pencil she still held. She shifted her position slightly to lay them on the bench beside her, moving one foot out a little. For the first time he saw that she was not wearing Vegan gypsy sandals, but only cheap imitations; the expensive Vegan leather was some kind of grained plastic, the silver buckle was gilded iron, the jewels were colored glass.
Her personal possessions on the Stardust would be taken back to her parents—they would neither be of much value nor occupy much storage space on the return voyage. He saw by the main temperature gauge that the room was at precisely normal temperature. There may not be much time left when he comes in—not much time to talk to him before he fades out.
I wish I could do something about it—I would call him right now if I could. Now I see how selfish I was. Like Gerry—he sent me a bracelet of fire rubies on my sixteenth birthday. Yet I remember him more for what he did the night my kitten got run over in the street. I was only six years old and he held me in his arms and wiped away my tears and told me not to cry, that Flossy was gone for just a little while, for just long enough to get herself a new fur coat, and she would be on the foot of my bed the very next morning.
I believed him and quit crying and went to sleep dreaming about my kitten coming back. When I woke up the next morning, there was Flossy on the foot of my bed in a brand-new white fur coat, just like he had said she would be. They could never think of you other than the way you would want them to, the way you looked the last time they saw you.