chemical reactions

download report

Transcript chemical reactions

CHEMICAL REACTIONS

Process which changes one set of chemicals into
another set of chemicals.




Ex. Combining Iron (Fe) and Oxygen (O) to form Rust.
Reactants - elements or compounds that enter
into a chemical reaction
Products - elements or compounds made by a
chemical reaction.
Bonds are broken in reactants and formed in
products.
CHEMICAL REACTIONS
ALWAYS INVOLVE CHANGES IN ENERGY
 REACTIONS THAT RELEASE ENERGY
SOMETIMES HAPPEN
SPONTANEOUSLY
 REACTIONS THAT ABSORB ENERGY
MUST HAVE A SOURCE OF ENERGY
 THE ENERGY NEEDED TO START A
REACTION IS CALLED ACTIVATION
ENERGY.
CATALYSTS
SUBSTANCES THAT SPEED UP RATE OF
REACTION.
WORK BY LOWERING THE ACTIVATION
ENERGY.
ENZYMES ARE PROTEINS THAT SPEED
UP CHEMICAL REACTIONS IN CELLS.
CAUSES THE REACTION TO TAKE PLACE
BY LOWERING THE ACTIVATION ENERGY
NEEDED.
EX. CO + H O  H CO
2

2
2
Carbonic anhydrase
3
SPEED OF REACTIONS
LEFT ALONE MANY BIOLOGICAL
REACTIONS WOULD HAPPEN TOO
SLOWLY.
Example of an enzyme

CARBONIC ANHYDRASE CAUSES THE
CHANGE INTO CARBONIC ACID TO HAPPEN
QUICKLY.
ENZYMES ARE SPECIFIC AND USUALLY
ONLY CATALYZE ONE REACTION.
ENZYME ACTION
REACTANTS IN CHEMICAL REACTIONS
MUST HIT WITH ENOUGH FORCE TO
BREAK OLD BONDS AND FORM NEW
ONES
ENZYMES PROVIDE THE PLACE WHERE
REACTANTS ARE BROUGHT TOGETHER
REDUCING THE ENERGY NEEDED FOR
THE REACTION TO OCCUR.
ENZYME SHAPE
SUBSTRATES - THE REACTANTS OF
ENZYME CATALYZED REACTIONS
EACH PROTEIN HAS A SPECIFIC SHAPE.
ACTIVE SITE ON THE PROTEIN HAS A
COMPLIMENTARY SHAPE TO THE
SUBSTRATE.
ENZYME AND PROTEIN FIT TOGETHER
LIKE PUZZLE PIECES.
SEE PG. 52
ENZYMES ARE REUSABLE.
ENZYME ACTIVITY
AFFECTED BY Ph
1. Many biological enzymes function best
at a pH of 7
2. Most biological enzymes function best
at normal human body temp.
Few enzymes function well at high
temperature
Activation Energy
What significance do these energy changes have to
do with living things?
In order to stay alive, organisms need to carry out
reactions that require energy.
Regulation of Enzyme
Activity
Because they are catalysts for reactions,
enzymes can be affected by any variable that
influences a chemical reaction.
Many enzymes are affected by temp, pH, etc.
http://www.youtube.com/watch?v=V4OPO6JQLO
E&list=FLos62yqwp6aQmbJI7D_f7CA&index=46
&feature=plpp_video
Difference between no enzyme and enzyme in solution Awesome
Animation
http://www.whfreeman.com/catalog/static/whf/thelifewire6e/con_inde
x.htm?99xex
How enzymes work in the body!
http://highered.mcgrawhill.com/sites/9834092339/student_view0/chapter3/enzyme_action_
and_the_hydrolysis_of_sucrose.html