Enzyme Review • Are you ready?
Define Catalyst. • A molecule that allows stable molecules to react quickly.
What is an enzyme? and what is it made of?
An enzyme is a biological catalyst • It is a protein and made of a • long chain of amino acids
What do enzymes do? They speed up chemical reactions by……. Lowering Activation Energy needed to start the reaction.
What enzyme did we use in our labs? Catalase What reaction does it speed up? The breakdown of Hydrogen Peroxide into water and oxygen. H2O2--------) H2O + O2
Why are enzymes necessary? • So that chemical reactions in living things can happen fast enough • Example- In the human body— • Hydrogen Peroxide would break down without catalase, but it would be so slow that H2O2 would build up and become TOXIC!
Name the two kinds of reactions. • Exothermic • Endothermic
Which requires energy inputand which gives off heat? • Endothermic RXNS require energy to be added IN to keep going. • Exothermic RXNS give off energy. Energy EXITS.
What does it mean to say a reaction is “spontaneous”? • Once it starts it will continue until the end. • No energy input is required after the activation energy.
Define Activation Energy. • The measure of how hard molecules have to collide to get a reaction to begin. • The push to get a reaction started.
Which kind of molecules have high activation energy—Stable or Unstable? • Stable molecules don’t interact easily– they have HIGH activation energy. Need a bigger push to get started. • Unstable molecules react more easily--They are highly reactive, have LOW activation energy.
What is KMT? Kinetic Molecular Theory The idea that molecules are always moving and when they collide hard enough with one another, they will react.
What happens when enzymes are exposed to heat? A little heat can speed up a reaction by making the molecules move faster---- BUT
What happens when there is too much heat or the wrong pH? • Enzymes DENATURE • They unravel. They no longer keep the same shape so they won’t fit the substrate any more. • They need to be in their OPTIMUM range of temp or pH to function the best!
Explain Lock and Key Model • Enzyme is the • Lock • Substrate is the • Key • The active site is the • Keyhole
What happens at the active site? The enzyme and the substrate bind together. What is Induced Fit?
Amino acids in the active site • Attract amino acids on the substrate due to different charges and polarity • They interact and the bonds are broken and new ones form.
NO • They are very SPECIFIC, SELECTIVE, PICKY • They only work with one substrate.
Are enzymes used up in a reaction? NO They can be used over and over again.
What happens when you add more enzyme? • The rate of reaction increases– Happens faster
What happens when you add more substrate? • No change in rate, BUT • You get more product.
Thanks for playing Enzyme Review
Biochemistry Review • Biology is the study of living things. • Organic or Biochemistry is the study of the chemical reactions in living things.
What is the smallest unit of matter? • An Atom
Atoms- What area is positive and what area is negative? • The nucleus is positive • The surrounding electron orbitals are negative • Where is the mass? • In the nucleus
Atoms • Atomic Number= # of p+ • Atomic Mass= p+ + n0 • Charge= p+ - e- • First Energy Level= can hold .. • 2 electrons • Second Energy level can hold.. • 8 Electrons
What is a molecule? • Atoms bonded together with covalent bonds
How are ions and isotopes same/different? • They are both atoms and the number of protons stays the same, BUT • Ions have different charges (different number of electrons) • Isotopes have different masses (different number of neutrons)
What makes a molecule polar? • Uneven sharing of electrons gives the molecule partially negative areas and partially positive areas • Give an example of a polar molecule. • Water – H20= Oxygen has a partial negative charge, hydrogen has a partial positive charge.
What is a compound? • A substance made of two or more different elements. • Could be bonded by ionic or covalent bonds
What is the most common element in living things? • Carbon • It is present in all four of the biomolecules • Which biomolecule contains nitrogen? • Protein
Let’s talk about bonds! • What are the three types we have covered? • Ionic, Covalent, and Hydrogen bonds
A Bond formed when molecules share electrons • Covalent Bonds
A Bond between two oppositely charged atoms or molecules (one positive one negative) • Ionic bonds
An intermolecular force between polar molecules • A Hydrogen Bond
What is the relative strength of these bonds? • Covalent/ Ionic >>>>>>>Hydrogen Bonds
pH scale 1-14 • What does it measure? • The acidity or basicity of a solution • 7 is neutral • Acids are … • Below 7 • Bases are … • Above 7
Four Categories of Biomolecules • Proteins • Carbohydrates • Lipids • Nucleic Acids • These are very large molecules so we call them Macromolecules!
Carbohydrates- What do we know? • Ratio of C:H:O is • 1:2:1 • Monomers are: • saccharides-simple sugars • Polymers are: • polysaccharides- starches
Lipids • Monomers are glycerol and fatty acids • Polymers are Trigycerides- a glycerol with three fatty acid chains • Lipids can be fats or oils, • They are nonpolar- don’t mix with water • Saturated fats are solid (butter, lard) • Unsaturated are oils (olive, vegetable)
Proteins • Monomer is an amino acid (20 types), each amino acid has an R group on its central carbon. • Polymers are polypeptides, two or more amino acids bonded together
What is the process that builds polymers from monomers? • Dehydration Synthesis (synthesize is to make) • Remember this process gives off a molecule of …… • H20
Breaking down polymers into monomers is called • Hydrolysis- “Lysis” is to break • What molecule is needed for this to happen? • H20 must be present and breaks into its parts to replace the H’s and O
In our lab, we tested for different biomolecules: • Iodine- What does it test for and what’s a positive reaction? • Iodine tests for starch- If starch is present it turns.. • Blue-Black
What tests for simple sugars (Glucose)? • Benedicts plus heat (it starts out blue) • Positive reaction is a change to green, yellow or red depending on how much glucose is present
What does Biuret test for? • Proteins • What color change do you see if protein is present? • It changes from blue to a purple-lavender to violet.
How did we check for Lipids? • Paper towel test • Translucent (can see through it) when lipids were present.