Enzyme review questions

What is an enzyme? A special type of protein that speeds up chemical reactions by lowering activation energy (the energy required to start a reaction)

What is a catalyst? How are enzymes related to catalysts? A catalyst gets reactions started and makes them happen faster by increasing the rate of reaction that otherwise might not happen or would take too long to sustain life. Enzymes are types of catalysts. Simplified: catalysts are molecules that help chemical reactions occur. They do this by lowering the activation energy needed to allow a reaction to occur.

What is activation energy? Each chemical reaction needs a minimum amount of energy to make it happen. This is called the activation energy. Enzymes lower the activation energy by attracting the substrate into the active site of the enzyme.

Where is the active site on an enzyme? How is related to substrates? Active site= where reaction takes place. This is where the substrate fits in to the enzyme

Enzyme structure Active site Substrate Enzyme

Lock and Key Model Enzymes show specificity, that is they are selective.

Can enzymes carry out more than one reaction? Why or why not? NO- each enzyme can only carry out one type of reaction. That is why they are often compared to locks and keys. Just like there is only one key that can open a lock, there is only one substrate that can fit into an enzymes active site. That is why we have thousands of different enzymes in our bodies…each one carries out only one type of reaction. Ex. Lactase breakes down the sugar lactose.

True or False: Enzymes can be used over and over again. True: Once a molecule is bound to the enzyme, the chemical reaction takes place. Then, the reaction products are released from the active site, and the enzyme is ready to start all over again with another substrate molecule.

Sucrose + water  glucose + fructose sucrase Sucrose + water  glucose + fructose In the following reaction, identify the reactants, products, enzyme and substrate Reactants: sucrose and water; products: glucose and fructose; enzyme: sucrase; substrate: sucrose

Is the enzyme sucrase considered a reactant, a product, or neither? Sucrose + water  glucose + fructose Is the enzyme sucrase considered a reactant, a product, or neither? Neither

What will happen to the enzyme sucrase at the end of the reaction? Sucrose + water  glucose + fructose What will happen to the enzyme sucrase at the end of the reaction? It will be free to be used again. It will continue to break down more sucrose molecules

# 1 # 2 What does the black arrow (#1) represent? What does the red arrow (#2) represent? #1 back arrow represents the activation energy without an enzyme #2 red arrow represents the activation energy with an enzyme

# 1 # 2 What does the black curve represent? What does the red curve represent? #1 back curve represents the reaction without an enzyme #2 red curve represents the reaction with an enzyme

Changes in some environmental factors, such as changes in ____ or increases in ______________, can disrupt the three-dimensional shape of enzymes pH; temperature

A protein (enzyme) that has changed shape due to changes in environmental variables is described as ____________________ denatured

What happens when an enzyme is “denatured” What happens when an enzyme is “denatured”? How is the active site affected? The enzyme changes shape, thus inactivating its active site.

What does hydrolysis mean What does hydrolysis mean? Is it the term used to describe a polymer being built or broken down? Broken down

Sucrose + water  glucose + fructose sucrase Sucrose + water  glucose + fructose What is the overall effect of an enzyme (sucrase) on the rate of sucrose hydrolysis? The presence of an enzyme increases the rate of product formation.

Sucrose + water  glucose + fructose sucrase Sucrose + water  glucose + fructose What trend would you see as a result of increasing enzyme concentration on the rate of product formation? The rate of reaction increases with increasing enzyme concentration, but once there are enough enzymes that the substrate is all reacted upon, the rate levels off. Think of the lab you did with the pop beads- how we added 2 people as enzymes (instead of just 1). You would be able to break down more pop beads, there were only so many pop beads you could break down.

Sucrose + water  glucose + fructose sucrase Sucrose + water  glucose + fructose 1. What is the limiting factor on the rate of product formation when there is one enzyme present? 2. What is the limiting factor on the rate of reaction when there are four enzymes in the reaction? When the enzyme concentration is low, it is the limiting factor on the rate of reaction. 2. When the enzyme concentration is high, the limiting factor is the substrate. Once all of the substrate is acted upon, no more reactions can occur.

Notice there is the same number of enzymes present for each of the three scenarios As substrate concentration increases, so does the number of substrate molecules that are broken into monomers. However, as the substrate concentration increases, the reaction rate will level off because the enzymes are all being used. Picture:https://www.pathwayz.org/Tree/Plain/ENZYMES+%26+SUBSTRATE+CONCENTRATION What trend do you see as a result of increasing substrate concentration on the rate of product formation?

