Chemical Reactions in Cells To keep your body alive, your cells undergo countless chemical...
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Transcript of Chemical Reactions in Cells To keep your body alive, your cells undergo countless chemical...
Chemical Reactions in Cells
• To keep your body alive, your cells undergo countless chemical reactions.– Many of these reactions are occurring 24/7.
These chemical reactions drive cellular processes!
Cells in your body produce CO2, then blood carries the CO2 from the cells to your lungs (you exhale it out).
PROBLEM
• CO2 is not soluble (dissolvable) in water, so it cannot be carried through your blood.
A chemical reaction in your body converts CO2
into a soluble compound.
In blood, CO2 is converted to a soluble compound:
CO2 + H2O H2CO3
In the lungs, the reaction is reversed to exhale the CO2:
H2CO3 CO2 + H2O
Chemical Reactions & Enzymes
Chemical Reactions
• A change of one set of chemicals into another– Can be slow or fast– Require collisions between
molecules– Involves changes in chemical bonds
Chemical Reactions
• Reactants: elements or compounds that enter into a chemical reaction– Bonds of reactants are broken in a chemical reaction.
• Products: elements or compounds that are produced in a chemical reaction– Bonds of products are formed in a chemical reaction.
What are the reactants in this reaction?The products?
Chemical reactions involve changes in chemical bonds!
Whenever a reaction occurs that rearranges the atoms of molecules, bonds in the reactants must be broken & new
bonds in the products must be formed.
Chemical Reactions & Energy
• Breaking & forming chemical bonds requires energy release or absorption.
• Reactions that release energy can occur spontaneously (but not all do).– Energy is released as heat.
• Reactions that absorb energy will not occur without an energy source.
Activation Energy
• The energy needed to get a reaction started
• BUT, some chemical reactions are very slow or require lots of energy, so they cannot occur on their own.
Activation Energy Video
Catalysts
• Catalysts are proteins that speed up the rate of a chemical reaction by lowering the activation energy of the reaction.
Enzymes
• An enzyme is a protein that acts as a biological catalyst.– Enzymes speed up reactions that take place in your body.
Enzymes
• Enzymes provide a site (called the active site) where reactants (substrate) can be brought together to react.– This decreases the activation energy.
Enzymes
• The structure formed when the substrate (reactants) bind to the active site is called the enzyme-substrate complex.
Enzymes
• Enzymes can be reused, but they are specific.– The enzyme’s structure
allows only certain substrates to bind to the enzyme.
The enzyme-substrate relationship is like a lock & key!
Only the correctly shaped key will open the lock…
Disruptions in homeostasis can prevent enzymes from functioning.
• Enzymes function best in a small range of conditions.
• In the wrong conditions, an enzyme can denature (lose its structure).– Temperature changes– pH changes– Other chemicals
The sugar found in milk is called LACTOSE.
• Lactose is a disaccharide.
This means that lactose is composed of 2 monosaccharides – glucose & galactose.
Remember!When you digest your food, your body breaks it up into
its smallest subunits.