Enzymes

Biology, Sumner HS

Created by Mr. Woodbury, Modified by Mrs. Slater

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 Action

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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Other CarbohydratesSucrose = Glucose + Fructose (a disaccharide)

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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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Starch vs. Cellulose vs. Glycogen

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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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Starch vs. Cellulose

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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

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Type of Carb

Example Structure Use Explanation

Glucose

Glycogen

Starch

Cellulose