Lab quiz #2 Topic 6

What are the characteristics of enzymes

- Speed up chemical reactions - Required in minute amounts - they are highly specific in their action - They are affected by temperature - they are affected by pH - Some catalyze reversible reactions - Some require enzymes - Inhibitors inhibit them

Guaiacol

-a dye that turns from colorless to brown as it is oxidized by oxygen - Some molecules that act as electron donors change color when they are oxidized in this reaction, and the color change can be used to follow reaction progress. Guiacol turns brown when oxidized.

Function of peroxidase equations

2H2O2 + -----peroxidase----> 2H2O2 + 2O - In this equation, R stands for another molecule that acts as an electron donor, even though it does not bind to the electrons' active site.

Substrate

A specific reactant acted upon by an enzyme

product

A substance produced in a chemical reaction. _ the result of the enzyme-substrate complex is a chemical change in the substrate that converts it into a new type of molecule called the product of the reaction.

enzyme-substrate complex

A temporary complex is formed when an enzyme binds to its substrate molecule(s). -The binding between enzymes and substrate consists if weak, noncovalent chemical bonds, forming an enzyme-substrate complex that exists for only a few microseconds. -During this instant, the covalent bonds of the substrate either come under stress or are orientated so that other molecules can attack them.

What does it mean for enzymes to be inhibited by inhibitors?

An enzyme inhibitor hinders ("inhibits") this process, either by binding to the enzyme's active site (thus preventing the substrate itself from binding) or by binding to another site on the enzyme such that the enzyme's catalysis of the reaction is blocked.

Peroxidase

An enzyme that catalyzes the oxidation of a particular substrate by hydrogen peroxide - A large protein containing just over 300 amino acids. It has an iron ion (coenzyme) located at its active site. - Peroxidase makes an ideal experimental material because it is easily prepared and assayed. -Turnips and horseradish roots are rich sources of the enzyme, as are many animal tissues. - The normal function of peroxidase is converting toxic hydrogen peroxide (h2o2), produced in specific metabolic reactions, into water and other harmless compounds.

spectrometer

An instrument that separates light into a spectrum. The change in the absorption and emission of the light intensity with wavelength allows for materials to be identified.

What is anaerobic respiration?

Anaerobic respiration is the release of energy from glucose without using oxygen. This produces lactic acid. Anaerobic respiration is the process of creating energy without the presence of oxygen. Sometimes the body cannot supply the muscles with the oxygen it needs to create energy, for example, during intense exercise.

What caused the sugar to inflate in the water bottles?

As the yeast feeds on the sugar, it produces carbon dioxide. With no place to go but up, this gas slowly fills the balloon.

Formula for anaerobic respiration in animal cells

C3H3O3 ---> 2C3H603 (lactic acid) + 2ATP Glucose----> product

Formula for anaerobic respiration in yeast

C6H12O6 ----> 2CH5OH + 2CO2 Glucose--> Ethanol + Carbon dioxide

Enzymes

Catalysts for chemical reactions in living things

Why do some enzymes need coenzymes?

Certain enzymes need coenzymes to bind to the substrate and cause a reaction. Since the chemical reaction changes the coenzymes, these are considered secondary substrates of the reaction. Though enzymes are specific to the substrate, coenzymes are not specific to the enzymes they assist. - Ofen metallic ions, such as Fe+++, Mg++, Ca++, or Mn++, aid in the binding process, as do vitamins or other small molecules.

Denaturing

Changing the conformation of a protein through pH, temperature, or salt concentration changes. - At very high temperatures, enzyme functions usually slow down because such temperatures break the hydrogen bonds that maintain the shape of the enzyme.

What was is test tube #2?

Cracker, iodine, and saliva

How are enzymes affected by pH?

Each enzyme works best at a certain pH. The effectiveness of an enzyme depends on the pH of the surrounding area. - The pH or salt concentrations of solutions affect the shape of enzymes by altering the distribution of + and - changes in the enzyme molecules, which, in turn, alters their 3D shape and substrate-binding efficiency.

What were the enzyme and substrate? What were the products?

Enzyme: Peroxidase Substrate: H2O2 (hydrogen peroxide) Product: 2H2O2 + R (R stands for another molecule that acts as an electron donor, even though it does not bind to the enzymes active site)

Why are enzymes highly specific?

Enzymes are specific because different enzymes have differently shaped active sites. The shape of the active site of an enzyme is complementary to the shape of its specific substrate . This means they are the correct shapes to fit together.

How do enzymes peed up chemical reactions?

Enzymes in our bodies are catalysts that speed up reactions by helping to lower the activation energy needed to start a reaction. - Like all catalysts, enzymes lower the activation energy of a reaction, the amount of energy necessary to trigger a reaction.

How do enzymes react in lower temperatures?

Enzymes slow down reactions

Results for enzymes lactose and lactase

Lactose is broken down more quickly with lactase because lactase is a catalyst that speeds up the chemical breakdown of lactose. CO2 is produced and goes into the air.

How are enzymes affected by temperature?

Raising temperature generally speeds up a reaction, and lowering temperature slows down a reaction. However, extremely high temperatures can cause an enzyme to lose its shape (denature) and stop working. - Temperature affects the frequency with which the enzymes and their substrates collide, affecting binding.

How does an enzymes react in higher temperatures?

Rising temperatures speeds up a reaction

reactants in order from ballon least inflated to most inflated

Starch, Sucrose, Lactose + lactase, glucose

Reaction in test tube 2

Start: Cracker + Saliva + Iodine -> Black color because of the presence of starch End: Black color gone-> starch broken down by amylase in the saliva.

Reaction in test tube 1

Start: Cracker + Saliva -> black color because of the presence of starch End: Still black color

Results for sucrose

Sucrose is a 12 carbon sugar, and it breaks down slightly faster than starch

Why was the black color gone in test tube 2

The amylase in the saliva broke down the starch.

Results for starch

The balloon that inflated the least. Starch is a polysaccharide with more than 12 carbons. so it doe not release carbon dioxide quickly

Why was the solution black when iodine was added in?

The iodine turns black in the presence of starch

active site

The part of an enzyme or antibody where the chemical reaction occurs. - The shape of an enzyme, primarily, in a relatively small region called the active site, determines its catalytic abilities. - The active site of each enzyme has a unique shape that allows an enzyme to bind with only certain kinds of molecules, called the substrate of the enzyme.

What was the blank in the original concentration experiment?

Tube 1: 5.0 ml buffer (pH 5) 2.0 ml H2O2 (hydrogen peroxide) 0.0 ml Peroxidase 1.1 ml Guaiacol (dye) total volume: 8.0 ml

What was in test tube #1?

cracker and iodine

Results for glucose

glucose reacts the fastest because it is a 6 carbon sugar. It takes a a lot faster for it to be broken down.

What is the best pH for oxidase?

the best pH for oxidase is a pH of 5

What is the best temperature for oxidase?

the best temperature for oxidase is Room temperature around 20-22 °C (68-72 °F)