Notice there is the same number of enzymes present for each of the three scenarios At the beginning of the experiment when substrate concentration is low, the substrate concentration is the limiting factor. However, when substrate concentration is high, the concentration of enzymes limits the reaction rate What is the limiting factor on the rate of product formation in this experiment?

Sucrose + water  glucose + fructose sucrase Sucrose + water  glucose + fructose Changes in what kind of variables in a cell can cause sucrase, a protein, to denature? Changes in pH and an increase in temperature

Sucrose + water  glucose + fructose sucrase Sucrose + water  glucose + fructose Optimal human body temperature averages around 98.6oF. Explain why exposure to extreme heat results in dangerous medical conditions such as heat stroke. If your temperature rises too high, your enzymes can denature and all cellular reactions slow or stop.

Sucrose + water  glucose + fructose sucrase Sucrose + water  glucose + fructose Fevers in mammals are a natural defense against bacterial and viral infections. Viruses and bacteria rely on properly shaped enzymes to complete their life cycles during an infection. State on hypothesis about how fevers help fight infection. As your temperature rises, the enzymes on the infectious agents are denatured, slowing their ability to grow and multiply in your body.

Sucrose + water  glucose + fructose sucrase Sucrose + water  glucose + fructose The normal pH range for human blood and most body tissues is considered to be 7.25-7.35. One possible complication of diabetes is a condition known as ketoacidosis, which causes blood to become more acidic. Explain why this condition can be dangerous, given what you know about proteins and changes in your pH. Changes in the pH of your blood will result in denaturing enzymes in your blood. Because blood provides the cells of your body with needed fluids, the pH of your body cells will change as well. The result is that cellular reactions that require enzymes will slow, including the reactions that convert energy for your cells.

Biomolecule review questions

How many bonds can carbon form? four

Name the 4 functional groups we learned about Name the 4 functional groups we learned about. What effect do functional groups have on a molecule? Carboxyl, amino, hydroxyl, phosphate Functional groups are clusters of atoms that influence the characteristics of the molecules they compose and the chemical reactions they undergo.

Starch, cellulose and glycogen are carbohydrates, which are polymers of ___________________ Glucose, fructose, galactose

http://www. nutrientsreview http://www.nutrientsreview.com/wp-content/uploads/2014/09/Glucose-formula.jpg

How does our body store glucose that it doesn’t need right away? Stored as glycogen in liver and muscles. Plants store glucose as starch.

How are carbohydrates used in our body? 1) Quick energy (glucose→ATP) 2) Energy storage (glycogen→ glucose → ATP) 3) Plant/insect structures

Proteins are polymers of _______________ Amino acids

Examples of amino acids

How are proteins used in our body? 1. Carry out chemical reactions (ENZYMES) 2. Pump molecules in and out of cells 3. Important in muscle contraction 4. Defensive proteins (antibodies) 5. Transports oxygen in the bloodstream (transport proteins) 6. Build new cells/repair damaged cells (help you grow!) 7. Building blocks of many structural components of an organism, like the membrane of a cell, hair, horns, hooves and nails 8. Some hormones (insulin)

What determines the job of a protein? The order of amino acids. STRUCTURE DETERMINES FUNCTION

What is the quaternary structure of a protein?

What’s the difference between dehydration synthesis & hydrolysis? Dehydration synthesis is the process where polymers are built (a water molecule is formed for each bond); Hydrolysis synthesis is the process where polymers are broken down (water molecules are needed for each bond broken)

The compound that most lipids have in common are _____________ Fatty acids

What is the function of lipids in our body? 1.Long term energy storage 2. Cushioning Bottom of feet 3. Insulation Protects organs, blubber, fat 4. Cell membranes

Where is energy stored in the biomolecules? In their bonds. That is why lipids provide a lot of energy…there are a lot of bonds in the fatty acid tails

Draw a phospholipid. Label it’s parts

Glycerol “head” Carboxyl group (part of fatty acid) Fatty acid “tails”

Nucleic acids (DNA, RNA) are polymers of _____________________ Nucleotides

Nucleotide

What is the function of nucleic acids in our body? 2 nucleic acids are: DNA- deoxyribonucleic acid RNA- ribonucleic acid Overall their job is to: DNA: store genetic information RNA: make proteins