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Welcome –Happy hump day –
Today a VERY SHORT batch of Pretty boring (yawn) notes 0n Enzymes and feedback – dig out note stuff`
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Enzymes and feedback Enzymes= special proteins that Control all reactions in living Things. Enzymes must be present for Any reaction to occur.
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Enzymes are catalysts – a
Substance that affects the rate Of a chemical reaction but Remains unchanged.
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Enzymes act only on certain
Substances due to a specific Shape.
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Where the enzyme hooks to
The substance it acts on Is known as the active site. Active site
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Substrate is the substance that
The enzyme is acting on. substrate
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Enzymes and all proteins are
Produced in the ribosomes of The cell.
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Enzymes control the reaction
Rate based on several factors, pH, shape and temp. PH= a measure of the acidity of Alkalinity of a substance. 0-6 = acid 7= neutral 8-14=base. Enzymes work best At a pH of 7
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Optimum temperature = the
Temp. at which the enzyme Works best. This is body temp. In humans. (98.6*f or 37*c)
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Feedback mechanisms – a cycle
Of input and response. Stimuli – changes in the Environment that cause a Response.
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Negative feedback system
A change (stimuli) causes a Response in an attempt to Maintain homeostasis. Ex. Blood sugar is high, Pancreas secretes insulin to Lower Blood sugar Ex= too hot – you sweat to Cool body down
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Negative feedback systems are
The most common. Positive feedback system = a Change causes a response Which leads to a greater change Ex.= childbirth – contractions, Then stronger contractions.
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Dynamic equilibrium = the many
Constant small changes that Keep the internal environment At the level needed for survival. = maintains homeostasis
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