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Lever

Lever

1. (Science: mechanics) a rigid piece which is capable of turning about one point, or axis (the fulcrum), and in which are two or more other points where forces are applied; used for transmitting and modifying force and motion. Specif, a bar of metal, wood, or other rigid substance, used to exert a pressure, or sustain a weight, at one point of its length, by receiving a force or power at a second, and turning at a third on a fixed point called a fulcrum. It is usually named as the first of the six mechanical powers, and is three kinds, according as either the fulcrum f, the weight W, or the power P. Respectively, is situated between the other two, as in the figures.

2. (Science: machinery) a bar, as a capstan bar, applied to a rotatory piece to turn it. An arm on a rock shaft, to give motion to the shaft or to obtain motion from it. Compound lever, a machine consisting of two or more levers acting upon each other. Lever escapement. See escapement. Lever jack. See jack. Lever watch, a watch having a vibrating lever to connect the action of the escape wheel with that of the balance. Universal lever, a machine formed by a combination of a lever with the wheel and axle, in such a manner as to convert the reciprocating motion of the lever into a continued rectilinear motion of some body to which the power is applied.

Origin: oe. Levour, OF. Leveor, prop, a lifter, fr. F. Lever to raise, L. Levare; akin to levis light in weight, E. Levity, and perh. to E. Light not heavy: cf. F. Levier. Cf. Alleviate, Elevate, Leaven, Legerdemain, levy.


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Re: (Facilitated Diffusion), Carrier protein.

... enough, you need some significant force. If the energy barrier is low enough, a little thermal wiggle might be sufficient. You've encountered levers (perhaps electrical switches) that contain a spring so that the lever can be on one end-position or the other (say, left or right) but you must ...

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by jonmoulton
Fri Jun 24, 2011 4:29 pm
 
Forum: Cell Biology
Topic: (Facilitated Diffusion), Carrier protein.
Replies: 3
Views: 8036

diff. pollination mechanisms

Pls explain the following pollination mechanisms....... 1. Jaculator mechanism 2. lever mechanism 3. translator mechanism 4. siphon mechanism What are ubisch bodies??

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by agent007
Fri Apr 16, 2010 1:27 am
 
Forum: Botany Discussion
Topic: diff. pollination mechanisms
Replies: 1
Views: 1159

Photosynthesis

... the right hand side, recording the EXPTL and graphing it as you go UNTIL you get to about 750 nm (note that above 600 nm, you have to shift the lever at the lower left of the machine). 0.1M Phosphate buffer: 174 g K2HP04 (dibasic) brought to 1 liter with distilled H20 and 136 g KH2P04 (monobasic) ...

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by dipjyoti
Sat Oct 14, 2006 10:41 am
 
Forum: Botany Discussion
Topic: Photosynthesis
Replies: 9
Views: 9404

why are skin cells smaller than liver cells? pls answer asap

han...functions of skin or other words - the requirements of skin & lever in the present environment...clue , & as its a proverb here- go tuitorial & u'll get it!

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by 2810712
Sun Jun 25, 2006 4:38 pm
 
Forum: Cell Biology
Topic: why are skin cells smaller than liver cells? pls answer asap
Replies: 3
Views: 1907

dsRNA effect on adult neural stem cells

... can answer me: what is the definition of noncoding RNA? is that one do not have the genetic code ATG or this RNA display it.s function at the RNA lever?

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by cartener
Fri Apr 21, 2006 10:23 am
 
Forum: Molecular Biology
Topic: dsRNA effect on adult neural stem cells
Replies: 10
Views: 7677
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