enzymes biology, sumner hs created by mr. woodbury, modified by mrs. slater
TRANSCRIPT
Enzymes Overview• Enzymes build and break bonds
• Enzymes mediate anabolism (making of bonds)
• Enzymes mediate digestion / catabolism (breaking of bonds)
• Enzymes have specific jobs that never change
• Different organisms have different enzymes that allow different functioning
Tell me how...
...you would start a camp fire?
Would the fire start without a “spark?”
...you would build a house?
Does the lumber cut itself or nail itself together?
You need energy and tools.
Remind me...
What happens to glucose molecules that don’t get used right away?
Does it do building or breaking reactions?
What happens in digestion?
Does it do building or breaking reactions?
Essential to lifeEnzymes
A group of proteins that make chemical reactions (rearranging molecules) happen more easily
Take less energy to start reaction
Bring pieces together to be worked on
Aren’t changed in the reaction
Enzymes
Are specific for what they do
Are reusable
End in -ase
Amylase
Lactase
DNA & RNA polymerase
DNA helicase
Enzymes in Action
Enzyme animation: http://www.lpscience.fatcow.com/jwanamaker/animations/Enzyme%20activity.html
Enzyme Functions
Can help with different reactions
Break covalent bonds = catabolic
Build covalent bonds = anabolic
Enzymes & MacrosEnzymes for carbs:
Sucrase breaks down sucrose / table sugar
Amylase in human saliva breaks down starch
Glycogen synthase builds glycogen from glucose
Enzymes & MacrosEnzymes for lipids: lipase breaks down fats so they can be absorbed by small intestine
Enzymes for proteins: protease breaks peptide bonds between amino acids
Enzymes & MacrosEnzymes for nucleic acids:
DNA & RNA polymerase build DNA & RNA strands
DNA helicase “unzips” DNA during replication
Enzyme FeaturesHave a specific shape that fits closely to one or more specific molecules
“Lock and key” model
Lock = enzyme
Key = substrate (what the enzyme builds or breaks)
Enzyme benefits
Make some reactions possible that wouldn’t happen on their own
Make reactions more efficient…
Less energy
Happen faster
We don’t give off smoke
Can be reused
Enzymes in a CellEnzymes in a Cell
• Active sites: http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_enzymes_work.html
• Enzyme interactions (or lack thereof) with active sites: http://www.kscience.co.uk/animations/anim_2.htm
Draw Enzyme Action
Draw Enzyme Action1. Choose whether your enzyme will make or break
bonds
2. Make a before, during & after part of your paper
3. Before: draw the enzyme with the active site and the substance that it is going to alter
4. During: draw the enzyme interacting with the substances it is altering
5. After: draw the products & what the enzyme would look like after the reaction
6. On each drawing, label the following parts (for all that are applicable): enzyme, monomer(s), polymer, active site
7. Write a brief description of what is happening in each part
8. Identify the type of reaction: anabolic or catabolic
Enzyme ActionBefore – Description During – Description After – Description
Before – Labeled Drawing During – Labeled Drawing
After – Labeled Drawing
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Important MonosaccharidesGlucose:
The basic carbohydrate monomer (C6H12O6)
Instant / immediate energy source
Main energy transport molecule & source for metabolism
All digested carbohydrates broken down to this for absorption in the small intestine.
Only fuel used by the brain/nervous tissue
glucose
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More MonosaccharidesYou don’t need to write these…
Fructose: sugar produced by fruit plants (same formula, different arrangement)
Ribose: building block of DNA/RNA and ATP the “energy currency” in a cell (5 carbons).
Raffinose: sugar found in beans and other vegetables, turned to intestinal gas by bacteria.
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PolysaccharidesEnergy source once all monosaccharides are used (still short-term energy) IF it can be digested
Three types:
Glycogen
Starch
Cellulose
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PolysaccharidesGlycogen: storage form of glucose in muscle and liver
Quickly broken down to produce blood glucose; used as an energy source once glucose is used up
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PolysaccharidesStarch: plant storage form
Food energy for us because we have the enzymes that can break those bonds
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PolysaccharidesCellulose: plant structural form
Different bond between glucose units
We don’t have the enzyme to break that particular bond, but cows do.
This is “fiber” (aka “roughage”) in our food.
Ruminants (cows, sheep) DO have the enzymes to break that bond, so they can turn it into usable energy
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Polymerization Simulation
• Take the H- from one glucose molecule and –OH from another
• This creates a water molecule, thus the reaction is called dehydration
• When we break these bonds (metabolize our food), it requires water and is called hydrolysis
• Another reason to stay hydrated!• http://bioweb.wku.edu/courses/biol115/wyatt/bioche
m/carbos.htm